arXiv - PHYS - Astrophysics of Galaxies最新文献

{"title":"Optical intraday variability analysis for the BL Lacertae object 1ES 1426+42.8","authors":"X. Chang, D. R. Xiong, T. F. Yi, C. X. Liu, G. Bhatta, J. R. Xu, Y. L. Gong","doi":"arxiv-2409.06983","DOIUrl":"https://doi.org/arxiv-2409.06983","url":null,"abstract":"The observation data of blazar 1ES 1426 + 42.8 were obtained using the 1.02 m\u0000optical telescope of Yunnan Observatories during $2021$ to $2023$. Intraday\u0000variability (IDV) is detected on seven nights. We use the turbulent model to\u0000investigate the mechanism of IDV in 1ES 1426 + 42.8. The fitting light curves\u0000match the actual IDV curves well. Using this model, we obtain the parameters\u0000such as the size of turbulent cells and the width of pulses in the jet. A\u0000possible short-lived Quasi-periodic oscillation (QPO) of $58.55 pm 8.09$\u0000minutes was detected on April 26, 2022 whose light curve exhibits eight cycles\u0000at $>3sigma$ global significance and confirmed by several different\u0000techniques. Through a more detailed analysis of the light curve of this night,\u0000we find that the period is shortened from 54.23 minutes ($4sigma$) to 29.71\u0000minutes ($3sigma$). The possible QPO and period shortening phenomenon are best\u0000explained by the processes of magnetic reconnections.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"JADES: Measuring reionization properties using Lyman-alpha emission","authors":"Gareth C. Jones, Andrew J. Bunker, Aayush Saxena, Santiago Arribas, Rachana Bhatawdekar, Kristan Boyett, Stefano Carniani, Stephane Charlot, Emma Curtis-Lake, Kevin Hainline, Benjamin D. Johnson, Nimisha Kumari, Michael V. Maseda, Hans-Walter Rix, Brant E. Robertson, Sandro Tacchella, Hannah Übler, Christina C. Williams, Chris Willott, Joris Witstok, Yongda Zhu","doi":"arxiv-2409.06405","DOIUrl":"https://doi.org/arxiv-2409.06405","url":null,"abstract":"Ly$alpha$ is the transition to the ground state from the first excited state\u0000of hydrogen (the most common element). Resonant scattering of this line by\u0000neutral hydrogen greatly impedes its emergence from galaxies, so the fraction\u0000of galaxies which show Ly$alpha$ is a tracer of the neutral fraction of the\u0000intergalactic medium (IGM), and thus the history of reionization. In previous\u0000works, we used early JWST/NIRSpec data from the JWST Advanced Deep\u0000Extragalactic Survey (JADES) to classify and characterise Ly$alpha$ emitting\u0000galaxies (LAEs). This survey is now approaching completion, and the current\u0000sample is nearly an order of magnitude larger. From a sample of 784 galaxies in\u0000JADES at $4.0<z<14.3$, we find evidence for Ly$alpha$ emission in 145 sources.\u0000We reproduce the previously found correlation between Ly$alpha$ escape\u0000fraction (fesc) - Ly$alpha$ rest-frame equivalent width (rew) and the\u0000negative correlation between Ly$alpha$ velocity offset - fesc. Both fesc and\u0000rew decrease with redshift ($zgtrsim5.5$), indicating the progression of\u0000reionization on a population scale. Our data are used to demonstrate an\u0000increasing IGM transmission of Ly$alpha$ from $zsim14-6$. We measure the\u0000completeness-corrected fraction of LAEs ($X_{Lyalpha}$) from $z=4-9.5$. An\u0000application of these $X_{Lyalpha}$ values to the results of cosmological\u0000models suggests a high neutral fraction at $z=7$ ($rm\u0000X_{HI}=0.81_{-0.10}^{+0.07}$), likely suggesting the need for models with\u0000updated rew distributions (based on comparison to other works). This large\u0000sample of LAEs and the completeness correction we have detailed will be\u0000paramount for unbiased population studies of galaxies in the EoR.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"No Redshift Evolution in the Fe II/Mg II Flux Ratios of Quasars across Cosmic Time","authors":"Danyang Jiang, Masafusa Onoue, Linhua Jiang, Samuel Lai, Eduardo Banados, George D. Becker, Manuela Bischetti, Sarah E. I. Bosman, Rebecca L. Davies, Valentina DOdorico, Emanuele Paolo Farina, Martin G. Haehnelt, Chiara Mazzucchelli, Jan-Torge Schindler, Fabian Walter, Yongda Zhu","doi":"arxiv-2409.06174","DOIUrl":"https://doi.org/arxiv-2409.06174","url":null,"abstract":"The Fe II/Mg II emission line flux ratio in quasar spectra serves as a proxy\u0000for the relative Fe to alpha-element abundances in the broad line regions of\u0000quasars. Due to the expected different enrichment timescales of the two\u0000elements, they can be used as a cosmic clock in the early Universe. We present\u0000a study of the Fe II/Mg II ratios in a sample of luminous quasars exploiting\u0000high-quality near-IR spectra taken primarily by the XQR-30 program with VLT\u0000XSHOOTER. These quasars have a median bolometric luminosity of log(L_bol[erg\u0000s^-1])~47.3 and cover a redshift range of z=6.0-6.6. The median value of the\u0000measured Fe II/Mg II ratios is ~7.9 with a normalized median absolute deviation\u0000of ~2.2. In order to trace the cosmic evolution of Fe II/Mg II in an unbiased\u0000manner, we select two comparison samples of quasars with similar luminosities\u0000and high-quality spectra from the literature, one at intermediate redshifts\u0000(z=3.5-4.8) and the other at low redshifts (z=1.0-2.0). We perform the same\u0000spectral analysis for all these quasars, including the usage of the same iron\u0000template, the same spectral fitting method, and the same wavelength fitting\u0000windows. We find no significant redshift evolution in the Fe II/Mg II ratio\u0000over the wide redshift range from z=1 to 6.6. The result is consistent with\u0000previous studies and supports the scenario of a rapid iron enrichment in the\u0000vicinity of accreting supermassive black holes at high redshift.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physical Processes Behind the Co-Evolution of Halos, Galaxies and Supermassive Black Holes in the IllustrisTNG Simulation","authors":"Hao Li, Yangyao Cheng, Huiyuan Wang, Houjun Mo","doi":"arxiv-2409.06208","DOIUrl":"https://doi.org/arxiv-2409.06208","url":null,"abstract":"We explore the co-evolution of dark matter halos, their central galaxies, and\u0000central supermassive black holes (SMBHs) using the IllustrisTNG (TNG)\u0000simulation. We find that the evolutionary histories of individual galaxies in\u0000the $M_{rm BH}$-$M_*$ plane can be decomposed into four distinct phases,\u0000separated by three transition points. We identify the driving processes of\u0000galaxy evolution within each phase and derive the conditions necessary and\u0000sufficient for transitions to subsequent phases. The first phase is dominated\u0000by star formation, with its duration primarily determined by the mass of the\u0000SMBH seed and the surrounding gas environment. The second phase is\u0000characterized by rapid SMBH growth, and the transition to the next phase occurs\u0000when the thermal-mode feedback of active galactic nucleus (AGN) can unbind gas\u0000from the galaxy. The third phase involves self-regulation of the SMBH, and the\u0000transition to the quenched phase occurs when the kinetic-mode feedback of AGN\u0000counterbalances gas cooling within the subhalo. The final phase is dominated by\u0000mergers. We investigate the use of scaling relations among different mass\u0000components and evolutionary phases to understand processes implemented in TNG\u0000and other simulations, and discuss how current and forthcoming observations can\u0000be used to constrain models.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FAST Ultra-Deep Survey (FUDS): Data Release for FUDS0","authors":"Hongwei Xi, Bo Peng, Lister Staveley-Smith, Bi-Qing For, Bin Liu, Dejian Ding","doi":"arxiv-2409.06153","DOIUrl":"https://doi.org/arxiv-2409.06153","url":null,"abstract":"We have used the Five-hundred-meter Aperture Spherical radio Telescope (FAST)\u0000to make a blind ultra-deep survey for neutral hydrogen (HI). We present the\u0000complete results from the first of six fields (FUDS0). This observation of 95\u0000hours allowed us to achieve a high sensitivity ($sim 50~mu$Jy beam$^{-1}$)\u0000and a high frequency resolution (22.9 kHz) over an area of 0.72 deg$^2$. We\u0000detected 128 galaxies in HI distributed over the redshift range of $0<z<0.4$\u0000with HI masses in the range of $6.67 leq log(M_{rm HI}/h_{70}^{-2} rm\u0000M_odot) leq 10.92$, and three faint high-velocity clouds (HVCs) with peak\u0000column density of $N_{rm HI} leq 3.1 times 10^{17}$ cm$^{-2}$. Of the\u0000galaxies, 95 are new detections and six have $z > 0.38$, where no unlensed HI\u0000emission has previously been directly detected. Estimates of completeness and\u0000reliability are presented for the catalog. Consistency of continuum and HI flux\u0000estimates with NVSS and AUDS, respectively, confirms the accuracy of\u0000calibration method and data reduction pipeline developed for the full FUDS\u0000survey.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"109 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Broad-Line AGN at $3.5","authors":"Anthony J. Taylor, Steven L. Finkelstein, Dale D. Kocevski, Junehyoung Jeon, Volker Bromm, Ricardo O. Amorin, Pablo Arrabal Haro, Bren E. Backhaus, Micaela B. Bagley, Eduardo Bañados, Rachana Bhatawdekar, Madisyn Brooks, Antonello Calabro, Oscar A. Chavez Ortiz, Yingjie Cheng, Nikko J. Cleri, Justin W. Cole, Kelcey Davis, Mark Dickinson, Callum Donnan, James S. Dunlop, Richard S. Ellis, Vital Fernandez, Adriano Fontana, Seiji Fujimoto, Mauro Giavalisco, Andrea Grazian, Jingsong Guo, Nimish P. Hathi, Benne W. Holwerda, Michaela Hirschmann, Kohei Inayoshi, Jeyhan S. Kartaltepe, Yana Khusanova, Anton M. Koekemoer, Vasily Kokorev, Rebecca L. Larson, Gene C. K. Leung, Ray A. Lucas, Derek J. McLeod, Lorenzo Napolitano, Masafusa Onoue, Fabio Pacucci, Casey Papovich, Pablo G. Pérez-González, Nor Pirzkal, Rachel S. Somerville, Jonathan R. Trump, Stephen M. Wilkins, L. Y. Aaron Yung, Haowen Zhang","doi":"arxiv-2409.06772","DOIUrl":"https://doi.org/arxiv-2409.06772","url":null,"abstract":"We present a sample of 50 H-alpha detected broad-line active galactic nuclei\u0000(BLAGN) at redshifts 3.5<z<6.8 using data from the CEERS and RUBIES surveys. We\u0000select these sources directly from JWST/NIRSpec G395M/F290LP spectra. We use a\u0000multi-step pre-selection and a Bayesian fitting procedure to ensure a\u0000high-quality sample of sources with broad Balmer lines and narrow forbidden\u0000lines. We compute rest-frame ultraviolet and optical spectral slopes for these\u0000objects, and determine that 10 BLAGN in our sample are also little red dots\u0000(LRDs). These LRD BLAGN, when examined in aggregate, show broader H-alpha line\u0000profiles and a higher fraction of broad-to-narrow component H-alpha emission\u0000than non-LRD BLAGN. Moreover, we find that ~66% of these objects are\u0000intrinsically reddened (beta (optical)>0), independent of the contributions of\u0000emission lines to the broadband photometry. We construct the black hole (BH)\u0000mass function at 3.5<z<6 after computing robust observational and line\u0000detection completeness corrections. This BH mass function shows broad agreement\u0000with both recent JWST/NIRSpec and JWST/NIRCam WFSS based BH mass functions,\u0000though we extend these earlier results to log(M(BH)/M(sun)) < 7. The derived BH\u0000mass function is consistent with a variety of theoretical models, indicating\u0000that the observed abundance of black holes in the early universe is not\u0000discrepant with physically-motivated predictions. The BH mass function shape\u0000resembles a largely featureless power-law, suggesting that any signature from\u0000black-hole seeding has been lost by redshift z~5-6. Finally, we compute the\u0000BLAGN UV luminosity function and find good agreement with JWST-detected BLAGN\u0000samples from recent works, finding that BLAGN hosts constitute <10% of the\u0000total observed UV luminosity at all but the brightest luminosities.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"168 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"No evidence for a significant evolution of $M_{bullet}$-$M_*$ relation up to z$sim$4","authors":"Yang Sun, Jianwei Lyu, George H. Rieke, Zhiyuan Ji, Fengwu Sun, Yongda Zhu, Andrew J. Bunker, Phillip A. Cargile, Chiara Circosta, Francesco D'Eugenio, Eiichi Egami, Kevin Hainline, Jakob M. Helton, Pierluigi Rinaldi, Brant E. Robertson, Jan Scholtz, Irene Shivaei, Meredith A. Stone, Sandro Tacchella, Christina C. Williams, Christopher N. A. Willmer, Chris Willott","doi":"arxiv-2409.06796","DOIUrl":"https://doi.org/arxiv-2409.06796","url":null,"abstract":"Over the past two decades, tight correlations between black hole masses\u0000($M_bullet$) and their host galaxy properties have been firmly established at\u0000low-$z$ ($z<1$), indicating coevolution of supermassive black holes and\u0000galaxies. However, the situation at high-$z$, especially beyond cosmic noon\u0000($zgtrsim2.5$), is controversial. With a combination of emph{JWST}\u0000NIRCam/wide field slitless spectroscopy (WFSS) from FRESCO, CONGRESS and deep\u0000multi-band NIRCam/image data from JADES in the GOODS fields, we study the black\u0000hole to galaxy mass relation at z$sim$1--4. After identifying 18 broad-line\u0000active galactic nuclei (BL AGNs) at $0.9<z<3.6$ (with 8 at $z>2.5$) from the\u0000WFSS data, we measure their black hole masses based on broad near-infrared\u0000lines (Pa $alpha$, Pa $beta$, and He,I $lambda$10833,AA), and constrain\u0000their stellar masses ($M_{*}$) from AGN-galaxy image decomposition or SED\u0000decomposition. Taking account of the observational biases, the intrinsic\u0000scatter of the $M_{bullet}-M_{*}$ relation, and the errors in mass\u0000measurements, we find no significant difference in the $M_{bullet}/M_{*}$\u0000ratio for 2.5 $< $ z $ <$ 3.6 compared to that at lower redshifts ($1 < z <\u00002.5$), suggesting no evolution of the $M_{bullet} - M_{*}$ relation up to\u0000z$sim$4.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"109 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Supermassive black hole feedback quenches disc galaxies and suppresses bar formation in TNG50","authors":"Matthew Frosst, Danail Obreschkow, Aaron Ludlow, Connor Bottrell, Shy Genel","doi":"arxiv-2409.06783","DOIUrl":"https://doi.org/arxiv-2409.06783","url":null,"abstract":"We use the cosmological magneto-hydrodynamical simulation TNG50 to study the\u0000relationship between black hole feedback, the presence of stellar bars, and\u0000star formation quenching in Milky Way-like disc galaxies. Of our sample of 198\u0000discs, about 63 per cent develop stellar bars that last until z=0. After the\u0000formation of their bars, the majority of these galaxies develop persistent 3-15\u0000kpc wide holes in the centres of their gas discs. Tracking their evolution from\u0000z=4 to 0, we demonstrate that barred galaxies tend to form within dark matter\u0000haloes that become centrally disc dominated early on (and are thus unstable to\u0000bar formation) whereas unbarred galaxies do not; barred galaxies also host\u0000central black holes that grow more rapidly than those of unbarred galaxies. As\u0000a result, most barred galaxies eventually experience kinetic wind feedback that\u0000operates when the mass of the central supermassive black hole exceeds $M_{BH} >\u000010^8 M_{odot}$. This feedback ejects gas from the central disc into the\u0000circumgalactic medium and rapidly quenches barred galaxies of their central\u0000star formation. If kinetic black hole feedback occurs in an unbarred disc it\u0000suppresses subsequent star formation and inhibits its growth, stabilising the\u0000disc against future bar formation. Consequently, most barred galaxies develop\u0000black hole-driven gas holes, though a gas hole alone does not guarantee the\u0000presence of a stellar bar. This subtle relationship between black hole\u0000feedback, cold gas disc morphology, and stellar bars may provide constraints on\u0000subgrid physics models for supermassive black hole feedback.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"115 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Intrinsic Flattening of Extragalactic Stellar Disks","authors":"Jeremy FavaroQueen's, Stéphane CourteauQueen's, Sébastien ComérónULL/IAC, Connor StoneUdeM/Ciela/MILA","doi":"arxiv-2409.06768","DOIUrl":"https://doi.org/arxiv-2409.06768","url":null,"abstract":"Highly inclined (edge-on) disk galaxies offer the unique perspective to\u0000constrain their intrinsic flattening, $c/a$, where $c$ and $a$ are respectively\u0000the vertical and long radial axes of the disk measured at suitable stellar\u0000densities. The ratio $c/a$ is a necessary quantity in the assessment of galaxy\u0000inclinations, three-dimensional structural reconstructions, total masses, as\u0000well as a constraint to galaxy formation models. 3.6 micron maps of 133 edge-on\u0000spiral galaxies from the Spitzer Survey of Stellar Structure in Galaxies (S4G)\u0000and its early-type galaxy extension are used to revisit the assessment of $c/a$\u0000free from dust extinction and away from the influence of a stellar bulge. We\u0000present a simple definition of $c/a$ and explore trends with other galactic\u0000physical parameters: total stellar mass, concentration index, total HI mass,\u0000mass of the central mass concentration, circular velocity, model-dependent\u0000scales, as well as Hubble type. Other than a dependence on early/late Hubble\u0000types, and a related trend with light concentration, no other parameters were\u0000found to correlate with the intrinsic flattening of spiral galaxies. The latter\u0000is mostly constant with $langle c/a rangle$ = 0.124 $pm$ 0.001 (stat) $pm$\u00000.033 (intrinsic/systematic) and greater for earlier types.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The molecular gas content throughout the low-z merger sequence","authors":"Mark T. Sargent, S. L. Ellison, J. T. Mendel, A. Saintonge, D. Cs. Molnár, J. M. Scudder, G. Violino","doi":"arxiv-2409.06572","DOIUrl":"https://doi.org/arxiv-2409.06572","url":null,"abstract":"Exploiting IRAM 30 m CO spectroscopy, we find that SDSS post-merger galaxies\u0000display gas fractions and depletion times enhanced by 25-50%, a mildly higher\u0000CO excitation, and standard molecular-to-atomic gas ratios, compared to\u0000non-interacting galaxies with similar redshift, stellar mass ($M_{star}$) and\u0000star-formation rate (SFR). To place these results in context, we compile\u0000further samples of interacting or starbursting galaxies, from pre-coalescence\u0000kinematic pairs to post-starbursts, carefully homogenising gas mass,\u0000$M_{star}$ and SFR measurements in the process. We explore systematics by\u0000duplicating our analysis for different SFR and $M_{star}$ estimators, finding\u0000good qualitative agreement in general. Molecular gas fractions and depletion\u0000times are enhanced in interacting pairs, albeit less than for post-mergers.\u0000Among all samples studied, gas fraction and depletion time enhancements appear\u0000largest in young (a few 100 Myr) post-starbursts. While there is only partial\u0000overlap between post-mergers and post-starbursts, this suggests that molecular\u0000gas reservoirs are boosted throughout most stages of galaxy interactions,\u0000plausibly due to torque-driven inflows of halo gas and gas compression. The gas\u0000fraction and depletion time offsets of mergers and post-starbursts\u0000anti-correlate with their distance from the galaxy main sequence $Delta({rm\u0000MS})$, evidencing the role of SFE in driving the high SFRs of the strongest\u0000starbursts. Post-starbursts display the steepest dependency of gas fraction and\u0000SFE-offsets on $Delta({rm MS})$, with an evolving normalisation that reflects\u0000gas reservoir depletion over time. Our multi-sample analysis paints a coherent\u0000picture of the starburst-merger throughout the low-z merger sequence. It\u0000reconciles contradictory literature findings by highlighting that gas fraction\u0000enhancements and SFE variations both play their part in merger-driven star\u0000formation.","PeriodicalId":501187,"journal":{"name":"arXiv - PHYS - Astrophysics of Galaxies","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}