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

Yishay Vadai, Dovi Poznanski, Dalya Baron, Peter E. Nugent, David Schlegel

Research output: Contribution to journalArticlepeer-review

Abstract

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. 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.

Original languageEnglish
Pages (from-to)799-807
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Volume472
Issue number1
DOIs
StatePublished - 2017

Keywords

  • Cosmological parameters
  • ISM: lines and bands
  • Large-scale structure of Universe

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