TY - JOUR
T1 - In and out star formation in z ~ 1.5 quiescent galaxies from rest-frame UV spectroscopy and the far-infrared
AU - Gobat, R.
AU - Daddi, E.
AU - Strazzullo, V.
AU - Garilli, B.
AU - Mignoli, M.
AU - Ma, Z.
AU - Jin, S.
AU - Maraston, C.
AU - Magdis, G.
AU - Béthermin, M.
AU - Cappellari, M.
AU - Carollo, M.
AU - Cimatti, A.
AU - Feruglio, C.
AU - Moresco, M.
AU - Onodera, M.
AU - Pozzetti, L.
AU - Renzini, A.
AU - Sargent, M.
AU - Valentino, F.
AU - Zanella, A.
PY - 2017/3/1
Y1 - 2017/3/1
N2 - We present a sample of 34 spectroscopically confirmed BzK-selected 1011 M quiescent galaxies (pBzK) in the COSMOS field. The targets were initially observed with VIMOS on the VLT to facilitate the calibration of the photometric redshifts of massive galaxies at z and 1:5. Here we describe the reduction and analysis of the data, and the spectrophotometric properties of these pBzK galaxies. In particular, using a spatially resolved median 2D spectrum, we find that the fraction of stellar populations with ages <1 Gyr is at least 3 times higher in the outer regions of the pBzK galaxies than in their cores. This results in a mild age gradient of age 0:4 Gyr over 6 kpc and suggests either the occurrence of widespread rejuvenation episodes or that inside-out quenching played a role in the passivization of this galaxy population. We also report on low-level star formation rates derived from the [OII]3727 emission line, with SFROII 3:74:5 M yr1. This estimate is confirmed by an independent measurement on a separate sample of similarly-selected quiescent galaxies in the COSMOS field, using stacked far-infrared data (SFRFIR 24 M yr1). This second, photometric sample also displays significant excess at 1.4 GHz, suggestive of the presence of radio-mode AGN activity.
AB - We present a sample of 34 spectroscopically confirmed BzK-selected 1011 M quiescent galaxies (pBzK) in the COSMOS field. The targets were initially observed with VIMOS on the VLT to facilitate the calibration of the photometric redshifts of massive galaxies at z and 1:5. Here we describe the reduction and analysis of the data, and the spectrophotometric properties of these pBzK galaxies. In particular, using a spatially resolved median 2D spectrum, we find that the fraction of stellar populations with ages <1 Gyr is at least 3 times higher in the outer regions of the pBzK galaxies than in their cores. This results in a mild age gradient of age 0:4 Gyr over 6 kpc and suggests either the occurrence of widespread rejuvenation episodes or that inside-out quenching played a role in the passivization of this galaxy population. We also report on low-level star formation rates derived from the [OII]3727 emission line, with SFROII 3:74:5 M yr1. This estimate is confirmed by an independent measurement on a separate sample of similarly-selected quiescent galaxies in the COSMOS field, using stacked far-infrared data (SFRFIR 24 M yr1). This second, photometric sample also displays significant excess at 1.4 GHz, suggestive of the presence of radio-mode AGN activity.
KW - Galaxies: elliptical and lenticular, cD
KW - Galaxies: formation
KW - Galaxies: high-redshift
KW - Galaxies: star formation
KW - Galaxies: stellar content
UR - http://www.scopus.com/inward/record.url?scp=85014701675&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201629852
DO - 10.1051/0004-6361/201629852
M3 - Article
AN - SCOPUS:85014701675
SN - 0004-6361
VL - 599
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A95
ER -