학술논문
A Steep Decline in the Galaxy Space Density Beyond Redshift 9 in the CANUCS UV Luminosity Function
Document Type
Working Paper
Author
Willott, Chris J.; Desprez, Guillaume; Asada, Yoshihisa; Sarrouh, Ghassan T. E.; Abraham, Roberto; Bradač, Maruša; Brammer, Gabe; Estrada-Carpenter, Vince; Iyer, Kartheik G.; Martis, Nicholas S.; Matharu, Jasleen; Mowla, Lamiya; Muzzin, Adam; Noirot, Gaël; Sawicki, Marcin; Strait, Victoria; Rihtaršič, Gregor; Withers, Sunna
Source
Subject
Language
Abstract
We present a new sample of 158 galaxies at redshift $z>7.5$ selected from deep \jwst\ NIRCam imaging of five widely-separated sightlines in the CANUCS survey. Two-thirds of the pointings and 80\% of the galaxies are covered by 12 to 14 NIRCam filters, including seven to nine medium bands, providing accurate photometric redshifts and robustness against low redshift interlopers. A sample of 28 galaxies at $z>7.5$ with spectroscopic redshifts shows a low systematic offset and scatter in the difference between photometric and spectroscopic redshifts. We derive the galaxy UV luminosity function at redshifts 8 to 12, finding a slightly higher normalization than previously seen with \hst\ at redshifts 8 to 10. We observe a steeper decline in the galaxy space density from $z=8$ to $12$ than found by most \jwst\ Cycle 1 studies. In particular, we find only eight galaxies at $z>10$ and none at $z>12.5$, with no $z>10$ galaxies brighter than F277W AB=28 or $M_{\rm UV}=-20$ in our unmasked, delensed survey area of 53.4 square arcminutes. We attribute the lack of bright $z>10$ galaxies in CANUCS compared to GLASS and CEERS to intrinsic variance in the galaxy density along different sightlines. The evolution in the CANUCS luminosity function between $z=8$ and $12$ is comparable to that predicted by simulations that assume a standard star formation efficiency, without invoking any special adjustments.
Comment: 30 pages, 12 figures, ApJ, in press
Comment: 30 pages, 12 figures, ApJ, in press