Accessing the Host Galaxies of Long Gamma-Ray Bursts with Next-Generation Telescopes

Abstract

We present a method to estimate the detection expectations of host galaxies of long gamma-ray bursts (LGRBs) in the {\it grizJHKL} bands. It is found that given the same limiting magnitude $m_{grizJHKL,\rm lim}$ in each band, the {\it z} band produces the largest number of overall LGRB hosts and low-mass hosts ($M_\ast\leq10^8$ M$_\odot$) at $m_{grizJHKL,\rm lim}\gtrsim 26$ mag. For the detection of high-redshift LGRB hosts (redshift $\geq5$), it is recommended to prioritize the {\it L} band due to its good performance at both low and high limiting magnitudes. We specifically estimate the expectation of LGRB-host detection with $m_{grizJHKL,\rm lim}=28$ mag, which the James Webb Space Telescope can partially attain. We find that there may exist 116, 259, 277, 439, 266, 294, 274, and 316 LGRB hosts, including 0.54, 31, 28, 143, 12, 20, 14, and 35 low-mass ones in the {\it grizJHKL} bands and 13, 14, 15, 14, and 15 high-redshift ones in the {\it zJHKL} bands, for 15 yr {\it Swift} LGRBs with $S\geq10^{-6}$ erg cm$^{-2}$. The results show that the study of LGRB hosts under next-generation observational conditions holds significant potential, especially for low-mass host studies. However, it appears that deeper sensitivities of galaxy telescopes may not significantly enhance statistical studies of high-redshift hosts. Strategies aimed at increasing the number of distant LGRB hosts may require the expansion of high-redshift LGRB detection.