Narciso Benítez

TL;DR: Apsis as mentioned in this paper is an automatic image processing pipeline for the Advanced Camera for Surveys (ACS) Guaranteed Time Observation (GTO) program that supports the different cameras available on the ACS instrument.

TL;DR: In this paper, a matched filter algorithm was proposed to determine the position, redshift and richness of the cluster through the maximization of a filter depending on galaxy luminosity, density and photometric redshift combined with a galaxy cluster prior.

Abstract: We present deep g475r625i775z850KS observations towards the radio galaxy TN J1338–1942 at z = 4.1. The radio galaxy is a ∼ 6L∗z=4 galaxy. The data allow us to study in detail 12 spectroscopically confirmed companions previously found through their excess Lyα emission by Venemans et al. (2002). We conclude that the Lyα emitters (LAEs) are young (a few ×10 yr), dust-free galaxies based on small sizes, steep UV slopes (β ≈ −2) and blue UV-optical colors with star formation rates (SFRs) of < 14 M⊙ yr . When stacking the KS-band fluxes, the LAEs seem to be less massive (masses of a few ×10 M⊙) than UV-selected Lyman break galaxies (LBGs) while having comparable UV SFRs. We estimate the LAE AGN fraction to be minimal. The field further contains 66 g475-dropouts to z850= 27 (5σ), 6 of which are in the LAE sample. Their SFRs, sizes, morphological parameters, UV slope-magnitude and (i775–KS) vs. KS color-magnitude relations are all similar to those found for LBGs in the ‘field’. We quantify the number density and cosmic variance of z ∼ 4 g475-dropouts extracted from a pixel-by-pixel transformation of the B435V606i775z850 GOODS survey to g475r625i775z850, and show that the field of TN J1338–1942 is richer than the average field at the > 5σ significance. The angular distribution is highly filamentary, with about half of the objects clustered in a 4.4 arcmin region that includes the radio galaxy and the brightest LBGs. A second, but much less pronounced concentration of objects is seen around another ∼ 6L LBG located within the same field, for which we obtained a spectroscopic redshift of z = 3.8. The generally fainter LAEs appear to favour regions that are devoid of LBGs, while LBGs detected in the rest-frame optical (KS) tend to lie in the richest region, suggesting a forming ageor mass-density relation. We compare the angular two-point correlation function, w(θ), to the signal measured in similarly sized mock samples with a built-in two-point clustering as measured for field LBGs at z ∼ 4. We find an excess signal (2σ) at separations of θ < 10, corresponding to the typical halo size of dark matter Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program # 9291. Based on observations carried out at the European Southern Observatory, Paranal, Chile, programs 071.A-0495(A) and 073.A-0286(A). Leiden Observatory, Postbus 9513, 2300 RA Leiden, Netherlands UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 Inst. Astrof́ısica de Andalućıa (CSIC), Camino Bajo de Huétor, 24, Granada 18008, Spain Max-Planck-Institut fr Astronomie, Knigstuhl 17, D-69117, Heidelberg, Germany National Aeronautics and Space Administration, Washington, DC

TL;DR: In this article, a list of candidates for high redshift late-type galaxies in the field around the z=3.79 quasar PC1643+4631A was presented.