Vigorous Star Formation with Low Efficiency in Massive Disk Galaxies at z = 1.5

By E. Daddi, H. Dannerbauer, D. Elbaz, Mark Dickinson, G. Morrison, Daniel Stern, S. Ravindranath. 2007

185 citations recorded by the source corpus.

We present the first detection of molecular gas cooling CO emission lines from ordinary massive galaxies at z = 1.5. Two sources were observed with the IRAM Plateau de Bure Interferometer, selected to lie in the mass-star formation rate correlation at their redshift, thus being representative of massive high-z galaxies. Both sources were detected with high confidence, yielding L′CO ∼ 2 × 1010 K km s−1 pc2. For one of the sources we find evidence of velocity shear, implying CO sizes of ~10 kpc. With an infrared luminosity of LFIR ∼ 1012 L☉, these disklike galaxies are borderline ULIRGs but with star formation efficiency similar to that of local spirals, and an order of magnitude lower than that in submillimeter galaxies. This suggests a CO to total gas conversion factor similar to local spirals, gas consumption timescales approaching 1 Gyr or longer, and molecular gas masses reaching ~1011 M☉, comparable to or larger than the estimated stellar masses. These results support a major role of in situ gas consumption over cosmological timescales and with relatively low star formation efficiency, analogous to that of local spiral disks, for the formation of today’s most massive galaxies and their central black holes. Given the high space density of similar galaxies, ~10−4 Mpc−3, this implies a widespread presence of gas-rich galaxies in the early universe, many of which might be within reach of detailed investigations of current and planned facilities.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/a226190ed7e59caf756ddda86172db6ceb4146b9

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In Astronomy and Astrophysics

1. P. Hopkins
2. L. Hernquist
3. A. Dekel
4. R. Dav'e
5. R. Somerville
6. D. M. Alexander
7. D. Narayanan
8. Thomas J. Cox

Citations in the corpus

• Rotational support of giant clumps in high-z disc galaxies (2011, background): “…the molecular gas to baryon fraction in the high-redshift discs, based on CO measurements, range from 0.2 to 0.8, with an average of∼ 0.4 − 0.6 at z ∼ 2 (Daddi et al. 2008, 2010; Tacconi et al. 2010), systematically higher than the molecular gas fraction of∼ 0.05 − 0.1 in today’s discs (Saintonge…”
• Cool Gas in High-Redshift Galaxies (2013, background): “All galaxies were detected in CO emission, implying large reservoirs of molecular gas in galaxies that are not forming stars at the extreme rates seen in quasars and SMGs (Daddi et al. 2008; 2010).”
• THE HIDDEN “AGN MAIN SEQUENCE”: EVIDENCE FOR A UNIVERSAL BLACK HOLE ACCRETION TO STAR FORMATION RATE RATIO SINCE z ∼ 2 PRODUCING AN MBH–M* RELATION (2012, background): “The rise of the specific growth of galaxies with redshift has recently been attributed to the strong increase in the gas fractions of galaxies from z = 0 to 2 (Daddi et al. 2008, 2010; Tacconi et al. 2010; Geach et al. 2011).”
• VERY HIGH GAS FRACTIONS AND EXTENDED GAS RESERVOIRS IN z = 1.5 DISK GALAXIES (2009, methodology): “We notice that in Daddi et al. (2008) we used the results of Yao et al. (2003) to define a bona fide comparison sample of local spirals, following Solomon & van den Bout (2005) and Greve et al. (2005).”
• DIFFERENT STAR FORMATION LAWS FOR DISKS VERSUS STARBURSTS AT LOW AND HIGH REDSHIFTS (2010, background): “RELATIONS BETWEEN IR LUMINOSITY AND GAS MASSES In this letter, we explore the validity of the SF law further by including new observations of CO emission in distant near-IR selected galaxies atz= 0.5 andz= 1.5 (Daddi et al. 2008, 2010, Salmi et al. in preparation).”
• TWO BRIGHT SUBMILLIMETER GALAXIES IN A z = 4.05 PROTOCLUSTER IN GOODS-NORTH, AND ACCURATE RADIO-INFRARED PHOTOMETRIC REDSHIFTS (2008, methodology): “Daddi et al. (2008) presented the CO[2-1] detection of the BzK galaxy with the D-configuration data.”
• THE LESSER ROLE OF STARBURSTS IN STAR FORMATION AT z = 2 (2011, background): “Observations of the CO molecular gas content of MS galaxies indicate that their star formation efficiency does not depend strongly on cosmic epoch to z ∼ 2, with the SFR increase being due to higher molecular gas fractions (Daddi et al. 2008; 2010a; Tacconi et al. 2010; Geach et al. 2011).”
• Tracing the molecular gas in distant submillimetre galaxies via CO(1-0) imaging with the EVLA (2010, background): “More recently, CO surveys of gas-rich disc galaxies at z = 1–2 (Daddi et al. 2008, 2010; Dannerbauer et al. 2009; Genzel et al. 2010) have shown that they too obey a S–K-like relation, albeit apparently offset from the SMGs (lower LIR/L′CO).”
• Evolution of the dust emission of massive galaxies up to z=4 and constraints on their dominant mode of star formation (2014, background): “Large gas reservoirs have been found in massive galaxies at high redshift (e.g., Daddi et al. 2008, 2010a; Tacconi et al. 2010, 2013; Aravena et al. 2013), which could Appendices are available in electronic form at http://www.aanda.org imply high SFRs with SFE similar to that of normal star-forming…”
• GOODS-Herschel: the far-infrared view of star formation in active galactic nucleus host galaxies since z ≈ 3 (2011, background): “However, this interpr tation would be difficult to reconcile with emerging evidence that long lived, internal processes were the main driver for star formation at these high redshifts (e.g., Daddi et al. 2008, 2010a).”
• THE SINS SURVEY: MODELING THE DYNAMICS OF z ∼ 2 GALAXIES AND THE HIGH-z TULLY–FISHER RELATION (2009, result): “The gas fraction estimate is also in agreement with the findings of Daddi et al. (2008), who directly observed molecular gas in two z ∼ 1.5 BzK galaxies, deriving gas fraction as high as Mgas ∼ M∗.”
• STAR FORMATION AND DUST OBSCURATION AT z ≈ 2: GALAXIES AT THE DAWN OF DOWNSIZING (2009, background): “New ideas on gas accretion modes (Dekel et al. 2009) and recent observations of widespread large molecular gas reservoirs (Daddi et al. 2008; Tacconi et al. 2008) in distant massive galaxies will likely provide crucial pathso understand these issues.”
• THE SINS SURVEY OF z ∼ 2 GALAXY KINEMATICS: PROPERTIES OF THE GIANT STAR-FORMING CLUMPS (2010, background): “%) baryonic cold gas fractions (Daddi et al. 2008, 2010a; Tacconi et al. 2008, 2010).”
• On the origin of the galaxy star‐formation‐rate sequence: evolution and scatter (2009, background): “Great progress is currently being made in measuring molecular gas masses in high redshift galaxies (e.g. Tacconi et al. 2006, 2008, 2010; Daddi et al. 2008, 2010).”
• A Herschel view of the far-infrared properties of submillimetre galaxies (2012, background): “The gas to total baryonic mass fraction of SMGs is comparable to that of typical galaxies at the same redshift (30 − 60%; Tacconi et al. 2008, 2010), implying that SMGs have higher star-formation efficiencies (Daddi et al. 2008, 2010; Genzel et al. 2010).”
• ON SIZES, KINEMATICS, M/L GRADIENTS, AND LIGHT PROFILES OF MASSIVE COMPACT GALAXIES AT z ∼ 2 (2010, background): “…support for increased gas fractions in star-forming galaxies towards higher redshift was inferred from Hα spectroscopy by Erb et al. (2006), and more recently confirmed on the basis of molecular line measurements (Baker et al. 2004; Coppin et al. 2007; Daddi et al. 2008; Tacconi et al. 2010).”