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The Sloan Digital Sky Survey Reverberation Mapping Project : biases in z > 1.46 redshifts due to quasar diversity
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dc.contributor.author | Denney, K. D. | |
dc.contributor.author | Horne, Keith | |
dc.contributor.author | Brandt, W. N. | |
dc.contributor.author | Grier, C. J. | |
dc.contributor.author | Ho, Luis C. | |
dc.contributor.author | Peterson, B. M. | |
dc.contributor.author | Trump, J. R. | |
dc.contributor.author | Ge, J. | |
dc.date.accessioned | 2017-01-06T13:30:09Z | |
dc.date.available | 2017-01-06T13:30:09Z | |
dc.date.issued | 2016-12-06 | |
dc.identifier | 248699734 | |
dc.identifier | 0227ca42-95b6-41b3-8b1c-336ba24f2f3e | |
dc.identifier | 85006701088 | |
dc.identifier | 000390556900006 | |
dc.identifier.citation | Denney , K D , Horne , K , Brandt , W N , Grier , C J , Ho , L C , Peterson , B M , Trump , J R & Ge , J 2016 , ' The Sloan Digital Sky Survey Reverberation Mapping Project : biases in z > 1.46 redshifts due to quasar diversity ' , Astrophysical Journal , vol. 833 , no. 1 , 33 . https://doi.org/10.3847/1538-4357/833/1/33 | en |
dc.identifier.issn | 0004-637X | |
dc.identifier.uri | https://hdl.handle.net/10023/10057 | |
dc.description.abstract | We use the coadded spectra of 32 epochs of Sloan Digital Sky Survey (SDSS) Reverberation Mapping Project observations of 482 quasars with z > 1.46 to highlight systematic biases in the SDSS- and Baryon Oscillation Spectroscopic Survey (BOSS)-pipeline redshifts due to the natural diversity of quasar properties. We investigate the characteristics of this bias by comparing the BOSS-pipeline redshifts to an estimate from the centroid of He ii λ1640. He ii has a low equivalent width but is often well-defined in high-S/N spectra, does not suffer from self-absorption, and has a narrow component which, when present (the case for about half of our sources), produces a redshift estimate that, on average, is consistent with that determined from [O ii] to within the He ii and [O ii] centroid measurement uncertainties. The large redshift differences of ∼1000 km s-1, on average, between the BOSS-pipeline and He ii-centroid redshifts, suggest there are significant biases in a portion of BOSS quasar redshift measurements. Adopting the He ii-based redshifts shows that C iv does not exhibit a ubiquitous blueshift for all quasars, given the precision probed by our measurements. Instead, we find a distribution of C iv-centroid blueshifts across our sample, with a dynamic range that (i) is wider than that previously reported for this line, and (ii) spans C iv centroids from those consistent with the systemic redshift to those with significant blueshifts of thousands of kilometers per second. These results have significant implications for measurement and use of high-redshift quasar properties and redshifts, and studies based thereon. | |
dc.format.extent | 16 | |
dc.format.extent | 828235 | |
dc.language.iso | eng | |
dc.relation.ispartof | Astrophysical Journal | en |
dc.subject | Galaxies: active | en |
dc.subject | Galaxies: distances and redshifts | en |
dc.subject | Galaxies: nuclei | en |
dc.subject | Quasars: emission lines | en |
dc.subject | Quasars: general | en |
dc.subject | Quasars: supermassive black holes | en |
dc.subject | QB Astronomy | en |
dc.subject | QC Physics | en |
dc.subject | Astronomy and Astrophysics | en |
dc.subject | Space and Planetary Science | en |
dc.subject | 3rd-NDAS | en |
dc.subject.lcc | QB | en |
dc.subject.lcc | QC | en |
dc.title | The Sloan Digital Sky Survey Reverberation Mapping Project : biases in z > 1.46 redshifts due to quasar diversity | en |
dc.type | Journal article | en |
dc.contributor.sponsor | Science & Technology Facilities Council | en |
dc.contributor.institution | University of St Andrews. School of Physics and Astronomy | en |
dc.contributor.institution | University of St Andrews. St Andrews Centre for Exoplanet Science | en |
dc.identifier.doi | https://doi.org/10.3847/1538-4357/833/1/33 | |
dc.description.status | Peer reviewed | en |
dc.identifier.grantnumber | ST/M001296/1 | en |
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