Shocked Superwinds from the z~2 Clumpy Star-forming Galaxy, ZC406690

Дата и время публикации : 2012-04-20T20:00:07Z

Авторы публикации и институты :
Sarah F. Newman
Kristen Shapiro Griffin
Reinhard Genzel
Ric Davies
Natascha M. Foerster-Schreiber
Linda J. Tacconi
Jaron Kurk
Stijn Wuyts
Shy Genel
Simon J. Lilly
Alvio Renzini
Nicolas Bouche
Andreas Burkert
Giovanni Cresci
Peter Buschkamp
C. Marcella Corollo
Frank Eisenhauer
Erin Hicks
Dieter Lutz
Chiara Mancini
Thorsten Naab
Yingjie Peng
Daniela Vergani

Ссылка на журнал-издание: 2012, ApJ 752, 111
Коментарии к cтатье: 21 pages, 7 figures, Accepted for publication in ApJ
Первичная категория: astro-ph.CO

Все категории : astro-ph.CO

Краткий обзор статьи: We have obtained high-resolution data of the z 2 ring-like, clumpy star-forming galaxy (SFG) ZC406690 using the VLT/SINFONI with AO (in K-band) and in seeing-limited mode (in H- and J-band). Our data includes all of the main strong optical emission lines: [OII], [OIII], Ha, Hb, [NII] and [SII]. We find broad, blueshifted Ha and [OIII] emission line wings in the spectra of the galaxy’s massive, star-forming clumps (sigma sim 85 km s^-1) and even broader wings (up to 70% of the total Ha flux, with sigma sim 290 km s^-1) in regions spatially offset from the clumps by sim 2 kpc. The broad emission likely originates from large-scale outflows with mass outflow rates from individual clumps that are 1-8x the SFR of the clumps. Based on emission line ratio diagnostics ([NII]/Ha and [SII]/Ha) and photoionization and shock models, we find that the emission from the clumps is due to a combination of photoionization from the star-forming regions and shocks generated in the outflowing component, with 5-30% of the emission deriving from shocks. In terms of the ionization parameter (6×10^7-10^8 cm/s, based on both the SFR and the O32 ratio), density (local electron densities of 300-1800 cm^-3 in and around the clumps, and ionized gas column densities of 1200-8000 Msol/pc^2), and SFR (10-40 Msol/yr), these clumps more closely resemble nuclear starburst regions of local ULIRGs and dwarf irregulars than HII regions in local galaxies. However, the star-forming clumps are not located in the nucleus as in local starburst galaxies but instead are situated in a ring several kpc from the center of their high-redshift host galaxy, and have an overall disk-like morphology. The two brightest clumps are quite different in terms of their internal properties, energetics and relative ages, and thus we are given a glimpse at two different stages in the formation and evolution of rapidly star-forming giant clumps at high-z.

Category: Physics