The stellar masses and specific star-formation rates of submillimetre galaxies

By M. Michałowski, J. Dunlop, M. Cirasuolo, J. Hjorth, C. Hayward, Darach Watson IfA Edinburgh, Dark Copenhagen, Cfa, Harvard. 2011

149 citations recorded by the source corpus.

Establishing the stellar masses, and hence specific star-formation rates of submillimetre galaxies is crucial for determining the role of such objects in the cosmic history of galaxy/star formation. However, there is as yet no consensus over the typical stellar masses of submillimetre galaxies, as illustrated by the widely differing results reported from recent optical-infrared studies of submillimetre galaxies with spectroscopic redshifts z � 2-3. Specifically, even for the same set of submillimetre galaxies, the reported average stellar masses have ranged over an order of magnitude, from � 5 × 10 10 Mto � 5 × 10 11 M� . Here we study how different methods of analysis can lead to such widely varying results. We find that, contrary to recent claims in the literature, potential contamination of IRAC 3-8 μm photometry from hot dust associated with an active nucleus is not the origin of the published discrepancies in derived stellar masses. Instead, we expose in detail how inferred stellar mass depends on assumptions made in the photometric fitting, and quantify the individual and cumulative effects of different choices of initial mass function, different "brands" of evolutionary synthesis models, and different forms of assumed star-formation history. We review current observational evidence for and against these alternatives as well as clues from the hydrodynamical simulations, and conclude that, for the most justifiable choices of these model inputs, the average stellar mass of luminous (S 850 5 mJy) submillimetre galaxies is � 2 × 10 11 Mto within a factor � 2. We also check and confirm that this number is perfectly reasonable in the light of the latest measurements of the dynamical masses of these objects (� 2−6 × 10 11 Mfrom CO (1-0) observations), and the evolving stellar mass function of the overall galaxy population. Galaxy stellar masses of this order imply that the average specific star-formation rate of submillimetre galaxies is comparable to that of other star-forming galaxies at z > 2, at 2-3 Gyr −1 . This supports the view that, while rare outliers may be found at any stellar mass, most submillimetre galaxies simply form the top end of the "main-sequence" of star-forming galaxies at these redshifts. Conversely, this argues strongly against the viewpoint, frequently simply asserted in the literature, that submillimetre galaxies are extreme pathological objects, of little relevance in the cosmic history of star-formation.

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

View Paper: https://www.semanticscholar.org/paper/b06d31eca9e87ce64e47c8c5b9ce152bfe8b713d

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The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

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

In Atomic and Molecular Physics, and Optics

1. L. Hernquist
2. J. Dunlop
3. A. Cooray
4. D. Narayanan
5. R. Ivison
6. D. Nelson
7. F. Walter
8. P. Hopkins

In Instrumentation

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

Citations in the corpus

• AN ALMA SURVEY OF SUB-MILLIMETER GALAXIES IN THE EXTENDED CHANDRA DEEP FIELD SOUTH: PHYSICAL PROPERTIES DERIVED FROM ULTRAVIOLET-TO-RADIO MODELING (2015, background): “The crucial difference between our analysis and that of Michałowski et al. (2012) is that we include a wide range of star formation histories, ages, metallicities, dust attenuations and redshifts, and when we fit the whole ultraviolet-to-radio SED we require self-consistency between the stellar and…”
• Dusty Star Forming Galaxies at High Redshift (2014, methodology): “Referring to Section 5.3, this includes only the most massive galaxies utilizing the Michałowski et al. (2012) estimates, which are at the upper end of SMG mass estimates and potentially not even valid since they exceed constraints from dynamical mass estimates.”
• The Morphologies of Massive Galaxies at 1<z<3 in the CANDELS-UDS Field: Compact Bulges, and the Rise and Fall of Massive Disks (2012, methodology): “However, while Michałowski et al. (2012) show that twocomponent models can produce significantly larger stellar masses than single-component models for extreme starbursting objects such as submillimetre galaxies, McLure et al. (2012) report that the mass difference is relatively small for more…”
• The star formation main sequence and stellar mass assembly of galaxies in the Illustris simulation (2014, background): “Such an approach could yield significant advantages because the accuracy and robustness of spectral energy distribution modelling can be very sensitive to the assumed SFH (e.g. Michałowski et al. 2012, 2014; C. Hayward & D. Smith, submitted; P. Torrey et al., submitted).”
• Submillimetre galaxies in a hierarchical universe: number counts, redshift distribution, and implications for the IMF (2012, background): “In previous work, we demonstrated that major mergers can reproduce the observed 850-μm fluxes and typical SED (Narayanan et al. 2010b); CO spatial extents, linewidths and excitation ladders (Narayanan et al. 2009); stellar masses (Narayanan et al. 2010b; H11; Michałowski et al. 2012); and the LIR–ef”
• Constraining the properties of AGN host galaxies with spectral energy distribution modelling (2015, background): “…to identify limitations and potential sources of systematics (e.g. Pozzetti et al. 2007; Marchesini et al. 2009; Conroy et al. 2009; Wuyts et al. 2009; Ilbert et al. 2010; Michałowski et al. 2012; Pforr et al. 2012; Banerji et al. 2013; Schaerer et al. 2013; Mitchell et al. 2013; Buat et al. 2014).”