A Luminosity Function of Lyα‐emitting Galaxies atz≈ 4.5

Abstract

We present a catalog of 59 z % 4:5 Ly -emitting galaxies spectroscopically confirmed in a campaign of Keck DEIMOS follow-up observations to candidates selected in the Large Area Ly (LALA) narrowband imaging survey. We targeted 97 candidates for spectroscopic follow-up; by accounting for the variety of conditions under which we performed spectroscopy, we estimate a selection reliability of $76%. Together with our previous sample of Keck LRIS confirmations, the 59 sources confirmed herein bring the total catalog to 73 spectroscopically confirmed z % 4:5 Lyemitting galaxies in the %0.7 deg 2 covered by the LALA imaging. As with the Keck LRIS sample, we find that a nonnegligible fraction of the confirmed Ly lines have rest-frame equivalent widths (W rest k ) that exceed the maximum predicted for normal stellar populations: 17%Y31% (93% confidence) of the detected galaxies show W rest k > 190 8, and 12%Y27% (90% confidence) show W rest k > 240 8. We construct a luminosity function of z % 4:5 Ly emission lines for comparison to Ly luminosity functions spanning 3:1 < z < 6:6. We find no significant evidence for Ly luminosity function evolution from z % 3 to z % 6. This result supports the conclusion that the intergalactic medium remains largely reionized from the local universe out to z % 6:5. It is somewhat at odds with the pronounced drop in the cosmic star formation rate density recently measured between z $ 3 and z $ 6 in continuum-selected Lyman-break galaxies, and therefore potentially sheds light on the relationship between the two populations.

The environments of Ly α blobs – I. Wide-field Ly α imaging of TN J1338−1942, a powerful radio galaxy at z ≃ 4.1 associated with a giant Ly α nebula★

“…At the brightest end of the LF, log L Lyα 43.9, we did not find any sources in the SXDS field, while we still found sources in the TNJ1338 field even when we exclude the radio galaxy itself. Such bright sources are almost never seen in blank-field surveys for LAEs at similar redshifts (Dawson et al 2007;O08).…”

Lyα EMITTER GALAXIES AT z ∼ 2.8 IN THE EXTENDED CHANDRA DEEP FIELD SOUTH. I. TRACING THE LARGE-SCALE STRUCTURE VIA Lyα IMAGING∗

“…Lyα LF at z = 2.8-2.9 in ECDFS We use the V /V max method (e.g., Dawson et al 2007;Zheng et al 2013) to calculate the Lyα luminosity function. V max is the comoving volume where the source could be selected by our survey.…”

“…Because the depths of our narrowband images are shallower than those of other surveys, LAEs with faint NB or V is less than those of other surveys. redshift (z < 2) LAEs from GALEX slitless UV spectra (Cowie et al 2010;Wold et al 2014), and high-redshift (z > 2) narrowband surveys (Ciardullo et al 2012;Ouchi et al 2008Ouchi et al , 2010Zheng et al 2013;Dawson et al 2007;Wang et al 2009;Kashikawa et al 2011;Hu et al 2010;Ouchi et al 2010;Matthee et al 2015). The SFRD from rest-frame UV measurements are extracted from Table 1 of Madau & Dickinson (2014).…”

PROBING THE PHYSICAL PROPERTIES OFz= 4.5 LyαEMITTERS WITHSPITZER

“…Detecting a higher fraction of massive LAEs as compared to Finkelstein et al (2009) is likely due to the much larger survey area of our study, allowing for detection of a fraction of LAEs that represent the rare, most massive, more evolved population of galaxies at this redshift. However, it is possible that some of these massive galaxies which are not yet spectroscopically confirmed could be lower redshift interlopers, though the fraction is likely small, given the overall ∼75% spectroscopic confirmation success rate (Dawson et al 2007). …”