Star Formation Efficiency in Nearby Galaxies Revealed with a New CO-to-H2 Conversion Factor Prescription
Determining how the galactic environment, especially the high gas densities and complex dynamics in bar-fed galaxy centers, alters the star formation efficiency (SFE) of molecular gas is critical to understanding galaxy evolution. However, these same physical or dynamical effects also alter the emis...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad10ae |
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| author | Yu-Hsuan Teng I-Da Chiang Karin M. Sandstrom Jiayi Sun Adam K. Leroy Alberto D. Bolatto Antonio Usero Eve C. Ostriker Miguel Querejeta Jérémy Chastenet Frank Bigiel Médéric Boquien Jakob den Brok Yixian Cao Mélanie Chevance Ryan Chown Dario Colombo Cosima Eibensteiner Simon C. O. Glover Kathryn Grasha Jonathan D. Henshaw María J. Jiménez-Donaire Daizhong Liu Eric J. Murphy Hsi-An Pan Sophia K. Stuber Thomas G. Williams |
| author_facet | Yu-Hsuan Teng I-Da Chiang Karin M. Sandstrom Jiayi Sun Adam K. Leroy Alberto D. Bolatto Antonio Usero Eve C. Ostriker Miguel Querejeta Jérémy Chastenet Frank Bigiel Médéric Boquien Jakob den Brok Yixian Cao Mélanie Chevance Ryan Chown Dario Colombo Cosima Eibensteiner Simon C. O. Glover Kathryn Grasha Jonathan D. Henshaw María J. Jiménez-Donaire Daizhong Liu Eric J. Murphy Hsi-An Pan Sophia K. Stuber Thomas G. Williams |
| author_sort | Yu-Hsuan Teng |
| collection | DOAJ |
| description | Determining how the galactic environment, especially the high gas densities and complex dynamics in bar-fed galaxy centers, alters the star formation efficiency (SFE) of molecular gas is critical to understanding galaxy evolution. However, these same physical or dynamical effects also alter the emissivity properties of CO, leading to variations in the CO-to-H _2 conversion factor ( α _CO ) that impact the assessment of the gas column densities and thus of the SFE. To address such issues, we investigate the dependence of α _CO on the local CO velocity dispersion at 150 pc scales using a new set of dust-based α _CO measurements and propose a new α _CO prescription that accounts for CO emissivity variations across galaxies. Based on this prescription, we estimate the SFE in a sample of 65 galaxies from the PHANGS–Atacama Large Millimeter/submillimeter Array survey. We find increasing SFE toward high-surface-density regions like galaxy centers, while using a constant or metallicity-based α _CO results in a more homogeneous SFE throughout the centers and disks. Our prescription further reveals a mean molecular gas depletion time of 700 Myr in the centers of barred galaxies, which is overall three to four times shorter than in nonbarred galaxy centers or the disks. Across the galaxy disks, the depletion time is consistently around 2–3 Gyr, regardless of the choice of α _CO prescription. All together, our results suggest that the high level of star formation activity in barred centers is not simply due to an increased amount of molecular gas, but also to an enhanced SFE compared to nonbarred centers or disk regions. |
| first_indexed | 2024-03-08T14:28:46Z |
| format | Article |
| id | doaj.art-227ad380121f4c09bd90d8e2ae191b68 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-08T14:28:46Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-227ad380121f4c09bd90d8e2ae191b682024-01-12T15:09:32ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0196114210.3847/1538-4357/ad10aeStar Formation Efficiency in Nearby Galaxies Revealed with a New CO-to-H2 Conversion Factor PrescriptionYu-Hsuan Teng0https://orcid.org/0000-0003-4209-1599I-Da Chiang1https://orcid.org/0000-0003-2551-7148Karin M. Sandstrom2https://orcid.org/0000-0002-4378-8534Jiayi Sun3https://orcid.org/0000-0003-0378-4667Adam K. Leroy4https://orcid.org/0000-0002-2545-1700Alberto D. Bolatto5https://orcid.org/0000-0002-5480-5686Antonio Usero6https://orcid.org/0000-0003-1242-505XEve C. Ostriker7https://orcid.org/0000-0002-0509-9113Miguel Querejeta8https://orcid.org/0000-0002-0472-1011Jérémy Chastenet9https://orcid.org/0000-0002-5235-5589Frank Bigiel10https://orcid.org/0000-0003-0166-9745Médéric Boquien11https://orcid.org/0000-0003-0946-6176Jakob den Brok12https://orcid.org/0000-0002-8760-6157Yixian Cao13https://orcid.org/0000-0001-5301-1326Mélanie Chevance14https://orcid.org/0000-0002-5635-5180Ryan Chown15https://orcid.org/0000-0001-8241-7704Dario Colombo16https://orcid.org/0000-0001-6498-2945Cosima Eibensteiner17https://orcid.org/0000-0002-1185-2810Simon C. O. Glover18https://orcid.org/0000-0001-6708-1317Kathryn Grasha19https://orcid.org/0000-0002-3247-5321Jonathan D. Henshaw20https://orcid.org/0000-0001-9656-7682María J. Jiménez-Donaire21https://orcid.org/0000-0002-9165-8080Daizhong Liu22https://orcid.org/0000-0001-9773-7479Eric J. Murphy23https://orcid.org/0000-0001-7089-7325Hsi-An Pan24https://orcid.org/0000-0002-1370-6964Sophia K. Stuber25https://orcid.org/0000-0002-9333-387XThomas G. Williams26https://orcid.org/0000-0002-0012-2142Center for Astrophysics and Space Sciences, Department of Physics, University of California San Diego , 9500 Gilman Drive, La Jolla, CA 92093, USA ; yuteng@ucsd.eduInstitute of Astronomy and Astrophysics , Academia Sinica, No. 1, Section 4, Roosevelt Road, Taipei 10617, TaiwanCenter for Astrophysics and Space Sciences, Department of Physics, University of California San Diego , 9500 Gilman Drive, La Jolla, CA 92093, USA ; yuteng@ucsd.edu; Department of Astronomy & Astrophysics, University of California San Diego , 9500 Gilman Drive, La Jolla, CA 92093, USADepartment of Physics and Astronomy, McMaster University , 1280 Main Street West, Hamilton, ON, L8S 4M1, Canada; Canadian Institute for Theoretical Astrophysics (CITA), University of Toronto , 60 St George Street, Toronto, ON, M5S 3H8, Canada; Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08544, USADepartment of Astronomy, The Ohio State University , 140 West 18th Avenue, Columbus, OH 43210, USADepartment of Astronomy, University of Maryland , College Park, MD 20742, USAObservatorio Astronómico Nacional (IGN) , C/Alfonso XII, 3, E-28014 Madrid, SpainDepartment of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08544, USAObservatorio Astronómico Nacional (IGN) , C/Alfonso XII, 3, E-28014 Madrid, SpainSterrenkundig Observatorium, Universiteit Gent , Krijgslaan 281 S9, B-9000 Gent, BelgiumArgelander-Institut für Astronomie, Universität Bonn , Auf dem Hügel 71, D-53121 Bonn, GermanyInstituto de Alta Investigación, Universidad de Tarapacá , Casilla 7D, Arica, ChileCenter for Astrophysics | Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USAMax-Planck-Institut für extraterrestrische Physik , Giessenbachstraße 1, D-85748 Garching, GermanyUniversität Heidelberg , Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Str 2, D-69120 Heidelberg, Germany; Cosmic Origins Of Life (COOL) Research DAO , coolresearch.io, GermanyDepartment of Astronomy, The Ohio State University , 140 West 18th Avenue, Columbus, OH 43210, USAArgelander-Institut für Astronomie, Universität Bonn , Auf dem Hügel 71, D-53121 Bonn, GermanyArgelander-Institut für Astronomie, Universität Bonn , Auf dem Hügel 71, D-53121 Bonn, GermanyUniversität Heidelberg , Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Str 2, D-69120 Heidelberg, GermanyCenter for Astrophysics | Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA; Research School of Astronomy and Astrophysics, Australian National University , Canberra, ACT 2611, Australia; ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) , AustraliaAstrophysics Research Institute, Liverpool John Moores University , 146 Brownlow Hill, Liverpool, L3 5RF, UK; Max-Planck-Institut für Astronomie , Königstuhl 17, D-69117, Heidelberg, GermanyObservatorio Astronómico Nacional (IGN) , C/Alfonso XII, 3, E-28014 Madrid, Spain; Centro de Desarrollos Tecnológicos , Observatorio de Yebes (IGN), E-19141 Yebes, Guadalajara, SpainMax-Planck-Institut für extraterrestrische Physik , Giessenbachstraße 1, D-85748 Garching, GermanyNational Radio Astronomy Observatory , 520 Edgemont Road, Charlottesville, VA 22903-2475, USADepartment of Physics, Tamkang University , No.151, Yingzhuan Road, Tamsui District, New Taipei City 251301, TaiwanMax-Planck-Institut für Astronomie , Königstuhl 17, D-69117, Heidelberg, GermanySub-department of Astrophysics, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UKDetermining how the galactic environment, especially the high gas densities and complex dynamics in bar-fed galaxy centers, alters the star formation efficiency (SFE) of molecular gas is critical to understanding galaxy evolution. However, these same physical or dynamical effects also alter the emissivity properties of CO, leading to variations in the CO-to-H _2 conversion factor ( α _CO ) that impact the assessment of the gas column densities and thus of the SFE. To address such issues, we investigate the dependence of α _CO on the local CO velocity dispersion at 150 pc scales using a new set of dust-based α _CO measurements and propose a new α _CO prescription that accounts for CO emissivity variations across galaxies. Based on this prescription, we estimate the SFE in a sample of 65 galaxies from the PHANGS–Atacama Large Millimeter/submillimeter Array survey. We find increasing SFE toward high-surface-density regions like galaxy centers, while using a constant or metallicity-based α _CO results in a more homogeneous SFE throughout the centers and disks. Our prescription further reveals a mean molecular gas depletion time of 700 Myr in the centers of barred galaxies, which is overall three to four times shorter than in nonbarred galaxy centers or the disks. Across the galaxy disks, the depletion time is consistently around 2–3 Gyr, regardless of the choice of α _CO prescription. All together, our results suggest that the high level of star formation activity in barred centers is not simply due to an increased amount of molecular gas, but also to an enhanced SFE compared to nonbarred centers or disk regions.https://doi.org/10.3847/1538-4357/ad10aeCO line emissionDisk galaxiesGalaxy nucleiGiant molecular cloudsStar formation |
| spellingShingle | Yu-Hsuan Teng I-Da Chiang Karin M. Sandstrom Jiayi Sun Adam K. Leroy Alberto D. Bolatto Antonio Usero Eve C. Ostriker Miguel Querejeta Jérémy Chastenet Frank Bigiel Médéric Boquien Jakob den Brok Yixian Cao Mélanie Chevance Ryan Chown Dario Colombo Cosima Eibensteiner Simon C. O. Glover Kathryn Grasha Jonathan D. Henshaw María J. Jiménez-Donaire Daizhong Liu Eric J. Murphy Hsi-An Pan Sophia K. Stuber Thomas G. Williams Star Formation Efficiency in Nearby Galaxies Revealed with a New CO-to-H2 Conversion Factor Prescription The Astrophysical Journal CO line emission Disk galaxies Galaxy nuclei Giant molecular clouds Star formation |
| title | Star Formation Efficiency in Nearby Galaxies Revealed with a New CO-to-H2 Conversion Factor Prescription |
| title_full | Star Formation Efficiency in Nearby Galaxies Revealed with a New CO-to-H2 Conversion Factor Prescription |
| title_fullStr | Star Formation Efficiency in Nearby Galaxies Revealed with a New CO-to-H2 Conversion Factor Prescription |
| title_full_unstemmed | Star Formation Efficiency in Nearby Galaxies Revealed with a New CO-to-H2 Conversion Factor Prescription |
| title_short | Star Formation Efficiency in Nearby Galaxies Revealed with a New CO-to-H2 Conversion Factor Prescription |
| title_sort | star formation efficiency in nearby galaxies revealed with a new co to h2 conversion factor prescription |
| topic | CO line emission Disk galaxies Galaxy nuclei Giant molecular clouds Star formation |
| url | https://doi.org/10.3847/1538-4357/ad10ae |
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