2014A&A...566A..19C


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.10CEST02:10:24

2014A&A...566A..19C - Astronomy and Astrophysics, volume 566A, 19-19 (2014/6-1)

Constraints on the star-formation rate of z ∼ 3 LBGs with measured metallicity in the CANDELS GOODS-South field.

CASTELLANO M., SOMMARIVA V., FONTANA A., PENTERICCI L., SANTINI P., GRAZIAN A., AMORIN R., DONLEY J.L., DUNLOP J.S., FERGUSON H.C., FIORE F., GALAMETZ A., GIALLONGO E., GUO Y., HUANG K.-H., KOEKEMOER A., MAIOLINO R., McLURE R.J., PARIS D., SCHAERER D., TRONCOSO P. and VANZELLA E.

Abstract (from CDS):

We aim to constrain the assembly history of high-redshift galaxies and the reliability of UV-based estimates of their physical parameters from an accurate analysis of a unique sample of z∼3 Lyman-break galaxies (LBGs). We analyse 14 LBGs at z∼2.8-3.8 constituting the only sample where both a spectroscopic measurement of their metallicity and deep IR observations (CANDELS+HUGS survey) are available. Fixing the metallicity of population synthesis models to the observed values, we determine best-fit physical parameters under different assumptions about the star-formation history (SFH) and also consider the effect of nebular emission. For comparison, we determine the UV slope of the objects, and use it to estimate their SFRUV99 by correcting the UV luminosity. A comparison between star-formation rate (SFR) obtained through SED-fitting (SFRfit) and the SFRUV99 shows that the latter are underestimated by a factor of 2-10, regardless of the assumed SFH. Other SFR indicators (radio, far-IR, X-ray, recombination lines) coherently indicate SFRs a factor of 2-4 larger than SFRUV99 and in closer agreement with SFRfit. This discrepancy is due to the solar metallicity implied by the usual β-A1600 conversion factor. We propose a refined relation, appropriate for subsolar metallicity LBGs: A1600=5.32+1.99*β. This relation reconciles the dust-corrected UV with the SED-fitting and the other SFR indicators. We show that the fact that z∼3 galaxies have subsolar metallicity implies an upward revision by a factor of ∼1.5-2 of the global SFRD, depending on the assumptions about the age of the stellar populations. We find very young best-fit ages (10-500Myr) for all our objects. From a careful examination of the uncertainties in the fit and the amplitude of the Balmer break we conclude that there is little evidence of the presence of old stellar population in at least half of the LBGs in our sample, suggesting that these objects are probably caught during a huge star-formation burst, rather than being the result of a smooth evolution.

Abstract Copyright:

Journal keyword(s): galaxies: distances and redshifts - galaxies: evolution - galaxies: high-redshift

Simbad objects: 17

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Number of rows : 17

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 [BIO2015] ERSB-2171342178 G 03 32 17.1337 -27 42 17.809   27.3     25.05 ~ 10 0
2 ZFOURGE CDFS 15992 EmG 03 32 17.20802 -27 47 54.1255   26.01   24.505 24.83 ~ 18 0
3 GOODS-MUSIC 9340 G 03 32 17.24 -27 47 53.4           ~ 6 0
4 GOODS J033218.05-274518.9 G 03 32 18.066 -27 45 18.78   28.1   24.797 24.74 ~ 14 0
5 [BIO2015] ERSB-2209343463 G 03 32 20.938 -27 43 46.34   26.7     24.56 ~ 13 0
6 GOODS J033222.59-275118.0 G 03 32 22.5940 -27 51 18.005   27.2 25.71   24.92 ~ 13 0
7 [LBX2017] 416 AGN 03 32 23.3376 -27 51 56.870   26.1   23.42 23.45 ~ 20 0
8 NAME Chandra Deep Field-South reg 03 32 28.0 -27 48 30           ~ 1812 1
9 NAME GOODS Southern Field reg 03 32 28.0 -27 48 30           ~ 1053 1
10 ZFOURGE CDFS 11462 EmG 03 32 33.3263 -27 50 07.365   27.3   24.80 24.79 ~ 14 0
11 [BIO2015] ERSB-2359541499 G 03 32 35.956 -27 41 49.97   26.11   24.214 24.15 ~ 17 0
12 VUDS 530051132 G 03 32 36.31718 -27 44 34.5026   25.56   24.430   ~ 11 0
13 NAME Hubble Ultra Deep Field reg 03 32 39.0 -27 47 29           ~ 1283 0
14 GOODS-MUSIC 11991 G 03 32 42.40 -27 45 51.6       24.23   ~ 4 0
15 GOODS-MUSIC 2528 G 03 32 45.50 -27 53 33.3       24.64   ~ 7 0
16 VUDS 539016841 G 03 32 46.93 -27 46 04.7   24.9       ~ 6 0
17 GMASS 920 G 03 32 47.9874 -27 46 39.398   24.55     23.62 ~ 5 0

    Equat.    Gal    SGal    Ecl

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2020.07.10-02:10:24

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