High-resolution Hubble Space Telescope Imaging Survey of Local Star-forming Galaxies. I. Spatially Resolved Obscured Star Formation with Hα and Paschen-β Recombination Lines
Clara Giménez-Arteaga, Gabriel Brammer, Danilo Marchesini, L. Colina, Varun Bajaj, Malte Brinch, Daniela Calzetti, Daniel Lange-Vagle, E. J. Murphy, Michele Perna, Javier Piqueras López, Gregory F. Snyder
Abstract
Abstract We present a sample of 24 local star-forming galaxies observed with broadband and narrowband photometry from the Hubble Space Telescope (HST) that are part of the Great Observatories All-sky Luminous Infrared Galaxies Survey of local luminous and ultraluminous infrared galaxies. With narrowband filters around the emission lines H α (and [N ii ]) and Pa β , we obtain robust estimates of the dust attenuation affecting the gas in each galaxy, probing higher attenuation than can be traced by the optical Balmer decrement H α /H β alone by a factor of >1 mag. We also infer the dust attenuation toward the stars via a spatially resolved spectral energy distribution fitting procedure that uses all available HST imaging filters. We use various indicators to obtain the star formation rate (SFR) per spatial bin and find that Pa β traces star-forming regions where the H α and the optical stellar continuum are heavily obscured. The dust-corrected Pa β SFR recovers the 24 μ m inferred SFR with a ratio of −0.14 ± 0.32 dex and the SFR inferred from the 8 to 1000 μ m infrared luminosity at −0.04 ± 0.23 dex. Both in a spatially resolved and integrated sense, rest-frame near-infrared recombination lines can paint a more comprehensive picture of star formation across cosmic time, particularly with upcoming JWST observations of Paschen-series line emission in galaxies as early as the epoch of reionization.