Toward a Resolution of the Discrepancy between Different Estimators of Star Formation Rate

By Andrew M. Hopkins, Andrew J. Connolly, D. Haarsma, L. W. U. O. Pittsburgh, Calvin College, U. Sydney. 2001

190 citations recorded by the source corpus.

Different wavelength regimes and methods for estimating the space density of the star formation rate (SFR) result in discrepant values. While it is recognized that ultraviolet (UV) and Hα emission-line data must be corrected for the effects of extinction, the magnitude of the required correction is uncertain. Even when these corrections are made there remains a significant discrepancy between SFRs derived from UV and Hα measurements compared with those derived from far-infrared (FIR) and radio luminosities. Since the FIR-radio–derived SFRs are not affected by extinction and simple corrections to reconcile the UV and Hα measurement with these do not fully account for the discrepancies, a more sophisticated correction may be required. Recent results suggest that at least part of the solution may be a form of extinction that increases with increasing SFR (or luminosity, given the common assumption that SFR is proportional to luminosity). We present an analysis of the effects of a dust reddening dependent on star formation rate applied to estimators of SFR. We show (1) that the discrepancies between Hα and FIR-radio SFR estimates may be explained by such an effect and we present an iterative method for applying the correction and (2) that UV-based estimates of SFR are harder to reconcile with FIR-radio estimates using this method, although the extent of the remaining discrepancy is less than for a non-SFR–dependent correction. Particularly at high redshift, our understanding of extinction at UV wavelengths may require a still more complex explanation.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/8ee6827b7d72a13122ffbb18a83605ff1e104fd6

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Citations in the corpus

The DEEP2 Galaxy Redshift Survey: the role of galaxy environment in the cosmic star formation history (2007, background): “3 have shown that extinction is well–correlated with star–formation rate (Hopkins et al. 2001).”
Dust Attenuation in the Nearby Universe: A Comparison between Galaxies Selected in the Ultraviolet and in the Far-Infrared (2004, result): “This result is consistent with findings of an increase of the dust attenuation with the star formation rate in nearby galaxies (Wang & Heckman 1996; Hopkins et al. 2001).”
On the Evolution of Star-forming Galaxies (2004, background): “2a and 3a of Hopkins et al. 2001a).”
Galaxy Star Formation as a Function of Environment in the Early Data Release of the Sloan Digital Sky Survey (2002, methodology): “For the remainder we just use the corrected SFR of Hopkins et al. (2001).”
UniverseMachine: The correlation between galaxy growth and dark matter halo assembly from z = 0−10 (2018, background): “As EL extinction correlates with stellar mass (e.g., Hopkins et al. 2001; An et al. 2014), assuming constant extinction will underestimate SFRs for massive galaxies and overestimate them for faint ones.”
DUST EXTINCTION FROM BALMER DECREMENTS OF STAR-FORMING GALAXIES AT 0.75 ⩽ z ⩽ 1.5 WITH HUBBLE SPACE TELESCOPE/WIDE-FIELD-CAMERA 3 SPECTROSCOPY FROM THE WFC3 INFRARED SPECTROSCOPIC PARALLEL SURVEY (2012, methodology): “The SDSS contours do not exactly match the Hopkins et al. (2001) results because the samples are not exactly the same.”
THE MOSDEF SURVEY: MEASUREMENTS OF BALMER DECREMENTS AND THE DUST ATTENUATION CURVE AT REDSHIFTS z ∼ 1.4–2.6 (2015, background): “Such a correlation has been noted before both at low (Wang & Heckman 1996; Hopkins et al. 2001) and high redshift (e.g., Adelberger & Steidel 2000; Reddy et al. 2006; Buat et al. 2007; Burgarella et al. 2009; Reddy et al. 2008; Buat et al. 2009; Reddy et al. 2010; Sobral et al. 2012; Domı́nguez et…”
Spitzer View on the Evolution of Star-forming Galaxies from z = 0 to z ~ 3 (2005, background): “This effect would be reasonable in galaxies with not very intense star formation (SFRP 5 M yr 1), given that the most violent star-forming galaxies show the highest dust attenuations (Hopkins et al. 2001; Sullivan et al. 2001; Pérez-González et al. 2003c).”
Star Formation in AEGIS Field Galaxies since z = 1.1: The Dominance of Gradually Declining Star Formation, and the Main Sequence of Star-forming Galaxies (2007, methodology): “We again apply for extinction corrections, cer-A p 1.30Ha tainly an overestimate since extinction is lower in more weakly star-forming galaxies (Hopkins et al. 2001).”
A sample of radio-loud active galactic nuclei in the Sloan Digital Sky Survey (2005, methodology): “For these models, the radio luminosities have been calculated using the prescription of Hopkins et al. (2001): L 1.4 GHz = 1.8 × 1021 (SFR/M ) W Hz−1, where SFR is the average star formation rate in the past 108 yr.”
Galaxy And Mass Assembly (GAMA): Spectroscopic analysis (2013, result): “…demonstrates that high line luminosity systems show a much broader distribution of obscuration properties than lower luminosity galaxies, consistent with earlier results (Hopkins et al. 2001, 2003; Pérez-González et al. 2003; Afonso et al. 2003; López-Sánchez 2010; Gunawardhana et al. 2011).”
Galaxy and Mass Assembly (GAMA): the star formation rate dependence of the stellar initial mass function (2011, background): “High SFR galaxies are subjected to greater dust obscuration than lower luminosity objects (Hopkins et al. 2001, 2003; Afonso et al. 2003; Pérez-González et al. 2003).”
Optical Star Formation Rate Indicators (2005, unknown): “…accuracy remains limited by a wide range of systematic uncertainties (Cram et al. 1998; Glazebrook et al. 1999; Bell & Kennicutt 2001; Sullivan et al. 2001; Hopkins et al. 2001, 2003; Charlot et al. 2002; Rosa-González et al. 2002; Kewley et al. 2002, 2004; Hirashita et al. 2003; Bell 2003).”
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Star Formation Properties of a Large Sample of Irregular Galaxies (2004, background): “Extinction due to dust is low, so we feel confident that Hα is revealing the bulk of the star formation in these galaxies (Hopkins et al. 2001).”
The physical properties of star-forming galaxies in the low-redshift universe (2003, background): “Given the major uncertainty in traditional star formation estimates due to dust attenuation (Sullivan et al. 2001; Hopkins et al. 2001a; Bell & Kennicutt 2001; Calzetti 1997), we should briefly summarize C© 2004 RAS, MNRAS 351, 1151–1179 Z The metallicity −1 < log Z/Z < 0.6 in 24 steps U The…”
The Calibration of Mid-Infrared Star Formation Rate Indicators (2007, background): “…by assumptions on the underlying stellar absorption and on the form of the high end of the stellar initial mass function (e.g., Calzetti, Kinney & Storchi–Bergmann 1994; Kennicutt 1998a; Hopkins et al. 2001; Sullivan et al. 2001; Kewley et al. 2002; Rosa–Gonzalez, Terlevich & Terlevich 2002).”
The Dust Opacity of Star‐forming Galaxies (2001, result): “2starb (6) (see, also, Hopkins et al. 2001).”