Large molecular gas reservoirs in ancestors of Milky Way-mass galaxies nine billion years ago

被引：0
作者：
C. Papovich
I. Labbé
K. Glazebrook
R. Quadri
G. Bekiaris
M. Dickinson
S. L. Finkelstein
D. Fisher
H. Inami
R. C. Livermore
L. Spitler
C. Straatman
K.-V. Tran
机构：
[1] George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy,Department of Physics and Astronomy
[2] Texas A&M University,Department of Astronomy
[3] Texas A&M University,Department of Physics & Astronomy
[4] Leiden Observatory,undefined
[5] Leiden University,undefined
[6] Centre for Astrophysics & Supercomputing,undefined
[7] Swinburne University,undefined
[8] National Optical Astronomy Observatory,undefined
[9] The University of Texas at Austin,undefined
[10] Centre de Recherche Astrophysique de Lyon,undefined
[11] Université de Lyon,undefined
[12] Université Lyon 1,undefined
[13] CNRS,undefined
[14] Observatoire de Lyon,undefined
[15] Macquarie University,undefined
[16] Australian Astronomical Observatory,undefined
来源：
Nature Astronomy | / 1卷
关键词：
D O I：
暂无
中图分类号：
学科分类号：
摘要：
The gas accretion and star formation histories of galaxies like the Milky Way remain an outstanding problem in astrophysics1,2. Observations show that 8 billion years ago, the progenitors to Milky Way-mass galaxies were forming stars 30 times faster than today and were predicted to be rich in molecular gas3, in contrast to the low present-day gas fractions (<10%)4–6. Here we show the detection of molecular gas from the CO (J = 3–2) emission (rest-frame 345.8 GHz) in galaxies at redshifts z = 1.2–1.3, selected to have the stellar mass and star formation rate of the progenitors of today’s Milky Way-mass galaxies. The CO emission reveals large molecular gas masses, comparable to or exceeding the galaxy stellar masses, and implying that most of the baryons are in cold gas, not stars. The total luminosities of the galaxies from star formation and CO luminosities yield long gas consumption timescales. Compared to local spiral galaxies, the star formation efficiency, estimated from the ratio of total infrared luminosity (LIR) to CO emission, has remained nearly constant since redshift z = 1.2, despite the order of magnitude decrease in gas fraction, consistent with the results for other galaxies at this epoch7–10. Therefore, the physical processes that determine the rate at which gas cools to form stars in distant galaxies appear to be similar to that in local galaxies.
引用
收藏
相关论文
共 92 条
  • [1] Guedes J(2011)Forming realistic late-type spirals in a ΛCDM universe: the Eris simulation Astrophys. J. 742 76-136
  • [2] Callegari S(2012)A diversity of progenitors and histories for isolated spiral galaxies Astrophys. J. 756 26-4696
  • [3] Madau P(2015)ZFOURGE/CANDELS: on the evolution of Astrophys. J. 803 26-60
  • [4] Mayer L(1993)* galaxy progenitors from Astron. Astrophys. 272 123-707
  • [5] Martig M(2009) =3 to 0.5 Astron. J. 137 4670-L117
  • [6] Bournaud F(2011)Molecular gas in nearby galaxies. I: CO observations of a distance-limited sample Mon. Not. R. Astron. Soc 415 32-987
  • [7] Croton DJ(2010)Heracles: The HERA CO line extragalactic survey Astrophys. J. 713 686-454
  • [8] Dekel A(2012)COLD GASS, an IRAM legacy survey of molecular gas in massive galaxies. I: relations between H Astrophys. J. 758 L9-789
  • [9] Teyssier R(2012), H Astron. Astrophys. 548 A22-784
  • [10] Papovich C(2013), stellar content and structural properties Astrophys. J. 768 74-2169
12345678910