http://arxiv.org/abs/2209.06830
The discovery of two galaxy candidates at $z\sim 13$, HD1 and HD2, laid the foundation for a new race to study the early Universe. These galaxies exhibit large UV luminosities, and previous investigations suggested that they are either powered by a supermassive black hole or by an extreme, transient burst of star formation. Given their uncertain nature, the critical question we investigate is whether these sources could be lensed by a hitherto undetected, faint foreground galaxy. We find that at the current limiting magnitude with which HD1 and HD2 were imaged, there is only a $7.39\%$ probability they are lensed and that the hypothetical lensing galaxy was too faint to be detected. Meanwhile, with the limiting magnitudes of the Hubble Space Telescope (HST) and James Webb Space Telescope (JWST) imaging capabilities, the probability drops precipitously to $0.058\%$ and $0.0012\%$, respectively. We further find it unlikely that the luminosities of both sources can be accounted for by lensing that produces a single, resolved image with sufficiently high magnification. Alternatively, in the unlikely low-probability event that their brightness does indeed result from lensing, there is a $30.9 \%$ probability that the lensing galaxy is too faint to be observable at the current limiting magnitude. Future HST (JWST) imaging will drop this probability to $0.245 \%$ ($0.0025 \%$). In summary, while deep imaging with HST and JWST is required to discard the lensing hypothesis entirely, it is unlikely that the exceptional luminosity of the two $z \sim 13$ sources can be accounted for by gravitational lensing.
R. Lee, F. Pacucci, P. Natarajan, et. al.
Fri, 16 Sep 22
36/84
Comments: Submitted for publication in MNRAS. 9 pages, 4 figures
You must be logged in to post a comment.