Star Formation in the Milky Way and Nearby Galaxies

“Various objections and caveats to this appealing picture have been registered (e.g., Swift & Williams 2008; Reid et al. 2010; Clark et al. 2007; Hatchell & Fuller 2008).”

“More recent determinations over a wider range of masses, including brown dwarfs, indicate a clear flattening at lower masses, either as broken power laws (Kroupa et al. 1993) or a log-normal distribution (Miller & Scalo 1979; Chabrier 2003).”

“This uncertainty range does not include all possible systematic errors, arising for example from changes in X(CO) or the IMF with increasing surface density or SFR. Major systematic changes in either of these could easily change the derived value of N by as much as 0.2–0.3.”

“The High-density Regime The two regimes discussed above were able to reproduce all of the early observations of the large-scale star formation law by Kennicutt (1989, 1998b) and Martin & Kennicutt (2001).”

“The results cited here use the Starburst99 models of Leitherer et al. (1999), which are regularly updated in the on-line version of the package.”

“The High-density Regime The two regimes discussed above were able to reproduce all of the early observations of the large-scale star formation law by Kennicutt (1989, 1998b) and Martin & Kennicutt (2001).”

“This section focusses on the transformational results which have come from the Spitzer Space Telescope (Werner et al. 2004) and the Herschel Space Observatory (Pilbratt et al. 2010).”

“The mass dependence of the SSFR has been explored by numerous investigators (e.g., Brinchmann et al. 2004; Salim et al. 2007; Schiminovich et al. 2007; Lee et al. 2007).”

“For extragalactic studies, this subject has been revolutionised by the launch of the Galaxy Evolution Explorer (GALEX) mission (Martin et al. 2005a).”

“The masses of embedded young clusters (Lada & Lada 2003), OB associations (McKee & Williams 1997), and massive open clusters (Elmegreen & Efremov 1997; Zhang & Fall 1999), follow a similar relation with γcluster ∼ 1.”

“This correction follows Boquien et al. (2016) who argue that kIR should not be a constant as commonly assumed (see e.g. Kennicutt & Evans 2012, and references therein) but is a linear function of the FUV-near-IR colors4. which is a proxy for sSFR.”

“The SFR is generally estimated from LIR scaling relations discussed in Kennicutt & Evans (2012): SFR [M⊙/yr] = 1.47× 10 −10 LIR [L⊙] (7) To convert LIR to LFIR, we use 〈LIR/LFIR〉 ∼1.38 obtained from the SEDs of SPT0529-54, SPT0532-50, SPT0538-50 and the Cloverleaf.”

“This timescale is chosen to match what is generally considered the characteristic sensitivity window of the FUV+24 µ m tracer (e.g., Kennicutt 1998; Kennicutt & Evans 2012) and to remain within the regime where the SFHs are best constrained.”