The ALMaQUEST Survey. XII. Dense Molecular Gas as Traced by HCN and HCO+ in Green Valley Galaxies
We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of two dense gas tracers, HCN (1−0) and HCO ^+ (1-0) for three galaxies in the green valley and two galaxies on the star-forming main sequence with comparable molecular gas fractions as traced by the CO (1−0) emissions, sele...
| Main Authors: | , , , , , , , , , , , , , |
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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/ad18b9 |
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| author | Lihwai Lin Hsi-An Pan Sara L. Ellison Nanase Harada María J. Jiménez-Donaire K. Decker French William M. Baker Bau-Ching Hsieh Yusei Koyama Carlos López-Cobá Tomonari Michiyama Kate Rowlands Sebastián F. Sánchez Mallory D. Thorp |
| author_facet | Lihwai Lin Hsi-An Pan Sara L. Ellison Nanase Harada María J. Jiménez-Donaire K. Decker French William M. Baker Bau-Ching Hsieh Yusei Koyama Carlos López-Cobá Tomonari Michiyama Kate Rowlands Sebastián F. Sánchez Mallory D. Thorp |
| author_sort | Lihwai Lin |
| collection | DOAJ |
| description | We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of two dense gas tracers, HCN (1−0) and HCO ^+ (1-0) for three galaxies in the green valley and two galaxies on the star-forming main sequence with comparable molecular gas fractions as traced by the CO (1−0) emissions, selected from the ALMaQUEST survey. We investigate whether the deficit of molecular gas star formation efficiency (SFE _mol ) that leads to the low specific star formation rate (sSFR) in these green valley galaxies is due to a lack of dense gas (characterized by the dense gas fraction f _dense ) or the low star formation efficiency of dense gas (SFE _dense ). We find that SFE _mol as traced by the CO emissions, when considering both star-forming and retired spaxels together, is tightly correlated with SFE _dense and depends only weakly on f _dense . The sSFR on kiloparsec scales is primarily driven by SFE _mol and SFE _dense , followed by the dependence on f _mol , and is least correlated with f _dense or the dense-gas-to-stellar mass ratio ( R _dense ). When compared with other works in the literature, we find that our green valley sample shows lower global SFE _mol and lower SFE _dense while exhibiting similar dense gas fractions when compared to star-forming and starburst galaxies. We conclude that the star formation of the three green valley galaxies with a normal abundance of molecular gas is suppressed, mainly due to the reduced SFE _dense rather than the lack of dense gas. |
| first_indexed | 2024-03-07T15:10:53Z |
| format | Article |
| id | doaj.art-341a3fea52a24010831e1e2e539ef01f |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-07T15:10:53Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-341a3fea52a24010831e1e2e539ef01f2024-03-05T18:39:28ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-01963211510.3847/1538-4357/ad18b9The ALMaQUEST Survey. XII. Dense Molecular Gas as Traced by HCN and HCO+ in Green Valley GalaxiesLihwai Lin0https://orcid.org/0000-0001-7218-7407Hsi-An Pan1https://orcid.org/0000-0002-1370-6964Sara L. Ellison2https://orcid.org/0000-0002-1768-1899Nanase Harada3María J. Jiménez-Donaire4K. Decker French5https://orcid.org/0000-0002-4235-7337William M. Baker6https://orcid.org/0000-0003-0215-1104Bau-Ching Hsieh7https://orcid.org/0000-0001-5615-4904Yusei Koyama8https://orcid.org/0000-0002-0479-3699Carlos López-Cobá9Tomonari Michiyama10https://orcid.org/0000-0003-2475-7983Kate Rowlands11https://orcid.org/0000-0001-7883-8434Sebastián F. Sánchez12https://orcid.org/0000-0001-6444-9307Mallory D. Thorp13Institute of Astronomy & Astrophysics , Academia Sinica, Taipei 10617, Taiwan ; lihwailin@asiaa.sinica.edu.twDepartment of Physics, Tamkang University , No.151, Yingzhuan Road, Tamsui District, New Taipei City 251301, TaiwanDepartment of Physics & Astronomy, University of Victoria , Finnerty Road, Victoria, BC V8P 1A1, CanadaNational Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Astronomical Science Program , Graduate Institute for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo, 181-1855 JapanObservatorio Astronómico Nacional (IGN) , C/Alfonso XII, 3, 28014E-28014 Madrid, Spain; Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), E-19141 Yebes, Guadalajara, SpainDepartment of Astronomy, University of Illinois , 1002 W. Green Street, Urbana, IL 61801, USACavendish Laboratory, University of Cambridge , 19 J.J. Thomson Avenue, Cambridge CB3 0HE, UK; Kavli Institute for Cosmology, University of Cambridge , Madingley Road, Cambridge, CB3 OHA, UKInstitute of Astronomy & Astrophysics , Academia Sinica, Taipei 10617, Taiwan ; lihwailin@asiaa.sinica.edu.twAstronomical Science Program , Graduate Institute for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo, 181-1855 Japan; Subaru Telescope, National Astronomical Observatory of Japan , 650 North Aóhoku Place, Hilo, HI 96720, USAInstitute of Astronomy & Astrophysics , Academia Sinica, Taipei 10617, Taiwan ; lihwailin@asiaa.sinica.edu.twFaculty of Welfare and Information, Shunan University , 43-4-2 Gakuendai, Shunan, Yamaguchi, 745-8566, JapanSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USAInstituto de Astronomía, Universidad Nacional Autónoma de México , Circuito Exterior, Ciudad Universitaria, Ciudad de México 04510, MexicoArgelander-Institut für Astronomie, Universität Bonn , Auf dem Hügel 71, D-53121 Bonn, GermanyWe present Atacama Large Millimeter/submillimeter Array (ALMA) observations of two dense gas tracers, HCN (1−0) and HCO ^+ (1-0) for three galaxies in the green valley and two galaxies on the star-forming main sequence with comparable molecular gas fractions as traced by the CO (1−0) emissions, selected from the ALMaQUEST survey. We investigate whether the deficit of molecular gas star formation efficiency (SFE _mol ) that leads to the low specific star formation rate (sSFR) in these green valley galaxies is due to a lack of dense gas (characterized by the dense gas fraction f _dense ) or the low star formation efficiency of dense gas (SFE _dense ). We find that SFE _mol as traced by the CO emissions, when considering both star-forming and retired spaxels together, is tightly correlated with SFE _dense and depends only weakly on f _dense . The sSFR on kiloparsec scales is primarily driven by SFE _mol and SFE _dense , followed by the dependence on f _mol , and is least correlated with f _dense or the dense-gas-to-stellar mass ratio ( R _dense ). When compared with other works in the literature, we find that our green valley sample shows lower global SFE _mol and lower SFE _dense while exhibiting similar dense gas fractions when compared to star-forming and starburst galaxies. We conclude that the star formation of the three green valley galaxies with a normal abundance of molecular gas is suppressed, mainly due to the reduced SFE _dense rather than the lack of dense gas.https://doi.org/10.3847/1538-4357/ad18b9Galaxy evolutionGreen valley galaxiesMolecular gas |
| spellingShingle | Lihwai Lin Hsi-An Pan Sara L. Ellison Nanase Harada María J. Jiménez-Donaire K. Decker French William M. Baker Bau-Ching Hsieh Yusei Koyama Carlos López-Cobá Tomonari Michiyama Kate Rowlands Sebastián F. Sánchez Mallory D. Thorp The ALMaQUEST Survey. XII. Dense Molecular Gas as Traced by HCN and HCO+ in Green Valley Galaxies The Astrophysical Journal Galaxy evolution Green valley galaxies Molecular gas |
| title | The ALMaQUEST Survey. XII. Dense Molecular Gas as Traced by HCN and HCO+ in Green Valley Galaxies |
| title_full | The ALMaQUEST Survey. XII. Dense Molecular Gas as Traced by HCN and HCO+ in Green Valley Galaxies |
| title_fullStr | The ALMaQUEST Survey. XII. Dense Molecular Gas as Traced by HCN and HCO+ in Green Valley Galaxies |
| title_full_unstemmed | The ALMaQUEST Survey. XII. Dense Molecular Gas as Traced by HCN and HCO+ in Green Valley Galaxies |
| title_short | The ALMaQUEST Survey. XII. Dense Molecular Gas as Traced by HCN and HCO+ in Green Valley Galaxies |
| title_sort | almaquest survey xii dense molecular gas as traced by hcn and hco in green valley galaxies |
| topic | Galaxy evolution Green valley galaxies Molecular gas |
| url | https://doi.org/10.3847/1538-4357/ad18b9 |
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