CANDELS Visual Classifications: Scheme, Data Release, and First Results
Creators: name: Kartaltepe, Jeyhan S.
name: Mozena, Mark
name: Kocevski, Dale
name: McIntosh, Daniel H.
name: Lotz, Jennifer
name: Bell, Eric F.
name: Faber, Sandra
name: Ferguson, Henry
name: Koo, David
name: Bassett, Robert
name: Bernyk, Maksym
name: Blancato, Kirsten
name: Bournaud, Frederic
name: Cassata, Paolo
name: Castellano, Marco
name: Cheung, Edmond
name: Conselice, Christopher J.
name: Croton, Darren
name: Dahlen, Tomas
name: de Mello, Duilia F.
name: DeGroot, Laura
name: Donley, Jennifer
name: Guedes, Javiera
name: Grogin, Norman
name: Hathi, Nimish
name: Hilton, Matt
name: Hollon, Brett
name: Inami, Hanae
name: Kassin, Susan
name: Koekemoer, Anton
name: Lani, Caterina
name: Liu, Nick
name: Lucas, Ray A.
name: Martig, Marie
name: McGrath, Elizabeth
name: McPartland, Conor
name: Mobasher, Bahram
name: Morlock, Alice
name: Mutch, Simon
name: O'Leary, Erin
name: Peth, Mike
name: Pforr, Janine
name: Pillepich, Annalisa
name: Poole, Gregory B.
name: Rizer, Zachary
name: Rosario, David
name: Soto, Emmaris
name: Straughn, Amber
name: Telford, Olivia
name: Sunnquist, Ben
name: Weiner, Benjamin
name: Wuyts, Stijn
Publisher: name: arXiv
Year: 2014
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We have undertaken an ambitious program to visually classify all galaxies in the five CANDELS fields down to H&lt;24.5 involving the dedicated efforts of 65 individual classifiers. Once completed, we expect to have detailed morphological classifications for over 50,000 galaxies up to z&lt;4 over all the fields. Here, we present our detailed visual classification scheme, which was designed to cover a wide range of CANDELS science goals. This scheme includes the basic Hubble sequence types, but also includes a detailed look at mergers and interactions, the clumpiness of galaxies, $k$-corrections, and a variety of other structural properties. In this paper, we focus on the first field to be completed -- GOODS-S. The wide area coverage spanning the full field includes 7634 galaxies that have been classified by at least three different people. In the deep area of the field, 2534 galaxies have been classified by at least five different people at three different depths. With this paper, we release to the public all of the visual classifications in GOODS-S along with the GUI that we developed to classify galaxies. We find that the level of agreement among classifiers is good and depends on both the galaxy magnitude and the galaxy type, with disks showing the highest level of agreement and irregulars the lowest. A comparison of our classifications with the Sersic index and rest-frame colors shows a clear separation between disk and spheroid populations. Finally, we explore morphological k-corrections between the V-band and H-band observations and find that a small fraction (84 galaxies in total) are classified as being very different between these two bands. These galaxies typically have very clumpy and extended morphology or are very faint in the V-band.
description: 15 pages, 14 figures, Accepted for publication in The Astrophysical Journal Supplement Series For access to data tables prior to publication contact jeyhan@astro.rit.edu