INSIGHTS ON THE FORMATION, EVOLUTION, AND ACTIVITY OF MASSIVE GALAXIES FROM ULTRACOMPACT AND DISKY GALAXIES AT z=2-3 Academic Article uri icon

abstract

  • We present our results on the structure and activity of massive galaxies at z = 1-3 using one of the largest (166 with M* 5 1010 M ) and most diverse samples of massive galaxies derived from the GOODS-NICMOS survey: (1) Srsic fits to deep NIC3 F160W images indicate that the rest-frame optical structures of massive galaxies are very different at z = 2-3 compared to z 0. Approximately 40% of massive galaxies are ultracompact (r e 2kpc), compared to less than 1% at z 0. Furthermore, most (65%) systems at z = 2-3 have a low Srsic index n 2, compared to 13% at z 0. We present evidence that the n 2 systems at z = 2-3 likely contain prominent disks, unlike most massive z 0 systems. (2) There is a correlation between structure and star formation rates (SFRs). The majority (85%) of non-active galactic nucleus (AGN) massive galaxies at z = 2-3, with SFR high enough to yield a 5 (30 Jy) 24 m Spitzer detection, have low n 2. Such n 2 systems host the highest SFR. (3) The frequency of AGNs is 40% at z = 2-3. Most (65%) AGN hosts have disky (n 2) morphologies. Ultracompact galaxies appear quiescent in terms of both AGN activity and star formation. (4) Large stellar surface densities imply massive galaxies at z = 2-3 formed via rapid, highly dissipative events at z > 2. The large fraction of n 2 disky systems suggests cold mode accretion complements gas-rich major mergers at z > 2. In order for massive galaxies at z = 2-3 to evolve into present-day massive E/S0s, they need to significantly increase (n, re ). Dry minor and major mergers may play an important role in this process. 2011. The American Astronomical Society. All rights reserved.

published proceedings

  • ASTROPHYSICAL JOURNAL

author list (cited authors)

  • Weinzirl, T., Jogee, S., Conselice, C. J., Papovich, C., Chary, R., Bluck, A., ... Bauer, A. E.

citation count

  • 62

complete list of authors

  • Weinzirl, Tim||Jogee, Shardha||Conselice, Christopher J||Papovich, Casey||Chary, Ranga-Ram||Bluck, Asa||Gruetzbauch, Ruth||Buitrago, Fernando||Mobasher, Bahram||Lucas, Ray A||Dickinson, Mark||Bauer, Amanda E

publication date

  • December 2011