J/MNRAS/431/2080 Lyman break galaxies (LBG) at z∼1 (Chen+, 2013)
Properties and morphologies of Lyman break galaxies at z∼1 in the Chandra Deep
Field South, inferred from spectral energy distributions.
Chen Z., Shu C.G., Burgarella D., Buat V., Huang J.-S., Luo Z.J.
<Mon. Not. R. Astron. Soc., 431, 2080-2105 (2013)>
=2013MNRAS.431.2080C 2013MNRAS.431.2080C
ADC_Keywords: Galaxies, photometry ; Redshifts
Keywords: galaxies: evolution - galaxies: formation -
galaxies: luminosity function, mass function - galaxies: statistics -
galaxies: structure
Abstract:
After carefully cross-identifying previously discovered - and selected
by the Galaxy Evolution Explorer (GALEX) - Lyman break galaxy (LBG)
candidates one-to-one with their optical counterparts in the field of
the Chandra Deep Field South (CDF-S), we re-estimate their photometric
redshifts using multiwavelength data from ultraviolet and optical to
near-infrared. Considering their re-estimated photometric redshifts
and spectral energy distributions, we refine a new updated sample of
383 LBGs at 0.7≲z≲1.4, with two confirmed active galactic nuclei
being excluded. There are 260 and 111 LBGs classified as starburst and
irregular types, respectively. The ages of the LBGs span from several
Myr to 1.5Gyr with a median of ∼50Myr. Their dust-corrected star
formation rates (SFRs) and stellar masses (M*) are 4-220M☉/yr
and from 2.3x108 to 4x1011M☉, with median values of
∼25M☉/yr and ∼1010M☉. The rest-frame far-ultraviolet
luminosity function of the LBGs is presented with the best-fitting
Schechter parameters of α=-1.61±0.40, M*=-20.40±0.22 and
φ*=(0.89±0.30)x10-3/Mpc3/dex. LBGs of irregular types are
mainly distributed along the main sequence of star-forming galaxies,
while most LBGs of starburst types are located in the starburst
region. Together with previous studies, we suggest that the star
formation mode for LBGs at z>3 is mainly starburst, and that it
evolves to be more significant to the quenching mode after z∼3. A
downsizing effect is clearly found, and we discuss the physical
implications and comparisons with previous studies in detail. LBGs
with larger SFRs are, on average, more compact. In the rest-frame
colour (U-B)-M* diagram, LBGs are distributed in the `blue' cloud. We
suggest that LBGs might evolve along the blue cloud from later to
earlier types. The Hubble Space Telescope images in F606W (V band) and
F850LP (z band) are taken from the Galaxy Evolution from Morphology
and SEDs (GEMS) survey and the Great Observatories Origins Deep Survey
South (GOODS-S) for morphological studies of LBGs. sextractor and
galfit are applied in order to obtain their morphological parameters.
We establish an image gallery of 277 LBGs, commonly detected in both
bands, by visually classifying individual LBGs into the following
types: chain, spiral, tadpole, bulge and clump. We define a
morphological sample of 142 LBGs with reliable results of Sersic
indices and sizes in both bands. We find that LBGs at z∼1 are
dominated by disc-like galaxies, with median sizes of 2.34 and 2.68kpc
in F606W and F850LP, respectively. The correlations between the
photometric and morphological properties of LBGs are investigated.
Strong correlations between their half-light radii and M* (i.e.
size-stellar mass relations) are found in both bands. We discuss the
physical connections between the correlations and the downsizing
effect.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table5.dat 65 383 Detailed photometric properties of LBGs at the
redshift range of 0.7≤zp≤1.4
table6.dat 31 277 Details of morphological properties of 277 LBGs
table6.pdf 512 44228 *Details of morphological properties of 277 LBGs
with images detected in both F606W and F850LP bands
--------------------------------------------------------------------------------
Note on table6.pdf: In the second row, LBG images detected by SExtractor,
modeled by GALFIT, and residual images with the upper and lower panels for
F606W and F850LP bands are shown respectively. Figures of corresponding SED
fittings are in the right-hand side of the second row.
--------------------------------------------------------------------------------
See also:
II/253 : Chandra Deep Field South: multi-colour data (Wolf+, 2008)
J/MNRAS/380/986 : Lyman-break galaxies from GALEX (Burgarella+, 2007)
J/ApJS/189/270 : MUSYC optical imaging in ECDF-S (Cardamone+, 2010)
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- IDUV UV identification number from Burgarella
et al. 2007 (J/MNRAS/380/986),
<[BLT2007] NNNNN> in Simbad
7- 11 I5 --- IDC17 COMBO 17 identification number (Cat. II/253)
<[WDK2001] NNNNN> in Simbad
13- 17 I5 --- IDMUSYC ?=- MUSYC identification (J/ApJS/189/270)
<[CVU2010] NNNNN> in Simbad
19- 23 F5.3 --- zp Photometric (or spectroscopic if specified)
redshift (1)
25- 29 F5.3 --- E_zp ? Error in zp (upper value)
31- 35 F5.3 --- e_zp ? Error in zp (lower value)
36- 39 A4 --- n_zp [zspe ] indicates a spectroscopic redshift
41- 45 F5.1 Msun/yr SFR Stellar formation rate
47- 50 F4.1 [Msun] logM* Stellar mass
52- 56 F5.2 mag [24] ?=99.99 Detection of MIPS 24um (2)
58- 62 F5.2 --- chi2 ?=- Goodness of SED fitting
64- 65 I2 --- SpT Resulted spectral type (3)
--------------------------------------------------------------------------------
Note (1): Re-estimated photometric redshifts zp of individual LBGs. Note that
zp are replaced by spectroscopic redshifts zspe if available except two with
bad spectroscopic observations.
Note (2): Detections of MIPS 24um compiled by Burgarella et al. (2007,
Cat. J/MNRAS/380/986) with number 99.99 indicating without detections.
Note (3): Table2: The SpTs (with the star formation time-scales τ if
available) and their corresponding SpT numbers of different templates
adopted for SED fittings.
---------------------------------------------------------
SpT Spectral type Templates τ(Gyr)
---------------------------------------------------------
1 = E BC03 1
2 = E CWW -
3 = S0 BC03 2
4 = Sa BC03 3
5 = Sb BC03 5
6 = Sbc CWW -
7 = Sc BC03 15
8 = Scd CWW -
9 = Sd BC03 30
10 = Irr BC03 ∞ (*)
11 = Irr CWW -
12 = Dusty CWW -
13 = Burst BC03 0 (*)
14 = Arp220-modifying Arp220-rebuilt -
15 = Arp220 Arp220 -
---------------------------------------------------------
(*) Note that τ=∞ and 0 correspond to a constant
SFR and a single burst, respectively.
BC03 denoting templates from Bruzual & Charlot (2003MNRAS.344.1000B 2003MNRAS.344.1000B),
CWW from Coleman et al. (1980ApJS...43..393C 1980ApJS...43..393C) and
Arp220 and Arp220-modifying from Huang et al. (2009ApJ...700..183H 2009ApJ...700..183H)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- IDUV UV identification number from Burgarella
et al. 2007 (J/MNRAS/380/986),
<[BLT2007] NNNNN> in Simbad
7- 10 F4.2 --- n(r) ?=9.99 Sersic index in F606W
12- 15 F4.2 --- n(z) ?=9.99 Sersic index in F850LP
17- 21 F5.2 kpc r(r) ?=9.99 Half-light radius for Sersic index
in F606W obtained by GALFIT
23- 27 F5.2 kpc r(z) ?=9.99 Half-light radius for Sersic index
in F850LP obtained by GALFIT
29 I1 --- Q [0/1] Quality of GALFIT result
(1=reliable, 0=unreliable)
31 I1 --- Cl [1/6] Visual classification of LBG image (4)
--------------------------------------------------------------------------------
Note (4): Type for visual classification as follows:
1 = tadpole (show very close companions in their images),
classified as starburst/Arp 220/irregular type.
2 = chain (anomalous mrophologies that display chaotic shapes, containing
multiple bright knots), classified as starbursts or irregulars.
3 = clump (display very clumpy star-forming regions),
classified as starburst-type Lyman break galaxies
4 = bulge (images show very regular shapes in both images),
mostly classified as starburst galaxies
5 = spiral Lyman break galaxy (LBG), classified as Sbc/Scd/E-type galaxies
6 = bad pixel images
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 13-Jun-2014