2023/08/28 by Huei Sears, Sears, Huei, R. Chornock +11 · 1 voice
Physics and Astronomy · Engineering · #Gamma-ray bursts and supernovae #CCD and CMOS Imaging Sensors
paper · pdf · doi:10.48550/arxiv.2308.14248
We present rest-frame UV Hubble Space Telescope imaging of the largest and most complete sample of 23 long duration gamma-ray burst (GRB) host galaxies between redshifts 4 and 6. Of these 23, we present new WFC3/F110W imaging for 19 of the hosts, which we combine with archival WFC3/F110W and WFC3/F140W imaging for the remaining four. We use the photometry of the host galaxies from this sample to characterize both the rest-frame UV luminosity function (LF) and the size-luminosity relation of the sample. We find that when assuming the standard Schechter-function parameterization for the UV LF, the GRB host sample is best fit with α= -1.30+0.30-0.25 and M_* = -20.33+0.44-0.54 mag, which is consistent with results based on z∼5 Lyman-break galaxies. We find that ∼68% of our size-luminosity measurements fall within or below the same relation for Lyman-break galaxies at z∼4. This study observationally confirms expectations that at z∼5 Lyman-break and GRB host galaxies should trace the same population and demonstrates the utility of GRBs as probes of hidden star-formation in the high-redshift universe. Under the assumption that GRBs unbiasedly trace star formation at this redshift, our non-detection fraction of 7/23 is consistent at the 95%-confidence level with 13 - 53% of star formation at redshift z∼5 occurring in galaxies fainter than our detection limit of M1600 A ∼ -18.3 mag.