J/MNRAS/495/1807 Stellar populations in LAEs and LBGs (Arrabal Haro+, 2020)
Differences and similarities of stellar populations in LAEs and LBGs at
z∼3.4-6.8.
Arrabal Haro P., Rodriguez Espinosa J.M., Munoz-Tunon C., Sobral D.,
Lumbreras-Calle A., Boquien M., Hernan-Caballero A., Rodriguez-Munoz L.,
Alcalde Pampliega B.
<Mon. Not. R. Astron. Soc., 495, 1807-1824 (2020)>
=2020MNRAS.495.1807A 2020MNRAS.495.1807A (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Redshifts ; Populations, stellar ; Stars, ages ;
Models ; Optical ; Infrared
Keywords: galaxies: evolution - galaxies: high-redshift -
galaxies: luminosity function, mass function -
cosmology: observations - dark ages, reionization, first stars
Abstract:
Lyman alpha emitters (LAEs) and Lyman break galaxies (LBGs) represent
the most common groups of star-forming galaxies at high z, and the
differences between their inherent stellar populations (SPs) are a key
factor in understanding early galaxy formation and evolution. We have
run a set of SP burst-like models for a sample of 1558 sources at
3.4<z<6.8 from the Survey for High-z Absorption Red and Dead Sources
(SHARDS) over the GOODS-N field. This work focuses on the differences
between the three different observational subfamilies of our sample:
LAE-LBGs, no-Lyα LBGs, and pure LAEs. Single and double SP
synthetic spectra were used to model the spectral energy
distributions, adopting a Bayesian information criterion to analyze
under which situations a second SP is required. We find that the
sources are well modelled using a single SP in ∼79 per cent of the
cases. The best models suggest that pure LAEs are typically young
low-mass galaxies (t∼26+41-25Myr;
Mstar∼5.6+12.0-5.5x108M☉), undergoing one of their first
bursts of star formation. On the other hand, no-Lyα LBGs require
older SPs (t∼71±12Myr), and they are substantially more massive
(Mstar∼3.5±1.1x109M☉). LAE-LBGs appear as the subgroup
that more frequently needs the addition of a second SP, representing
an old and massive galaxy caught in a strong recent star-forming
episode. The relative number of sources found from each subfamily at
each z supports an evolutionary scenario from pure LAEs and single SP
LAE-LBGs to more massive LBGs. Stellar mass functions are also
derived, finding an increase of M* with cosmic time and a possible
steepening of the low-mass slope from z∼6 to z∼5 with no significant
change to z∼4. Additionally, we have derived the SFR-Mstar relation,
finding an SFR∝Mstarβ behaviour with negligible
evolution from z∼4 to z∼6.
Description:
Arrabal Haro et al. (2018MNRAS.478.3740A 2018MNRAS.478.3740A, Cat. J/MNRAS/478/3740) used
the 25 medium-width filters (full width at half-maximum∼17nm) of the
SHARDS ESO/Gran Telescopio Canarias (GTC) survey (Perez-Gonzalez et
al. 2013ApJ...762...46P 2013ApJ...762...46P, Cat. J/ApJ/762/46) to simultaneously select
LAEs and LBGs. The sample of high-z galaxies was selected via colour
excesses and photometric fits of their SEDs.
The final sample consists of 1558 sources at z∼3.4-6.8, distributed
into 1434 LBGs (404 of them showing Lyα emission line with
EW0>5.1Å), and 124 pure LAEs (m1500≳27.0AB; Lyα
EW0>35Å). In order to further extend our SEDs beyond the SHARDS
wavelength range, we also use ancillary broad-band GOODS-N data from
HST/ACS (Giavalisco et al. 2004ApJ...600L..93G 2004ApJ...600L..93G, Cat. II/261; Riess et
al. 2007ApJ...659...98R 2007ApJ...659...98R), HST/WFC3 (Grogin et al. 2011ApJS..197...35G 2011ApJS..197...35G;
Koekemoer et al. 2011ApJS..197...36K 2011ApJS..197...36K), and Spitzer/IRAC (Fazio et al.
2004ApJS..154...39F 2004ApJS..154...39F; Perez-Gonzalez et al. 2005ApJ...630...82P 2005ApJ...630...82P,
2008ApJ...675..234P 2008ApJ...675..234P, Cat. J/ApJ/675/234; Ashby et al.
2015ApJS..218...33A 2015ApJS..218...33A, Cat. J/ApJS/218/33), as available in the Rainbow
Cosmological Surveys Database (Barro et al. 2011ApJS..193...13B 2011ApJS..193...13B, Cat.
J/ApJS/193/13, 2011ApJS..193...30B 2011ApJS..193...30B, Cat. J/ApJS/193/30,
2019ApJS..243...22B 2019ApJS..243...22B).
Single and double stellar population (SP) models are used to fit every
SED, using a Bayesian Information Criterion (BIC) calibration to
decide in which situations an extra SP is needed. In Table 2, we
present the IDs, coordinates, ages, and stellar masses derived for our
1555 well-modelled galaxies.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 101 1555 Main physical parameters derived from the best
models fitted to each source
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See also:
J/MNRAS/478/3740 : High-z LAEs and LBGs in SHARDS survey (Arrabal Haro+, 2018)
J/ApJ/762/46 : SHARDS: GOODS-N spectrophotometry survey
(Perez-Gonzalez+, 2013)
II/261 : GOODS initial results (Giavalisco+, 2004)
J/ApJ/675/234 : Stellar mass functions for galaxies 0<z<4
(Perez-Gonzalez+, 2008)
J/ApJS/218/33 : Spitzer-CANDELS catalog within 5 deep fields (Ashby+, 2015)
J/ApJS/193/13 : Spitzer/IRAC sources in the EGS I. SEDs (Barro+, 2011)
J/ApJS/193/30 : UV-to-FIR analysis of sources in the EGS. II.
(Barro+, 2011)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Source name (SHARDSNNNNNNNN)
16- 17 I2 h RAh Right ascension (J2000)
19- 20 I2 min RAm Right ascension (J2000)
22- 25 F4.1 s RAs Right ascension (J2000)
27 A1 --- DE- Declination sign (J2000)
28- 29 I2 deg DEd Declination (J2000)
31- 32 I2 arcmin DEm Declination (J2000)
34- 37 F4.1 arcsec DEs Declination (J2000)
39- 42 F4.2 --- z Redshift
44- 47 F4.2 --- e_z Error on z
49- 53 F5.1 10+9Msun Mstarm Main stellar population mass
55- 59 F5.1 10+9Msun e_Mstarm Error on Mstarm
61- 64 I4 Myr Agem Main stellar population age
66- 68 I3 Myr e_Agem Error on Agem
70- 72 F3.1 Myr tau0 Main stellar population e-folding time
stellar populations
74- 76 F3.1 Myr e_tau0 Error on tau0
78- 81 F4.1 10+9Msun Mstarb ? Burst stellar mass (1)
83- 86 F4.1 10+9Msun e_Mstarb ? Error on Mstarb
88- 89 I2 Myr Ageb ? Burst age (1)
91- 92 I2 Myr e_Ageb ? Error on Ageb
94- 97 F4.1 Myr tau1 ? Burst e-folding time (1)
99- 101 F3.1 Myr e_tau1 ? Error on tau1
--------------------------------------------------------------------------------
Note (1): If no double stellar population (DSP) model was required, these
columns are left empty
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 13-Jun-2023