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dc.contributor.authorCucchiara, A.
dc.contributor.authorProchaska, J. X.
dc.contributor.authorZhu, G.
dc.contributor.authorMenard, Brice
dc.contributor.authorFynbo, J. P. U.
dc.contributor.authorFox, Derek B.
dc.contributor.authorChen, H.-W.
dc.contributor.authorCooksey, Kathy
dc.contributor.authorCenko, S. Bradley
dc.contributor.authorPerley, D.
dc.contributor.authorBloom, Joshua S.
dc.contributor.authorBerger, E.
dc.contributor.authorTanvir, N. R.
dc.contributor.authorD'Elia, V.
dc.contributor.authorLopez, S.
dc.contributor.authorChornock, R.
dc.contributor.authorde Jaeger, T.
dc.date.accessioned2015-02-06T19:48:45Z
dc.date.available2015-02-06T19:48:45Z
dc.date.issued2013-08
dc.date.submitted2012-11
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357
dc.identifier.urihttp://hdl.handle.net/1721.1/93911
dc.description.abstractIn 2006, Prochter et al. reported a statistically significant enhancement of very strong Mg II absorption systems intervening the sight lines to gamma-ray bursts (GRBs) relative to the incidence of such absorption along quasar sight lines. This counterintuitive result has inspired a diverse set of astrophysical explanations (e.g., dust, gravitational lensing) but none of these has obviously resolved the puzzle. Using the largest set of GRB afterglow spectra available, we reexamine the purported enhancement. In an independent sample of GRB spectra with a survey path three times larger than Prochter et al., we measure the incidence per unit redshift of ≥1 Å rest-frame equivalent width Mg II absorbers at z ≈ 1 to be ℓ(z) = 0.18 ± 0.06. This is fully consistent with current estimates for the incidence of such absorbers along quasar sight lines. Therefore, we do not confirm the original enhancement and suggest those results suffered from a statistical fluke. Signatures of the original result do remain in our full sample (ℓ(z) shows an ≈1.5 enhancement over ℓ(z)QSO), but the statistical significance now lies at ≈90% c.l. Restricting our analysis to the subset of high-resolution spectra of GRB afterglows (which overlaps substantially with Prochter et al.), we still reproduce a statistically significant enhancement of Mg II absorption. The reason for this excess, if real, is still unclear since there is no connection between the rapid afterglow follow-up process with echelle (or echellette) spectrographs and the detectability of strong Mg II doublets. Only a larger sample of such high-resolution data will shed some light on this matter.en_US
dc.description.sponsorshipNational Science Foundation (U.S.)en_US
dc.description.sponsorshipNatural Sciences and Engineering Research Council of Canadaen_US
dc.description.sponsorshipComisión Nacional de Investigación Ciencia y Tecnología (Chile)en_US
dc.description.sponsorshipAustralian Research Councilen_US
dc.description.sponsorshipBrazil. Ministério da Ciência, tecnologia e Inovaçãoen_US
dc.description.sponsorshipConsejo Nacional de Investigaciones Científicas y Técnicas (Argentina)en_US
dc.description.sponsorshipFondo Nacional de Desarrollo Científico y Tecnológico (Chile) (FONDECYT grant number 1100214)en_US
dc.description.sponsorshipCenter for Excellence in Astrophysics and Associated Technologies (CATA) (PFB 06))en_US
dc.description.sponsorshipEuropean Research Council (ERC-StG grant EGGS-278202)en_US
dc.language.isoen_US
dc.publisherInstitute of Physics/American Astronomical Societyen_US
dc.relation.isversionofhttp://dx.doi.org/10.1088/0004-637x/773/2/82en_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.sourceAmerican Astronomical Societyen_US
dc.titleAN INDEPENDENT MEASUREMENT OF THE INCIDENCE OF Mg II ABSORBERS ALONG GAMMA-RAY BURST SIGHT LINES: THE END OF THE MYSTERY?en_US
dc.typeArticleen_US
dc.identifier.citationCucchiara, A., J. X. Prochaska, G. Zhu, B. Ménard, J. P. U. Fynbo, D. B. Fox, H.-W. Chen, et al. “AN INDEPENDENT MEASUREMENT OF THE INCIDENCE OF Mg II ABSORBERS ALONG GAMMA-RAY BURST SIGHT LINES: THE END OF THE MYSTERY?” The Astrophysical Journal 773, no. 2 (July 29, 2013): 82. © 2013 American Astronomical Society.en_US
dc.contributor.departmentMIT Kavli Institute for Astrophysics and Space Researchen_US
dc.contributor.mitauthorCooksey, Kathyen_US
dc.relation.journalAstrophysical Journalen_US
dc.eprint.versionFinal published versionen_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dspace.orderedauthorsCucchiara, A.; Prochaska, J. X.; Zhu, G.; Ménard, B.; Fynbo, J. P. U.; Fox, D. B.; Chen, H.-W.; Cooksey, K. L.; Cenko, S. B.; Perley, D.; Bloom, J. S.; Berger, E.; Tanvir, N. R.; D'Elia, V.; Lopez, S.; Chornock, R.; de Jaeger, T.en_US
mit.licensePUBLISHER_POLICYen_US
mit.metadata.statusComplete


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