Astrophysics of Galaxies
- [1] arXiv:2405.15851 [pdf, ps, html, other]
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Title: Forecasting the Population of Globular Cluster Streams in Milky Way-type GalaxiesComments: 21 pages, 13 figures, submitted to AAS journals, comments welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA)
Thin stellar streams originating from globular clusters are among the most sensitive tracers of low-mass dark-matter subhalos. Joint analysis of the entire population of stellar streams will place the most robust constraints on the dark-matter subhalo mass function, and therefore the nature of dark matter. Here we use a hierarchical model of globular cluster formation to forecast the total number, masses and radial distribution of dissolved globular cluster in Milky Way-like galaxies. Furthermore, we generate mock stellar streams from these progenitors' orbital histories taking into account the clusters' formation and accretion time, mass, and metallicity. Out of $\sim$10,000 clusters more massive than $10^4$ M$_{\odot}$, $\sim$9000 dissolved in the central bulge and are fully phase-mixed at the present, while the remaining $\sim$1000 survive as coherent stellar streams. This suggests that the current census of $\sim$80 globular cluster streams in the Milky Way is severely incomplete. Beyond 15 kpc from the Galactic center we are missing hundreds of streams, of which the vast majority are from accreted GCs. Deep Rubin photometry $(g\lesssim27.5)$ would be able to detect these streams, even the most distant ones beyond $> 75$ kpc. We also find that M31 will have an abundance of streams at galactocentric radii of 30-100 kpc. We conclude that future surveys will find a multitude of stellar streams from globular clusters which can be used for dark matter subhalo searches.
- [2] arXiv:2405.15859 [pdf, ps, html, other]
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Title: The density-bounded twilight of starbursts in the early UniverseWilliam McClymont, Sandro Tacchella, Francesco D'Eugenio, Callum Witten, Xihan Ji, Aaron Smith, Roberto Maiolino, Jan Scholtz, Charlotte Simmonds, Joris WitstokComments: 12 pages, 9 figures, submitted to MNRAS, comments welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA)
The peculiar nebular emission displayed by galaxies in the early Universe presents a unique opportunity to gain insight into the regulation of star formation in extreme environments. We investigate 500 (109) galaxies with deep NIRSpec/PRISM observations from the JADES survey at $z>2$ ($z>5.3$), finding 52 (26) galaxies with Balmer line ratios more than $1\sigma$ inconsistent with Case B recombination. These anomalous Balmer emitters (ABEs) cannot be explained by dust attenuation, indicating a departure from Case B recombination. To address this discrepancy, we model density-bounded nebulae with the photoionisation code CLOUDY. Density-bounded nebulae show anomalous Balmer line ratios due to Lyman line pumping and a transition from the nebulae being optically thin to optically thick for Lyman lines with increasing cloud depth. The H$\alpha$/H$\beta$ versus H$\gamma$/H$\beta$ trend of density-bounded models is robust to changes in stellar age of the ionising source, gas density, and ionisation parameter; however, increasing the stellar metallicity drives a turnover in the trend. This is due to stronger stellar absorption features around Ly$\gamma$ reducing H$\beta$ fluorescence, allowing density-bounded models to account for all observed Balmer line ratios. ABEs show higher [OIII]/[OII], have steeper ultra-violet slopes, are fainter, and are more preferentially Ly$\alpha$ emitters than galaxies which are consistent with Case B and little dust. These findings suggest that ABEs are galaxies that have become density bounded during extreme quenching events, representing a transient phase of $\sim$20 Myr during a fast breathing mode of star formation.
- [3] arXiv:2405.15972 [pdf, ps, html, other]
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Title: SMILES Initial Data Release: Unveiling the Obscured Universe with MIRI Multi-band ImagingStacey Alberts, Jianwei Lyu, Irene Shivaei, George H. Rieke, Pablo G. Perez-Gonzalez, Nina Bonventura, Yongda Zhu, Jakob M. Helton, Zhiyuan Ji, Jane Morrison, Brant E. Robertson, Meredith A. Stone, Yang Sun, Christina C. Williams, Christopher N. A. WillmerComments: 23 pages, 19 figures, submitted to ApJ. Comments welcome! Data release will go live at this https URL in the next few weeksSubjects: Astrophysics of Galaxies (astro-ph.GA)
The James Webb Space Telescope (JWST) is revolutionizing our view of the Universe through unprecedented sensitivity and resolution in the infrared, with some of the largest gains realized at its longest wavelengths. We present the Systematic Mid-infrared Instrument (MIRI) Legacy Extragalactic Survey (SMILES), an eight-band MIRI survey with Near-Infrared Spectrograph (NIRSpec) spectroscopic follow-up in the GOODS-S/HUDF region. SMILES takes full advantage of MIRI's continuous coverage from $5.6-25.5\,\mu$m over a $\sim34$ arcmin$^2$ area to greatly expand our understanding of the obscured Universe up to cosmic noon and beyond. This work, together with a companion paper by Rieke et al., covers the SMILES science drivers and technical design, early results with SMILES, data reduction, photometric catalog creation, and the first data release. As part of the discussion on early results, we additionally present a high-level science demonstration on how MIRI's wavelength coverage and resolution will advance our understanding of cosmic dust using the full range of polycyclic aromatic hydrocarbon (PAH) emission features from $3.3-18\,\mu$m. Using custom background subtraction, we produce robust reductions of the MIRI imaging that maximize the depths reached with our modest exposure times ($\sim0.6 - 2.2$ ks per filter). Included in our initial data release are (1) eight MIRI imaging mosaics reaching depths of $0.2-18\,\mu$Jy ($5\sigma$) and (2) a $5-25.5\,\mu$m photometric catalog with over 3,000 sources. Building upon the rich legacy of extensive photometric and spectroscopy coverage of GOODS-S/HUDF from the X-ray to the radio, SMILES greatly expands our investigative power in understanding the obscured Universe.
- [4] arXiv:2405.16187 [pdf, ps, html, other]
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Title: An X-Ray High-Frequency QPO in NGC 1365Comments: 6 pages, 5 figures, 1 tableSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
This study presents the detection of a high-frequency Quasi-Periodic Oscillation (QPO) in the Seyfert galaxy NGC 1365, based on observational data obtained by the XMM-Newton in January 2004. Utilizing the Weighted Wavelet Z-transform (WWZ) and Lomb-Scargle Periodogram (LSP) methods, a QPO signal was identified at a frequency of 2.19 * 10^-4 Hz (4566 s), with a confidence level of 3.6 sigma. The signal was notably absent in the lower 0.2-1.0 keV energy band, with the primary contribution emerging from the 2.0-10.0 keV band, where the confidence level reached 3.9 sigma. Spectral analysis shows that there are multiple absorption and emission lines in the high-energy band (> 6 keV). The correlation between the QPO frequency (f_QPO) and the mass of NGC 1365 central black hole (M_BH) aligns with the established logarithmic trend observed across black holes, indicating the QPO is of high frequency. This discovery provides new clues for studying the generation mechanism of QPO in Seyfert galaxies, which helps us understand the accretion process around supermassive black holes and the characteristics of strong gravitational fields in active galactic nuclei.
- [5] arXiv:2405.16367 [pdf, ps, html, other]
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Title: Orbital dynamics in galactic potentials under mass transferComments: 13 pages, 13 figures (including the Appendix). The article is submitted to Astronomy & Astrophysics and is under revision. Comments are welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Chaotic Dynamics (nlin.CD)
Time-dependent potentials are common in galactic systems that undergo significant evolution, interactions, or encounters with other galaxies, or when there are dynamic processes like star formation and merging events. Recent studies show that an ensemble approach along with the so-called snapshot framework in dynamical system theory provide a powerful tool to analyze time dependent dynamics.
In this work, we aim to explore and quantify the phase space structure and dynamical complexity in time-dependent galactic potentials consisting of multiple components. We apply the classical method of Poincaré-surface of section to analyze the phase space structure in a chaotic Hamiltonian system subjected to parameter drift. This, however, makes sense only when the evolution of a large ensemble of initial conditions is followed. Numerical simulations explore the phase space structure of such ensembles while the system undergoes a continuous parameter change. The pair-wise average distance of ensemble members allows us to define a generalized Lyapunov-exponent, that might also be time dependent, to describe the system stability. We revise the system parameters for the Milky Way galaxy and provide a comprehensive dynamical analysis of the system under circumstances where linear mass transfer undergoes between the disk and bulge components of the model. - [6] arXiv:2405.16416 [pdf, ps, other]
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Title: Kinematical and Ellipsoidal Properties of the Inner-Halo Hot Subdwarfs Observed in Gaia DR3 and LAMOST DR7Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Here, we report the kinematical parameters of inner-halo hot subdwarfs located within (d lower than or equal 15 kpc) at high Galactic latitudes (b^o greater than or equal 20). The study included three program stars for one of the extreme He-rich groups (eHe-1) with eccentricity (e=0.65) and the z-component of the angular momentum (J_z=4288.66 kpc km s-1), the inner halo program I with 121 points (T_eff greater than or equal 24,000) and their subsections, i.e. inner halo program II (sdB; 79 points) with (40,000 greater than or equal T_eff greater than or equal 24,000) and inner halo program III (sdO; 42 points) with (80,000 greater than or equal T_eff greater than or equal 40,000). First, we calculated the spatial velocities (U_avg, V_avg, W_avg; km s-1) along the Galactic coordinates and subsequently their subsections sdB and sdO. Second, we calculated the vertex longitudes (l_2) and the Solar motion (S_sun=41.24 +/- 6.42 km s-1) as well as their subsections. Finally, based on the kinematic relation of the ratio (s_2/s_1) and our previously computed numerical value of the angular rotation rate (|A-B|=26.07 +/- 5.10; km s-1 kpc-1), we obtained the average Oort's constant.
- [7] arXiv:2405.16626 [pdf, ps, html, other]
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Title: Magnetized compressible turbulence with a fluctuation dynamo and Reynolds numbers over a millionComments: 22 pages. 10 figures. Currently the world's largest MHD turbulence simulation on a grid of 10,080^3 (Re and Rm over a million). Comments welcome, email james.beattie@princeton.eduSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR); Computational Physics (physics.comp-ph); Fluid Dynamics (physics.flu-dyn); Plasma Physics (physics.plasm-ph)
Supersonic magnetohydrodynamic (MHD) turbulence is a ubiquitous state for many astrophysical plasmas. However, even the basic statistics for this type of turbulence remains uncertain. We present results from supersonic MHD turbulence simulations at unparalleled resolutions, with plasma Reynolds numbers of over a million. In the kinetic energy spectrum we find a break between the scales that are dominated by kinetic energy, with spectral index $-2$, and those that become strongly magnetized, with spectral index $-3/2$. By analyzing the Helmholtz decomposed kinetic energy spectrum, we find that the compressible modes are not passively mixed through the cascade of the incompressible modes. At high magnetic Reynolds number, above $10^5$, we find a power law in the magnetic energy spectrum with spectral index $-9/5$. On the strongly magnetized, subsonic scales the plasma tends to self-organize into locally relaxed regions, where there is strong alignment between the current density, magnetic field, velocity field and vorticity field, depleting both the nonlinearities and magnetic terms in the MHD equations, which we attribute to plasma relaxation on scales where the magnetic fluctuations evolve on shorter timescales than the velocity fluctuations. This process constrains the cascade to inhomogenous, volume-poor, fractal surfaces between relaxed regions, which has significant repercussions for understanding the nature of magnetized turbulence in astrophysical plasmas and the saturation of the fluctuation dynamo.
- [8] arXiv:2405.16744 [pdf, ps, html, other]
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Title: CH_3OH and Its Deuterated Species in the Disk/Envelope System of the Low-Mass Protostellar Source B335Yuki Okoda, Yoko Oya, Nami Sakai, Yoshimasa Watanabe, Ana López-Sepulcre, Takahiro Oyama, Shaoshan Zeng, Satoshi YamamotoSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Deuterium fractionation in the closest vicinity of a protostar is important in understanding its potential heritage to a planetary system. Here, we have detected the spectral line emission of CH3OH and its three deuterated species, CH2DOH, CHD2OH, and CH3OD, toward the low-mass protostellar source B335 at a resolution of 0.''03 (5 au) with Atacama Large Millimeter/submillimeter Array. They have a ring distribution within the radius of 24 au with the intensity depression at the continuum peak. We derive the column densities and abundance ratios of the above species at 6 positions in the disk/envelope system as well as the continuum peak. The D/H ratio of CH3OH is ~[0.03-0.13], which is derived by correcting the statistical weight of 3 for CH2DOH. The [CHD2OH]/[CH2DOH] ratio is derived to be higher ([0.14-0.29]). On the other hand, the [CH2DOH]/[CH3OD] ratio ([4.9-15]) is higher than the statistical ratio of 3, and is comparable to those reported for other low-mass sources. We study the physical structure on a few au scale in B335 by analyzing the CH3OH (183,15-182,16, A) and HCOOH (120,12-110,11) line emission. Velocity structures of these lines are reasonably explained as the infalling-rotating motion. The protostellar mass and the upper limit to centrifugal barrier are thus derived to be 0.03-0.07 M_{\odot} and <7 au, respectively, showing that B335 harbors a young protostar with a tiny disk structure. Such youth of the protostar may be related to the relatively high [CH2DOH]/[CH3OH] ratio.
- [9] arXiv:2405.16773 [pdf, ps, html, other]
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Title: On the origin of infrared bands attributed to tryptophan in Spitzer observations of IC 348Aditya Dhariwal, Thomas H. Speak, Linshan Zeng, Amirhossein Rashidi, Brendan Moore, Olivier Berné, Anthony J. Remijan, Ilane Schroetter, Brett A. McGuire, Víctor M. Rivilla, Arnaud Belloche, Jes K. Jørgensen, Pavle Djuricanin, Takamasa Momose, Ilsa R. CookeSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Infrared emission features toward interstellar gas of the IC 348 star cluster in Perseus have been recently proposed to originate from the amino acid tryptophan. The assignment was based on laboratory infrared spectra of tryptophan pressed into pellets, a method which is known to cause large frequency shifts compared to the gas phase. We assess the validity of the assignment based on the original Spitzer data as well as new data from JWST. In addition, we report new spectra of tryptophan condensed in para-hydrogen matrices to compare with the observed spectra. The JWST MIRI data do not show evidence for tryptophan, despite deeper integration toward IC 348. In addition, we show that several of the lines attributed to tryptophan are likely due to instrumental artifacts. This, combined with the new laboratory data, allows us to conclude that there is no compelling evidence for the tryptophan assignment.
- [10] arXiv:2405.16804 [pdf, ps, html, other]
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Title: Gas-phase formation of fullerene/9-hydroxyfluorene cluster cationsComments: 13 pages, 11 figure, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
In interstellar environment, fullerene species readily react with large molecules (e.g., PAHs and their derivatives) in the gas phase, which may be the formation route of carbon dust grains in space. In this work, the gas-phase ion-molecule collision reaction between fullerene cations (Cn+, n=32, 34, ..., 60) and functionalized PAH molecules (9-hydroxyfluorene, C13H10O) are investigated both experimentally and theoretically. The experimental results show that fullerene/9-hydroxyfluorene cluster cations are efficiently formed, leading to a series of large fullerene/9-hydroxyfluorene cluster cations (e.g., [(C13H10O)C60]+, [(C13H10O)3C58+, and [(C26H18O)(C13H10O)2C48]+). The binding energies and optimized structures of typical fullerene/9-hydroxyfluorene cluster cations were calculated. The bonding ability plays a decisive role in the cluster formation processes. The reaction surfaces, modes and combination reaction sites can result in different binding energies, which represent the relative chemical reactivity. Therefore, the geometry and composition of fullerene/9-hydroxyfluorene cluster cations are complicated. In addition, there is an enhanced chemical reactivity for smaller fullerene cations, which is mainly attributed to the newly formed deformed carbon rings (e.g., 7 C-ring). As part of the coevolution network of interstellar fullerene chemistry, our results suggest that ion-molecule collision reactions contribute to the formation of various fullerene/9-hydroxyfluorene cluster cations in the ISM, providing insights into different chemical reactivity caused by oxygenated functional groups (e.g., hydroxyl, OH, or ether, C-O-C) on the cluster formations.
- [11] arXiv:2405.16811 [pdf, ps, html, other]
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Title: Gas-phase hydrogenation of large, astronomically relevant PAH cationsComments: 24 pages, 9 figures, 3 tables, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
To investigate the gas-phase hydrogenation processes of large, astronomically relevant cationic polycyclic aromatic hydrocarbon (PAH) molecules under the interstellar environments, the ion-molecule collision reaction between six PAH cations and H-atoms is studied. The experimental results show that the hydrogenated PAH cations are efficiently formed, and no even-odd hydrogenated mass patterns are observed in the hydrogenation processes. The structure of newly formed hydrogenated PAH cations and the bonding energy for the hydrogenation reaction pathways are investigated with quantum theoretical calculations. The exothermic energy for each reaction pathway is relatively high, and the competition between hydrogenation and dehydrogenation is confirmed. From the theoretical calculation, the bonding ability plays an important role in the gas-phase hydrogenation processes. The factors that affect the hydrogenation chemical reactivity are discussed, including the effect of carbon skeleton structure, the side-edged structure, the molecular size, the five- and six-membered C-ring structure, the bay region structure, and the neighboring hydrogenation. The IR spectra of hydrogenated PAH cations are also calculated. These results we obtain once again validate the complexity of hydrogenated PAH molecules, and provide the direction for the simulations and observations under the coevolution interstellar chemistry network. We infer that if we do not consider other chemical evolution processes (e.g., photo-evolution), then the hydrogenation states and forms of PAH compounds are intricate and complex in the interstellar medium (ISM).
- [12] arXiv:2405.16826 [pdf, ps, html, other]
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Title: Image formation near hyperbolic umbilic in strong gravitational lensingComments: 14 pages, 11 figures, 1 table. Comments welcome!Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Hyperbolic umbilic (HU) is a point singularity of the gravitational lens equation, giving rise to a ring-shaped image formation made of four highly magnified images, off-centred from the lens centre. Recent observations have revealed new strongly lensed image formations near HU singularities, and many more are expected in ongoing and future observations. Like fold/cusp, image formations near HU also satisfy magnification relation ($R_{\rm hu}$), i.e., the signed magnification sum of the four images equals zero. Here, we study how $R_{\rm hu}$ deviates from zero as a function of area ($A_{\rm hu}$) covered by the image formation near HU and the distance ($d$) of the central maxima image (which is part of the HU image formation) from the lens centre for ideal single- and double-component cluster-scale lenses. For lens ellipticity values $\geq0.3$, the central maxima image will form sufficiently far from the lens centre ($d\gtrsim5''$), similar to the observed HU image formations. We also find that, in some cases, double-component and actual cluster-scale lenses can lead to large cross-sections for HU(-like) image formations for sources at $z\gtrsim5$ effectively increasing the chances to observe HU(-like) image formation at high redshift. Finally, we study the time delay distribution in the observed HU image formation, finding that not only are these images highly magnified, but the relative time delay between various pairs of HU characteristic image formation has a typical value of $\sim100$ days, an order of magnitude smaller than generic five-image formations in cluster lenses, making such image formations a promising target for time delay studies.
- [13] arXiv:2405.16897 [pdf, ps, html, other]
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Title: The Formation of Filaments and Dense cores in the Cocoon Nebula (IC~5146)Comments: 26 pages, 19 figures, 3 tables, Accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present 850~$\mu$m linear polarization and C$^{18}$O~(3-2) and $^{13}$CO~(3-2) molecular line observations toward the filaments (F13 and F13S) in the Cocoon Nebula (IC~5146) using the JCMT POL-2 and HARP instruments. F13 and F13S are found to be thermally supercritical with identified dense cores along their crests. Our findings include that the polarization fraction decreases in denser regions, indicating reduced dust grain alignment efficiency. The magnetic field vectors at core scales tend to be parallel to the filaments, but disturbed at the high density regions. Magnetic field strengths measured using the Davis-Chandrasekhar-Fermi method are 58$\pm$31 and 40$\pm$9~$\mu$G for F13 and F13S, respectively, and it reveals subcritical and sub-Alfvénic filaments, emphasizing the importance of magnetic fields in the Cocoon region. Sinusoidal C$^{18}$O~(3-2) velocity and density distributions are observed along the filaments' skeletons, and their variations are mostly displaced by $\sim1/4 \times$wavelength of the sinusoid, indicating core formation occurred through the fragmentation of a gravitationally unstable filament, but with shorter core spacings than predicted. Large scale velocity fields of F13 and F13S, studied using $^{13}$CO~(3-2) data, present V-shape transverse velocity structure. We propose a scenario for the formation and evolution of F13 and F13S, along with the dense cores within them. A radiation shock front generated by a B-type star collided with a sheet-like cloud about 1.4~Myr ago, the filaments became thermally critical due to mass infall through self-gravity $\sim$1~Myr ago, and subsequently dense cores formed through gravitational fragmentation, accompanied by the disturbance of the magnetic field.
- [14] arXiv:2405.16949 [pdf, ps, other]
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Title: Spectral similarities in galaxies through an unsupervised classification of spaxelsHugo Chambon (IPAG), Didier Fraix-Burnet (IPAG)Comments: Astronomy and Astrophysics - A\&A, In pressSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We present the first unsupervised classification of spaxels in hyperspectral images of individual galaxies. Classes identify regions by spectral similarity and thus take all the information into account that is contained in the data cubes (spatial and spectral).We used Gaussian mixture models in a latent discriminant subspace to find clusters of spaxels. The spectra were corrected for small-scale motions within the galaxy based on emission lines with an automatic algorithm. Our data consist of two MUSE/VLT data cubes of JKB 18 and NGC 1068 and one NIRSpec/JWST data cube of NGC 4151.Our classes identify many regions that are most often easily interpreted. Most of the 11 classes that we find for JKB 18 are identified as photoionised by stars. Some of them are known HII regions, but we mapped them as extended, with gradients of ionisation intensities. One compact structure has not been reported before, and according to diagnostic diagrams, it might be a planetary nebula or a denser HII region. For NGC 1068, our 16 classes are of active galactic nucleus-type (AGN) or star-forming regions. Their spatial distribution corresponds perfectly to well-known structures such as spiral arms and a ring with giant molecular clouds. A subclassification in the nuclear region reveals several structures and gradients in the AGN spectra. Our unsupervised classification of the MUSE data of NGC 1068 helps visualise the complex interaction of the AGN and the jet with the interstellar medium in a single map. The centre of NGC 4151 is very complex, but our classes can easily be related to ionisation cones, the jet, or H2 emission. We find a new elongated structure that is ionised by the AGN along the N-S axis perpendicular to the jet direction. It is rotated counterclockwise with respect to the axis of the H2 emission. Our work shows that the unsupervised classification of spaxels takes full advantage of the richness of the information in the data cubes by presenting the spectral and spatial information in a combined and synthetic way.
- [15] arXiv:2405.16999 [pdf, ps, html, other]
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Title: Binary-single interactions with different mass ratiosComments: 14 pages, 7 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
Dynamical interactions in star clusters are an efficient mechanism to produce the coalescing binary black holes (BBHs) that have been detected with gravitational waves (GWs). We want to understand how BBH coalescence can occur during - or after - binary-single interactions with different mass ratios. We perform gravitational scattering experiments of binary-single interactions using different mass ratios of the binary components ($q_2\equiv m_2/m_1\le1$) and the incoming single ($q_3\equiv m_3/m_1$). We extract cross sections and rates for (i) GW capture during resonant interactions; (ii) GW inspiral in between resonant interactions and apply the results to different globular cluster conditions. We find that GW capture during resonant interactions is most efficient if $q_2\simeq q_3$ and that the mass-ratio distribution of BBH coalescence due to inspirals is $\propto m_1^{-1}q^{2.9+\alpha}$, where $\alpha$ is the exponent of the BH mass function. The total rate of GW captures and inspirals depends mostly on $m_1$ and is relatively insensitive to $q_2$ and $q_3$. We show that eccentricity increase by non-resonant encounters approximately doubles the rate of BBH inspiral in between resonant encounters. For a given GC mass and radius, the BBH merger rate in metal-rich GCs is approximately double that of metal-poor GCs, because of their (on average) lower BH masses ($m_1$) and steeper BH mass function, yielding binaries with lower $q$. Our results enable the translating from the mass-ratio distribution of dynamically formed BBH mergers to the underlying BH mass function. The additional mechanism that leads to a doubling of the inspirals provides an explanation for the reported high fraction of in-cluster inspirals in $N$-body models of clusters.
- [16] arXiv:2405.17000 [pdf, ps, html, other]
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Title: MHONGOOSE discovery of a gas-rich low-surface brightness galaxy in the Dorado GroupF. M. Maccagni, W. J. G. de Blok, P. E. Mancera Piña, R. Ragusa, E. Iodice, M. Spavone, S. McGaugh, K. A. Oman, T. A. Oosterloo, B. S. Koribalski, M. Kim, E. A. K. Adams, P. Amram, A. Bosma, F. Bigiel, E. Brinks, L. Chemin, F. Combes, B. Gibson, J. Healy, B. W. Holwerda, G. I. G. Józsa, P. Kamphuis, D. Kleiner, S. Kurapati, A. Marasco, K. Spekkens, S. Veronese, F. Walter, N. Zabel, A. ZijlstraComments: 18 pages, 14 figures, 5 tables; accepted for publication in A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
We present the discovery of a low-mass gas-rich low-surface brightness galaxy in the Dorado Group, at a distance of 17.7 Mpc. Combining deep MeerKAT 21-cm observations from the MeerKAT HI Observations of Nearby Galactic Objects: Observing Southern Emitters (MHONGOOSE) survey with deep photometric images from the VST Early-type Galaxy Survey (VEGAS) we find a stellar and neutral atomic hydrogen (HI) gas mass of $M_\star = 2.23\times10^6$ M$_\odot$ and $M_{\rm HI}=1.68\times10^6$ M$_\odot$, respectively. This low-surface brightness galaxy is the lowest mass HI detection found in a group beyond the Local Universe ($D\gtrsim 10$ Mpc). The dwarf galaxy has the typical overall properties of gas-rich low surface brightness galaxies in the Local group, but with some striking differences. Namely, the MHONGOOSE observations reveal a very low column density ($\sim 10^{18-19}$ cm$^{-2}$) HI disk with asymmetrical morphology possibly supported by rotation and higher velocity dispersion in the centre. There, deep optical photometry and UV-observations suggest a recent enhancement of the star formation. Found at galactocentric distances where in the Local Group dwarf galaxies are depleted of cold gas (at $390$ projected-kpc distance from the group centre), this galaxy is likely on its first orbit within the Dorado group. We discuss the possible environmental effects that may have caused the formation of the HI disk and the enhancement of star formation, highlighting the short-lived phase (a few hundreds of Myr) of the gaseous disk, before either SF or hydrodynamical forces will deplete the gas of the galaxy.
- [17] arXiv:2405.17077 [pdf, ps, html, other]
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Title: High Redshift Merger Model for Low Frequency Gravitational Wave BackgroundComments: 17 pages, 10 figures. Submitted to ApJ for reviewSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)
In 2023, the Pulsar Timing Array (PTA) Collaborations announced the discovery of a gravitational wave background (GWB), predominantly attributed to supermassive black hole binary (SMBHB) mergers. However, the detected GWB is several times stronger than the default value expected from galactic observations at low and moderate redshifts. Recent findings by the James Webb Space Telescope (JWST) have unveiled a substantial number of massive, high-redshift galaxies, suggesting more massive SMBHB mergers at these early epochs. Motivated by these findings, we propose an "early merger" model that complements the standard merger statistics by incorporating these early, massive galaxies. We compare the early and standard "late merger" models, which assume peak merger rates in the local universe, and match both merger models to the current detected GWB. Our analysis shows that the early merger model has a significantly lower detection probability for single binaries and predicts a $\sim 30 \%$ likelihood that the first detectable single source will be highly redshifted and remarkably massive with rapid frequency evolution. In contrast, the late merger model predicts a nearly monochromatic first source at low redshift. The future confirmation of an enhanced population of massive high-redshift galaxies and the detection of fast-evolving binaries would strongly support the early merger model, offering significant insights into galaxy and SMBH redshift evolution.
- [18] arXiv:2405.17128 [pdf, ps, html, other]
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Title: The response of the inner dark matter halo to stellar barsComments: 18 pages, 9 figures, accepted for publication in GalaxiesSubjects: Astrophysics of Galaxies (astro-ph.GA)
Barred galaxies constitute about two thirds of observed disc galaxies. Bars affect not only the mass distribution of gas and stars, but also that of the dark matter. An elongation of the inner dark matter halo is known as the halo bar. We aim to characterise the structure of the halo bars, with the goal of correlating them with the properties of the stellar bars. We use a suite of simulated galaxies with various bar strengths, including gas and star formation. We quantify strengths, shapes, and densities of these simulated stellar bars. We carry out numerical experiments with frozen and analytic potentials in order to understand the role played by a live responsive stellar bar. We find that the halo bar generally follows the trends of the disc bar. The strengths of the halo and stellar bars are tightly correlated. Stronger bars induce a slight increase of dark matter density within the inner halo. Numerical experiments show that a non-responsive frozen stellar bar would be capable of inducing a dark matter bar, but it would be weaker than the live case by a factor of roughly two.
- [19] arXiv:2405.17338 [pdf, ps, html, other]
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Title: From Seed to Supermassive Black Holes: Capture, Growth, Migration, and Pairing in Dense Proto-Bulge EnvironmentsComments: 9 pages, 5 figures, comments welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
The origins and mergers of supermassive black holes (BHs) remain a mystery. We describe a scenario from a novel multi-physics simulation featuring rapid ($\lesssim 1\,$Myr) hyper-Eddington gas capture by a $\sim 1000\,{\rm M}_{\odot}$ ``seed'' BH up to supermassive ($\gtrsim 10^{6}\,M_{\odot}$) masses, in a massive, dense molecular cloud complex typical of high-redshift starbursts. Due to the high cloud density, stellar feedback is inefficient and most of the gas turns into stars in star clusters which rapidly merge hierarchically, creating deep potential wells. Relatively low-mass BH seeds at random positions can be ``captured'' by merging sub-clusters and migrate to the center in $\sim1$ free-fall time (vastly faster than dynamical friction). This also efficiently produces a paired BH binary with $\sim 0.1$\,pc separation. The centrally-concentrated stellar density profile (akin to a ``proto-bulge'') allows the cluster as a whole to capture and retain gas and build up a large (pc-scale) circum-binary accretion disk with gas coherently funnelled to the central BH (even when the BH radius of influence is small). The disk is ``hyper-magnetized'' and ``flux-frozen'': dominated by a toroidal magnetic field with plasma $\beta \sim 10^{-3}$, with the fields amplified by flux-freezing. This drives hyper-Eddington inflow rates $\gtrsim 1\,\rm M_\odot yr^{-1}$, which also drive the two BHs to nearly-equal masses. The late-stage system appears remarkably similar to recently-observed high-redshift ``little red dots.'' This scenario can provide an explanation for rapid SMBH formation, growth and mergers in high-redshift galaxies.
- [20] arXiv:2405.17359 [pdf, ps, html, other]
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Title: EPOCHS Paper X: Environmental effects on Galaxy Formation and Protocluster Galaxy candidates at $4.5<z<10$ from JWST observationsQiong Li, Christopher J. Conselice, Florian Sarron, Tom Harvey, Duncan Austin, Nathan Adams, James A. A. Trussler, Qiao Duan, Leonardo Ferreira, Lewi Westcott, Honor Harris, Hervé Dole, Norman A. Grogin, Brenda Frye, Anton M. Koekemoer, Clayton Robertson, Rogier A. Windhorst, Maria del Carmen Polletta, Nimish P. HathiComments: 23 pages, 14 figures and 7 table, submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
In this paper we describe our search for galaxy protocluster candidates at $4.5< z < 10$ and explore the environmental and physical properties of their member galaxies identified through JWST wide-field surveys within the CEERS, JADES, and PEARLS NEP-TDF fields. Combining with HST data, we identify 2948 robust $z>4.5$ candidates within an area of 185.4 arcmin$^2$. We determine nearest neighbour statistics and galaxy environments. We find that high-$z$ galaxies in overdense environments exhibit higher star formation activity compared to those in underdense regions. Galaxies in dense environments have a slightly increased SFR at a given mass compared with galaxies in the lower density environments. At the high mass end we also find a gradual flattening of the $M_{\star}$-SFR slope. We find that galaxies in high-density regions often have redder UV slopes than those in low-density regions, suggesting more dust extinction, weaker Lyman-alpha emission and / or a higher damped Lyman-alpha absorption. We also find that the mass-size relation remains consistent and statistically similar across all environments. Furthermore, we quantitatively assess the probability of a galaxy belonging to a protocluster candidate. In total, we identified 26 overdensities at $z=5-7$ and estimate their dark matter halo masses. We find that all protocluster candidates could evolve into clusters with $M_{\rm halo} > 10^{14}M_{\odot}$ at $z = 0$, thereby supporting the theoretical and simulation predictions of cluster formation. Notably, this marks an early search for protocluster candidates in JWST wide field based on photometric data, providing valuable candidates to study cosmic structure formation at the early stages.
- [21] arXiv:2405.17389 [pdf, ps, html, other]
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Title: Turbulent circumnuclear disc and cold gas outflow in the newborn radio source 4C 31.04Comments: 9 pages, 4 figures. Accepted for publication in Astronomy & AstrophysicsSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present deep kpc- and pc-scale neutral atomic hydrogen (HI) absorption observations of a very young radio source (< 5000 yrs), 4C 31.04, using the WSRT and the Global VLBI array. Using $z=0.0598$, we detect a broad absorption feature centred at the systemic velocity, and narrow absorption redshifted by 220 km/s both previously observed. Additionally, we detect a new blueshifted, broad, shallow absorption wing. At pc scales, the broad absorption at the systemic velocity is detected across the entire radio source while the shallow wing is only seen against part of the eastern lobe. The velocity dispersion of the gas is overall high ($\geq$40 km/s), and is highest (>60 km/s) in the region including the outflow and the radio hot spot. While we detect a velocity gradient along the western lobe and parts of the eastern lobe, most of the gas along the rest of the eastern lobe exhibits no signs of rotation. We therefore conclude that the radio lobes of 4C 31.04 are expanding into a circumnuclear disc, partially disrupting it and making the gas highly turbulent. The distribution of gas is predominantly smooth at the spatial resolution of ~4 pc studied here. However, clumps of gas are also present, particularly along the eastern lobe. This lobe is strongly interacting with the clouds and driving an outflow ~35 pc from the radio core, with a mass-outflow rate of $0.3 \leq \dot{M} \leq 1.4$ M$_\odot$/yr. We compare our observations with a model on the survival of atomic gas clouds in radio-jet-driven outflows and find that the existence of a sub-kpc outflow implies high gas density and inefficient mixing of the cold gas with the hot medium, leading to shorter cooling times. Overall, this provides further evidence of the strong impact of young radio jets on cold ISM and supports the predictions of simulations regarding jet$-$ISM interactions and the nature of the gas into which the jets expand.
New submissions for Tuesday, 28 May 2024 (showing 21 of 21 entries )
- [22] arXiv:2405.16454 (cross-list from astro-ph.IM) [pdf, ps, html, other]
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Title: Cross-Matching of OGLE, GAIA, and Hubble Catalogs: Evaluating the Probability of Resolving Lens Stars in Microlensing EventsComments: 8 pages, 9 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc)
This study commenced by cross-matching data from the GAIA and OGLE telescopes with the aim of resolving the source star, long after microlensing is finished. The aim is breaking degeneracy between parameters of the microlensing equation, and ultimately calculating the mass of lens. We have examined different catalogs and found no evidence. Subsequently, employing the Monte Carlo method and guided by sensible assumptions, we embarked a simulation to discern the distribution of angular separation and to probe the feasibility of detecting this phenomenon. The results revealed that a mere 0.029% of gravitational microlensing events exhibited separations exceeding 50 milliarcseconds. Consequently, the likelihood of observing this phenomenon utilizing the OGLE and GAIA telescopes appears exceedingly far available. However, it is worth noting that instruments with very high angular resolution in the range of several tens of milliarcseconds present a viable avenue for such observations. Finally, we proposed 60 microlensing events for which the observation of separation is more probable based on the measured proper velocity.
- [23] arXiv:2405.16484 (cross-list from astro-ph.CO) [pdf, ps, html, other]
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Title: Accurate Measurement of the Lensing Magnification by BOSS CMASS Galaxies and Its Implications for Cosmology and Dark MatterKun Xu (SJTU, Durham), Y.P. Jing (SJTU, TDLI), Hongyu Gao (SJTU), Xiaolin Luo (SJTU), Ming Li (NAOC)Comments: 24 pages, 19 figures. Main results in Figure 9 (dust) and Figure 18 (matter). Submitted to ApJSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
Magnification serves as an independent and complementary gravitational lensing measurement to shear. We develop a novel method to achieve an accurate and robust magnification measurement around BOSS CMASS galaxies across physical scales of $0.016h^{-1}\,{\rm Mpc} < r_{\rm p} < 10h^{-1}\,{\rm Mpc}$. We first measure the excess total flux density $\delta M$ of the source galaxies in deep DECaLS photometric catalog that are lensed by CMASS galaxies. We convert $\delta M$ to magnification $\mu$ by establishing the $\delta \mu-\delta M$ relation using a deeper photometric sample. By comparing magnification measurements in three optical bands ($grz$), we constrain the dust attenuation curve and its radial distribution, discovering a steep attenuation curve in the circumgalactic medium of CMASS galaxies. We further compare dust-corrected magnification measurements to model predictions from high-resolution dark matter-only (DMO) simulations in WMAP and Planck cosmologies, as well as the hydrodynamic simulation TNG300-1, using precise galaxy-halo connections from the Photometric objects Around Cosmic webs method and the accurate ray-tracing algorithm P3MLens. For $r_{\rm p} > 70h^{-1}\,$kpc, our magnification measurements are in good agreement with both WMAP and Planck cosmologies. Assuming a linear correlation between the magnification signal and the fluctuation amplitude $S_8$, we obtain a tight constraint of $S_8 = 0.816 \pm 0.024$. However, at $r_{\rm p} < 70h^{-1}\,$kpc, we observe an excess magnification signal, which is higher than the DMO model in Planck cosmology at $2.8\sigma$ and would be exacerbated if significant baryon feedback is included. Implications of the potential small scale discrepancy for the nature of dark matter and for the processes governing galaxy formation are discussed.
- [24] arXiv:2405.16505 (cross-list from astro-ph.SR) [pdf, ps, html, other]
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Title: He-enriched STAREVOL models for globular cluster multiple populations. Self-consistent isochrones from ZAMS to the TP-AGB phaseG. Costa, T. Dumont, A. Lançon, A. Palacios, C. Charbonnel, P. Prugniel, S. Ekstrom, C. Georgy, V. Branco, P. Coelho, L. Martins, S. Borisov, K. Voggel, W. ChantereauComments: 15 pages, 12 figures, accepted for publication in Astronomy & AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
A common property of globular clusters (GC) is to host multiple populations characterized by peculiar chemical abundances. Recent photometric studies suggest that the He content could vary between the populations of a GC by up to $\Delta$He $\sim$ 0.13, in mass fraction. The initial He content impacts the evolution of low-mass stars by ultimately modifying their lifetimes, luminosity, temperatures, and, more generally, the morphology of post-RGB evolutionary tracks in the Hertzsprung-Russell diagram. We present new physically accurate isochrones with different initial He-enrichments and metallicities, with a focus on the methods implemented to deal with the post-RGB phases. The isochrones are based on tracks computed with the stellar evolution code STAREVOL for different metallicities (Z = 0.0002, 0.0009, 0.002, and 0.008) and with different He-enrichment (from 0.25 to 0.6 in mass fraction). We describe the effect of He-enrichment on the morphology of the isochrones and test these by comparing the predicted number counts of HB and AGB stars with those of selected GCs. Comparing the number ratios, we find that our new theoretical ones agree with the observed values within $1\sigma$ in most cases. The work presented here sets the ground for future studies on stellar populations in globular clusters, in which the abundances of light elements in He-enhanced models will rely on different assumptions for the causes of this enrichment. The developed methodology permits the computation of isochrones from new stellar tracks with non-canonical stellar processes. The checked number counts ensure that, at least in this reference set, the contribution of the luminous late stages of stellar evolution to the integrated light of a GC is represented adequately.
- [25] arXiv:2405.16650 (cross-list from astro-ph.CO) [pdf, ps, html, other]
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Title: Bounding Dark Energy from the SPARC rotation curves: Data driven probe for galaxy virializationComments: 12 pages; 6 figures;Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
Dark Energy (DE) acts as a repulsive force that opposes gravitational attraction. Assuming galaxies maintain a steady state over extended periods, the estimated upper bound on DE studies its resistance to the attractive gravitational force from dark matter. Using the SPARC dataset, we fit the Navarro-Frenk-White (NFW) and Hernquist models to identify the most suitable galaxies for these models. Introducing the presence of DE in these galaxies helps establish the upper limit on its repulsive force. This upper bound on DE sits around $\rho_{\left(<\Lambda\right)} \sim 10^{-25}$~kg/m$^3$, only two orders of magnitude higher than the one measured by Planck. We discuss the conditions for detecting DE in different systems and show the consistency of the upper bound from galaxies to other systems. The upper bound is of the same order of magnitude as $\rho_{200} = 200 \rho_c$ for both dark matter profiles. We also address the implications for future measurements on that upper bound and the condition for detecting the impact of $\Lambda$ on galactic scales.
- [26] arXiv:2405.16857 (cross-list from astro-ph.EP) [pdf, ps, html, other]
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Title: KMT-2023-BLG-2669: Ninth Free-floating Planet Candidate with $\theta_{\rm E}$ measurementsYoun Kil Jung, Kyu-Ha Hwang, Hongjing Yang, Andrew Gould, Jennifer C. Yee, Cheongho Han, Michael D. Albrow, Sun-Ju Chung, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Weicheng Zang, Sang-Mok Cha, Dong-Jin Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. PoggeComments: 17 pages, 5 figures, submitted to AJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
We report a free-floating planet (FFP) candidate identified from the analysis of the microlensing event KMT-2023-BLG-2669. The lensing light curve is characterized by a short duration $(\lesssim 3\,{\rm days})$ and a small amplitude $(\lesssim 0.7\,{\rm mag})$. From the analysis, we find the Einstein timescale of $t_{\rm E} \backsimeq 0.33\,{\rm days}$ and the Einstein radius of $\theta_{\rm E} \backsimeq 4.41\,{\mu}{\rm as}$. These measurements enable us to infer the lens mass as $M = 8\,M_{\oplus} (\pi_{\rm rel} / 0.1\,{\rm mas})^{-1}$, where $\pi_{\rm rel}$ is the relative lens-source parallax. The inference implies that the lens is a sub-Neptune- to Saturn-mass object depending on its unknown distance. This is the ninth isolated planetary-mass microlens with $\theta_{\rm E} < 10\,{\mu}{\rm as}$, which (as shown by \citealt{gould22}) is a useful threshold for a FFP candidate. We conduct extensive searches for possible signals of a host star in the light curve, but find no strong evidence for the host. We discuss the possibility of using late-time high-resolution imaging to probe for possible hosts.
- [27] arXiv:2405.17219 (cross-list from astro-ph.EP) [pdf, ps, html, other]
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Title: How likely is the interstellar origin of CNEOS14? On the reliability of the CNEOS databaseSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)
This paper investigates the likelihood that the CNEOS 2014-01-08 superbolide (CNEOS14) was caused by an interstellar object. This issue has remained controversial due to lack of information on the capabilities of the classified satellite sensors that recorded the fireball. We critically evaluate previous studies, specifically addressing the reliability of the CNEOS database and the associated measurement uncertainties. With proper statistical analysis of existing data and the addition of a relevant new event (the 2024 Iberian superbolide), we disprove some claims in previous work, such as: a) the existence of a purported correlation between CNEOS velocity errors and bolide speed; b) the presence of large velocity errors of 10-15 km/s in the CNEOS database; and c) the assertion that CNEOS14 is most likely a solar system object with a hyperbolic trajectory due to measurement errors. We present a quantitative estimate of the probability that CNEOS14 is interstellar. If its measurement errors are drawn from the same underlying distribution as the 18 calibrated events, then the probability that CNEOS14 is interstellar is 94.1%. This probability is lower than the 99.7% confidence (3-sigma) generally required to claim a scientific discovery. However, it is sufficiently high to be considered significant and, by far, the most likely explanation for the currently available empirical evidence.
Cross submissions for Tuesday, 28 May 2024 (showing 6 of 6 entries )
- [28] arXiv:2311.12120 (replaced) [pdf, ps, html, other]
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Title: The Coherent Magnetic Field of the Milky WayComments: Accepted for publication in ApJ. New appendices on foreground contamination and parameter correlations. Fix typo for twistX $w_d$ parameter in Tab.3 (no changes required for the source code distributed with v2 of this preprint as it is not affected by the typo). Covariance matrices of model parameters now available on zenodoSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
We present a suite of models of the coherent magnetic field of the Galaxy (GMF) based on new divergence-free parametric functions describing the global structure of the field. The model parameters are fit to the latest full-sky Faraday rotation measures of extragalactic sources (RMs) and polarized synchrotron intensity (PI) maps from WMAP and Planck. We employ multiple models for the density of thermal and cosmic-ray electrons in the Galaxy, needed to predict the skymaps of RMs and PI for a given GMF model. The robustness of the inferred properties of the GMF is gauged by studying many combinations of parametric field models and electron density models. We determine the pitch angle of the local magnetic field (11+/-1 deg.), explore the evidence for a grand-design spiral coherent magnetic field (inconclusive), determine the strength of the toroidal and poloidal magnetic halo fields below and above the disk (magnitudes the same for both hemispheres within 10%), set constraints on the half-height of the cosmic-ray diffusion volume (>2.9 kpc), investigate the compatibility of RM- and PI-derived magnetic field strengths (compatible under certain assumptions) and check if the toroidal halo field could be created by the shear of the poloidal halo field due to the differential rotation of the Galaxy (possibly). A set of eight models is identified to help quantify the present uncertainties in the coherent GMF -- spanning different functional forms, data products and auxiliary input, and maximizing the differences in their predictions. We present the corresponding skymaps of rates for axion-photon conversion in the Galaxy, and deflections of ultra-high energy cosmic rays.
- [29] arXiv:2311.12691 (replaced) [pdf, ps, html, other]
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Title: MIDIS: The Relation between Strong (Hb+[OIII]) Emission, Star Formation and Burstiness Around the Epoch of ReionizationKarina I. Caputi, Pierluigi Rinaldi, Edoardo Iani, Pablo G. Pérez-González, Göran Ostlin, Luis Colina, Thomas R. Greve, Hans-Ulrik Nørgaard-Nielsen, Gillian S. Wright, Javier Alvarez-Márquez, Andreas Eckart, Jens Hjorth, Alvaro Labiano, Olivier Le Fèvre, Fabian Walter, Paul van der Werf, Leindert Boogaard, Luca Costantin, Alejandro Crespo-Gómez, Steven Gillman, Iris Jermann, Danial Langeroodi, Jens Melinder, Florian Peissker, Manuel Güdel, Thomas Henning, Pierre-Olivier Lagage, Thomas P. RayComments: 14 pages, 8 figures. Accepted for publication at the ApJ. The new manuscript version has minor changes with respect to v1 and no conclusion has changedSubjects: Astrophysics of Galaxies (astro-ph.GA)
We investigate the properties of strong (Hb+[OIII]) emitters before and after the end of the Epoch of Reionization from z=8 to z=5.5. We make use of ultra-deep JWST/NIRCam imaging in the Parallel Field of the MIRI Deep Infrared Survey (MIDIS) in the Hubble eXtreme Deep Field (P2-XDF), in order to select prominent (Hb+[OIII]) emitters (with rest EW_0 > 100 Angstroms) at z=5.5-7, based on their flux density enhancement in the F356W band with respect to the spectral energy distribution continuum. We complement our selection with other (Hb+[OIII]) emitters from the literature at similar and higher (z=7-8) redshifts. We find (non-independent) anti-correlations between EW_0(Hb+[OIII]) and both galaxy stellar mass and age, in agreement with previous studies, and a positive correlation with specific star formation rate (sSFR). On the SFR-M* plane, the (Hb+[OIII]) emitters populate both the star-formation main sequence and the starburst region, which become indistinguishable at low stellar masses (log10(M*) < 7.5). We find tentative evidence for a non-monotonic relation between EW_0(Hb+[OIII]) and SFR, such that both parameters correlate with each other at SFR > 1 Msun/yr, while the correlation flattens out at lower SFRs. This suggests that low metallicities producing high EW_0(Hb+[OIII]) could be important at low SFR values. Interestingly, the properties of the strong emitters and other galaxies (33% and 67% of our z=5.5-7 sample, respectively) are similar, including, in many cases, high sSFR. Therefore, it is crucial to consider both emitters and non-emitters to obtain a complete picture of the cosmic star formation activity around the Epoch of Reionization.
- [30] arXiv:2402.16942 (replaced) [pdf, ps, html, other]
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Title: A NIRCam-dark galaxy detected with the MIRI/F1000W filter in the MIDIS/JADES Hubble Ultra Deep FieldPablo G. Pérez-González, Pierluigi Rinaldi, Karina I. Caputi, Javier Álvarez-Márquez, Marianna Annunziatella, Danial Langeroodi, Thibaud Moutard, Leindert Boogaard, Edoardo Iani, Jens Melinder, Luca Costantin, Goran Östlin, Luis Colina, Thomas R. Greve, Gillian Wright, Almudena Alonso-Herrero, Arjan Bik, Sarah E. I. Bosman, Alejandro Crespo Gómez, Daniel Dicken, Andreas Eckart, Macarena García-Marín, Steven Gillman, Manuel Güdel, Thomas Henning, Jens Hjorth, Iris Jermann, Álvaro Labiano, Romain A. Meyer, Florian Peisker, John P. Pye, Thomas P. Ray, Tuomo Tikkanen, Fabian Walter, Paul P. van der WerfComments: Accepted for publication in ApJL, results unchanged, manuscript shortened to publish as a letterSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We report the discovery of Cerberus, an extremely red object detected with the MIRI Deep Imaging Survey (MIDIS) observations in the F1000W filter of the Hubble Ultra Deep Field. The object is detected at $S/N\sim6$, with $\mathrm{F1000W}\sim27$ mag, and undetected in the NIRCam data gathered by the JWST Advanced Deep Extragalactic Survey, JADES, fainter than the 30.0-30.5 mag $5\sigma$ detection limits in individual bands, as well as in the MIDIS F560W ultra-deep data ($\sim$29 mag, $5\sigma$). Analyzing the spectral energy distribution built with low-$S/N$ ($<5$) measurements in individual optical-to-mid-infrared filters and higher $S/N$ ($\gtrsim5$) in stacked NIRCam data, we discuss the possible nature of this red NIRCam-dark source using a battery of codes. We discard the possibility of Cerberus being a Solar System body based on the $<0.016$" proper motion in the 1-year apart JADES and MIDIS observations. A sub-stellar Galactic nature is deemed unlikely, given that the Cerberus' relatively flat NIRCam-to-NIRCam and very red NIRCam-to-MIRI flux ratios are not consistent with any brown dwarf model. The extragalactic nature of Cerberus offers 3 possibilities: (1) A $z\sim0.4$ galaxy with strong emission from polycyclic aromatic hydrocarbons; the very low inferred stellar mass, $\mathrm{M}_\star=10^{5-6}$ M$_\odot$, makes this possibility highly improbable. (2) A dusty galaxy at $z\sim4$ with an inferred stellar mass $\mathrm{M}_\star\sim10^{8}$ M$_\odot$. (3) A galaxy with observational properties similar to those of the reddest little red dots discovered around $z\sim7$, but Cerberus lying at $z\sim15$, with the rest-frame optical dominated by emission from a dusty torus or a dusty starburst.
- [31] arXiv:2403.04850 (replaced) [pdf, ps, html, other]
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Title: Complex angular structure of three elliptical galaxies from high-resolution ALMA observations of strong gravitational lensesComments: In print with A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
The large-scale mass distributions of galaxy-scale strong lenses have long been assumed to be well-described by a singular ellipsoidal power-law density profile with external shear. However, the inflexibility of this model could lead to systematic errors in astrophysical parameters inferred with gravitational lensing observables. Here, we present observations with the Atacama Large (sub-)Millimetre Array (ALMA) of three strongly lensed dusty star-forming galaxies at $\simeq30$ mas angular resolution and investigate the sensitivity of these data to angular structure in the lensing galaxies. We jointly infer the lensing mass distribution and the full surface brightness of the lensed sources with multipole expansions of the power-law density profile up to fourth order using a technique developed for interferometric data. All three data sets strongly favour third and fourth-order multipole amplitudes of $\approx1$ percent of the convergence. While the infrared stellar isophotes and isodensity shapes agree for one lens system, for the other two the isophotes disagree to varying extents, suggesting contributions to the angular structure from dark matter intrinsic or extrinsic to the lensing galaxy.
- [32] arXiv:2403.07717 (replaced) [pdf, ps, html, other]
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Title: Resolving Dual Active Galactic Nuclei with ~100 pc separation in MCG-03-34-64Comments: Submitted to ApJLSubjects: Astrophysics of Galaxies (astro-ph.GA)
We report the serendipitous multiwavelength discovery of a candidate dual black hole system with a separation of $\sim$100 pc, in the gas-rich luminous infrared galaxy MCG-03-34-64 (z=0.016). Hubble Space Telescope/ACS observations show three distinct optical centroids in the [O III] narrow-band and F814W images. Subsequent analysis of Chandra/ACIS data shows two spatially-resolved peaks of equal intensity in the neutral Fe K$\alpha$ (6.1-6.6 keV) band, while high-resolution radio continuum observations with the Very Large Array at 8.46 GHz (3.6 cm band) show two spatially-coincident radio peaks. Fast shocks as the ionizing source seem unlikely, given the energies required for production of Fe K$\alpha$. If confirmed, the separation of $\sim$100 pc would represent the closest dual AGN reported to date with spatially-resolved, multiwavelength observations.
- [33] arXiv:2404.08780 (replaced) [pdf, ps, html, other]
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Title: The Population of Massive Stars in Active Galactic Nuclei DisksComments: Published in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
Gravitational instability in the outskirts of Active Galactic Nuclei (AGN) disks lead to disk fragmentation and formation of super-massive (several 10^2Msun) stars with potentially long lifetimes. Alternatively, stars can be captured ex-situ and grow from gas accretion in the AGN disk. However, the number density distribution throughout the disk is limited by thermal feedback as their luminosities provide the dominant heating source. We derive equilibrium stellar surface density profiles under two limiting contexts: in the case where the stellar lifetimes are prolonged due to recycling of hydrogen rich disk gas, only the fraction of gas converted into heat is removed from the disk accretion flow. Alternatively, if stellar composition recycling is inefficient and stars can evolve off the main sequence, the disk accretion rate is quenched towards smaller radii resembling a classical star-burst disk, albeit the effective removal rate depends not only on the stellar lifetime, but also the mass of stellar remnants. For AGNs with central Supermassive Black Hole (SMBH) masses of \sim 10^6 to 10^8Msun accreting at \sim 0.1 Eddington efficiency, we estimate a total number of 10^3 to 10^5 coexisting massive stars and the rate of stellar mergers to be 10^-3 to 1 per year. We motivate the detailed study of interaction between a swarm of massive stars through hydro and N body simulations to provide better prescriptions of dynamical processes in AGN disks, and to constrain more accurate estimates of the stellar population.
- [34] arXiv:2405.13108 (replaced) [pdf, ps, html, other]
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Title: The impact of mass-dependent stochasticity at cosmic dawnComments: 11 pages, 7 figures, submitted to ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
JWST is unveiling a surprising lack of evolution in the number densities of ultraviolet-selected (UV) galaxies at redshift $z\gtrsim 10$. At the same time, observations and simulations are providing evidence for highly bursty star formation in high-$z$ galaxies, resulting in significant scatter in their UV luminosities. Galaxies in low-mass dark matter halos are expected to experience most stochasticity due to their shallow potential wells. Here, we explore the impact of a mass-dependent stochasticity using a simple analytical model. We assume that scatter in the $M_\mathrm{UV}-M_h$ relation increases towards lower halo masses, following the decrease in halo escape velocity, $\sigma_\mathrm{UV} \sim M_h^{-1/3}$, independent of redshift. Since low-mass halos are more dominant in the early universe, this model naturally predicts an increase in UV luminosity functions (LFs) at high redshifts compared to models without scatter. We make predictions for additional observables which would be affected by stochasticity and could be used to constrain its amplitude, finding: (i) galaxies are less clustered compared to the no-scatter scenario, with the difference increasing at higher-$z$; (ii) assuming star-bursting galaxies dominate the ionizing photon budget implies reionization starts earlier and is more gradual compared to the no-scatter case, (iii) at fixed UV magnitude galaxies should exhibit wide ranges of UV slopes, nebular emission line strengths and Balmer breaks. Comparing to observations, the mass-dependent stochasticity model successfully reproduces the observed LFs up to $z\sim12$. However, the model cannot match the observed $z\sim14$ LFs, implying additional physical processes enhance star formation efficiency in the earliest galaxies.
- [35] arXiv:2312.15760 (replaced) [pdf, ps, html, other]
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Title: Gravitational Lensing of Spherically Symmetric Black Holes in Dark Matter HalosComments: 29 pages, 9 figures, 2 appendicesSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
The gravitational lensing of supermassive black holes surrounded by dark matter halo has attracted a great number of interests in recent years. However, many studies employed simplified dark matter density models, which makes it very hard to give a precise prediction on the dark matter effects in real astrophysical galaxies. In this work, to more accurately describe the distribution of dark matter in real astrophysical galaxies, we study the gravitational lensing of black holes in astrophysical dark matter halo models (Beta, Burkert, Brownstein, and Moore). The deflection angle is obtained using a generalized Gibbons-Werner approach. The visual angular positions and the Einstein rings are also calculated by adopting the gravitational lens equation. Specifically, we choose the supermassive black holes in Milky Way Galaxy, Andromeda galaxy (M31), Virgo galaxy (M87), and ESO138-G014 galaxy as examples, including the corresponding fitted value of dark matter halos. The results suggest that the dark matter halo described by the Beta model has non-negligible influences on the gravitational deflection angle and gravitational lensing observations. However, the Burkert, Brownstein, and Moore models have relatively small influences on angular position of images and the Einstein ring.
- [36] arXiv:2402.07177 (replaced) [pdf, ps, html, other]
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Title: The orbital evolution of the tidally stripped star and disk-driven stable mass transfer for QPEs in GSN 069Comments: 9 pages, 9 figures, Comments welcomeSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
The origin of the quasi-periodic eruptions (QPEs) is possibly mass loss at the periastron of a body moving around the supermassive black hole (SMBH) in a high eccentric orbit. Such a tidally stripped star is expected to radiate gravitational wave thereby leading to shrinkage of the periastron distance, and thus will eventually be disrupted by the SMBH in the previous studies. This scenario predicts a gradually increasing mass transfer, contradicting the long term evolution of the observed intensity of the QPEs in GSN this http URL this paper, we first revisited the orbital evolution of the stripped star. Then we suggested a model of a tidal stripped WD moving inside an accretion disk for QPEs in GSN 069.We found the effect of the mass transfer finally dominates the orbital evolution, resulting in the stripped star finally escaping the SMBH rather than being disrupted by it. The drag force by the disk can effectively reduce mass transfer and thus explain the observed long term evolution in the intensity of the QPEs in GSN 069. The disk is likely a fallback disk of the tidal disruption event in GSN 069. Considering the evolution of its accretion rate, the increase in the intensity of the latest eruption can also be explained.
- [37] arXiv:2405.13650 (replaced) [pdf, ps, html, other]
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Title: Identifying type II quasars at intermediate redshift with few-shot learning photometric classificationP.A.C. Cunha, A. Humphrey, J. Brinchmann, S.G. Morais, R. Carvajal, J.M. Gomes, I. Matute, A. Paulino-AfonsoComments: 20 pages, 9 figures, Accepted for publication in A&ASubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)
We aim to identify QSO2 candidates in the redshift desert using optical and infrared photometry. At this intermediate redshift range, most of the prominent optical emission lines in QSO2 sources (e.g. CIV1549; [OIII]4959,5008) fall either outside the wavelength range of the SDSS optical spectra or in particularly noisy wavelength ranges, making QSO2 identification challenging. Therefore, we adopted a semi-supervised machine learning approach to select candidates in the SDSS galaxy sample. Recent applications of machine learning in astronomy focus on problems involving large data sets, with small data sets often being overlooked. We developed a few-shot learning approach for the identification and classification of rare-object classes using limited training data (200 sources). The new AMELIA pipeline uses a transfer-learning based approach with decision trees, distance-based, and deep learning methods to build a classifier capable of identifying rare objects on the basis of an observational training data set. We validated the performance of AMELIA by addressing the problem of identifying QSO2s at 1 $\leq$ z $\leq$ 2 using SDSS and WISE photometry, obtaining an F1-score above 0.8 in a supervised approach. We then used AMELIA to select new QSO2 candidates in the redshift desert and examined the nature of the candidates using SDSS spectra, when available. In particular, we identified a sub-population of [NeV]3426 emitters at z $\sim$ 1.1, which are highly likely to contain obscured AGNs. We used X-ray and radio cross-matching to validate our classification and investigated the performance of photometric criteria from the literature showing that our candidates have an inherent dusty nature. Finally, we derived physical properties for our QSO2 sample using photoionisation models and verified the AGN classification using an SED fitting.
- [38] arXiv:2405.13822 (replaced) [pdf, ps, html, other]
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Title: Estimation of radial velocities of BHB starsComments: 8 pages, 7 figures, 3 tablesSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We studied blue horizontal branch stars (BHBs), and calculated their radial velocities. Spectra of these stars have been obtained with moderate signal-to-noise ratio for five blue horizontal-branch stars using the 2 meter telescope and Echelle Spectrograph in Ondrejov observatory, Czech republic.