Where stars form: inside-out growth and coherent star formation from HST hα maps of 3200 galaxies across the main sequence at 0.7 < z < 1.5

Journal Article · Thu Sep 01 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/828/1/27· OSTI ID:22868741

Nelson, Erica June; Van Dokkum, Pieter G.; Momcheva, Ivelina G.; Leja, Joel; Bosch, Frank C. van den; Oesch, Pascal A.; Dickey, Claire ^[1]; Förster Schreiber, Natascha M.; Wuyts, Stijn; Tacconi, Linda J. ^[2]; Franx, Marijn; Fumagalli, Mattia; Labbé, Ivo ^[3]; Brammer, Gabriel B. ^[4]; Whitaker, Katherine E. ^[5]; Skelton, Rosalind E. ^[6]; Hayward, Christopher C. ^[7]; Kriek, Mariska ^[8]; Rix, Hans-Walter; Wel, Arjen van der ^[9] ; others, and

---

1. Astronomy Department, Yale University, New Haven, CT 06511 (United States)
2. Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany)
3. Leiden Observatory, Leiden University, Leiden (Netherlands)
4. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
5. Astrophysics Science Division, Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
6. South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 (South Africa)
7. TAPIR, California Institute of Technology, Pasadena, CA 91125 (United States)
8. Department of Astronomy, University of California, Berkeley, CA 94720 (United States)
9. Max Planck Institute for Astronomy (MPIA), Königstuhl 17, D-69117, Heidelberg (Germany)

We present Hα maps at 1 kpc spatial resolution for star-forming galaxies at z ∼ 1, made possible by the Wide Field Camera 3 grism on Hubble Space Telescope (HST). Employing this capability over all five 3D-HST/CANDELS fields provides a sample of 3200 galaxies enabling a division into subsamples based on stellar mass and star formation rate (SFR). By creating deep stacked Hα images, we reach surface brightness limits of 1 × 10{sup −18} erg s{sup −1} cm{sup −2} arcsec{sup −2}, allowing us to map the distribution of ionized gas to ∼10 kpc for typical L* galaxies at this epoch. We find that the spatial extent of the Hα distribution increases with stellar mass as r{sub Hα}=1.5(M{sub ∗}/10{sup 10}M{sub ⊙}){sup 0.23} kpc. The Hα emission is more extended than the stellar continuum emission, consistent with inside-out assembly of galactic disks. This effect grows stronger with mass as r{sub Hα}/r{sub ∗}=1.1 (M{sub ∗}/10{sup 10}M{sub ⊙}){sup 0.054}. We map the Hα distribution as a function of SFR(IR+UV) and find evidence for “coherent star formation” across the SFR–M {sub *} plane: above the main sequence (MS), Hα is enhanced at all radii; below the MS, Hα is depressed at all radii. This suggests that at all masses the physical processes driving the enhancement or suppression of star formation act throughout the disks of galaxies. At high masses (10{sup 10.5}

• OSTI ID: 22868741
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 828; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BLACK HOLES
BRIGHTNESS
DISTRIBUTION
EMISSION
GALACTIC EVOLUTION
GALAXIES
MAIN SEQUENCE STARS
MASS
RED SHIFT
SPACE
SPATIAL RESOLUTION
STAR EVOLUTION
TELESCOPES