Connecting Galactic Outflows and Star Formation: Inferences from H-alpha Maps and Absorption Line Spectroscopy at 1 < z < 1.5

Abstract

We investigate the connection between galactic outflows and star formation using two independent data sets covering a sample of 22 galaxies between $1\lesssim z\lesssim 1.5$. The HST WFC3/G141 grism provides low spectral resolution, high spatial resolution spectroscopy yielding H$\alpha$ emission line maps from which we measure the spatial extent and strength of star formation. In the rest-frame near-UV, Keck/DEIMOS observes Fe II and Mg II interstellar absorption lines, which provide constraints on the intensity and velocity of the outflows. We compare outflow properties from individual and composite spectra with the star formation rate (SFR) and SFR surface density (SigmaSFR), as well as the stellar mass and specific star formation rate (sSFR). The Fe II and Mg II equivalent widths (EWs) increase with both SFR and SigmaSFR at $\gtrsim 3\sigma$ significance, while the composite spectra show larger Fe II EWs and outflow velocities in galaxies with higher SFR, SigmaSFR, and sSFR. Absorption line profiles of the composite spectra further indicate that the differences between subsamples are driven by outflows rather than the ISM. While these results are consistent with those of previous studies, the use of H$\alpha$ images makes them the most direct test of the relationship between star formation and outflows at $z>1$ to date. Future facilities such as the James Webb Space Telescope and the upcoming Extremely Large Telescopes will extend these direct, H$\alpha$-based studies to lower masses and star formation rates, probing galactic feedback across orders of magnitude in galaxy properties and augmenting the correlations we find here.

20 pages, 8 figures. Accepted for publication in AJ

References in corpus (14)

• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• 3D-HST WFC3-selected Photometric Catalogs in the Five CANDELS/3D-HST Fields: Photometry, Photometric Redshifts and Stellar Masses
• Ubiquitous outflows in DEEP2 spectra of star-forming galaxies at z=1.4
• UV Luminosity Functions at z~4, 5, and 6 from the HUDF and other Deep HST ACS Fields: Evolution and Star Formation History
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: II. Formation of Red Ellipticals
• The Discovery of 1000 km/s Outflows in Massive Post-starburst Galaxies at z=0.6
• The Cosmic Baryon and Metal Cycles
• Dynamical Properties of z~2 Star Forming Galaxies and a Universal Star Formation Relation
• Galactic Angular Momentum in the Illustris Simulation: Feedback and the Hubble Sequence
• On the Formation of Galactic Thick Disks
• Feedback and the Structure of Simulated Galaxies at redshift z=2
• The impact of feedback on cosmological gas accretion
• Why stellar feedback promotes disc formation in simulated galaxies
• UVI colour gradients of 0.4<z<1.4 star-forming main sequence galaxies in CANDELS: dust extinction and star formation profiles

Cited by in corpus (3)

• The Near Infrared Imager and Slitless Spectrograph for the James Webb Space Telescope -- II. Wide Field Slitless Spectroscopy
• Kinematics, Structure, and Mass Outflow Rates of Extreme Starburst Galactic Outflows
• The Lockman-SpReSO project. Galactic flows in a sample of far-infrared galaxies