We follow the structural evolution of star-forming galaxies (SFGs) like the Milky Way by selecting progenitors to z ~{} 1.3 based on the stellar mass growth inferred from the evolution of the star... Show moreWe follow the structural evolution of star-forming galaxies (SFGs) like the Milky Way by selecting progenitors to z ~{} 1.3 based on the stellar mass growth inferred from the evolution of the star-forming sequence. We select our sample from the 3D-HST survey, which utilizes spectroscopy from the HST/WFC3 G141 near-IR grism and enables precise redshift measurements for our sample of SFGs. Structural properties are obtained from Sérsic profile fits to CANDELS WFC3 imaging. The progenitors of z = 0 SFGs with stellar mass M = 10$^{10.5}$ M $_{☉}$ are typically half as massive at z ~{} 1. This late-time stellar mass growth is consistent with recent studies that employ abundance matching techniques. The descendant SFGs at z ~{} 0 have grown in half-light radius by a factor of ~{}1.4 since z ~{} 1. The half-light radius grows with stellar mass as r$_e$ vpropM $^{0.29}$. While most of the stellar mass is clearly assembling at large radii, the mass surface density profiles reveal ongoing mass growth also in the central regions where bulges and pseudobulges are common features in present day late-type galaxies. Some portion of this growth in the central regions is due to star formation as recent observations of H{$α$} maps for SFGs at z ~{} 1 are found to be extended but centrally peaked. Connecting our lookback study with galactic archeology, we find the stellar mass surface density at R = 8 kpc to have increased by a factor of ~{}2 since z ~{} 1, in good agreement with measurements derived for the solar neighborhood of the Milky Way. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. Show less
Tal, T.; Dokkum, P.G. van; Franx, M.; Leja, J.; Wake, D.; Whitaker, K. 2013
We present a statistical study of the environments of massive galaxies in four redshift bins between z = 0.04 and z = 1.6, using data from the Sloan Digital Sky Survey and the NEWFIRM Medium Band... Show moreWe present a statistical study of the environments of massive galaxies in four redshift bins between z = 0.04 and z = 1.6, using data from the Sloan Digital Sky Survey and the NEWFIRM Medium Band Survey. We measure the projected radial distribution of galaxies in cylinders around a constant number density selected sample of massive galaxies and utilize a statistical subtraction of contaminating sources. Our analysis shows that massive primary galaxies typically live in group halos and are surrounded by 2-3 satellites with masses more than one-tenth of the primary galaxy mass. The cumulative stellar mass in these satellites roughly equals the mass of the primary galaxy itself. We further find that the radial number density profile of galaxies around massive primaries has not evolved significantly in either slope or overall normalization in the past 9.5 Gyr. A simplistic interpretation of this result can be taken as evidence for a lack of mergers in the studied groups and as support for a static evolution model of halos containing massive primaries. Alternatively, there exists a tight balance between mergers and accretion of new satellites such that the overall distribution of galaxies in and around the halo is preserved. The latter interpretation is supported by a comparison to a semi-analytic model, which shows a similar constant average satellite distribution over the same redshift range. Show less
