Austin Hoag

The grism lens-amplified survey from space (glass). i. survey overview and first data release

We give an overview of the Grism Lens Amplified Survey from Space (GLASS), a large Hubble Space Telescope program aimed at obtaining grism spectroscopy of the fields of ten massive clusters of galaxies at redshift z=0.308-0.686, including the Hubble Frontier Fields (HFF). The Wide Field Camera 3 yields near infrared spectra of the cluster cores, covering the wavelength range 0.81-1.69mum through grisms G102 and G141, while the Advanced Camera for Surveys in parallel mode provides G800L spectra of the infall regions of the clusters. The WFC3 spectra are taken at two almost orthogonal position angles in order to minimize the effects of confusion. After summarizing the scientific drivers of GLASS, we describe the sample selection as well as the observing strategy and data processing pipeline. We then utilize MACSJ0717.5+3745, a HFF cluster and the first one observed by GLASS, to illustrate the data quality and the high-level data products. Each spectrum brighter than H_AB=23 is visually inspected by at least two co-authors and a redshift is measured when sufficient information is present in the spectra. Furthermore, we conducted a thorough search for emission lines through all the GLASS WFC3 spectra with the aim of measuring redshifts for sources with continuum fainter than H_AB=23. We provide a catalog of 139 emission-line based spectroscopic redshifts for extragalactic sources, including three new redshifts of multiple image systems (one probable, two tentative). In addition to the data itself we also release software tools that are helpful to navigate the data.

Through the Looking GLASS: HST Spectroscopy of Faint Galaxies Lensed by the Frontier Fields Cluster MACSJ0717.5+3745

The Grism Lens-Amplified Survey from Space (GLASS) is a Hubble Space Telescope (HST) Large Program, which will obtain 140 orbits of grism spectroscopy of the core and infall regions of 10 galaxy clusters, selected to be among the very best cosmic telescopes. Extensive HST imaging is available from many sources including the CLASH and Frontier Fields programs. We introduce the survey by analyzing spectra of faint multiply-imaged galaxies and z ≳ 6 galaxy candidates obtained from the first 7 orbits out of 14 targeting the core of the Frontier Fields cluster MACSJ0717.5+3745. Using the G102 and G141 grisms to cover the wavelength range 0.8-1.7 μm, we confirm four strongly lensed systems by detecting emission lines in each of the images. For the 9 z ≳ 6 galaxy candidates clear from contamination, we do not detect any emission lines down to a 7 orbit 1σ noise level of ∼5 × 10 -18 erg s-1 cm-2. Taking lensing magnification into account, our flux sensitivity reaches ∼0.2-5 × 10-18 erg s-1cm-2. These limits over an uninterrupted wavelength range rule out the possibility that the high-z galaxy candidates are instead strong line emitters at lower redshift. These results show that by means of careful modeling of the background - and with the assistance of lensing magnification - interesting flux limits can be reached for large numbers of objects, avoiding pre-selection and the wavelength restrictions inherent to ground-based multi-slit spectroscopy. These observations confirm the power of slitless HST spectroscopy even in fields as crowded as a cluster core.

THE GRISM LENS-AMPLIFIED SURVEY FROM SPACE (GLASS). III. A CENSUS OF Lyα EMISSION AT z ≳ 7 FROM HST SPECTROSCOPY

Draft version November 16, 2015 Preprint typeset using L A TEX style emulateapj v. 5/2/11 THE GRISM LENS-AMPLIFIED SURVEY FROM SPACE (GLASS). III. A CENSUS OF Lyα EMISSION AT z & 7 FROM HST SPECTROSCOPY ˇ 4 , B. Vulcani 5 , K.-H., Huang 4 , A. Hoag 4 , M. Maseda 6 L. Guaita 7 K. B. Schmidt 1,2 , T. Treu 3 , M. Brada c L. Pentericci 7 , G. B. Brammer 8 , M. Dijkstra 9 , A. Dressler 10 A. Fontana 7 , A. L. Henry 11 , T. A. Jones 1 , C. Mason 1 , M. Trenti 12 , X. Wang 1 , 1 Department of Physics, University of California, Santa Barbara, CA, 93106-9530, USA Leibniz-Institut f¨ ur Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany 3 Department of Physics and Astronomy, UCLA, Los Angeles, CA, 90095-1547, USA 4 Department of Physics, University of California, Davis, CA, 95616, USA Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, the University of Tokyo, Kashiwa, 277-8582, Japan 6 Max-Planck-Institut f¨ ur Astronomie, K¨ onigstuhl 17, D-69117 Heidelberg, Germany 7 INAF - Osservatorio Astronomico di Roma Via Frascati 33 - 00040 Monte Porzio Catone, I 8 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, 21218, USA 9 Institute of Theoretical Astrophysics, University of Oslo, Postboks 1029, 0858 Oslo, Norway 10 The Observatories of the Carnegie Institution for Science, 813 Santa Barbara St., Pasadena, CA 91101, USA 11 Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 and 12 School of Physics, The University of Melbourne, VIC, 3010 Australia Draft version November 16, 2015 arXiv:1511.04205v1 [astro-ph.GA] 13 Nov 2015 ABSTRACT We present a census of Lyα emission at z & 7 utilizing deep near infrared HST grism spectroscopy from the first six completed clusters of the Grism Lens-Amplified Survey from Space (GLASS). In 24/159 photometrically selected galaxies we detect emission lines consistent with Lyα in the GLASS spectra. Based on the distribution of signal-to-noise ratios and on simulations we expect the com- pleteness and the purity of the sample to be 40-100% and 60-90%, respectively. For the objects without detected emission lines we show that the observed (not corrected for lensing magnification) 1σ flux limits reaches 5 × 10 −18 erg/s/cm 2 per position angle over the full wavelength range of GLASS (0.8–1.7µm). Based on the conditional probability of Lyα emission measured from the ground at z ∼ 7 we would have expected 12-18 Lyα emitters. This is consistent with the number of detections, within the uncertainties, confirming the drop in Lyα emission with respect to z ∼ 6. Deeper follow-up spectroscopy, here exemplified by Keck spectroscopy, is necessary to improve our estimates of com- pleteness and purity, and to confirm individual candidates as true Lyα emitters. These candidates include a promising source at z = 8.1. The spatial extent of Lyα in a deep stack of the most convincing Lyα emitters with hzi = 7.2 is consistent with that of the rest-frame UV continuum. Extended Lyα emission, if present, has a surface brightness below our detection limit, consistent with the properties of lower redshift comparison samples. From the stack we estimate upper limits on rest-frame UV emission line ratios and find f CIV /f Lyα . 0.32 and f CIII] /f Lyα . 0.23 in good agreement with other values published in the literature. Subject headings: galaxies: high-redshift – techniques: spectroscopic – methods: data analysis 1. INTRODUCTION With the deployment of the wide field camera 3 (WFC3) on the Hubble Space Telescope (HST ) in 2009, the samples of galaxies at the epoch of reionization, the phase-transition from a completely neutral inter-galactic medium (IGM) to a fully ionized IGM at z & 6, have grown dramatically. One of the main results of the WFC3 imaging campaigns has been the accurate deter- mination of the luminosity function of star forming high- redshift (based on their photometry) Lyman break galax- ies (e.g. Bouwens et al. 2015b; Finkelstein et al. 2015b). The UV luminosity functions of Lyman break galaxies have provided key constraints on the physics of reioniza- tion (e.g. Robertson et al. 2013; Schmidt et al. 2014a; Duffy et al. 2014). For example, it is clear that the pop- ulation of galaxies that has been detected so far cannot produce enough hard photons to keep the universe ion- ized. However, the luminosity function is found to have kbschmidt@aip.de a steep faint end slope (approximately φ ∝ L −2 ). Thus, faint galaxies could in principle provide enough ionizing photons (Bouwens et al. 2015a; Robertson et al. 2015; Barone-Nugent et al. 2015; Dressler et al. 2015). even though a contribution from AGN might end up being necessary (Madau & Haardt 2015; Giallongo et al. 2015). Also ground based spectroscopic follow-up of photo- metrically selected high-redshift candidates has been an important part of these studies and has provided addi- tional clues about the reionization epoch. Remarkably, only a handful of sources have been confirmed above red- shift 7 (Vanzella et al. 2011; Schenker et al. 2012, 2014; Ono et al. 2012; Finkelstein et al. 2013; Oesch et al. 2015; Roberts-Borsani et al. 2015; Zitrin et al. 2015b). The low probability of detecting Lyα in Lyman break galaxies, could be interpreted as the result of an increased optical depth in the IGM due to a significant fraction of neutral hydrogen. Thus the decline in detected Lyα is poten- tially a “smoking gun” of reionization (Fontana et al. 2010). The conditional probability of Lyα emission for

THE GRISM LENS-AMPLIFIED SURVEY FROM SPACE (GLASS). IV. MASS RECONSTRUCTION OF THE LENSING CLUSTER ABELL 2744 FROM FRONTIER FIELD IMAGING AND GLASS SPECTROSCOPY

We present a strong and weak lensing reconstruction of the massive cluster Abell 2744, the first cluster for which deep Hubble Frontier Field (HFF) images and spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS) are available. By performing a targeted search for emission lines in multiply imaged sources using the GLASS spectra, we obtain 5 high-confidence spectroscopic redshifts and 2 tentative ones. We confirm 1 strongly lensed system by detecting the same emission lines in all 3 multiple images. We also search for additional line emitters blindly and use the full GLASS spectroscopic catalog to test reliability of photometric redshifts for faint line emitters. We see a reasonable agreement between our photometric and spectroscopic redshift measurements, when including nebular emission in photometric redshift estimations. We introduce a stringent procedure to identify only secure multiple image sets based on colors, morphology, and spectroscopy. By combining 7 multiple image systems with secure spectroscopic redshifts (at 5 distinct redshift planes) with 18 multiple image systems with secure photometric redshifts, we reconstruct the gravitational potential of the cluster pixellated on an adaptive grid, using a total of 72 images. The resulting mass map is compared with a stellar mass map obtained from the deep Spitzer Frontier Fields data to study the relative distribution of stars and dark matter in the cluster. We find that the stellar to total mass ratio varies substantially across the cluster field, suggesting that stars do not trace exactly the total mass in this interacting system. The maps of convergence, shear, and magnification are made available in the standard HFF format.

The Frontier Fields lens modelling comparison project

Gravitational lensing by clusters of galaxies offers a powerful probe of their structure and mass distribution. Several research groups have developed techniques independently to achieve this goal. While these methods have all provided remarkably high-precision mass maps, particularly with exquisite imaging data from the Hubble Space Telescope (HST), the reconstructions themselves have never been directly compared. In this paper, we present for the first time a detailed comparison of methodologies for fidelity, accuracy and precision. For this collaborative exercise, the lens modelling community was provided simulated cluster images that mimic the depth and resolution of the ongoing HST Frontier Fields. The results of the submitted reconstructions with the un-blinded true mass profile of these two clusters are presented here. Parametric, free-form and hybrid techniques have been deployed by the participating groups and we detail the strengths and trade-offs in accuracy and systematics that arise for each methodology. We note in conclusion that several properties of the lensing clusters are recovered equally well by most of the lensing techniques compared in this study. For example, the reconstruction of azimuthally averaged density and mass profiles by both parametric and free-form methods matches the input models at the level of ∼10 per cent. Parametric techniques are generally better at recovering the 2D maps of the convergence and of the magnification. For the best-performing algorithms, the accuracy in the magnification estimate is ∼10 per cent at μ_(true) = 3 and it degrades to ∼30 per cent at μ_(true) ∼ 10.

SPITZERULTRA FAINT SURVEY PROGRAM (SURFS UP). II. IRAC-DETECTED LYMAN-BREAK GALAXIES AT 6 ≲z≲ 10 BEHIND STRONG-LENSING CLUSTERS

We study the stellar population properties of the IRAC-detected

The Grism Lens-Amplified Survey from Space (GLASS). VI. Comparing the Mass and Light in MACSJ0416.1-2403 using Frontier Field imaging and GLASS spectroscopy

6 \lesssim z \lesssim 10

First Results from the KMOS Lens-Amplified Spectroscopic Survey (KLASS): Kinematics of Lensed Galaxies at Cosmic Noon

galaxy candidates from the Spitzer UltRa Faint SUrvey Program (SURFS UP). Using the Lyman Break selection technique, we find a total of 16 new galaxy candidates at

The Grism Lens-Amplified Survey from Space (GLASS). XI. Detection of C IV in Multiple Images of the z = 6.11 Lyα Emitter behind RXC J2248.7-4431

6 \lesssim z \lesssim 10

DETECTION OF LYMAN-ALPHA EMISSION FROM A TRIPLY IMAGEDz= 6.85 GALAXY BEHIND MACS J2129.4−0741

with