The Ultraviolet Luminosity Function at 0.6 < z < 1 from UVCANDELS
Authors: Sun Lei , Wang Xin , Teplitz Harry I. , Mehta Vihang , Alavi Anahita , Rafelski Marc , Windhorst Rogier A. , Scarlata Claudia , Gardner Jonathan P. , Smith Brent M. , Sunnquist Ben , Prichard Laura , Cheng Yingjie , Grogin Norman , Hathi Nimish P. , Hayes Matthew , Koekemoer Anton M. , Mobasher Bahram , Nedkova Kalina V. , O’Connell Robert , Robertson Brant , Taamoli Sina , Yung L. Y. Aaron , Brammer Gabriel , Colbert James , Conselice Christopher , Gawiser Eric , Guo Yicheng , Jansen Rolf A. , Ji Zhiyuan , Lucas Ray A. , Rutkowski Michael , Siana Brian , Vanzella Eros , Ashcraft Teresa , Bagley Micaela , Baronchelli Ivano , Barro Guillermo , Blanche Alex , Broussard Adam , Carleton Timothy , Chartab Nima , Codoreanu Alex , Cohen Seth , Dai Y. Sophia , Darvish Behnam , Davé Romeel , DeGroot Laura , De Mello Duilia , Dickinson Mark , Emami Najmeh , Ferguson Henry , Ferreira Leonardo , Finkelstein Keely , Finkelstein Steven , Gburek Timothy , Giavalisco Mauro , Grazian Andrea , Gronwall Caryl , Hemmati Shoubaneh , Howell Justin , Iyer Kartheik , Kaviraj Sugata , Kurczynski Peter , Lazar Ilin , MacKenty John , Mantha Kameswara Bharadwaj , Martin Alec , Martin Garreth , McCabe Tyler , Olsen Charlotte , Otteson Lillian , Ravindranath Swara , Redshaw Caleb , Sattari Zahra , Soto Emmaris , Zabelle Bonnabelle ,   the UVCANDELS team
Published: August 2024

Abstract
UVCANDELS is a Hubble Space Telescope Cycle-26 Treasury Program awarded 164 orbits of primary ultraviolet (UV) F275W imaging and coordinated parallel optical F435W imaging in four CANDELS fields—GOODS-N, GOODS-S, EGS, and COSMOS—covering a total area of ∼426 arcmin2. This is ∼2.7 times larger than the area covered by previous deep-field space UV data combined, reaching a depth of about 27 and 28 ABmag (5σ in 0.”2 apertures) for F275W and F435W, respectively. Along with new photometric catalogs, we present an analysis of the rest-frame UV luminosity function (LF), relying on our UV-optimized aperture photometry method, yielding a factor of 1.5 increase over H-isophot aperture photometry in the signal-to-noise ratios of galaxies in our F275W imaging. Using well-tested photometric redshift measurements, we identify 5810 galaxies at redshifts 0.6 < z < 1, down to an absolute magnitude of M
UV = −14.2. In order to minimize the effect of uncertainties in estimating the completeness function, especially at the faint end, we restrict our analysis to sources above 30% completeness, which provides a final sample of 4726 galaxies at −21.5 < M
UV < −15.5. We performed a maximum likelihood estimate to derive the best-fit parameters of the UV LF. We report a best-fit faint-end slope of

α
=
−

1.359

−
0.041

+
0.041

at z ∼ 0.8. Creating subsamples at z ∼ 0.7 and z ∼ 0.9, we observe a possible evolution of α with redshift. The unobscured UV luminosity density at M
UV < −10 is derived as

ρ

U

V

=

1.339

−
0.030

+
0.027

(
×

10

26

e

r

g

s

−
1

H

z

−
1

M

p

c

−
3

)

using our best-fit LF parameters. The new F275W and F435 photometric catalogs from UVCANDELS have been made publicly available on the Barbara A. Mikulski Archive for Space Telescopes.