MUSEQuBES: Calibrating the redshifts of Lyman-\alpha emitters using stacked circumgalactic medium absorption profiles
, , , , , , , , , , , , , , , , , , , and .
(2019)cite arxiv:1910.03593Comment: 9 Pages, Submitted to MNRAS, Comments Welcome!.

Lyman-(Ly\alpha) emission lines are typically found to be redshifted with respect to the systemic redshifts of galaxies, likely due to resonant scattering of Lyphotons. Here we measure the average velocity offset for a sample of 96 z ~ 3.3 Lyemitters (LAEs) with a median Lyflux (luminosity) of ~10^-17 erg cm^-2 s^-1 (~10^42 erg s^-1) and a median unobscured star formation rate (SFR) of ~1.3 Msun/yr, detected by the Multi-Unit Spectroscopic Explorer as part of our MUSEQuBES circumgalactic medium (CGM) survey. By postulating that the stacked CGM absorption profiles of these LAEs, probed by 8 background quasars, must be centered on the systemic redshift, we measure an average velocity offset, Voffset = 169 10 km/s, between the Lyemission peak and the systemic redshift. The observed Voffset is lower by factors of ~1.4 and ~2.6 compared to the velocity offsets measured for narrow-band selected LAEs and Lyman break galaxies, respectively, which probe galaxies with higher masses and SFRs. Consistent with earlier studies based on direct measurements for individual objects, we find that the Voffset is correlated with the full width at half-maximum of the red peak of the Lyline, and anti-correlated with the rest-frame equivalent width. Moreover, we find that Voffset is correlated with SFR with a sub-linear scaling relation, Voffset ~ SFR^(0.16 0.03). Adopting the mass scaling for main sequence galaxies, such a relation suggests that Voffset scales with the circular velocity of the dark matter halos hosting the LAEs.
  • @gpkulkarni
This publication has not been reviewed yet.

rating distribution
average user rating0.0 out of 5.0 based on 0 reviews
    Please log in to take part in the discussion (add own reviews or comments).