Z-FOURGE - the FourStar Galaxy Evolution Survey Status Report at the 1.3-year mark

Team Ivo Labbe (PI) & Caroline Straatman - Leiden Persson, Murphy, Monson, Kelson, McCarthy, Quadri - Carnegie Lee Spitler, Karl Glazebrook, Glenn Kacprzak, Greg Poole - Swinburne Casey Papovich, Kim-Vy Tran, Vithal Tilvi - Texas A&M Pieter van Dokkum - Yale

Galaxy evolution at 1 < z < 3.5 Redshifts and high quality imaging for thousands of galaxies Redshifts, photometry plus models give the following: Luminosity and LF Stellar Mass and MF Star Formation Rate Extinction Formation redshift Imaging data gives: Galaxy size Morphology Environment

The key: Photometric Redshifts Enable large samples of galaxies (not feasible with NIR spectroscopy) Observations Medium bandwidth ( /  ~ 10) near-IR filters enable:  z/(1+z) = More accurate photo-z than broadband filters Existing ground-based optical, Hubble, and Spitzer data Techniques 4000 or Balmer break in near-IR, overall SED

Model SEDs and Filters

FourStar Observations FOV 10.8’ x 10.8’ (4K x 4K) scale 0.159”/pixel Six filters: J1, J2, J3, Hs, Hl, plus Ks ~10 hours per filter Median seeing in Ks: 0.5” FWHM Deepest Ks image: 25.4 AB, 5  total for a point source

First result - a z ~ 2.2 cluster in COSMOS (Spitler et al. 2012, ApJ, 148, L21)

Deep Optical HST

FourStar J1,J2,J3

FourStar Ks, 10 hr / ACS I, 1 hr

Data and SED fits (medium bands are red points)

Results A & B are robust, C slightly less so. Possible overdensity D has the most luminous galaxy in the vicinity. Spectra of 4 galaxies confirm cluster redshift. Halo mass estimates 6x, 1x, and 1x Msun; may grow 10x to z = 0. Simulations suggest high probability that one or more of ABC will merge by z = 0.

Two interesting objects A Z-band (Ly  ) dropout at z ~ 7.1 A T7 brown dwarf

Project Status COSMOS: 13,500 galaxies, 6500 at z > 1, several at z ~ 3.5 (age of universe ~ 1.8 Gyr). CDF-S: 9,000 galaxies, no large mature cluster detected ( expect 1±1 over the three fields). UDS: next and final field in 2012B. Upon completion, we will have > 15,000 with z > 1 –Divided into 5 bins of mass, redshift, and environment gives 120/bin => robust statistics

Metal-poor star-forming galaxies [OIII] 5007 in J3 filter and H  in Hl filter in a RGB display. z ~ 1.5

Results pertaining to this cluster 1.First, clusters are found by slicing redshift catalog, then using nearest neighbor statistic of Papovich et al. (2010, ApJ, 716, 1503): for each galaxy measure the angular distance to 7th nearest neighbor, then compute the corresponding surface density. 2.7, 13, 9 galaxies within 30” of A, B, C in a slice (313 total). Different statistical tests indicate that A & B are robust, C slightly less so. E.g., surface densities in adjacent slices are ~ 2.5 arcmin -2

More … 6.No new large mature cluster in CDF-S; expect 1±1 over the three fields (variance method of Somerville et al. 2004, ApJ 600, L171). 7. Other high-z clusters are either blue protoclusters, e.g., AzTEC-3, or the one mature one of Gobat et al. (2011, A&A, 526, 133), z ~ Finally, spectra of 4 galaxies confirm cluster at z = (  z due to filters)

Observations Three fields: COSMOS, CDF-S, UDS. (these have a large amount of ancillary data (deep optical, Spitzer) and more to come from Alma and Herschel). COSMOS: 70 hours 56 t(eff) hours CDF-S: UDS: (50 hopefully)

FourStar vs ACS/HST (Core of A)

Model SEDs and Filters