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Title: The effect of interstellar absorption on measurements of the baryon acoustic peak in the Lyman α forest

In recent years, the autocorrelation of the hydrogen Lyman α forest has been used to observe the baryon acoustic peak at redshift 2 < z < 3.5 using tens of thousands of QSO spectra from the BOSS survey. However, the interstellar medium of the Milky Way introduces absorption lines into the spectrum of any extragalactic source. These lines, while weak and undetectable in a single BOSS spectrum, could potentially bias the cosmological signal. In order to examine this, we generate absorption line maps by stacking over a million spectra of galaxies and QSOs. Here, we find that the systematics introduced are too small to affect the current accuracy of the baryon acoustic peak, but might be relevant to future surveys such as the Dark Energy Spectroscopic Instrument (DESI). We outline a method to account for this with future data sets.
 [1] ;  [1] ;  [1] ;  [2] ;  [3]
  1. Tel Aviv Univ., Tel Aviv (Israel). School of Physics and Astronomy
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Computational Cosmology Center
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physics Division
Publication Date:
Grant/Contract Number:
AC02-05CH11231; 2014413
Accepted Manuscript
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Volume: 472; Journal Issue: 1; Journal ID: ISSN 0035-8711
Royal Astronomical Society
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC); United States-Israel Binational Science Foundation (BSF); National Science Foundation (NSF); Alfred P. Sloan Foundation
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; ISM: lines and bands, cosmological parameters, large-scale structure of Universe
OSTI Identifier: