2010/12/22 by Ken-ichi Tadaki, Tadayuki Kodama, Yusei Koyama +3 · 1 citation
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Flux (metallurgy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Line (geometry) #Luminosity #Luminosity function #Physics #Redshift #Scientific Research and Discoveries #Solar mass #Star formation #Stellar mass #astro-ph.CO
paper · pdf · doi:10.1093/pasj/63.sp2.s437
Accepted for publication in PASJ Subaru Special Issue, 11 pages, 10 figures
arxiv created 2010/12/22 · openalex publication_date 2011/03/25 · arxiv updated 2015/05/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract We present a pilot narrow-band survey of Hα emitters at z = 2.2 in the Great Observatories Origins Deep Survey North (GOODS-N) field with MOIRCS instrument on the Subaru Telescope. The survey reached a 3 σ limiting magnitude of 23.6 (NB209), which corresponds to a 3 σ limiting line flux of 2.5 × 10-17 erg s-1 cm-2 over a 56 arcmin2 contiguous area (excluding a shallower area). From this survey, we have identified eleven Hα emitters and one AGN at z = 2.2 on the basis of narrow-band excesses and photometric redshifts. We obtained spectra for seven out of the new objects, including one AGN; also, an emission line above 3 σ was detected from all of them. We estimated star-formation rates (SFR) and stellar masses (Mstar) for individual galaxies. The average SFR and Mstar are 27.8 M\odot yr-1 and 4.0 × 1010 M_\odot, respectively. Their specific star-formation rates negatively correlate with their stellar masses. Fitting to a Schechter function yields the Hα luminosity function with logL = 42.82, logφ = -2.78, and α = -1.37. The average star-formation rate density in the survey volume is estimated to be 0.31 M\odot yr-1 Mpc-3 according to the Kennicutt relation between the Hα luminosity and the star-formation rate. We compared our Hα emitters at z = 2.2 in GOODS-N with narrow-band line emitters in other fields and clusters to see their time evolution and environmental dependence. We found that the star-formation activity is rapidly reduced from z = 2.5 to z = 0.8 in the cluster environment, while it only moderately changed in the field environment. This result suggests that the time scale of galaxy formation differs among different environments, and the star-forming activities in high density regions eventually overtake those in lower-density regions as a consequence of “galaxy-formation bias” at high redshifts.