2009A&A...496...31F


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.05CET21:48:31

2009A&A...496...31F - Astronomy and Astrophysics, volume 496, 31-44 (2009/3-2)

The nature of NV absorbers at high redshift.

FECHNER C. and RICHTER P.

Abstract (from CDS):

We present a study of NV absorption systems at 1.5≲z≲2.5 in the spectra of 19 QSOs, based on data obtained with the VLT/UVES instrument. Our analysis includes both the absorbers arising from the intergalactic medium, as well as systems in the vicinity of the background quasar. We construct detailed photoionization models to study the physical conditions and abundances in the absorbers and to constrain the spectral hardness of the ionizing radiation. The rate of incidence for intervening NV components is dN/dz=3.38±0.43, corresponding to dN/dX=1.10±0.14. The column density distribution function is fitted by the slope β=1.89±0.22, consistent with measurements of CIV and OVI. The narrow line widths (buppercase++{N}v∼6km/s) imply photoionization rather than collisions as the dominating ionization process. The column densities of CIV and NV are correlated but show different slopes for intervening and associated absorbers, which indicates different ionizing spectra. Associated systems are found to be more metal-rich, denser, and more compact than intervening absorbers. This conclusion is independent of the adopted ionizing radiation. For the intervening NV systems we find typical values of [C/H]~-0.6 and nH∼10–3.6cm–3 and sizes of a few kpc, while for associated NV absorbers we obtain [C/H]~+0.7, nH∼10–2.8cm–3 and sizes of several 10pc. The abundance of nitrogen relative to carbon [N/C] and α-elements like oxygen and silicon [N/α] is correlated with [N/H], indicating the enrichment by secondary nitrogen. The larger scatter in [N/α] in intervening systems suggests an inhomogeneous enrichment of the IGM. There is an anti-correlation between [N/α] and [α/C], which could be used to constrain the initial mass function of the carbon- and nitrogen-producing stellar population.

Abstract Copyright:

Journal keyword(s): galaxies: intergalactic medium - galaxies: quasars: absorption lines - cosmology: observations

CDS comments: Paragraph 5.1, paragraph 5.2 HE 1158-1543 is a misprint for HE 1158-1843. Table B.1 HE 1347-2357 is a misprint for HE 1347-2457.

Simbad objects: 19

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Number of rows : 19

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 QSO J0003-2323 QSO 00 03 44.9144470879 -23 23 55.075352888     16.7     ~ 69 0
2 QSO B0002-422 QSO 00 04 48.2718823544 -41 57 28.150311306   17.44 17.21     ~ 155 0
3 QSO B0109-353 QSO 01 11 43.6321355926 -35 03 00.586979841   16.6 16.9     ~ 72 0
4 QSO B0122-379 QSO 01 24 17.3723276055 -37 44 22.919153842     17.1     ~ 113 0
5 QSO J0153-4311 QSO 01 53 27.1919509912 -43 11 38.096734050     16.80     ~ 45 0
6 QSO B0237-2322 QSO 02 40 08.1742481040 -23 09 15.727160394   16.78 16.63     ~ 483 0
7 QSO B0329-385 QSO 03 31 06.3780192488 -38 24 04.653743031   17.63 16.92     ~ 75 0
8 PHL 4444 QSO 03 31 08.9205312901 -25 24 43.264751845   17.82 17.51 18.2   ~ 94 1
9 QSO J0422-3844 BLL 04 22 14.7829518039 -38 44 52.824921025   17.70 16.92 16.3   ~ 191 1
10 QSO J0455-4216 QSO 04 55 23.0623318803 -42 16 17.398158654   17.77 17.06     ~ 133 0
11 QSO B0940-1050 QSO 09 42 53.5076745009 -11 04 25.929146122   16.96 16.6 16.6   ~ 87 0
12 QSO B1122-168 QSO 11 24 42.8660012281 -17 05 17.386970324   16.5 16.5 16.1   ~ 123 1
13 QSO B1158-1842 QSO 12 00 44.9453271433 -18 59 44.478488620   17.22 16.93     ~ 55 0
14 NAME LOCAL SUPERCL SCG 12 31 +12.4           ~ 461 0
15 QSO J1344-1035 QSO 13 44 27.0638968862 -10 35 41.748550205     17.1     ~ 47 0
16 QSO B1448-232 QSO 14 51 02.5094965667 -23 29 31.105639377   17.13 16.96     ~ 121 2
17 QSO B2126-15 QSO 21 29 12.17589777 -15 38 41.0413097   17.61 17.3 17.3   ~ 472 1
18 QSO J2220-2803 QSO 22 20 06.7586653848 -28 03 23.466203761     16.0 16.10   ~ 89 0
19 QSO B2347-4342 QSO 23 50 34.2595236845 -43 25 59.680334378   16.3 16.3     ~ 160 0

    Equat.    Gal    SGal    Ecl

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2021.03.05-21:48:31

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