2007A&A...470..431D


Query : 2007A&A...470..431D

2007A&A...470..431D - Astronomy and Astrophysics, volume 470, 431-448 (2007/8-1)

A new comprehensive set of elemental abundances in DLAs. III. Star formation histories.

DESSAUGES-ZAVADSKY M., CALURA F., PROCHASKA J.X., D'ODORICO S. and MATTEUCCI F.

Abstract (from CDS):

We obtained comprehensive sets of elemental abundances for eleven damped Lyα systems (DLAs) at zDLA=1.7-2.5. For nine of them, we accurately constrained their intrinsic abundance patterns accounting for dust depletion and ionization effects. In Paper I of this series (Dessauges-Zavadsky et al., 2004A&A...416...79D), we showed for three DLA galaxies that we can derive their star formation histories and ages from a detailed comparison of their intrinsic abundance patterns with chemical evolution models. We determine in this paper the star formation properties of six additional DLA galaxies. The derived results confirm that no single star formation history explains the diverse sets of abundance patterns in DLAs. We demonstrate that the various star formation histories reproducing the DLA abundance patterns are typical of local irregular, dwarf starburst and quiescent spiral galaxies. Independent of the star formation history, the DLAs have a common characteristic of being weak star forming galaxies; models with high star formation efficiencies are ruled out. The distribution of the DLA star formation histories shows a trend of finding more galaxies with a star formation history typical of dwarf irregulars with a bursting star formation toward high redshifts, z>2. Only two DLA galaxies (each at z<2) in our sample of nine objects have a star formation history typical of spiral galaxies. Since DLAs sample the broad distribution of galaxies at high redshift, this trend indicates that young and less evolved proto-galactic structures with low masses and low star formation rates are more common toward higher redshifts. This is further supported by the star formation rate and age distributions. Indeed, all the derived DLA star formation rates per unit area are moderate or low, with values between -3.2<logSFR←1.1M/yr/kpc2. The DLA abundance patterns also require a large spread in ages ranging from 20Myr up to 3Gyr. Enhanced α over iron-peak ratios are associated with young objects having undergone a recent burst of star formation, while solar α over iron-peak ratios are associated with old objects undergoing an inefficient continuous star formation. The oldest DLA in our sample is observed at zDLA=1.864 with an age estimated to more than 3Gyr; it nicely indicates that galaxies were already forming at zf>10. But, most of the DLAs show ages much younger than that of the Universe at the epoch of observation. Young galaxies thus seem to populate the high redshift Universe at z>2, suggesting relatively low redshifts of formation (z∼3) for most high-redshift galaxies. The large dispersion in star formation history and age indicates that the DLAs are drawn from a diverse population of galaxies. The DLA star formation properties are compared with those of other high-redshift galaxies identified in deep imaging surveys with the aim of obtaining a global picture of high-redshift objects.

Abstract Copyright:

Journal keyword(s): cosmology: observations - quasars: absorption lines - galaxies: abundances - galaxies: evolution

Simbad objects: 25

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Number of rows : 25
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 GRB 021004 gB 00 26 54.68 +18 55 41.6           ~ 531 0
2 PHL 957 QSO 01 03 11.2741573824 +13 16 17.809871484   16.97 16.57     ~ 336 0
3 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 6418 1
4 QSO B0450-1310 QSO 04 53 13.5744238944 -13 05 55.085318988   13.2 16.5     ~ 88 2
5 4C -02.19 QSO 05 01 12.8099394264 -01 59 14.258630148   19.1 18.4 19.04   ~ 547 1
6 QSO B0841+129 BLL 08 44 24.2445546984 +12 45 46.526286780   18.28 18.5     ~ 114 0
7 Mrk 116 PaG 09 34 02.1 +55 14 25           ~ 1061 1
8 GRB 011211 gB 11 15 16 -21 56.0           ~ 291 0
9 [FJM2003] S1211-6 G 11 15 17.98 -21 56 56.2           ~ 16 0
10 QSO B1157+014 QSO 11 59 44.8278142392 +01 12 06.985999764   17.87 17.52     ~ 212 1
11 LBQS 1210+1731 QSO 12 13 03.0135468360 +17 14 23.237180160   18.21 18.03     ~ 82 0
12 NAME Hubble Deep Field reg 12 36 49.5 +62 12 58           ~ 1879 1
13 QSO B1331+170 QSO 13 33 35.7827544072 +16 49 04.013500728   16.84 16.71 16.41   ~ 428 0
14 NAME MS 1512-cB58 AGN 15 14 22.2751 +36 36 25.674     20.64   20.35 ~ 321 0
15 QSO B1543+5921 QSO 15 44 20.2979128848 +59 12 27.082778112   16.1 17.63 16.4   ~ 49 0
16 SBSG 1543+593 LSB 15 44 20.30 +59 12 24.2   17.5 16.9     ~ 53 2
17 [FGD2001] GRB 000926 Host G G 17 04 09.8 +51 47 11           ~ 11 1
18 GRB 000926 gB 17 04 15 +51 46.0           ~ 351 0
19 LBQS 2206-1958A QSO 22 08 52.0729138920 -19 43 59.866776948   17.49 17.33     ~ 210 0
20 [MFF2004] DLAg2206-19 G 22 08 52.1019 -19 43 58.456           ~ 18 0
21 KODIAQ J223235+024755 QSO 22 32 35.2154152488 +02 47 55.814764596   18.387 18.038     ~ 91 0
22 NAME HDF-S reg 22 32 56 -60 33.0           ~ 555 0
23 KODIAQ J223408+000001 QSO 22 34 08.9971751592 +00 00 01.703853180   18.09 17.39 17.3   ~ 128 0
24 QSO B2343+125 QSO 23 46 28.200 +12 49 00.00     17.5     ~ 131 2
25 QSO B2348-147 BLL 23 51 29.8153792680 -14 27 56.840819544     16.9     ~ 76 1

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2022.10.01-14:51:04

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