The Main Sequence at z ∼ 1.3 Contains a Sizable Fraction of Galaxies with Compact Star Formation Sizes: A New Population of Early Post-starbursts?

被引：52

作者：

Puglisi, A. ^{[1
,2
]}

Daddi, E. ^{[1
]}

Liu, D. ^{[3
]}

Bournaud, F. ^{[1
]}

Silverman, J. D. ^{[4
,5
]}

Circosta, C. ^{[6
]}

Calabro, A. ^{[1
]}

Aravena, M. ^{[7
]}

Cibinel, A. ^{[8
]}

Dannerbauer, H. ^{[9
,10
]}

Delvecchio, I ^{[1
]}

Elbaz, D. ^{[1
]}

Gao, Y. ^{[11
]}

Gobat, R. ^{[12
]}

Jin, S. ^{[13
]}

Le Floc'h, E. ^{[1
]}

Magdis, G. E. ^{[14
,15
,16
,17
]}

Mancini, C. ^{[2
,18
]}

Riechers, D. A. ^{[3
,19
]}

Rodighiero, G. ^{[2
,18
]}

Sargent, M. ^{[8
]}

Valentino, F. ^{[14
,15
]}

Zanist, L. ^{[20
]}

机构：

[1] Univ Paris Diderot, Univ Paris Saclay, Sorbonne Paris Cite, CEA,IRFU,DAp,AIM,CNRS, F-91191 Gif Sur Yvette, France

[2] INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy

[3] Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany

[4] Univ Tokyo, Kavli Inst Phys & Math Universe WPI, Todai Inst Adv Study, Kashiwa, Chiba 2778583, Japan

[5] Univ Tokyo, Sch Sci, Dept Astron, Bunkyo Ku, 7-3-1 Hongo, Tokyo 1130033, Japan

[6] ESO, Karl Schwarschild Str 2, D-85748 Garching, Germany

[7] Univ Diego Portales, Fac Ingn, Nucleo Astron, Av Ejercito 441, Santiago, Chile

[8] Univ Sussex, Astron Ctr, Dept Phys & Astron, Brighton BN1 9QH, E Sussex, England

[9] IAC, E-38205 Tenerife, Spain

[10] Univ La Laguna, Dept Astrofis, E-38206 Tenerife, Spain

[11] Chinese Acad Sci, Key Lab Radio Astron, Purple Mt Observ, Nanjing 210034, Jiangsu, Peoples R China

[12] Pontificia Univ Catolica Valparaiso, Inst Fis, Casilla 4059, Valparaiso, Chile

[13] Nanjing Univ, Sch Astron & Space Sci, Minist Educ, Key Lab Modern Astron & Astrophys, Nanjing 210093, Jiangsu, Peoples R China

[14] Univ Copenhagen, Niels Bohr Inst, Cosm Dawn Ctr, Copenhagen, Denmark

[15] Tech Univ Denmark, DTU Space, Lyngby, Denmark

[16] Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen O, Denmark

[17] Natl Observ Athens, Inst Astron Astrophys Space Applicat & Remote Sen, Athens 15236, Greece

[18] Univ Padua, Dipartimento Fis & Astron, Vicolo Osservatorio 2, I-35122 Padua, Italy

[19] Cornell Univ, Space Sci Bldg, Ithaca, NY 14853 USA

[20] Univ Southampton, Dept Phys & Astron, Highfield SO17 1BJ, England

来源：

ASTROPHYSICAL JOURNAL LETTERS | 2019年 / 877卷 / 02期

基金：

美国国家科学基金会; 新加坡国家研究基金会; 国家重点研发计划;

关键词：

galaxies: evolution; galaxies: high-redshift; galaxies: interactions; galaxies: ISM; galaxies: star formation; MAJOR MERGERS; EMISSION;

D O I：

10.3847/2041-8213/ab1f92

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Atacama Large Millimeter/submillimeter Array (ALMA) measurements for 93 Herschel-selected galaxies at 1.1 <= z <= 1.7 in COSMOS reveal a sizable (>29%) population with compact star formation (SF) sizes, lying on average > x 3.6 below the optical stellar mass (M-*)-size relation of disks. This sample widely spans the star-forming main sequence (MS), having 10(8) <= M-* <= 10(11.5 )M(circle dot) and 20 star formation rate (SFR) <= 680 M-circle dot yr(-1). The 32 size measurements and 61 upper limits are measured on ALMA images that combine observations of CO(5-4), CO(4-3), CO(2-1), and lambda(obs )similar to 1.1-1.3 mm continuum, all tracing the star-forming molecular gas. These compact galaxies have instead normally extended K-band sizes, suggesting strong specific SFR gradients. Compact galaxies comprise the 50 +/- 18% of MS galaxies at M-* > 10(11) M-circle dot. This is not expected in standard bimodal scenarios, where MS galaxies are mostly steadily growing extended disks. We suggest that compact MS objects are early post-starburst galaxies in which the merger-driven boost of SF has subsided. They retain their compact SF size until either further gas accretion restores premerger galaxy-wide SF, or until becoming quenched. The fraction of merger-affected SF inside the MS seems thus larger than anticipated and might reach similar to 50% at the highest M-*. The presence of large galaxies above the MS demonstrates an overall poor correlation between galaxy SF size and specific SFR.

引用

页数：6