Calibration of Ultraviolet, Mid-infrared, and Radio Star Formation Rate Indicators

Abstract

We present calibrations for star formation rate (SFR) indicators in the ultraviolet, mid-infrared, and radiocontinuum bands, including one of the first direct calibrations of 150 MHz as an SFR indicator. Our calibrations utilize 66 nearby star-forming galaxies with Balmer-decrement-corrected Ha luminosities, which span five orders of magnitude in SFR and have absolute magnitudes of M 24 12 r -< < -. Most of our photometry and spectrophotometry are measured from the same region of each galaxy, and our spectrophotometry has been validated with SDSS photometry, so our random and systematic errors are small relative to the intrinsic scatter seen in SFR indicator calibrations. We find that the Wide-field Infrared Space Explorer W4 (22.8 μm), Spitzer24 μm, and 1.4 GHz bands have tight correlations with the Balmer-decrement-corrected Hα luminosity, with a scatter of only 0.2dex. Our calibrations are comparable to those from the prior literature for L * galaxies, but for dwarf galaxies, our calibrations can give SFRs that are far greater than those derived from most previous literature.

Calibrating Star Formation Rate Prescriptions at Different Scales (10 pc–1 kpc) in M31

“…Combining our largest apertures and the integrated fields, we observe that our data altogether are consistent with a single slope that is shallower than most of the monochromatic SFR prescriptions in the literature. These data fall between relations from Catalán-Torrecilla et al (2015), Cluver et al (2017), and Brown et al (2017). Fig.…”

The 1.4-GHz cosmic star formation history at z &lt; 1.3

“…(1) where L c = 6.4 × 10 21 W Hz −1 . This SFR calibration has been used by both Smolčić et al (2009) andNovak et al (2017), and is comparable to recent calibrations by Boselli et al (2015) and Brown et al (2017) for < L * galaxies. We then used the 1/V max method (Schmidt, 1968), with the SFR divided by the volume in which the galaxy could be detected, to find the SFRD contribution for each galaxy.…”

“…Using the Brown et al (2017) nearby galaxy sample, we find star forming galaxies have i-band to 1.4 GHz flux density ratios that range from 0.1 to 30, so we expect low redshift S 1.4 = 40 µJy star forming galaxies to be brighter than i = 22.4. At z = 1.15 the i-band and 1.4 GHz correspond to u-band and 3.0 GHz respectively, and we find the Brown et al (2017) nearby galaxy sample u-band to 3.0 GHz flux density ratios range from 0.05 to 20, so we expect z ∼ 1.15 S 1.4 = 40 µJy star forming galaxies to be brighter than i = 23.2. We thus conclude that the bulk of the radio sources without i < 26.5 optical counterparts are AGNs or z > 1.3 galaxies.…”

Integral field spectroscopy of Green Peas – I. Disentangling disc-like turbulence and strong outflow kinematics in SDSS J083843.63+385350.5

“…We find that SDSS J0838 is in the WISE point source catalog and we can derive its SFR from its observed mid-IR magnitudes. Following Brown et al (2017) we will focus our comparison using the luminosity estimated in the W3 bandpass centered in 22 µm (L22) which displays the best correlation with other independent estimators. Several regressions for different SFR estimators have been derived recently by Lee et al (2013), Wen et al (2014), Davies et al (2016) and Catalán-Torrecilla et al (2015) for different samples of galaxies.…”