COS-Weak: probing the CGM using analogs of weak Mg ii absorbers at z < 0.3
Author
dc.contributor.author
Muzahid, S.
Author
dc.contributor.author
Fonseca, G.
Author
dc.contributor.author
Roberts, A.
Author
dc.contributor.author
Rosenwasser, B.
Author
dc.contributor.author
Richter, P.
Author
dc.contributor.author
Narayanan, A.
Author
dc.contributor.author
Churchill, C.
Author
dc.contributor.author
Charlton, J.
Admission date
dc.date.accessioned
2018-10-08T13:37:05Z
Available date
dc.date.available
2018-10-08T13:37:05Z
Publication date
dc.date.issued
2018
Cita de ítem
dc.identifier.citation
Monthly Notices of the Royal Astronomical Society, Volumen 476, Issue 4, 2018, Pages 4965-4986
es_ES
Identifier
dc.identifier.other
10.1093/mnras/sty529
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/151986
Abstract
dc.description.abstract
We present a sample of 34 weak metal line absorbers at z < 0.3 selected by the simultaneous > 3 sigma detections of the Si II lambda 1260 and CII lambda 1334 absorption lines, with W-r (Si II) < 0.2 angstrom and W-r (C II) < 0.3 angstrom, in archival HST/COS spectra. Our sample increases the number of known low-z 'weak absorbers' by a factor of > 5. The column densities of HI and low-ionization metal lines obtained from Voigt profile fitting are used to build simple photoionization models. The inferred densities and line-of-sight thicknesses of the absorbers are in the ranges of -3.3 < log n(H)/cm(-3) < -2.4 and similar to 1 pc-50 kpc (median approximate to 500 pc), respectively. Most importantly, 85 per cent (50 per cent) of these absorbers show a metallicity of [Si/H] > -1.0(0.0). The fraction of systems showing near-/supersolar metallicity in our sample is significantly higher than in the HI-selected sample of Wotta et al., and the galaxy-selected sample of Prochaska et al., of absorbers probing the circum-galactic medium at similar redshift. A search for galaxies has revealed a significant galaxy-overdensity around these weak absorbers compared to random positions with a median impact parameter of 166 kpc from the nearest galaxy. Moreover, we find the presence of multiple galaxies in approximate to 80 per cent of the cases, suggesting group environments. The observed dN/dz of 0.8 +/- 0.2 indicates that such metal-enriched, compact, dense structures are ubiquitous in the haloes of low-z group galaxies. We suggest that these are transient structures that are related to galactic outflows and/or stripping of metal-rich gas from galaxies.
es_ES
Patrocinador
dc.description.sponsorship
NASA through Space Telescope Science Institute
HST AR-12644
NASA
NAS5-26555
European Research Council (ERC)
278594
Alfred P. Sloan Foundation
U.S. Department of Energy Office of Science
Center for High-Performance Computing at the University of Utah
Brazilian Participation Group
Carnegie Institution for Science, Carnegie Mellon University
Chilean Participation Group
French Participation Group
Harvard-Smithsonian Center for Astrophysics
Instituto de Astrofisica de Canarias
Johns Hopkins University
Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo
Lawrence Berkeley National Laboratory
Leibniz Institut fur Astrophysik Potsdam (AIP)
Max-Planck-Institut fur Astronomie (MPIA Heidelberg)
Max-Planck-Institut fur Astrophysik (MPA Garching)
Max-Planck-Institut fur Extraterrestrische Physik (MPE)
National Astronomical Observatories of China
New Mexico State University
New York University
University of Notre Dame
Observatario Nacional / MCTI
Ohio State University
Pennsylvania State University
Shanghai Astronomical Observatory
United Kingdom Participation Group
Universidad Nacional Autonoma de Mexico
University of Arizona
University of Colorado Boulder
University of Oxford
University of Portsmouth
University of Utah
University of Virginia
University of Washington
University of Wisconsin
Vanderbilt University
Yale University