J/A+A/616/A158 z>1.5 QSO VLT-XSHOOTER spectra (Zou+, 2018)
Near infrared spectroscopic observations of high redshift CI absorbers.
Zou S., Petitjean P., Noterdaeme P., Ledoux C., Krogager J.-K.,
Fathivavsari H., Srianand R., Lopez S.
<Astron. Astrophys. 616, A158 (2018)>
=2018A&A...616A.158Z 2018A&A...616A.158Z (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Spectroscopy
Keywords: infrared: galaxies - methods: observational -
techniques: spectroscopic - Galaxy: abundances -
galaxies: kinematics and dynamics
Abstract:
We study a sample of 17 z>1.5 absorbers selected based on the presence
of strong neutral carbon (CI) absorption lines in Sloan Digital Sky
Survey (SDSS) spectra and observed with the European Southern
Observatory Very Large Telescope (ESO-VLT) spectrograph X-shooter. We
derive metallicities, depletion onto dust, and extinction by dust, and
analyse the absorption from MgII, MgI, CaII, and NaI that are
redshifted into the near infrared wavelength range. We show that most
of these CI absorbers have high metallicity and dust content. We
detect nine CaII absorptions with W(CaI 3934)>0.23Å out of 14
systems where we have appropriate wavelength coverage. The observed
equivalent widths are similar to what has been measured in other lower
redshift surveys of CaII systems. We detect ten NaI absorptions in
the 11 systems where we could observe this absorption. The median
equivalent width (W(NaI 5891)=0.68Å) is larger than what is
observed in local clouds with similar HI column densities but also in
z<0.7 CaII systems detected in the SDSS. The systematic presence of
NaI absorption in these CI systems strongly suggests that the gas is
neutral and cold, maybe part of the diffuse molecular gas in the
interstellar medium (ISM) of high-redshift galaxies.
Most of the systems (12 out of 17) have W(MgII 2796)>2.5Å and six
of them have logN(HI)<20.3, with the extreme case of J1341+1852 that
has log N(HI)=18.18. The MgII absorptions are spread over more than
Δv∼400km/s for half of the systems; three absorbers have
Δv>500km/s. The kinematics are strongly perturbed for most of
these systems, which indicates that these systems probably do not
arise in quiet disks and must be close to regions with intense
star-formation activity and/or are part of interacting objects. All
this suggests that a large fraction of the cold gas at high redshift
arises in disturbed environments.
Description:
17 CI-selected QSO spectra with z>1.5 are observed by VLT-XSHOOTER.
The full CI sample is described in Ledoux et al.
(2015A&A...580A...8L 2015A&A...580A...8L). Full RA,DEC, Plate, Program ID, PI are
described in ci_xsh.dat.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ci-xhs.dat 93 17 Xshooter subsample from DR7, published in
Ledoux et al. (2015A&A...580A...8L 2015A&A...580A...8L)
sp/* . 51 Individual spectra
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See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
Byte-by-byte Description of file: ci-xhs.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Name (JHHMM+DDMM)
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 22 F5.2 s RAs Right ascension (J2000)
24 A1 --- DE- Declination sign (J2000)
25- 26 I2 deg DEd Declination (J2000)
28- 29 I2 arcmin DEm Declination (J2000)
31- 35 F5.2 arcsec DEs Declination (J2000)
37- 40 I4 --- Plate SDSS Plate number
42- 46 I5 d MJD SDSS MJD number
48- 50 I3 --- Fiber SDSS Fiber number
52- 55 F4.2 --- zem Emission redshift
57- 61 F5.3 --- zabs Absorption redshift
63- 70 A8 --- Follow-up [Xshooter] Follow-up
72- 93 A22 --- PrgmID Program ID(s) (1)
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Note (1): Program ID as follows:
060.A-9024 = PI UVES Team - X-shooter Commissioning
084.A-0699 = PI Lopez - CO molecules at high redshift:
Complete sample of CI absorbers with extreme properties
086.A-0074 = PI Fynbo - Galaxy counterparts of metal rich damped
lyman-alpha absorbers
086.A-0643 = PI Noterdaeme - Complete sample of CI absorbers:
the first study of translucent clouds at high redshift
087.A-0548 = PI Noterdaeme - Probing star-formation activity in DLAs with
high cooling rates
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Byte-by-byte Description of file (#): sp/*
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Bytes Format Units Label Explanations
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1- 12 F12.6 0.1nm lambda Vacuum heliocentric wavelength
17- 27 E11.5 10mW/m2/nm Flux Flux corrected for Galactic foreground
(erg/s/cm^2/Å)
33- 42 E10.5 10mW/m2/nm e_Flux rms uncertainty on Flux (erg/s/cm^2/Å)
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Acknowledgements:
Siwei Zou, zou(at)iap.fr
(End) Siwei Zou [IAP, Paris], Patricia Vannier [CDS] 28-Aug-2018