MOST SUBMILLIMETER GALAXIES ARE MAJOR MERGERS

By H. Engel, L. Tacconi, Roger Davies, R. Neri, I. Smail, S. Chapman, R. Genzel, P. Cox, T. Greve, R. Ivison and 3 more. 2010

217 citations recorded by the source corpus.

We analyze subarcsecond resolution interferometric CO line data for 12 submillimeter-luminous (S850 μm ⩾ 5 mJy) galaxies with redshifts between 1 and 3, presenting new data for 4 of them. Morphologically and kinematically, most of the 12 systems appear to be major mergers. Five of them are well-resolved binary systems, and seven are compact or poorly resolved. Of the four binary systems for which mass measurements for both separate components can be made, all have mass ratios of 1:3 or closer. Furthermore, comparison of the ratio of compact to binary systems with that observed in local ULIRGs indicates that at least a significant fraction of the compact submillimeter-luminous galaxies (SMGs) must also be late-stage mergers. In addition, the dynamical and gas masses we derive are most consistent with the lower end of the range of stellar masses published for these systems, favoring cosmological models in which SMGs result from mergers. These results all point to the same conclusion that most of the bright SMGs with LIR ≳ 5 × 1012 L☉ are likely major mergers.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/5bdca7c9c903c4a98b5307c45e20cceb5d864bfd

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In Astronomy and Astrophysics

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

In Atomic and Molecular Physics, and Optics

1. Christopher J. Conselice
2. R. Dav'e
3. P. Hopkins
4. A. Blain
5. S. Chapman
6. E. Ostriker
7. R. Ivison
8. I. Smail

Citations in the corpus

• GOODS-HERSCHEL AND CANDELS: THE MORPHOLOGIES OF ULTRALUMINOUS INFRARED GALAXIES AT z ∼ 2 (2011, background): “…of LIR) have found evidence for disk-like rotation and clumpy disks (e.g., Genzel et al. 2008; Daddi et al. 2010) while similar studies of submillimeter galaxies (typically more luminous than BzK selected galaxies) have found evidence for mergers (e.g., Tacconi et al. 2008; Engel et al. 2010).”
• THE IMPACT OF INTERACTIONS, BARS, BULGES, AND ACTIVE GALACTIC NUCLEI ON STAR FORMATION EFFICIENCY IN LOCAL MASSIVE GALAXIES (2012, background): “…activity in the most extreme cases (ultraluminous infrared galaxies and sub-millimeter galaxies, e.g. Solomon et al. 1997; Veilleux et al. 2002; Engel et al. 2010), there is no one-to-one correlation between a high infrared luminosity (LFIR > 10 11L⊙) and the need for a low value of αCO, nor…”
• EVIDENCE FOR A CLUMPY, ROTATING GAS DISK IN A SUBMILLIMETER GALAXY AT z = 4 (2012, background): “There are multiple examples of SMGs with very disturbed kinematics and even showing multiple components, providing direct observational evidence for the merger picture (e.g., Tacconi et al. 2008; Engel et al. 2010; Ivison et al. 2011; Riechers et al. 2011a,b).”
• Dusty Star Forming Galaxies at High Redshift (2014, background): “Similarly, Riechers et al. (2011c) find source radii of∼3–15 kpc in a sample of 3 SMGs detected in CO (J = 1–0), and note again that these sizes are notably more extended than the CO (J = 4–3) and (J = 6–5) sizes measured by Engel et al. (2010) for the same galaxies.”
• The stellar masses and specific star-formation rates of submillimetre galaxies (2011, methodology): “Perhaps of most relevance for the present discussion is the fact that Engel et al. (2010) used high excitation lines (CO J=7-6, 6-5, 4-3 and 3-2), which trace denser and hotter gas, very likely confined to the more central regions of a galaxy.”
• The LABOCA survey of the Extended Chandra Deep Field-South: clustering of submillimetre galaxies (2011, background): “…to the potential nonisotropic orientation of the QSO hosts on the sky and the lack of high-resolution velocity fields necessary to solve for this (Coppin et al. 2008), as well as the general difficulties in modelling CO kinematics (e.g. Tacconi et al. 2006; Bothwell et al. 2010; Engel et al. 2010).”
• THE INTERSTELLAR MEDIUM IN DISTANT STAR-FORMING GALAXIES: TURBULENT PRESSURE, FRAGMENTATION, AND CLOUD SCALING RELATIONS IN A DENSE GAS DISK AT z = 2.3 (2011, result): “…mass within this system, we find that the dynamics of the disk are baryon dominated, (Mgas+M∗)/Mdyn=1.1±0.2, with a molecular gas fraction of Mgas/(Mgas +M⋆) = 0.6 ± 0.1, which is comparable to that found in other starburst galaxies at these epochs (Tacconi et al. 2008, 2010; Engel et al. 2010).”
• Energetic galaxy-wide outflows in high-redshift ultraluminous infrared galaxies hosting AGN activity (2012, background): “However, part of the outflow c uld be obscured by material in the host galaxy, as is likely to be the case in clumpy and dusty systems such as high-redshift ULIRGs (e.g., Ivison et al. 2007; Tacconi et al. 2008; Engel et al. 2010).”
• Molecular and atomic gas along and across the main sequence of star-forming galaxies (2016, background): “…well above the main sequence have star formation effici ncies enhanced by an order of magnitude (e.g.Gao & Solomon 2004; Genzel et al. 2010; Daddi et al. 2010), and that almost all of these most extreme systems are major mergers (Sanders & Mirabel 1996; Veilleux et al. 2002; Engel et al. 2010).”
• A survey of molecular gas in luminous sub-millimetre galaxies (2012, background): “31+571952.0 104.12 0.12 0.68 19.3 0923+392 Engel et al. (2010) SMM J105151.”
• THE SCUBA-2 COSMOLOGY LEGACY SURVEY: ALMA RESOLVES THE REST-FRAME FAR-INFRARED EMISSION OF SUB-MILLIMETER GALAXIES (2014, background): “However, as discussed by Chen et al. (2014), the SMGs in their sample are predominantly disturbed systems, with indications that the intense star formation is triggered by merger activity (see also Frayer et al. 1999; Greve et al. 2005; Tacconi et al. 2006; Engel et al. 2010; Ivison et al. 2013).”
• Cool Gas in High-Redshift Galaxies (2013, methodology): “…(Frayer et al. 1998, Frayer et al. 1999 using OVRO) and extensive campaigns, in particular done at the PdBI (Neri et al. 2003, Greve et al. 2005, Tacconi et al. 2006, 2008, Engel et al. 2010, Bothwell et al. 2010, 2013) have characterized the molecular interstellar medium in exquisite detail.”
• ALMA REDSHIFTS OF MILLIMETER-SELECTED GALAXIES FROM THE SPT SURVEY: THE REDSHIFT DISTRIBUTION OF DUSTY STAR-FORMING GALAXIES (2013, background): “The sample of source radii in the literature (Tacconi et al. 2008; Engel et al. 2010; Rujopakarn et al. 2011), which were directly measured from high-resolution imaging, show no clear evidence for size evolution above z>0.4.”
• What drives the growth of black holes (2011, background): “The most powerful starbursts at high redshift, submillimeter galaxies (SMGs), have gas kinematics and morphologies that are characteristic of mergers (e.g., Tacconi et al., 2008; Engel et al., 2010; Riechers et al., 2011).”
• Evolution of the dust emission of massive galaxies up to z=4 and constraints on their dominant mode of star formation (2014, methodology): “The main limitation of this method is the uncertainty on this conversion factor, which is expected to be different from the local calibrations in high-redshift galaxies with strongly sub-solar metallicities (Bothwell et al. 2010; Engel et al. 2010; Genzel et al. 2012, 2014; Tan et al. 2013).”
• COLD GASS, an IRAM legacy survey of molecular gas in massive galaxies - II. The non-universality of the molecular gas depletion time-scale (2011, background): “…galaxies (SMGs; e.g. Frayer et al. 1998; Downes & Solomon 2003; Genzel et al. 2003; Neri et al. 2003; Kneib et al. 2005; Tacconi et al. 2008; Bothwell et al. 2010; Engel et al. 2010) and normal star-forming galaxies at z > 1 (e.g. Daddi et al. 2010; Genzel et al. 2010; Tacconi et al. 2010).”
• An ALMA survey of sub-millimetre Galaxies in the Extended Chandra Deep Field South: the far-infrared properties of SMGs (2013, background): “Along with corroborating kinematic and morphological evidence (Tacconi et al. 2006, 2008; Engel et al. 2010; Swinbank et al. 2010; Alaghband-Zadeh et al. 2012), inevitably it has been argued that SMGs can be understood as “scaled-up” analogs of local ULIRGs which are dominated by merger induced…”
• AN ALMA SURVEY OF SUBMILLIMETER GALAXIES IN THE EXTENDED CHANDRA DEEP FIELD SOUTH: SOURCE CATALOG AND MULTIPLICITY (2013, background): “J (J > 2) CO transitions, which typically report sizes in the range 4–6 kpc (FWHM; Tacconi et al. 2006, 2008; Bothwell et al. 2010; Engel et al. 2010; Bothwell et al. 2012).”