J/MNRAS/382/109 Massive galaxies in Extended Groth Strip (Trujillo+, 2007)
Strong size evolution of the most massive galaxies since z∼2.
Trujillo I., Conselice C.J., Bundy K., Cooper M.C., Eisenhardt P.,
Ellis R.S.
<Mon. Not. R. Astron. Soc., 382, 109-120 (2007)>
=2007MNRAS.382..109T 2007MNRAS.382..109T
ADC_Keywords: Galaxies, photometry ; Morphology ; Redshifts
Keywords: galaxies: elliptical and lenticular, cD - galaxies: evolution -
galaxies: formation - galaxies: fundamental parameters -
galaxies: high-redshift - galaxies: structure
Abstract:
Using the combined capabilities of the large near-infrared
Palomar/DEEP-2 survey, and the superb resolution of the Advanced
Camera for Surveys HST camera, we explore the size evolution of 831
very massive galaxies (M*≥1011h-270M☉) since z∼2. We
split our sample according to their light concentration using the
Sersic index n. At a given stellar mass, both low (n<2.5) and high
(n>2.5) concentrated objects were much smaller in the past than
their local massive counterparts. This evolution is particularly
strong for the highly concentrated (spheroid like) objects. At z∼1.5,
massive spheroid-like objects were a factor of 4(±0.4) smaller (i.e.
almost two orders of magnitudes denser) than those we see today. These
small sized, high-mass galaxies do not exist in the nearby Universe,
suggesting that this population merged with other galaxies over
several billion years to form the largest galaxies we see today.
Description:
We use the Palomar Observatory Wide-field Infrared (POWIR)/DEEP-2
survey (Davis et al., 2003, SPIE, Vol. 4834, p. 161; Bundy et al.,
2006ApJ...651..120B 2006ApJ...651..120B ; Conselice et al., 2007ApJ...660L..55C 2007ApJ...660L..55C,
2007MNRAS.381..962C 2007MNRAS.381..962C) to define a sample of 831 galaxies with masses
larger than 1011h70-2M☉ located over ∼710arcmin2 in the
Extended Groth Strip (EGS). This field (63 Hubble Space Telescope
tiles) was imaged with the Advanced Camera for Surveys (ACS) in the V
band (F606W, 2660s) and I band (F814W, 2100s). Each tile was observed
in four exposures that were combined to produce a pixel scale of
0.03arcsec, with a point spread function (PSF) of 0.12arcsec full
width half-maximum (FWHM). In addition to the HST data, optical
imaging from the CanadaFranceHawaii Telescope 3.6-m telescope in the
B, R and I bands taken with the CFH12K camera was used. Integration
times for these observations were 1h in B and R, and 2h in I. Limiting
magnitudes reached are B=24.5 (AB, 8σ), R=24.2 (AB, 8σ)
and I=23.5 (AB, 8σ). The details of the data reduction for this
data are provided in Coil et al. (2004ApJ...617..765C 2004ApJ...617..765C).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 63 796 Properties of the Palomar/DEEP2 sample galaxies
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- [TCB2007] Galaxy identification number
10- 14 F5.2 mag Ks Ks magnitude (in Vega system)
16- 19 F4.2 arcsec ae Effectif radius along semi-major axis
21- 24 F4.2 --- n Sersic index (f(r)∝r1/n)
26- 29 F4.2 --- eps Ellipticity of the source
31- 35 F5.2 10+10solMass Mstar Stellar mass of the galaxy
(in 1010(h70)-2M☉
37- 40 F4.2 --- z Measured redshift (see 'n_z' column)
42- 51 F10.6 deg RAdeg Right ascension in decimal degrees (J2000)
53- 61 F9.6 deg DEdeg Declination in decimal degrees (J2000)
63 I1 --- n_z [0/1] spectroscopic (0) or photometric (1)
redshift
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 31-Mar-2008