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 spectrum implies a stellar mass of ~4x10^11 Msun. We determine the morphology of the galaxy from a deep WFC3 F160W image. Similar to other massive galaxies at z~2 the galaxy is compact, with an effective radius of 2.1+-0.3 kpc. Although most of the light is in a compact core, the galaxy has two red, smooth spiral arms that appear to be tidally-induced. The spatially-resolved spectroscopy demonstrates that the center of the galaxy is quiescent and the surrounding disk is forming stars, as it shows Hbeta in emission. The galaxy is interacting with a companion at a projected distance of 18 kpc, which also shows prominent tidal features. The companion has a slightly redder spectrum than the primary galaxy but is a factor of ~10 fainter and may have a lower metallicity. It is tempting to interpret these observations as "smoking gun" evidence for the growth of compact, quiescent high redshift galaxies through minor mergers, which has been proposed by several recent observational and theoretical studies. Interestingly both objects host luminous AGNs, as indicated by their X-ray luminosities, which implies that these mergers can be accompanied by significant black hole growth. This study illustrates the power of moderate dispersion, low background near-IR spectroscopy at HST resolution, which is now available with the WFC3 grism.
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 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…
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…
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…
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…
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 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 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 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…
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 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 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 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…
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…
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 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…
The combination of Baryonic Acoustic Oscillation (BAO) data together with light element abundance measurements from Big Bang Nucleosynthesis (BBN) has been shown to constrain the cosmological expansion history to an unprecedented degree. Using the newest LUNA data and DR16 data from SDSS, the BAO+BBN probe puts tight constraints on the Hubble parameter ($H_0 = 67.6 \pm 1.0 \mathrm{km/s/Mpc}$), resulting in a $3.7σ$ tension with the local distance ladder determination from SH0ES in a $Λ$CDM model. In the updated BAO data the high- and low-redshift subsets are mutually in excellent agreement, an…
The massive cluster MACSJ1149.5+2223(z=0.544) displays five very large lensed images of a well resolved spiral galaxy at $z_{\rm spect}=1.491$. It is within one of these images that the first example of a multiply-lensed supernova has been detected recently as part of the Grism Lens-Amplified Survey from Space. The depth of this data also reveals many HII regions within the lensed spiral galaxy which we identify between the five counter-images. Here we expand the capability of our free-form method to incorporate these HII regions locally, with other reliable lensed galaxies added for a global …
We present the WFC3 Infrared Spectroscopic Parallel (WISP) Survey. WISP is obtaining slitless, near-infrared grism spectroscopy of ~ 90 independent, high-latitude fields by observing in the pure parallel mode with Wide Field Camera-3 on the Hubble Space Telescope for a total of ~ 250 orbits. Spectra are obtained with the G102 (lambda=0.8-1.17 microns, R ~ 210) and G141 grisms (lambda=1.11-1.67 microns, R ~ 130), together with direct imaging in the J- and H-bands (F110W and F140W, respectively). In the present paper, we present the first results from 19 WISP fields, covering approximately 63 sq…
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…
We report the discovery of a Type Ia supernova (SNIa) at redshift z=1.55 with the infrared detector of the Wide Field Camera 3 (WFC3-IR) on the Hubble Space Telescope (HST). This object was discovered in CANDELS imaging data of the Hubble Ultra Deep Field, and followed as part of the CANDELS+CLASH Supernova project, comprising the SN search components from those two HST multi-cycle treasury programs. This is the highest redshift SNIa with direct spectroscopic evidence for classification. It is also the first SN Ia at z>1 found and followed in the infrared, providing a full light curve in rest-…
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 report the results of deep (4.6h) H band spectroscopy of the well studied z~12 H-band dropout galaxy candidate UDFj-39546284 with MOSFIRE on Keck-I. These data reach a sensitivity of 5-10 x 10^-19 erg s^-1 cm^-2 per 4.4 Angstrom resolution element between sky lines. Previous papers have argued this source could either be a large equivalent width line emitting galaxy at 2<z<3.5 or a luminous galaxy at z~12. We find a 2.2 sigma peak associated with a line candidate in deep Hubble-Space-Telescope Wide-Field-Camera 3 Infrared grism observations, but at a lower flux than what was expected. After…
We demonstrate that the UV brightest quasars at z=1-2 live in overdense environments. This is based on an analysis of deep Hubble Space Telescope WFC3 G141 grism spectroscopy of the galaxies along the lines-of-sight to UV luminous quasars in the redshift range z=1-2. This constitutes some of the deepest grism spectroscopy performed by WFC3, with 4 roll angles spread over a year of observations to mitigate the effect of overlapping spectra. Of the 12 quasar fields studied, 8 display evidence for a galaxy overdensity at the redshift of the quasar. One of the overdensities, PG0117+213 at z=1.50, …
Supermassive black holes (BHs) appear to be ubiquitous at the center of all galaxies which have been observed at high enough sensitivities and resolution with the Hubble Space Telescope. Their masses are found to be tightly linked with the masses and velocity dispersions of their host galaxies. On the other hand, BHs are widely held to constitute the central engines of quasars and active galactic nuclei (AGN) in general. It is however still unclear how BHs have grown, and whether they have co-evolved with their hosts. In this Review I discuss how, in ways independent of specific models, constr…
Spectroscopic observations of Halpha and Hbeta emission lines of 128 star-forming galaxies in the redshift range 0.75<z<1.5 are presented. These data were taken with slitless spectroscopy using the G102 and G141 grisms of the Wide-Field-Camera 3 (WFC3) on board the Hubble Space Telescope as part of the WFC3 Infrared Spectroscopic Parallel (WISP) survey. Interstellar dust extinction is measured from stacked spectra that cover the Balmer decrement (Halpha/Hbeta). We present dust extinction as a function of Halpha luminosity (down to 3 x 10^{41} erg/s), galaxy stellar mass (reaching 4 x 10^{8} Ms…
The effect of progenitor metallicity on Type Ia Supernovae (SNe Ia) has important cosmological implications due to the need for these standardizable candles to be compared across large spans of cosmic time in which the progenitor stars might have different properties. Theoretical models have come to different conclusions as to the wavelength range impacted by metallicity differences, leading to differing interpretations of the growing sample of UV observations. Recent work has claimed a correlation between the mid-UV flux of SNe Ia measured from Swift grism spectra and the gas-phase metallicit…
We present a novel unsupervised learning approach to automatically segment and label images in astronomical surveys. Automation of this procedure will be essential as next-generation surveys enter the petabyte scale: data volumes will exceed the capability of even large crowd-sourced analyses. We demonstrate how a growing neural gas (GNG) can be used to encode the feature space of imaging data. When coupled with a technique called hierarchical clustering, imaging data can be automatically segmented and labelled by organising nodes in the GNG. The key distinction of unsupervised learning is tha…
We have succeeded in establishing a cosmological model with a non-minimally coupled scalar field $ϕ$ that can account not only for the spatial periodicity or the {\it picket-fence structure} exhibited by the galaxy $N$-$z$ relation of the 2dF survey but also for the spatial power spectrum of the cosmic microwave background radiation (CMB) temperature anisotropy observed by the WMAP satellite. The Hubble diagram of our model also compares well with the observation of Type Ia supernovae. The scalar field of our model universe starts from an extremely small value at around the nucleosynthesis epo…
We identify a sample of spectroscopically measured emission line galaxy (ELG) pairs up to z=1.6 from the WFC3 Infrared Spectroscopic Parallels (WISP) survey. WISP obtained slitless, near-infrared grism spectroscopy along with direct imaging in the J and H bands by observing in the pure-parallel mode with the Wide Field Camera Three (WFC3) on the Hubble Space Telescope (HST). From our search of 419 WISP fields covering an area of ~0.5 deg$^{2}$, we find 413 ELG pair systems, mostly Halpha emitters. We then derive reliable star formation rates (SFRs) based on the attenuation-corrected Halpha flu…
