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dc.contributor.authorPerrotta, S.
dc.contributor.authorD'Odorico, V.
dc.contributor.authorProchaska, J. Xavier
dc.contributor.authorCristiani, S.
dc.contributor.authorCupani, G.
dc.contributor.authorEllison, S.
dc.contributor.authorLópez, S.
dc.contributor.authorBecker, G. D.
dc.contributor.authorBerg, T. A. M.
dc.contributor.authorChristensen, L.
dc.contributor.authorDenney, K. D.
dc.contributor.authorHamann, F.
dc.contributor.authorPâris, I.
dc.contributor.authorVestergaard, M.
dc.contributor.authorWorseck, G.
dc.date.accessioned2016-12-16T00:15:46Z
dc.date.available2016-12-16T00:15:46Z
dc.date.issued2016-11-01
dc.identifier.citationNature and statistical properties of quasar associated absorption systems in the XQ-100 Legacy Survey 2016, 462 (3):3285 Monthly Notices of the Royal Astronomical Societyen
dc.identifier.issn0035-8711
dc.identifier.issn1365-2966
dc.identifier.doi10.1093/mnras/stw1703
dc.identifier.urihttp://hdl.handle.net/10150/621733
dc.description.abstractWe statistically study the physical properties of a sample of narrow absorption line (NAL) systems looking for empirical evidences to distinguish between intrinsic and intervening NALs without taking into account any a priori definition or velocity cut-off. We analyse the spectra of 100 quasars with 3.5 < z(em) < 4.5, observed with X-shooter/Very Large Telescope in the context of the XQ-100 Legacy Survey. We detect an similar to 8 sigma excess in the CIV number density within 10 000 km s(-1) of the quasar emission redshift with respect to the random occurrence of NALs. This excess does not show a dependence on the quasar bolometric luminosity and it is not due to the redshift evolution of NALs. It extends far beyond the standard 5000 km s(-1) cutoff traditionally defined for associated absorption lines. We propose to modify this definition, extending the threshold to 10 000 km s(-1) when weak absorbers (equivalent width < 0.2 angstrom) are also considered. We infer NV is the ion that better traces the effects of the quasar ionization field, offering the best statistical tool to identify intrinsic systems. Following this criterion, we estimate that the fraction of quasars in our sample hosting an intrinsic NAL system is 33 per cent. Lastly, we compare the properties of the material along the quasar line of sight, derived from our sample, with results based on close quasar pairs investigating the transverse direction. We find a deficiency of cool gas (traced by C II) along the line of sight connected to the quasar host galaxy, in contrast with what is observed in the transverse direction.
dc.description.sponsorshipDARK cosmology centre; PRIN INAF; NSF [AST-1109447]; NSERC; DNRF; FONDECYT [1140838]; NSF AAPF fellowship under NSF Grant [AST-1302093]; Danish Council for Independent Research [DFF 4002-00275]; UCSC; [PFB-06 CATA]en
dc.language.isoenen
dc.publisherOXFORD UNIV PRESSen
dc.relation.urlhttp://mnras.oxfordjournals.org/lookup/doi/10.1093/mnras/stw1703en
dc.rights© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Societyen
dc.subjectgalaxies: high-redshiften
dc.subjectintergalactic mediumen
dc.subjectquasars: absorption linesen
dc.titleNature and statistical properties of quasar associated absorption systems in the XQ-100 Legacy Surveyen
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Dept Astronen
dc.contributor.departmentUniv Arizona, Steward Observen
dc.identifier.journalMonthly Notices of the Royal Astronomical Societyen
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
refterms.dateFOA2018-04-25T18:14:48Z
html.description.abstractWe statistically study the physical properties of a sample of narrow absorption line (NAL) systems looking for empirical evidences to distinguish between intrinsic and intervening NALs without taking into account any a priori definition or velocity cut-off. We analyse the spectra of 100 quasars with 3.5 < z(em) < 4.5, observed with X-shooter/Very Large Telescope in the context of the XQ-100 Legacy Survey. We detect an similar to 8 sigma excess in the CIV number density within 10 000 km s(-1) of the quasar emission redshift with respect to the random occurrence of NALs. This excess does not show a dependence on the quasar bolometric luminosity and it is not due to the redshift evolution of NALs. It extends far beyond the standard 5000 km s(-1) cutoff traditionally defined for associated absorption lines. We propose to modify this definition, extending the threshold to 10 000 km s(-1) when weak absorbers (equivalent width < 0.2 angstrom) are also considered. We infer NV is the ion that better traces the effects of the quasar ionization field, offering the best statistical tool to identify intrinsic systems. Following this criterion, we estimate that the fraction of quasars in our sample hosting an intrinsic NAL system is 33 per cent. Lastly, we compare the properties of the material along the quasar line of sight, derived from our sample, with results based on close quasar pairs investigating the transverse direction. We find a deficiency of cool gas (traced by C II) along the line of sight connected to the quasar host galaxy, in contrast with what is observed in the transverse direction.


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