AN OBJECTIVE DEFINITION FOR THE MAIN SEQUENCE OF STAR-FORMING GALAXIES

By A. Renzini, Yingjie Peng. 2015

182 citations recorded by the source corpus.

The main sequence (MS) of star-forming (SF) galaxies plays a fundamental role in driving galaxy evolution and our efforts to understand it. However, different studies find significant differences in the normalization, slope, and shape of the MS. These discrepancies arise mainly from the different selection criteria adopted to isolate SF galaxies, which may include or exclude galaxies with a specific star formation rate (SFR) substantially below the MS value. To obviate this limitation of all current criteria, we propose an objective definition of the MS that does not rely at all on a pre-selection of SF galaxies. Constructing the 3D SFR–mass–number plot, the MS is then defined as the ridge line of the SF peak, as illustrated with various figures. The advantages of such a definition are manifold. If generally adopted, it will facilitate the inter-comparison of results from different groups using the same SFR and stellar mass diagnostics, or it will highlight the relative systematics of different diagnostics. All of this could help to understand MS galaxies as systems in a quasi-steady state equilibrium and would also provide a more objective criterion for identifying quenching galaxies.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/46df87884ecbbbb8ef74dee1bf3e289722c6a65d

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In Astronomy and Astrophysics

1. L. Hernquist
2. P. Hopkins
3. A. Dekel
4. R. Somerville
5. R. Dav'e
6. Volker Springel
7. T. Naab
8. D. Narayanan

In Instrumentation

1. L. Hernquist
2. P. Hopkins
3. A. Dekel
4. Volker Springel
5. R. Dav'e
6. R. Somerville
7. Thomas J. Cox
8. T. Naab

Citations in the corpus

• The Star Formation Main Sequence in the Hubble Space Telescope Frontier Fields (2017, background): “According to some work (e.g. Renzini & Peng 2015; Whitaker et al. 2015), it seems to arise from an incorrect separation of passive and quenched galaxies from star-forming ones.”
• A deep ALMA image of the Hubble Ultra Deep Field (2016, background): “…rest-frame UV luminosity), as expected from the ‘main sequence’ of star-forming galaxies (e.g. Noeske et al. 2007; Daddi et al. 2007; Elbaz et al. 2010; Micha lowski et al. 2012b; Roseboom et al. 2013; Speagle et al. 2014; Koprowski et al. 2014, 2016; Renzini & Peng 2015; Schreiber et al. 2015).”
• The faint radio sky: radio astronomy becomes mainstream (2016, background): “The slope of the correlation is approximately constant but the normalization increases by about a factor of 20 from the local Universe toz∼ 2 (Renzini & Peng, 2015, and references therein).”
• The confinement of star-forming galaxies into a main sequence through episodes of gas compaction, depletion and replenishment (2015, methodology): “A detailed definition of the MS ridge is provided by Renzini & Peng (2015). pletion time (Magdis et al. 2012; Sargent et al. 2014; Huang & Kauffmann 2014; Genzel et al. 2015; Silverman et al. 2015; Scoville et al. 2015).”
• PHIBSS: Unified Scaling Relations of Gas Depletion Time and Molecular Gas Fractions (2017, methodology): “There are different MS-prescriptions proposed in the literature (e.g. W12, W14, S14), with differences in zeropoints and slopes in the mass and redshift relations dependent on sample selections (redshift range, survey bands), survey completeness, and methodologies applied to derive M* and SFRs (Renz”
• Supermassive black holes and their feedback effects in the IllustrisTNG simulation (2017, background): “…numerous observations in this area (e.g. Noeske et al. 2007; Rodighiero et al. 2011; Wuyts et al. 2011; Whitaker et al. 2012; Speagle et al. 2014; Renzini & Peng 2015; Schreiber et al. 2015; Tasca et al. 2015) to future work, and use the star formation rate in this paper only as a proxy for…”
• The star formation activity of IllustrisTNG galaxies: main sequence, UVJ diagram, quenched fractions, and systematics (2018, background): “…rate (SFR), this relation being commonly called ‘star-forming main sequence’ (hereafter MS or SFMS; e.g. Noeske et al. 2007; Rodighiero et al. 2011; Wuyts et al. 2011; Whitaker et al. 2012; Speagle et al. 2014; Renzini & Peng 2015; Schreiber et al. 2015; Tasca et al. 2015; Shivaei et al. 2015).”