REQUIEM-2D: Spatially Resolved Stellar Populations from HST 2D Grism Spectroscopy [article]

Mohammad Akhshik, Katherine E. Whitaker, Gabriel Brammer, Guillaume Mahler, Keren Sharon, Joel Leja, Matthew B. Bayliss, Rachel Bezanson, Michael D. Gladders, Allison Man, Erica J. Nelson, Jane R. Rigby (+4 others)
2020 arXiv   pre-print
We present a novel Bayesian methodology to jointly model photometry and deep Hubble Space Telescope (HST) 2d grism spectroscopy of high-redshift galaxies. Our requiem2d code measures both unresolved and resolved stellar populations, ages, and star-formation histories (SFHs) for the ongoing REQIUEM (REsolving QUIEscent Magnified) Galaxies Survey, which targets strong gravitationally lensed quiescent galaxies at z 2. We test the accuracy of requiem2d using a simulated sample of massive galaxies
more » ... z 2 from the Illustris cosmological simulation and find we recover the general trends in SFH and median stellar ages. We further present a pilot study for the REQUIEM Galaxies Survey: MRG-S0851, a quintuply-imaged, massive (log M_* / M_ = 11.02 ± 0.04) red galaxy at z=1.883± 0.001. With an estimated gravitational magnification of μ = 5.7^+0.4_-0.2, we sample the stellar populations on 0.6 kpc physical size bins. The global mass-weighted median age is constrained to be 1.8_-0.2^+0.3 Gyr, and our spatially resolved analysis reveals that MRG-S0851 has a flat age gradient in the inner 3 kpc core after taking into account the subtle effects of dust and metallicity on age measurements, favoring an early formation scenario. The analysis for the full REQUIEM-2D sample will be presented in a forthcoming paper with a beta-release of the requiem2d code.
arXiv:2008.02276v1 fatcat:u6zvlbqgirftvlzcwiaaroljuy