Dawn of Brackett-gamma: Evidence for a clean, efficient star formation indicator in the era of JWST
Abstract
The James Webb Space Telescope will for the first time allow restframe near-infrared emission lines to be measured beyond the local universe for a large sample of galaxies. These lines are expected to provide more accurate single-measure star formation rates, as they are less affected by dust attenuation. In light of this, we use the Bayesian inference framework Prospector to predict the expected scatter between SFR and Brackett-gamma (2.16 um), given the standard modeling assumptions. We also vet the Prospector predictions against observations of a local sample of 21 galaxies for which we obtained Brackett-gamma via aperture-matched force-scan spectroscopy. We find that Prospector predicts Brackett-gamma to within the measurement uncertainties for almost all galaxies in our sample, and that both the predicted and measured scatter (and offset) between marginalized SFR and Brackett-gamma are significantly improved over the current gold-standard emission line H-alpha. We conclude that for JWST multi-object spectroscopy, Brackett-gamma will be an invaluable emission line for inferring accurate single-measure SFRs.
- Publication:
-
American Astronomical Society Meeting Abstracts #235
- Pub Date:
- January 2020
- Bibcode:
- 2020AAS...23534506P