Gabriel Brammer, Pieter van Dokkum, Marijn Franx, Mattia Fumagalli, Shannon Patel, Hans-Walter Rix, Rosalind Skelton, Mariska Kriek, Erica Nelson, Kasper Schmidt, Rachel Bezanson, Elisabete da Cunha, Dawn Erb, Xiaohui Fan, Natascha Förster Schreiber, Garth Illingworth, Ivo Labbé, Joel Leja, Britt Lundgren, Dan Magee, Danilo Marchesini, Patrick McCarthy, Ivelina Momcheva, Adam Muzzin, Ryan Quadri, Charles Steidel, Tomer Tal, David Wake, Katherine Whitaker, Anna Williams
备注：
Replacement reflects version now accepted by ApJS. A preliminary data release intended to provide a general illustration of the WFC3 grism data is available at http://3dhst.research.yale.edu/
We present 3D-HST, a near-infrared spectroscopic Treasury program with the Hubble Space Telescope for studying the processes that shape galaxies in the distant Universe. 3D-HST provides rest-frame optical spectra for a sample of ~7000 galaxies at 1<z<3.5, the epoch when 60% of all star formation took place, the number density of quasars peaked, the first galaxies stopped forming stars, and the structural regularity that we see in galaxies today must have emerged. 3D-HST will cover 3/4 (625 sq.arcmin) of the CANDELS survey area with two orbits of primary WFC3/G141 grism coverage and two to four parallel orbits with the ACS/G800L grism. In the IR these exposure times yield a continuum signal-to-noise of ~5 per resolution element at H~23.1 and a 5sigma emission line sensitivity of 5x10-17 erg/s/cm2 for typical objects, improving by a factor of ~2 for compact sources in images with low sky background levels. The WFC3/G141 spectra provide continuous wavelength coverage from 1.1-1.6 um at a spatial resolution of ~0."13, which, combined with their depth, makes them a unique resource for studying galaxy evolution. We present the preliminary reduction and analysis of the grism observations, including emission line and redshift measurements from combined fits to the extracted grism spectra and photometry from ancillary multi-wavelength catalogs. The present analysis yields redshift estimates with a precision of sigma(z)=0.0034(1+z), or sigma(v)~1000 km/s. We illustrate how the generalized nature of the survey yields near-infrared spectra of remarkable quality for many different types of objects, including a quasar at z=4.7, quiescent galaxies at z~2, and the most distant T-type brown dwarf star known. The CANDELS and 3D-HST surveys combined will provide the definitive imaging and spectroscopic dataset for studies of the 1<z<3.5 Universe until the launch of the James Webb Space Telescope.
We present observations of a luminous galaxy at redshift z=6.573 --- the end of the reioinization epoch --- which has been spectroscopically confirmed twice. The first spectroscopic confirmation comes from slitless HST ACS grism spectra from the PEARS survey (Probing Evolution And Reionization Spectroscopically), which show a dramatic continuum break in the spectrum at restframe 1216 A wavelength. The second confirmation is done with Keck + DEIMOS. The continuum is not clearly detected with ground-based spectra, but high wavelength resolution enables the Lyman alpha emission line profile to be…
Galaxies selected on the basis of their emission line strength show low metallicities, regardless of their redshifts. We conclude this from a sample of faint galaxies at redshifts between 0.6 < z < 2.4, selected by their prominent emission lines in low-resolution grism spectra in the optical with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST) and in the near-infrared using Wide-Field Camera 3 (WFC3). Using a sample of 11 emission line galaxies (ELGs) at 0.6 < z < 2.4 with luminosities of -22 < M_B < -19, which have [OII], Hβ, and [OIII] line flux measurements from th…
We present results of a search for emission-line galaxies in the Southern Fields of the Hubble Space Telescope PEARS (Probing Evolution And Reionization Spectroscopically) grism survey. The PEARS South Fields consist of five ACS pointings (including the Hubble Ultra Deep Field) with the G800L grism for a total of 120 orbits, revealing thousands of faint object spectra in the GOODS-South region of the sky. Emission-line galaxies (ELGs) are one subset of objects that are prevalent among the grism spectra. Using a 2-dimensional detection and extraction procedure, we find 320 emission lines orgina…
3D-HST is a 248-orbit Treasury program to provide WFC3 and ACS grism spectroscopy over four extra-galactic fields (AEGIS, COSMOS, GOODS-South, and UDS), augmented with previously obtained data in GOODS-North. We present a new data release of the 3D-HST survey, version v3.0. This release follows the initial v0.5 release that accompanied the survey description paper (Brammer et al. 2012). The new v3.0 release includes the deepest near-IR HST grism spectra currently in existence, extracted from the 8-17 orbit depth observations in the Hubble Ultra Deep Field. Contamination-corrected 2D and 1D spe…
We present grism spectra of emission-line galaxies (ELGs) from 0.6-1.6 microns from the Wide Field Camera 3 on the Hubble Space Telescope. These new infrared grism data augment previous optical Advanced Camera for Surveys G800L 0.6-0.95 micron grism data in GOODS-South from the PEARS program, extending the wavelength covereage well past the G800L red cutoff. The ERS grism field was observed at a depth of 2 orbits per grism, yielding spectra of hundreds of faint objects, a subset of which are presented here. ELGs are studied via the Ha, [OIII], and [OII] emission lines detected in the redshift …
We present Hubble Space Telescope (HST) imaging and spectroscopy of the gravitational lens SL2SJ02176-0513, a cusp arc at z=1.847. The UV continuum of the lensed galaxy is very blue, which is seemingly at odds with its redder optical colors. The 3D-HST WFC3/G141 near-infrared spectrum of the lens reveals the source of this discrepancy to be extremely strong [OIII]5007 and H-beta emission lines with rest-frame equivalent widths of 2000 +/- 100 and 520 +/- 40 Angstroms, respectively. The source has a stellar mass ~10^8 Msun, sSFR \sim 100/Gyr, and detection of [OIII]4363 yields a metallicity of …
We present the first characterisation of the average dust attenuation curve at $z\sim1.3$ by combining rest-frame ultraviolet through near-IR photometry with Balmer decrement ($\mathrm{H}α$/$\mathrm{H}β$) constraints for $\sim$900 galaxies with $8\lesssim\log (M_\star /M_\odot)<10.2$ at $0.75<z<1.5$ in the HST WFC3 IR Spectroscopic Parallel (WISP) and 3D-HST grism surveys. Using galaxies in SDSS, we establish that the ($\mathrm{H}α$+[NII])/[OIII] line ratio and stellar mass are good proxies for the Balmer decrement in low-spectral resolution grism data when only upper-limits on $\mathrm{H}β$ a…
We take advantage of gravitational lensing amplification by Abell 1689 (z=0.187) to undertake the first space-based census of emission line galaxies (ELGs) in the field of a massive lensing cluster. Forty-three ELGs are identified to a flux of i_775=27.3 via slitless grism spectroscopy. One ELG (at z=0.7895) is very bright owing to lensing magnification by a factor of ~4.5. Several Balmer emission lines detected from ground-based follow-up spectroscopy signal the onset of a major starburst for this low-mass galaxy (M_* = 2 x 10^9 solar masses) with a high specific star formation rate (~20 /Gyr…
We present spectroscopy of 76 emission-line galaxies (ELGs) in CDF-S taken with the LDSS3 spectrograph on Magellan Telescope. These galaxies are selected to have emission lines with ACS grism data in the Hubble Space Telescope Probing Evolution and Reionization Spectroscopically (PEARS) grism Survey. The ACS grism spectra cover the wavelength range 6000-9700 Å and most PEARS grism redshifts are based on a single emission line + photometric redshifts from broad-band colors; the Magellan spectra cover a wavelength range from 4000 Å to 9000 Å, and provide a check on redshifts derived from PEARS d…
We present Hubble Space Telescope Wide Field Camera 3 photometric and grism observations of the candidate ultra-high-redshift (z>7) radio galaxy, GLEAM J0917-0012. This radio source was selected due to the curvature in its 70-230 MHz, low-frequency Murchison Widefield Array radio spectrum and its faintness in K-band. Follow-up spectroscopic observations of this source with the VLA and ALMA were inconclusive as to its redshift. Our F105W and F0986M imaging observations detect the host of GLEAM J0917-0012 and a companion galaxy, ~one arcsec away. The G102 grism observations reveal a single weak …
We present HST/WFC3 grism spectroscopy of the brightest galaxy at z>1.5 in the GOODS-South WFC3 Early Release Science grism pointing, covering the wavelength range 0.9-1.7 micron. The spectrum is of remarkable quality and shows the redshifted Balmer lines Hbeta, Hgamma, and Hdelta in absorption at z=1.902, correcting previous erroneous redshift measurements from the rest-frame UV. The average rest-frame equivalent width of the Balmer lines is 8+-1 Angstrom, which can be produced by a post-starburst stellar population with a luminosity-weighted age of ~0.5 Gyr. The M/L ratio inferred from the s…
A public release of slitless spectra, obtained with ACS/WFC and the G800L grism, is presented. Spectra were automatically extracted in a uniform way from 153 archival fields (or "associations") distributed across the two Galactic caps, covering all observations to 2008. The ACS G800L grism provides a wavelength range of 0.55-1.00 μ$m, with a dispersion of $40 \ Å/ pixel$ and a resolution of $\sim 80\ Å$ for point-like sources. The ACS G800L images and matched direct images were reduced with an automatic pipeline that handles all steps from archive retrieval, alignment and astrometric calibrati…
Lyman-break galaxies are now regularly found in the high redshift Universe by searching for the break in the galaxy spectrum caused by the Lyman-limit redshifted into the optical or even near-IR. At lower redshift, this break is covered by the GALEX UV channels and small samples of z ~ 1 LBGs have been presented in the literature. Here we give results from fitting the spectral energy distributions of a small sub-set of low redshift LBGs and demonstrate the advantage of including photometric points derived from HST ACS slitless grism observations. The results show these galaxies to have very yo…
The mutually complementary Euclid and Roman galaxy redshift surveys will use Halpha- and [OIII]-selected emission line galaxies as tracers of the large scale structure at $0.9 \lesssim z \lesssim 1.9$ (Halpha) and $1.5 \lesssim z \lesssim 2.7$ ([OIII]). It is essential to have a reliable and sufficiently precise knowledge of the expected numbers of Halpha-emitting galaxies in the survey volume in order to optimize these redshift surveys for the study of dark energy. Additionally, these future samples of emission-line galaxies will, like all slitless spectroscopy surveys, be affected by a compl…
We present reduced data and data products from the 3D-HST survey, a 248-orbit HST Treasury program. The survey obtained WFC3 G141 grism spectroscopy in four of the five CANDELS fields: AEGIS, COSMOS, GOODS-S, and UDS, along with WFC3 $H_{140}$ imaging, parallel ACS G800L spectroscopy, and parallel $I_{814}$ imaging. In a previous paper (Skelton et al. 2014) we presented photometric catalogs in these four fields and in GOODS-N, the fifth CANDELS field. Here we describe and present the WFC3 G141 spectroscopic data, again augmented with data from GO-1600 in GOODS-N. The data analysis is complicat…
We present a full analysis of the Probing Evolution And Reionization Spectroscopically (PEARS) slitess grism spectroscopic data obtained with the Advanced Camera for Surveys on HST. PEARS covers fields within both the Great Observatories Origins Deep Survey (GOODS) North and South fields, making it ideal as a random survey of galaxies, as well as the availability of a wide variety of ancillary observations to support the spectroscopic results. Using the PEARS data we are able to identify star forming galaxies within the redshift volume 0< z<1.5. Star forming regions in the PEARS survey are pin…
The Hubble Space Telescope (HST) has proven to be uniquely suited for the measurement of proper motions (PMs) of stars and galaxies in the nearby Universe. Here we summarize the main results and ongoing studies of the HSTPROMO collaboration, which over the past decade has executed some two dozen observational and theoretical HST projects on this topic. This is continuing to revolutionize our dynamical understanding of many objects, including: globular clusters; young star clusters; stars and stellar streams in the Milky Way halo; Local Group galaxies, including dwarf satellite galaxies, the Ma…
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 $z\gtrsim6$ galaxy candidates obtained from the first seven orbits out of fourteen targeting the core of the Frontier Fields cluster MACS0717.5+3745. Using…
We present deep WFC3 grism observations of the candidate z~12 galaxy UDFj-39546284 in the HST Ultra Deep Field (UDF), by combining spectroscopic data from the 3D-HST and CANDELS surveys. The total exposure time is 40.5 ks and the spectrum covers 1.10 < λ < 1.65μm. We search for faint emission lines by cross-correlating the 2D G141 spectrum with the observed H160 morphology, a technique that is unique to slitless spectroscopy at HST resolution. We find a 2.7σ detection of an emission line at 1.599 μm---just redward of the JH140 filter---with flux 3.5 +/- 1.3x10-18 erg/s/cm2. Assuming the line i…
We present a complete theoretical scenario for classical Cepheids in the most commonly used HST/WFC3 filters, going from optical (F555W, F606W and F814W) to near-infrared (F160W) bands. The importance of such a study is related to the recent release of new classical Cepheids observed with HST/WFC3 in 8 distant galaxies where SNIa are hosted. These observations have posed sound constraints to the current distance scale with uncertainties on the Hubble constant Ho smaller than 3%. Our models explore a large range of metallicity and Helium content, thus providing a robust and unique theoretical t…
We present near-infrared emission line counts and luminosity functions from the HST WFC3 Infrared Spectroscopic Parallels (WISP) program for 29 fields (0.037 deg^2) observed using both the G102 and G141 grisms. Altogether we identify 1048 emission line galaxies with observed equivalent widths greater than 40 Angstroms, 467 of which have multiple detected emission lines. The WISP survey is sensitive to fainter flux levels (3-5x10^-17 ergs/s/cm^2) than the future space near-infrared grism missions aimed at baryonic acoustic oscillation cosmology (1-4x10^-16 ergs/s/cm^2), allowing us to probe the…
The 3D-HST and CANDELS programs have provided WFC3 and ACS spectroscopy and photometry over ~900 square arcminutes in five fields: AEGIS, COSMOS, GOODS-North, GOODS-South, and the UKIDSS UDS field. All these fields have a wealth of publicly available imaging datasets in addition to the HST data, which makes it possible to construct the spectral energy distributions (SEDs) of objects over a wide wavelength range. In this paper we describe a photometric analysis of the CANDELS and 3D-HST HST imaging and the ancillary imaging data at wavelengths 0.3um to 8um. Objects were selected in the WFC3 nea…
Assuming the Central Limit Theorem, experimental uncertainties in any data set are expected to follow the Gaussian distribution with zero mean. We propose an elegant method based on Kolmogorov-Smirnov statistic to test the above; and apply it on the measurement of Hubble constant which determines the expansion rate of the Universe. The measurements were made using Hubble Space Telescope. Our analysis shows that the uncertainties in the above measurement are non-Gaussian.
Near infrared slitless spectroscopy with the Wide Field Camera 3, onboard the Hubble Space Telescope, offers a unique opportunity to study low-mass galaxy populations at high-redshift ($z\sim$1-2). While most high$-z$ surveys are biased towards massive galaxies, we are able to select sources via their emission lines that have very-faint continua. We investigate the star formation rate (SFR)-stellar mass ($M_{\star}$) relation for about 1000 emission-line galaxies identified over a wide redshift range of $0.3 \lesssim z \lesssim 2.3$. We use the H$_α$ emission as an accurate SFR indicator and c…
We present Hubble Space Telescope imaging and grism spectroscopy in the field of the distant galaxy cluster JKCS 041 using the Wide Field Camera 3. We confirm that JKCS 041 is a rich cluster and derive a redshift z=1.80 via the spectroscopic identification of 19 member galaxies, of which 15 are quiescent. These are centered upon diffuse X-ray emission seen by the Chandra observatory. As JKCS 041 is the most distant known cluster with such a large, spectroscopically confirmed quiescent population, it provides a unique opportunity to study the effect of the environment on galaxy properties at ea…
We use ultradeep HST WFC3/IR imaging of the HUDF to investigate the rest-frame optical morphologies of a mass-selected sample of galaxies at z~2. We find a large variety of galaxy morphologies, ranging from large, blue, disk-like galaxies to compact, red, early-type galaxies. We derive rest-frame u-g color profiles for these galaxies and show that most z~2 galaxies in our sample have negative color gradients such that their cores are red. Although these color gradients may partly be caused by radial variations in dust content, they point to the existence of older stellar populations in the cen…
Extending over three Hubble Space Telescope (HST) cycles, the Hubble Frontier Fields (HFF) initiative constitutes the largest commitment ever of HST time to the exploration of the distant Universe via gravitational lensing by massive galaxy clusters. We here present models of the mass distribution in the six HFF cluster lenses, derived from a joint strong- and weak-lensing analysis anchored by a total of 88 multiple-image systems identified in existing HST data. The resulting maps of the projected mass distribution and of the gravitational magnification effectively calibrate the HFF clusters a…
We examine in this paper a stellar mass selected sample of galaxies at 1 < z < 3 within the Hubble Ultra Deep Field, utilising WFC3 imaging to study the rest-frame optical morphological distribution of galaxies at this epoch. We measure how apparent morphologies (disk, elliptical, peculiar) correlate with physical properties, such as quantitative structure and spectral-types. One primary result is that apparent morphology does not correlate strongly with stellar populations, nor with galaxy structure at this epoch, suggesting a chaotic formation history for Hubble types at z > 1. By using a lo…
The Hubble Space Telescope (HST) archives constitute a rich dataset of high resolution images to mine for strong gravitational lenses. While many HST programs specifically target strong lenses, they can also be present by coincidence in other HST observations. We aim to identify non-targeted strong gravitational lenses in almost two decades of images from the ESA it Hubble Space Telescope archive (eHST), without any prior selection on the lens properties. We used crowdsourcing on the Hubble Asteroid Hunter (HAH) citizen science project to identify strong lenses, alongside asteroid trails, in p…
We present near-IR images, obtained with the Hubble Space Telescope (HST) and the WFC3/IR camera, of six passive and massive galaxies at redshift 1.3<z<2.4 (SSFR<10^{-2} Gyr^{-1}; stellar mass M~10^{11} M_{sun}), selected from the Great Observatories Origins Deep Survey (GOODS). These images, which have a spatial resolution of ~1.5 kpc, provide the deepest view of the optical rest-frame morphology of such systems to date. We find that the light profile of these galaxies is regular and well described by a Sersic model with index typical of today's spheroids. Their size, however, is generally mu…
In this paper we present a quantitative study of the classification of Extremely Red Objects (EROs). The analysis is based on the multi-band spatial- and ground-based observations (HST/ACS-$BViz$, HST/NICMOS-$JH$, VLT-$JHK$) in the Hubble Ultra Deep Field (UDF). Over a total sky area of 5.50 arcmin$^2$ in the UDF, we select 24 EROs with the color criterion $(i-K)_{\rm Vega}>3.9$, corresponding to $(I-K)_{\rm Vega}\gsim4.0$, down to $\Kv=22$. We develop four methods to classify EROs into Old passively evolving Galaxies (OGs) and Dusty star-forming Galaxies (DGs), including $(i-K)$ vs. $(J-K)$ c…
We present deep Hubble Space Telescope Wide Field Camera 3 slitless spectroscopic observations of the distant cluster Cl J1449+0856. These cover a single pointing with 18 orbits of G141 spectroscopy and F140W imaging, allowing us to derive secure redshifts down to m_140~25.5 AB and 3sigma line fluxes of 5*10^(-18) erg/s/cm^2. In particular, we were able to spectroscopically confirm 12 early-type galaxies in the field up to z~3, 6 of which in the cluster core, which represents the first direct spectroscopic confirmation of passive galaxies in a z=2 cluster environment. With 140 redshifts in a ~…
We exploit the strong lensing effect to explore the properties of intrinsically faint and compact galaxies at intermediate redshift, at the highest possible resolution at optical wavelengths. Our sample consists of 46 strongly-lensed emission line galaxies discovered by the Sloan Lens ACS (SLACS) Survey. The galaxies have been imaged at high resolution with HST in three bands (V_HST, I_814 and H_160), allowing us to infer their size, luminosity, and stellar mass using stellar population synthesis models. Lens modeling is performed using a new fast and robust code, klens, which we test extensiv…
HST-1, a knot along the M87 jet located 0.85 arcsec from the nucleus of the galaxy has experienced dramatic and unexpected flaring activity since early 2000. We present analysis of Hubble Space Telescope Near-Ultraviolet (NUV) imaging of the M87 jet from 1999 May to 2006 December that reveals that the NUV intensity of HST-1 has increased 90 times over its quiescent level and outshines the core of the galaxy. The NUV light curve that we derive is synchronous with the light curves derived in other wavebands. The correlation of X-ray and NUV light curves during the HST-1 flare confirms the synchr…
We present Hubble Space Telescope Wide Field Camera 3 slitless grism spectroscopy of 28 emission-line galaxies at z~2, in the GOODS-S region of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). The high sensitivity of these grism observations, with 1-sigma detections of emission lines to f > 2.5x10^{-18} erg/s/cm^2, means that the galaxies in the sample are typically ~7 times less massive (median M_* = 10^{9.5} M_sun) than previously studied z~2 emission-line galaxies. Despite their lower mass, the galaxies have OIII/Hb ratios which are very similar to previously st…
Cosmology is intrinsically intertwined with questions in fundamental physics. The existence of non-baryonic dark matter requires new physics beyond the Standard Model of elemenatary-particle interactions and Einstein's general relativity, as does the accelerating expansion of the universe. Current tensions between various cosmological measurements may be harbingers of yet more new physics. Progress on understanding dark matter and cosmic acceleration requires long term, high-precision measurements and excellent control of systematics, demanding observational programs that are often outside the…
We report the discovery of a redshift 1.71 supernova in the GOODS North field. The Hubble Space Telescope (HST) ACS spectrum has almost negligible contamination from the host or neighboring galaxies. Although the rest frame sampled range is too blue to include any Si ii line, a principal component analysis allows us to confirm it as a Type Ia supernova with 92% confidence. A recent serendipitous archival HST WFC3 grism spectrum contributed a key element of the confirmation by giving a host-galaxy redshift of 1.713 +/- 0.007. In addition to being the most distant SN Ia with spectroscopic confir…
High-precision astrometry throughout the Local Group is a unique capability of the Hubble Space Telescope (HST), with potential for transformative science, including constraining the nature of dark matter, probing the epoch of reionization, and understanding key physics of galaxy evolution. While Gaia will provide unparalleled astrometric precision for bright stars in the inner halo of the Milky Way, HST is the only current mission capable of measuring accurate proper motions for systems at greater distances (> 80 kpc), which represents the vast majority of galaxies in the Local Group. The nex…
We present a strong and weak gravitational lens model of the galaxy cluster MACSJ0416.1-2403, constrained using spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS) and Hubble Frontier Fields (HFF) imaging data. We search for emission lines in known multiply imaged sources in the GLASS spectra, obtaining secure spectroscopic redshifts of 31 multiple images belonging to 16 distinct source galaxies. The GLASS spectra provide the first spectroscopic measurements for 6 of the source galaxies. The weak lensing signal is acquired from 884 galaxies in the F606W HFF image. By combining…
We present measurements of the dependence of the clustering amplitude of galaxies on their star formation rate (SFR) and stellar mass ($M_*$) at $0.7 < z < 1.5$ to assess the extent to which environment affects these properties. While these relations are well determined in the local universe, they are much more poorly known at earlier times. For this analysis we make use of the near-IR HST WFC3 grism spectroscopic data in the five CANDELS fields obtained as part of the 3D-HST survey. We make projected 2-point correlation function measurements using $\sim$6,000 galaxies with accurate redshifts,…
We derive new constraints on the Hubble parameter $H_0$ using the available data on $H(z)$ from cosmic chronometers (CCH), and the Hubble rate data points from the supernovae of Type Ia (SnIa) of the Pantheon compilation and the Hubble Space Telescope (HST) CANDELS and CLASH Multy-Cycle Treasury (MCT) programs. We employ two alternative techniques, Gaussian Processes (GPs) and the Weighted Polynomial Regression (WPR) method, to reconstruct the Hubble function, determine the derived values of $H_0$, and compare them with the local HST measurement provided by Riess {\it et al.} (2018), $H_0^{\rm…
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 spectr…
In this work, we propose a new strategy for the pixel-lensing observation of M87 in the Virgo cluster using the {\it Hubble Space Telescope} (HST). In contrast to the previous observational strategy by Baltz et al., we show that a few days intensive observation with the duration of $\sim 90 $min in each HST orbit will increase the observational efficiency of the high-magnification events by more than one order of magnitude. We perform a Monte-Carlo simulation for this strategy and we show that the number of high magnification microlensing events will increase at the rate of 4.2 event per day w…
The assembly of galaxies can be described by the distribution of their star formation as a function of cosmic time. Thanks to the WFC3 grism on HST it is now possible to measure this beyond the local Universe. Here we present the spatial distribution of Halpha emission for a sample of 54 strongly star-forming galaxies at z~1 in the 3D-HST Treasury survey. By stacking the Halpha emission we find that star formation occurred in approximately exponential distributions at z~1, with median Sersic index of n=1.0+-0.2. The stacks are elongated with median axis ratios of b/a=0.58+-0.09 in Halpha, cons…
Using HST/ACS slitless grism spectra from the PEARS program, we study the stellar populations of morphologically selected early-type galaxies in the GOODS North and South fields. The sample - extracted from a visual classification of the (v2.0) HST/ACS images and restricted to redshifts z>0.4 - comprises 228 galaxies (F775W<24 ABmag) out to z~1.3 over 320 arcmin2, with a median redshift zM=0.75. This work significantly increases our previous sample from the GRAPES survey in the HUDF (18 galaxies over ~11 arcmin2; Pasquali et al. 2006b). The grism data allow us to separate the sample into `red'…
We use a newly developed observing mode on the Hubble Space Telescope (HST) and Wide Field Camera 3 (WFC3), spatial scanning, to increase source sampling a thousand-fold and measure changes in source positions to a precision of 20--40 microarcseconds, more than an order of magnitude better than attainable in pointed observations. This observing mode can usefully measure the parallaxes of bright stars at distances of up to 5 kpc, a factor of ten farther than achieved thus far with HST. Long-period classical Cepheid variable stars in the Milky Way, nearly all of which reside beyond 1 kpc, are es…
We constrain the properties of the progenitor system of the highly reddened Type Ia supernova (SN) 2014J in Messier 82 (M82; d ~ 3.5 Mpc). We determine the SN location using Keck-II K-band adaptive optics images, and we find no evidence for flux from a progenitor system in pre-explosion near-ultraviolet through near-infrared Hubble Space Telescope (HST) images. Our upper limits exclude systems having a bright red giant companion, including symbiotic novae with luminosities comparable to that of RS Ophiuchi. While the flux constraints are also inconsistent with predictions for comparatively coo…
Charge Transfer Inefficiency (CTI) due to radiation damage above the Earth's atmosphere creates spurious trailing in Hubble Space Telescope (HST) images. Radiation damage also creates unrelated warm pixels - but these happen to be perfect for measuring CTI. We model CTI in the Advanced Camera for Surveys (ACS)/Wide Field Channel (WFC) and construct a physically motivated correction scheme. This operates on raw data, rather than secondary science products, by returning individual electrons to pixels from which they were unintentionally dragged during readout. We apply our correction to images f…
We have acquired Hubble Space Telescope (HST) and Very Large Telescope near-infrared spectra and images of supernova (SN) Refsdal after its discovery as an Einstein cross in Fall 2014. The HST light curve of SN Refsdal matches the distinctive, slowly rising light curves of SN 1987A-like supernovae (SNe), and we find strong evidence for a broad H-alpha P-Cygni profile in the HST grism spectrum at the redshift (z = 1.49) of the spiral host galaxy. SNe IIn, powered by circumstellar interaction, could provide a good match to the light curve of SN Refsdal, but the spectrum of a SN IIn would not sho…
We present a new technique for wide and shallow observations using the near-infrared channel of Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). Wide-field near-IR surveys with HST are generally inefficient, as guide star acquisitions make it impractical to observe more than one pointing per orbit. This limitation can be circumvented by guiding with gyros alone, which is possible as long as the telescope has three functional gyros. The method presented here allows us to observe mosaics of eight independent WFC3-IR pointings in a single orbit by utilizing the fact that HST drifts…
