The triply-ionized carbon forest from eBOSS: cosmological correlations with quasars in SDSS-IV DR14

Journal Article · 08 May 2018 · Journal of Cosmology and Astroparticle Physics

DOI: https://doi.org/10.1088/1475-7516/2018/05/029 · OSTI ID:1460817

Blomqvist, Michael ^[1]; Pieri, Matthew M. ^[1]; du Mas des Bourboux, Helion ^[2]; Busca, Nicolas G. ^[3]; Slosar, Anze ^[4]; Bautista, Julian E. ^[2]; Brinkmann, Jonathan ^[5]; Brownstein, Joel R. ^[2]; Dawson, Kyle ^[2]; Agathe, Victoria de Sainte ^[3]; Guy, Julien ^[6]; Percival, Will J. ^[7]; Perez-Rafols, Ignasi ^[1]; Rich, James ^[8]; Schneider, Donald P. ^[9]

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1. Aix Marseille Univ., Marseille (France)
2. Univ. of Utah, Salt Lake City, UT (United States)
3. Univ. Pierre et Marie Curie Paris 6, Univ. Denis Diderot Paris, Paris Cedex (France)
4. Brookhaven National Lab. (BNL), Upton, NY (United States)
5. Apache Point Observatory, Sunspot, NM (United States)
6. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
7. Univ. of Portsmouth, Portsmouth (United Kingdom)
8. Univ. Paris-Saclay, Gif-sur-Yvette (France)
9. The Pennsylvania State Univ., University Park, PA (United States)

Here, we present measurements of the cross-correlation of the triply-ionized carbon (CIV) forest with quasars using Sloan Digital Sky Survey Data Release 14. The study exploits a large sample of new quasars from the first two years of observations by the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). The CIV forest is a weaker tracer of large-scale structure than the Lyα forest, but benefits from being accessible at redshifts z<2 where the quasar number density from eBOSS is high. Our data sample consists of 287,651 CIV forest quasars in the redshift range 1.4<3.5 and 387,315 tracer quasars with 1.2<3.5. We measure large-scale correlations from CIV absorption occuring in three distinct quasar rest-frame wavelength bands of the spectra referred to as the CIV forest, the SiIV forest and the Lyα forest. From the combined fit to the quasar-CIV cross-correlations for the CIV forest and the SiIV forest, the CIV redshift-space distortion parameter is β_CIV=0.27 _{–0.14 –0.26} ^{+0.16 +0.34} and its combination with the CIV linear transmission bias parameter is b_CIV(1+β_CIV)=–0.0183 _{–0.0014 –0.0029} ^{+0.0013 +0.0025} (1σ and 2σ statistical errors) at the mean redshift z=2.00. Splitting the sample at z=2.2 to constrain the bias evolution with redshift yields the power-law exponent γ=0.60±0.63, indicating a significantly weaker redshift-evolution than for the Lyα forest linear transmission bias. Additionally, we demonstrate that CIV absorption has the potential to be used as a probe of baryon acoustic oscillations (BAO). While the current data set is insufficient for a detection of the BAO peak feature, the final quasar samples for redshifts 1.4<2.2 from eBOSS and the Dark Energy Spectroscopic Instrument (DESI) are expected to provide measurements of the isotropic BAO scale to ~7% and ~3% precision, respectively, at zsime1.6.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: SC0012704
• OSTI ID: 1460817
• Report Number(s): BNL-207846-2018-JAAM; TRN: US1901920
• Journal Information: Journal of Cosmology and Astroparticle Physics, Vol. 2018, Issue 05; ISSN 1475-7516
• Publisher: Institute of Physics (IOP)Copyright Statement
• Country of Publication: United States
• Language: English