3C 186, a radio-loud quasar at z = 1.0685, was previously reported to have both velocity and spatial offsets from its host galaxy, and has been considered as a promising candidate for a gravitational wave recoiling black hole triggered by a black hole merger. Another possible scenario is that 3C 186 is in an ongoing galaxy merger, exhibiting a temporary displacement. In this study, we present analyses of new deep images from the Hubble Space Telescope WFC3-IR and Advanced Camera for Surveys, aiming to characterize the host galaxy and test this alternative scenario. We carefully measure the light-weighted center of the host and reveal a significant spatial offset from the quasar core (11.1 ± 0.1 kpc). The direction of the confirmed offset aligns almost perpendicularly to the radio jet. We do not find evidence of a recent merger, such as a young starburst in disturbed outskirts, but only marginal light concentration in F160W at ∼30 kpc. The host consists of mature (≳200 Myr) stellar populations and one compact star-forming region. We compare with hydrodynamical simulations and find that those observed features are consistently seen in late-stage merger remnants. Taken together, those pieces of evidence indicate that the system is not an ongoing/young merger remnant, suggesting that the recoiling black hole scenario is still a plausible explanation for the puzzling nature of 3C 186.

What are the faintest distant galaxies we can see with the Hubble Space Telescope (HST) now, before the launch of the James Webb Space Telescope? This is the challenge taken up by the Frontier Fields, a Director's discretionary time campaign with HST and the Spitzer Space Telescope to see deeper into the universe than ever before. The Frontier Fields combines the power of HST and Spitzer with the natural gravitational telescopes of massive high-magnification clusters of galaxies to produce the deepest observations of clusters and their lensed galaxies ever obtained. Six clusters-Abell 2744, MACSJ0416.1-2403, MACSJ0717.5+3745, MACSJ1149.5+2223, Abell S1063, and Abell 370-have been targeted by the HST ACS/WFC and WFC3/IR cameras with coordinated parallel fields for over 840 HST orbits. The parallel fields are the second-deepest observations thus far by HST with 5s point-source depths of similar to 29th ABmag. Galaxies behind the clusters experience typical magnification factors of a few, with small regions magnified by factors of 10-100. Therefore, the Frontier Field cluster HST images achieve intrinsic depths of similar to 30-33 mag over very small volumes. Spitzer has obtained over 1000 hr of Director's discretionary imaging of the Frontier Field cluster and parallels in IRAC 3.6 and 4.5 mu m bands to 5 sigma point-source depths of similar to 26.5, 26.0 ABmag. We demonstrate the exceptional sensitivity of the HST Frontier Field images to faint high-redshift galaxies, and review the initial results related to the primary science goals.

We study the cluster environment for a sample of 21 radio loud active galactic nuclei from the 3CR catalog at z > 1 -->?> , 12 radio galaxies (RGs) and nine quasars, with Hubble Space Telescope (HST) images in the optical and IR. We use two different approaches to determine cluster candidates. We identify the early-type galaxies (ETGs) in every field by modeling each of the sources within a 40″ radius of the targets with a Sèrsic profile. Using a simple passive evolution model, we derive the expected location of the ETGs on the red sequence (RS) in the color–magnitude diagram for each of the fields of our sources. For seven targets, the model coincides with the position of the ETGs. A second approach involves a search for over densities. We compare the object densities of the sample as a whole and individually against control fields taken from the GOODS-S region of 3D-HST survey. With this method we determine the fields of ten targets to be cluster candidates. Four cluster candidates are found by both methods. The two methods disagree in some cases, depending on the specific properties of each field. For the most distant RG in the 3CR catalog (3C 257 at z = 2.47), we identify a population of bluer ETGs that lie on the expected location of the RS model for that redshift. This appears to be the general behavior of ETGs in our fields and it is possibly a signature of the evolution of such galaxies. Our results are consistent with half of the z > 1 RGs being located in dense, rapidly evolving environments.

ABSTRACT We present new rest-frame UV and visible observations of 22 high- z (1 < z < 2.5) 3C radio galaxies and QSOs obtained with the Hubble Space Telescope ’s Wide Field Camera 3 instrument. Using a custom data reduction strategy in order to assure the removal of cosmic rays, persistence signal, and other data artifacts, we have produced high-quality science-ready images of the targets and their local environments. We observe targets with regions of UV emission suggestive of active star formation. In addition, several targets exhibit highly distorted host galaxy morphologies in the rest frame visible images. Photometric analyses reveal that brighter QSOs generally tend to be redder than their dimmer counterparts. Using emission line fluxes from the literature, we estimate that emission line contamination is relatively small in the rest frame UV images for the QSOs. Using archival VLA data, we have also created radio map overlays for each of our targets, allowing for analysis of the optical and radio axes alignment.

The Wide Field Camera 3 was installed into the Hubble Space Telescope in May 2009. Our presentation discusses the performance of the WFC3 near infrared slitless spectroscopy mode, improvements to the definition and use of detector subarrays, and recent experiments aimed at determining the limits of high contrast imaging. We also discuss the implementation status of a new mode to achieve very high signal to noise observations of bright sources in the infrared channel via controlled motion of the telescope. This offers the potential for high S/N photometry and spectroscopy of very bright targets with excellent time resolution. Spatial Scans for Enhanced S/N WFC3 Spectroscopy • STScI and the HST Project are developing a scanning capability that allows the light from astronomical objects to be trailed across the WFC3 detectors in a predictable and repeatable manner during exposures. • This, if it works as expected, will enable significantly increased S/N observations – especially for infrared spectroscopy of bright sources • The default mode of operation will be to move a user defined distance in the cross-dispersion direction. • Rates up to 1 arc second per second will be supported in Cycle 19 (higher rates may become possible in future cycles). • Testing is planned for Feb-April 2011 and the TAC will be informed of the outcome. • Modest overheads combined with the accurate timing information inherent in the MULTIACCUM readouts of the IR detector should make this a powerful capability for infrared spectroscopy of bright time variable sources. • More details are available in the WFC3 STAN at www.stsci.edu/hst/wfc3/documents/newsletters/STAN_01_06_2011 WFC3 Slit-less Spectroscopy (GRISMs) • WFC3 provides low resolution slit-less spectroscopy in the low background ultraviolet and near infrared • UVIS G280 Grism  λ/δλ ~70 over 190 450 nm (with some response to <180nm) • IR G102 Grism  λ/δλ ~210 over 800 – 1150 nm • IR G141 Grism  λ/δλ ~210 over 1075 – 1700 nm • ESA’s ST-ECF supported the WFC3 Grisms during instrument ground testing, commissioning, and in Cycles 17 and 18. They have provided documentation, simulation and analysis software (aXeSim and aXe), calibration, and user support. • With the end of the ECF in December 2010, these responsibilities at now at STScI •We extend our thanks to the ST-ECF team for their years of outstanding work. Subarray Improvements •Improved sub-arrays defined for WFC3 starting in Cycle 18 • Support some of ACS/HRC parameter space with 1024 x 1024 subarrays in UVIS • IR subarrays supported for GRISM • Cycle 19 Enhancement • Image Header limitation of 100 will increase to 304 in Cycle 19 • Note: each IR readout produces a header High Contrast Imaging • Cycle 18 calibration program 12354 characterized the profile of the WFC3 Point Spread Function to explore high contrast imaging. • UVIS F487N, F467N, F680N, F555W, and F775W plus IR F128N • Carefully dithered to measure contrast out to ~2 arc seconds. • WFC3 is capable of detecting sources at ~1 arc sec with ∆mag ~10 • For UVIS, these calibrations specifically examine the case of a carefully dithered 12th magnitude star • Observers considering observations of high contrast sources sources should examine the 12354 dataset and our analysis. •Early results in posters 254.37 & .41 •UVIS: WFC3 ISR 2011-03 (Gilliland and Rajan) •IR results to be published soon CCD Charge Injection and CTE Mitigation • WFC3 was installed during solar min thus radiation damage to the CCDs is 2-3 times that seen in the first years of ACS (2002-2004) • The WFC3 e2v CCDs have a charge injection gate that permits ~17,000 electrons to be placed into every Nth row • With N=10, this appears to restore CTE to pre-flight levels • Injected row has readnoise ~20ebut returns to 4-5ein rest of rows • Charge Injection will become an option for WFC3/UVIS in Cycle 19 For more on WFC3 at this conference, see posters 254.37, 254.38, 254.39, 254.40, and 254.41. For further information: http://www.stsci.edu/hst/wfc3 and http://www.stsci.edu/hst/wfc3/documents/ISRs ID PI Orbits Title 12177 Van Dokkum 248 3D-HST: A Spectroscopic Galaxy Evolution Treasury 12181 Deming 115 The Atmospheric Structure of Giant Hot Exoplanets 12190 Koekemoer 32 WFC3/IR Spectroscopy of the Highest Redshift Black Hole Candidates 12203 Stanford 30 Rest Frame Optical Spectroscopy of Galaxy Clusters at 1.6<z<1.9 12217 Lucas 6 Spectroscopy of faint T dwarf calibrators: understanding the substellar mass function and the coolest brown dwarfs 12230 Swain 18 The effect of radiation forcing on an exoplanet atmosphere 12247 Tanvir 18x3 Identifying and studying gamma-ray bursts at very high redshifts 12251 Berta 24 The First Characterization of a Super-Earth Atmosphere 12283 Malkan 280p WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time 12314 Apai 24 Mapping Brown Dwarfs: The Evolution of Cloud Properties Through the L/T Transition • UVIS Grism has significant order overlap and full CCD bandpass background • It has been used successfully with relatively bright emission line targets • IR Grisms have excellent primary order energy concentration and out of band rejection •Successfully used in Cycles 17 and 18 plus a key component of the MCT observations of SN1a • Broad range of science programs in Cycle 18 (see Table below)

Installed in the Hubble Space Telescope (HST) in May 2009, the Wide Field Camera 3 (WFC3) is performing extremely well on-orbit. Designed to complement the other instruments on-board the Hubble Space Telescope (HST) and enhance the overall science performance of the observatory, WFC3 is effectively two instruments in one. The UVIS channel, with its pair of e2v 4Kx2K CCD chips provides coverage from 200 to 1000 nm while the IR channel, with a Teledyne HgCdTe focal plane array (FPA) on a Hawaii-1R multiplexer, covers the 800-1700 nm range. This report summarizes the performance of the WFC3 detectors, including primary characteristics such as quantum efficiency, read noise, dark current levels, and cosmetics, as well as hysteresis prevention and the impact of radiation damage in the CCDs. In addition, we discuss effects in the IR detector such as persistence, count rate non-linearity, 'snowballs', and 'negative' cosmic rays.

Using data collected during Servicing Mission Observatory Verification (SMOV) and Cycle 17, we have created an updated bad pixel mask for WFC3’s IR channel. The bad pixel table contains flags that mark the position of pixels which are dead, unstable, have a bad zeroth read value, or are affected by “blobs”. In all, 20,700 of the science pixels (2.0%) are flagged as bad. Observers are encouraged to dither their observations as a means of lessening the effects of these bad pixels.

Flat fielding is a standard calibration step for astronomical data, which allows us to correct for variations in the local response of a detector and improve the accuracy of photometric analysis. As for other Hubble Space Telescope (HST) instruments, ground based flat-fields are, and will be, the base to remove the pixel-to-pixel variations in the Wide Field Camera 3 (WFC3) data. Tests performed during the Servicing Mission Observatory Verification (SMOV4), that followed the installation of WFC3 on Hubble, indicate that ground based flat-fields do not completely remove local variation in the response of the detector, but that low-frequency structures are still present in both the UVIS and IR data. As part of the WFC3 standard calibration process we have used observations of the rich globular cluster Omega Centauri to compare the flux of the same stars at different positions on the WFC3 detectors and derive a correction to remove the remaining low-frequency structures. Here we will present the characteristics of the ground-based high frequency flat (better known as P-flat) and the low-frequency (or L-flat) flat fields, how these files are created and their impact on the processed astronomical data.

Using data taken during the 2009 Servicing Mission Observatory Verification (SMOV), we have analyzed the quality of the Thermal Vacuum 3 (TV3) derived flat fields for the F110W, F125W, F140W, and F160W filters. These ground-based flats are currently used in the standard calibration of all WFC3/IR observations. By comparing photometry results from a set of stars observed on orbit at multiple locations on the detector, we are able to quantify residual differences in detector response after the application of the TV3 flat fields. We find variations in photometry of up to 1.5% across the detector in all four filters.

The IRAF/STSDAS program calwf3, which is used to calibrate WFC3 images, has been subjected to a rigorous testing campaign. The operation of each individual calibration step for WFC3 UVIS and IR images has been tested, as well as the ability of the overall calwf3 infrastructure to handle certain error conditions. Several identified problem areas have been corrected and included in the public release of calwf3 version 1.4.

We present an analysis and the measurements of the Charge Transfer Efficiency (CTE) using the Extended Pixel Edge Response (EPER) technique for the WFC3 UVIS flight detector tested during the ground-based thermal vacuum campaign in April 2008. We present an algorithm for CTE calculation and a power-law functional dependence between CTE and signal level. The analysis shows that CTE is approximately 0.999999 for each amplifier. These CTE pre-flight measurements will serve as a first epoch for WFC3/UVIS CTE internal monitoring.

Using data taken during WFC3's Thermal Vacuum 3 (TV3) testing campaign, we have calculated the correction coefficients necessary to remove non-linearity effects from IR detector (IR-4, FPA165) data. We find that a set of coefficients for each quadrant of the detector produces a better correction than calculating and applying a separate set of coefficients to each pixel.

The Wide-field Camera 3 (WFC3) is a fourth-generation instrument planned for installation in Hubble Space Telescope (HST). Designed as a panchromatic camera, WFC3's UVIS and IR channels will complement the other instruments onboard HST and enhance the observatory's scientific performance. UVIS images are obtained via two 4096×2051 pixel e2v CCDs while the IR images are taken with a 1024×1024 pixel HgCdTe focal plane array from Teledyne Imaging Sensors. Based upon characterization tests performed at NASA/GSFC, the final flight detectors have been chosen and installed in the instrument. This paper summarizes the performance characteristics of the WFC3 flight detectors based upon component and instrument-level testing in ambient and thermal vacuum environments.

Using data taken during thermal vacuum 3 (TV3) testing, we have measured the magnitude and stability of the dark current plus thermal background signal present in WFC3's IR channel. We find that the IR channel with the flight detector (IR4) meets the Contract End Item (CEI) specifications for total background signal and background stability. Additionally, the background levels presented here should be interpreted as upper limits, due to persistence effects from a previous test.

Images taken during WFC3's Thermal Vacuum 2 (TV2) testing have been used to characterize the performance of the UVIS channel shutter. Images with exposure times ranging from 0.5 to 30 seconds have been used to examine shutter shading, accuracy, and repeatability. Fits to ratio images reveal no shutter shading effects down to the 0.77% level, corresponding to an exposure time difference across the image of no more than 0.004 sec (CEI Spec is 0.01 sec). Measured exposure times are within 2.4% of commanded values in all cases except the 0.5 second images. Similar to results from TV1, these data show the UVIS shutter fails to meet the CEI Spec for shutter repeatability in 5 of the 9 commanded exposure times.