Status Report

NASA Hubble Space Telescope Daily Report #4996

By SpaceRef Editor
December 23, 2009
Filed under , ,


Continuing to Collect World Class Science

PERIOD COVERED: 5am December 18 – 5am December 21, 2009 (DOY 352/10:00z-355/10:00z)


WFC3/IR/S/C 11929

IR Dark Current Monitor

Analyses of ground test data showed that dark current signals are more reliably removed from science data using darks taken with the same exposure sequences as the science data, than with a single dark current image scaled by desired exposure time. Therefore, dark current images must be collected using all sample sequences that will be used in science observations. These observations will be used to monitor changes in the dark current of the WFC3-IR channel on a day-to-day basis, and to build calibration dark current ramps for each of the sample sequences to be used by Gos in Cycle 17. For each sample sequence/array size combination, a median ramp will be created and delivered to the calibration database system (CDBS).

WFC3/UVIS 11914

UVIS Earth Flats

This program is an experimental path finder for Cycle 18 calibration. Visible-wavelength flat fields will be obtained by observing the dark side of the Earth during periods of full moon illumination. The observations will consist of full-frame streaked WFC3 UVIS imagery: per 22-min total exposure time in a single “dark-sky” orbit, we anticipate collecting 7000 e/pix in F606W or 4500 e/pix in F814W. To achieve Poisson S/N > 100 per pixel, we require at least 2 orbits of F606W and 3 orbits of F814W.

For UVIS narrowband filters, exposures of 1 sec typically do not saturate on the sunlit Earth, so we will take sunlit Earth flats for three of the more-commonly used narrowband filters in Cycle 17 plus the also-popular long-wavelength quad filters, for which we get four filters at once.

Why not use the Sunlit Earth for the wideband visible-light filters? It is too bright in the visible for WFC3 UVIS minimum exposure time of 0.5 sec. Similarly, for NICMOS the sunlit-Earth is too bright which saturates the detector too quickly and/or induces abnormal behaviors such as super-shading (Gilmore 1998, NIC 098-011). In the narrowband visible and broadband near-UV its not too bright (predictions in Cox et al. 1987 “Standard Astronomical Sources for HST: 6. Spatially Flat Fields.” and observations in ACS Program 10050).

Other possibilities? Cox et al.’s Section II.D addresses many other possible sources for flat fields, rejecting them for a variety of reasons. A remaining possibility would be the totally eclipsed moon. Such eclipses provide approximately 2 hours (1 HST orbit) of opportunity per year, so they are too rare to be generically useful. An advantage of the moon over the Earth is that the moon subtends less than 0.25 square degree, whereas the Earth subtends a steradian or more, so scattered light and light potentially leaking around the shutter presents additional problems for the Earth. Also, we’re unsure if HST can point 180 deg from the Sun.

WFC3/UVIS 11912

UVIS Internal Flats

This proposal will be used to assess the stability of the flat field structure for the UVIS detector throughout the 15 months of Cycle 17. The data will be used to generate on- orbit updates for the delta-flat field reference files used in the WFC3 calibration pipeline, if significant changes in the flat structure are seen.

WFC3/UVIS 11908

Cycle 17: UVIS Bowtie Monitor

Ground testing revealed an intermittent hysteresis type effect in the UVIS detector (both CCDs) at the level of ~1%, lasting hours to days. Initially found via an unexpected bowtie-shaped feature in flatfield ratios, subsequent lab tests on similar e2v devices have since shown that it is also present as simply an overall offset across the entire CCD, i.e., a QE offset without any discernable pattern. These lab tests have further revealed that overexposing the detector to count levels several times full well fills the traps and effectively neutralizes the bowtie. Each visit in this proposal acquires a set of three 3×3 binned internal flatfields: the first unsaturated image will be used to detect any bowtie, the second, highly exposed image will neutralize the bowtie if it is present, and the final image will allow for verification that the bowtie is gone.

WFC3/UVIS 11905

WFC3 UVIS CCD Daily Monitor

The behavior of the WFC3 UVIS CCD will be monitored daily with a set of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K subarray biases are acquired at less frequent intervals throughout the cycle to support subarray science observations. The internals from this proposal, along with those from the anneal procedure (Proposal 11909), will be used to generate the necessary superbias and superdark reference files for the calibration pipeline (CDBS).

ACS/WFC3 11879

CCD Daily Monitor (Part 1)

This program comprises basic tests for measuring the read noise and dark current of the ACS WFC and for tracking the growth of hot pixels. The recorded frames are used to create bias and dark reference images for science data reduction and calibration. This program will be executed four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To facilitate scheduling, this program is split into three proposals. This proposal covers 352 orbits (22 weeks) from 31 August 2009 to 31 January 2010.

FGS 11872

Monitoring FGS1R’s Interferometric Response as a Function of Spectral Color

This proposal uses FGS1R in Transfer mode to observe four stars with B-V values 0.2, 0.6, 1.4, and 2.0, to form the basis of the FGS point source library of interference fringes as a function of a star’s spectral color. This library will be used to analyze binary star science observations, and to monitor any long-term changes in the FGS1R S-curves. In addition, this proposal uses FGS1R in Position mode to observe the B-V = 0.2 and 2.0 stars and several nearby reference stars, all of which “fit” in the FGS1R pickle at the selected HST orients in visits 01 and 02. These Visits are to execute when the target field is in the anti-Sun direction (Dec 20-23, 2009). The orient of visit 01 differs from that of visit 02 by ~195 degrees so that the “lateral color” induced shift of the star’s centroid can be determined as a function of B-V. Visit 03 (Upgren69) is to execute before SM4. Visit 04 (HD233877) is to execute Feb-April 2010 as a stability monitor.

STIS/CCD 11846

CCD Bias Monitor-Part 1

The purpose of this proposal is to monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns.

STIS/CCD 11844

CCD Dark Monitor Part 1

The purpose of this proposal is to monitor the darks for the STIS CCD.


Observing Cluster Assembly Around the Massive Cluster RXJ0152-13

We request ACS imaging for groups and filaments in the outskirts of two z=0.8 forming clusters of galaxies. These images will be combined with an unparalleled dataset of wide-field spectroscopy from Magellan, with ~2200 confirmed members (~3200 by the summer) of the superstructures surrounding the two clusters. We will estimate merger rates and determine the morphological composition of the galaxy populations within the infalling groups and filaments identified in our spectroscopic dataset. The HST data are critical to understand how the early-type galaxy fraction remains constant in cluster centers, while clusters double in mass through the steady accretion of lower mass groups. One possibility is that the galaxies in the filaments and infalling groups already have predominantly early-type morphologies, while another is that galaxies transform during, and possibly even in connection with, the process of infall. Our unique dataset of spectroscopic membership, when combined with the exquisite high-resolution imaging of ACS and WF3, will enable us to witness the accretion of galaxies unto massive clusters and how this process affects their properties.


UV Spectroscopy of Local Lyman Break Galaxy Analogs: New Clues to Galaxy Formation in the Early Universe

Much of our information about galaxy evolution and the interaction between galaxies and the IGM at high-z has been provided by the Lyman Break Galaxies (LBGs). However, it is difficult to investigate these faint and distant objects in detail. To address this, we have used the GALEX All-Sky Imaging Survey and the SDSS to identify for the first time a rare population of low-redshift galaxies with properties remarkably similar to the high-redshift LBGs. These local “Lyman Break Analogs” (LBAs) resemble LBGs in terms of morphology, size, UV luminosity, star formation rate, UV surface brightness, stellar mass, velocity dispersion, metallicity, and dust content. We are assembling a wide range of data on these objects with the goal of using them as local laboratories for better understanding the relevant astrophysical processes in LBGs. These data include HST imaging (95 orbits in Cy15 and 16), Spitzer photometry and spectroscopy, Chandra and XMM X-ray imaging and spectroscopy, and near-IR integral field spectroscopy (VLT, Keck, and Gemini). In this proposal we are requesting the most important missing puzzle piece: far-UV spectra with a signal-to-noise and spectral resolution significantly better than available for typical LBGs. We will use these spectra to study the LBA’s galactic winds, probe the processes that regulate the escape of Ly-a and Lyman continuum radiation, determine chemical abundances for the stars and gas, and constrain the form of the high-end of the Initial Mass Function. Adding these new COS data will give us vital information about these extraordinary sites of star formation in the local universe. In so-doing it will also shed new light on the processes that led to the formation of stars, the building of galaxies, and the enrichment and heating of the IGM in the early universe.


Detailed Analysis of Carbon Atmosphere White Dwarfs

We propose to obtain UV spectra for the newly discovered white dwarf stars with a carbon-dominated atmosphere. Model calculations show that these stars emit most of their light in the UV part of the electromagnetic spectrum and that an accurate determination of the flux in this region is crucial for an accurate determination of the atmospheric parameters. It will also provide a unique opportunity to test the atomic data and broadening theory in stellar conditions never met before. This will play a primordial role in our path to understand the origin of these objects as well to obtain a better understanding of the evolution of stars in general. The principal objective we hope to achieve with these observations are 1) obtain accurate surface gravity/mass for these stars, 2) constrain/determine the abundance of other elements (O, He, Mg, Ne etc.), especially oxygen, 3) verify the accuracy of the various theoretical atomic data used in the model calculations, 4) understand the origin and evolution of carbon atmosphere white dwarfs, in particular whether progenitor stars as massive as 10.5 solar masses can produce white dwarfs, rather than supernovae. We propose to observe 5 objects chosen carefully to cover the range of observed properties among carbon atmosphere white dwarfs (effective temperature, surface gravity, abundance of hydrogen/helium and magnetic field).

WFC3/IR 11712

Calibration of Surface Brightness Fluctuations for WFC3/IR

We aim to characterize galaxy surface brightness fluctuations (SBF), and calibrate the SBF distance method, in the F110W and F160W filters of the Wide Field Camera 3 IR channel. Because of the very high throughput of F110W and the good match of F160W to the standard H band, we anticipate that both of these filters will be popular choices for galaxy observations with WFC3/IR. The SBF signal is typically an order of magnitude brighter in the near-IR than in the optical, and the characteristics (sensitivity, FOV, cosmetics) of the WFC3/IR channel will be enormously more efficient for SBF measurements than previously available near-IR cameras. As a result, our proposed SBF calibration will allow accurate distance derivation whenever an early-type or bulge- dominated galaxy is observed out to a distance of 150 Mpc or more (i.e., out to the Hubble flow) in the calibrated passbands. For individual galaxy observations, an accurate distance is useful for establishing absolute luminosities, black hole masses, linear sizes, etc. Eventually, once a large number of galaxies have been observed across the sky with WFC3/IR, this SBF calibration will enable accurate mapping of the total mass density distribution in the local universe using the data available in the HST archive. The proposed observations will have additional important scientific value; in particular, we highlight their usefulness for understanding the nature of multimodal globular cluster color distributions in giant elliptical galaxies.

WFC3/UVIS/IR 11700

Bright Galaxies at z>7.5 with a WFC3 Pure Parallel Survey

The epoch of reionization represents a special moment in the history of the Universe as it is during this era that the first galaxies and star clusters are formed. Reionization also profoundly affects the environment where subsequent generations of galaxies evolve. Our overarching goal is to test the hypothesis that galaxies are responsible for reionizing neutral hydrogen. To do so we propose to carry out a pure parallel WFC3 survey to constrain the bright end of the redshift z>7.5 galaxy luminosity function on a total area of 176 arcmin^2 of sky. Extrapolating the evolution of the luminosity function from z~6, we expect to detect about 20 Lyman Break Galaxies brighter than M_* at z~8 significantly improving the current sample of only a few galaxies known at these redshifts. Finding significantly fewer objects than predicted on the basis of extrapolation from z=6 would set strong limits to the brightness of M_*, highlighting a fast evolution of the luminosity function with the possible implication that galaxies alone cannot reionize the Universe. Our observations will find the best candidates for spectroscopic confirmation, that is bright z>7.5 objects, which would be missed by small area deeper surveys. The random pointing nature of the program is ideal to beat cosmic variance, especially severe for luminous massive galaxies, which are strongly clustered. In fact our survey geometry of 38 independent fields will constrain the luminosity function like a contiguous single field survey with two times more area at the same depth. Lyman Break Galaxies at z>7.5 down to m_AB=26.85 (5 sigma) in F125W will be selected as F098M dropouts, using three to five orbits visits that include a total of four filters (F606W, F098M, F125W, F160W) optimized to remove low-redshift interlopers and cool stars. Our data will be highly complementary to a deep field search for high-z galaxies aimed at probing the faint end of the luminosity function, allowing us to disentangle the degeneracy between faint end slope and M_* in a Schechter function fit of the luminosity function. We waive proprietary rights for the data. In addition, we commit to release the coordinates and properties of our z>7.5 candidates within one month from the acquisition of each field.

WFC3/IR 11696

Infrared Survey of Star Formation Across Cosmic Time

We propose to use the unique power of WFC3 slitless spectroscopy to measure the evolution of cosmic star formation from the end of the reionization epoch at z>6 to the close of the galaxy-building era at z~0.3.Pure parallel observations with the grisms have proven to be efficient for identifying line emission from galaxies across a broad range of redshifts. The G102 grism on WFC3 was designed to extend this capability to search for Ly-alpha emission from the first galaxies. Using up to 250 orbits of pure parallel WFC3 spectroscopy, we will observe about 40 deep (4-5 orbit) fields with the combination of G102 and G141, and about 20 shallow (2-3 orbit) fields with G141 alone.

Our primary science goals at the highest redshifts are: (1) Detect Lya in ~100 galaxies with z>5.6 and measure the evolution of the Lya luminosity function, independent of of cosmic variance; 2) Determine the connection between emission line selected and continuum-break selected galaxies at these high redshifts, and 3) Search for the proposed signature of neutral hydrogen absorption at re-ionization. At intermediate redshifts we will (4) Detect more than 1000 galaxies in Halpha at 0.5< z<1.8 to measure the evolution of the extinction-corrected star formation density across the peak epoch of star formation. This is over an order-of-magnitude improvement in the current statistics, from the NICMOS Parallel grism survey. (5) Trace ``cosmic downsizing" from 0.5< z<2.2; and (6) Estimate the evolution in reddening and metallicty in star-forming galaxies and measure the evolution of the Seyfert population. For hundreds of spectra we will be able to measure one or even two line pair ratios -- in particular, the Balmer decrement and [OII]/[OIII] are sensitive to gas reddening and metallicity. As a bonus, the G102 grism offers the possibility of detecting Lya emission at z=7-8.8. To identify single-line Lya emitters, we will exploit the wide 0.8–1.9um wavelength coverage of the combined G102+G141 spectra. All [OII] and [OIII] interlopers detected in G102 will be reliably separated from true LAEs by the detection of at least one strong line in the G141 spectrum, without the need for any ancillary data. We waive all proprietary rights to our data and will make high-level data products available through the ST/ECF. COS/NUV/FUV/STIS/CCD/MA1 11692 The LMC as a QSO Absorption Line System We propose to obtain high resolution, high signal-to-noise observations of QSOs behind the Large Magellanic Clouds. These QSOs are situated beyond the star forming disk of the galaxy, giving us the opportunity to study the distribution of metals and energy in regions lacking significant star formation. In particular, we will derive the metallicities and study the ionization characteristics of LMC gas at impact parameters 3-17 kpc. We will compare our results with high-z QSO absorption line systems. WFC3/UVIS/IR 11644 A Dynamical-Compositional Survey of the Kuiper Belt: A New Window Into the Formation of the Outer Solar System The eight planets overwhelmingly dominate the solar system by mass, but their small numbers, coupled with their stochastic pasts, make it impossible to construct a unique formation history from the dynamical or compositional characteristics of them alone. In contrast, the huge numbers of small bodies scattered throughout and even beyond the planets, while insignificant by mass, provide an almost unlimited number of probes of the statistical conditions, history, and interactions in the solar system. To date, attempts to understand the formation and evolution of the Kuiper Belt have largely been dynamical simulations where a hypothesized starting condition is evolved under the gravitational influence of the early giant planets and an attempt is made to reproduce the current observed populations. With little compositional information known for the real Kuiper Belt, the test particles in the simulation are free to have any formation location and history as long as they end at the correct point. Allowing compositional information to guide and constrain the formation, thermal, and collisional histories of these objects would add an entire new dimension to our understanding of the evolution of the outer solar system. While ground based compositional studies have hit their flux limits already with only a few objects sampled, we propose to exploit the new capabilities of WFC3 to perform the first ever large-scale dynamical-compositional study of Kuiper Belt Objects (KBOs) and their progeny to study the chemical, dynamical, and collisional history of the region of the giant planets. The sensitivity of the WFC3 observations will allow us to go up to two magnitudes deeper than our ground based studies, allowing us the capability of optimally selecting a target list for a large survey rather than simply taking the few objects that can be measured, as we have had to do to date. We have carefully constructed a sample of 120 objects which provides both overall breadth, for a general understanding of these objects, plus a large enough number of objects in the individual dynamical subclass to allow detailed comparison between and within these groups. These objects will likely define the core Kuiper Belt compositional sample for years to come. While we have many specific results anticipated to come from this survey, as with any project where the field is rich, our current knowledge level is low, and a new instrument suddenly appears which can exploit vastly larger segments of the population, the potential for discovery — both anticipated and not — is extraordinary. STIS/CCD 11596 Coronagraphic Imaging of Debris Disks Containing Gas We recently found a new sample of edge-on debris disks using the Spitzer Space Telescope. These disks are particularly valuable because they have observable circumstellar gas as well as dust. They double the small number of debris disks that can be used to study gas-dust interactions in optically-thin disks, as well as the evolution of circumstellar gas during the terrestrial planet-forming phase. We propose HST-STIS coronagraphic imaging of the two closest disks from our sample, in order to image light scattered from the dust disks in a broad optical bandpass. These observations will provide a wealth of information about the disks, including their sizes, radial surface brightness profiles, and basic morphologies (ring-like or smooth disk). They may also reveal dust structures (e.g. clumps) that are often seen in optical images of debris disks and may be generated by the influence of unseen planets. This proposed program is a crucial step towards full characterization of the circumstellar material in two important debris disks. COS/FUV/STIS/CCD/MA1 11592 Testing the Origin(s) of the Highly Ionized High-Velocity Clouds: A Survey of Galactic Halo Stars at z>3 kpc

Cosmological simulation predicts that highly ionized gas plays an important role in the formation and evolution of galaxies and their interplay with the intergalactic medium. The NASA HST and FUSE missions have revealed high-velocity CIV and OVI absorption along extragalactic sightlines through the Galactic halo. These highly ionized high- velocity clouds (HVCs) could cover 85% of the sky and have a detection rate higher than the HI HVCs. Two competing, equally exciting, theories may explain the origin of these highly ionized HVCs: 1) the “Galactic” theory, where the HVCs are the result of feedback processes and trace the disk-halo mass exchange, perhaps including the accretion of matter condensing from an extended corona; 2) the “Local Group” theory, where they are part of the local warm-hot intergalactic medium, representing some of the missing baryonic matter of the Universe. Only direct distance determinations can discriminate between these models. Our group has found that some of these highly ionized HVCs have a Galactic origin, based on STIS observations of one star at z<5.3 kpc. We propose an HST FUV spectral survey to search for and characterize the high velocity NV, CIV, and SiIV interstellar absorption toward 24 stars at much larger distances than any previous searches (4< d<21 kpc, 3<|z|<13 kpc). COS will provide atomic to highly ionized species (e.g.,OI, CII, CIV, SiIV) that can be observed at sufficient resolution (R~22, 000) to not only detect these highly ionized HVCs but also to model their properties and understand their physics and origins. This survey is only possible because of the high sensitivity of COS in the FUV spectral range. WFC3/UVIS 11589 Hypervelocity Stars as Unique Probes of the Galactic Center and Outer Halo We propose to obtain high-resolution images of 11 new hypervelocity stars in the Galactic halo in order to establish the first-epoch astrometric frame, as a part of a long- term program to measure precise proper motions in an absolute inertial frame. The origin of these recently discovered stars with extremely large positive radial velocities, in excess of the escape speed from the Galaxy, is consistent only with being ejected from the deep potential well of the massive black hole at the Galactic center. Reconstructing the full three-dimensional space motion of the hypervelocity stars, through astrometric proper motions, provides a unique opportunity to measure the shape and orientation of the triaxial dark matter halo. The hypervelocity stars allow determination of the Galactic potential out to 120 kpc, independently of and at larger distances than is afforded by tidal streams of satellite galaxies such as the Sagittarius dSph galaxy. Proper motions of the full set of hypervelocity stars will provide unique constraints on massive star formation in the environment of the Galactic center and on the history of stellar ejection by the supermassive black hole. We request one orbit with WFC3 for each of the 11 hypervelocity stars to establish their current positions relative to background galaxies. We request a repeated observation of these stars in Cycle 19, which will conclusively measure the astrometric proper motions. WFC3/UVIS 11588 Galaxy-Scale Strong Lenses from the CFHTLS Survey We aim to investigate the origin and evolution of early-type galaxies using gravitational lensing, modeling the mass profiles of objects over a wide range of redshifts. The low redshift (z = 0.2) sample is already in place following the successful HST SLACS survey; we now propose to build up and analyze a sample of comparable size (~50 systems) at high redshift (0.4 < z < 0.9) using HST WFC3 Snapshot observations of lens systems identified by the SL2S collaboration in the CFHT legacy survey. STIS/CCD 11572 Characterizing Atmospheric Sodium in the Transiting Hot-Jupiter HD189733b We propose STIS transit observations of the exoplanet HD189733b with the goal of measuring atmospheric atomic sodium. Our strategy is to repeat the observing methods used for HD209458b, which resulted in a successful exoplanetary atmospheric sodium detection. Initial ground-based measurements suggest that the sodium signature on HD189733 could be up to three times larger than HD209458b, making a robust 8 detection possible within a 12 orbit program observing three transits. Transit transmission spectra resulting from space-based measurements have the advantage of retaining absolute transit depths when features are measured, which will make it possible to provide an observational link between sodium and atmospheric haze detected with ACS. Such a link can break modeling degeneracies and providing stringent constraints on the overall atmospheric properties, making such atmospheric information as abundances and the temperature-pressure-altitude relation known. A successful measurement will also allow for comparative atmospheric exoplanetology, as an atmospheric feature will be measured with the same instrument in two separate planets. WFC3/ACS/UVIS/IR 11570 Narrowing in on the Hubble Constant and Dark Energy A measurement of the Hubble constant to a precision of a few percent would be a powerful aid to the investigation of the nature of dark energy and a potent “end-to end” test of the present cosmological model. In Cycle 15 we constructed a new streamlined distance ladder utilizing high-quality type Ia supernova data and observations of Cepheids with HST in the near-IR to minimize the dominant sources of systematic uncertainty in past measurements of the Hubble constant and reduce its total uncertainty to a little under 5%. Here we propose to exploit this new route to reduce the remaining uncertainty by more than 30%, translating into an equal reduction in the uncertainty of the equation of state of dark energy. We propose three sets of observations to reach this goal: a mosaic of NGC 4258 with WFC3 in F160W to triple its sample of long period Cepheids, WFC3/F160W observations of the 6 ideal SN Ia hosts to triple their samples of Cepheids, and observations of NGC 5584 the host of a new SN Ia, SN 2007af, to discover and measure its Cepheids and begin expanding the small set of SN Ia luminosity calibrations. These observations would provide the bulk of a coordinated program aimed at making the measurement of the Hubble constant one of the leading constraints on dark energy. COS/FUV 11541 COS-GTO: Cool, Warm, and Hot Gas in the Cosmic Web and in Galaxy Halos COS G130M and G160M 20, 000 resolution observations will be obtained for 17 QSOs to study cool, warm and hot gas in the cosmic web and in galaxy halos. 5 QSOs with z from 0.177 to 0.574 and sum z = 1.68 will be observed with S/N = 40-50 per resolution element. 12 QSOs with z = 0.286 to 0.669 and sum z = 5.57 will be observed with S/N = 30-40. The observations will allow a wide range of IGM studies including determining the frequency of occurrence of the different types of absorption systems detected, along with studies of the physical conditions and elemental abundances in the different systems. Special emphasis will be given to a study of the properties of highly ionized IGM as traced by O VI, O V, O IV, N V, and C IV. The high S/N of the observations will allow a search for broad Lyman alpha absorption and weak metal line absorption that can be crucial for the evaluation of physical conditions and elemental abundances. Supporting ground based observations will allow studies of the association of the absorbers with galaxy structures along the 17 lines of sight. The overall goal of the program will be to obtain the information that will allow an assessment of the baryonic content of the IGM as revealed by UV and EUV absorption lines seen in the spectra of QSOs. WFC3/IR 11208 The Co-Evolution of Spheroids and Black Holes in the Last Six Billion Years The masses of giant black holes are correlated with the luminosities, masses, and velocity dispersions of the bulges of their host galaxies. This empirical correlation of phenomena on widely different scales (from pcs to kpcs) suggests that the formation and evolution of galaxies and central black holes are closely linked. In Cycle 13, we have started a campaign to map directly the co-evolution of spheroids and black-holes by measuring in observationally favorable redshift windows the empirical correlations connecting their properties. By focusing on Seyfert 1s, where the nucleus and the stars contribute comparable fractions of total light, black hole mass and bulge dispersion are obtained from Keck spectroscopy. HST is required for accurate measurement of the non- stellar AGN continuum, the morphology of the galaxy, and the structural parameters of the bulge. The results at z=0.36 indicate a surprisingly fast evolution of bulges in the past 4 Gyrs (significant at the 95%CL), in the sense that bulges were significantly smaller for a given black hole mass. Also, the large fraction of mergers and disturbed galaxies (4+2 out of 20) identifies gas-rich mergers as the mechanisms responsible for bulge- growth. Going to higher redshift – where evolutionary trends should be stronger – is needed to confirm these tantalizing results. We propose therefore to push our investigation to the next suitable redshift window z=0.57 (lookback-time 6 Gyrs). Fifteen objects are the minimum number required to map the evolution of the empirical correlations between bulge properties and black-hole mass, and to achieve a conclusive detection of evolution (>99%CL).

NIC3/WFC3/IR 11153

The Physical Nature and Age of Lyman Alpha Galaxies

In the simplest scenario, strong Lyman alpha emission from high redshift galaxies would indicate that stellar populations younger than 10 Myrs dominate the UV. This does not, however, constrain the stellar populations older than 100 Myrs, which do not contribute to UV light. Also, the Lyman alpha line can be boosted if the interstellar medium is both clumpy and dusty. Different studies with small samples have reached different conclusions about the presence of dust and old stellar populations in Lyman alpha emitters. We propose HST-NICMOS and Spitzer-IRAC photometry of 35 Lyman-alpha galaxies at redshift 4.5< z<6.5, in order to determine their spectral energy distribution (SED) extending through rest-frame optical. This will allow us to measure accurately (1) The total stellar mass in these objects, including old stars which may have formed at redshifts (z > 8) not easily probed by any other means. (2) The dust extinction in the rest- frame UV, and therefore a correction to their present star-formation rates. Taken together, these two quantities will yield the star-formation histories of Lyman alpha galaxies, which form fully half of the known galaxies at z=4-6. They will tell us whether these are young or old galaxies by straddling the 4000A break. Data from NICMOS is essential for these compact and faint (i=25-26th magnitude AB) high redshift galaxies, which are too faint for good near-IR photometry from the ground.

NIC2/WFC3/IR 11143

NICMOS Imaging of Submillimeter Galaxies with CO and PAH Redshifts

We propose to obtain F110W and F160W imaging of 10 z~2.4 submillimeter galaxies (SMGs) whose optical redshifts have been confirmed by the detection of millimeter CO and/or mid-infrared PAH emission. With the 4000A break falling within/between the two imaging filters, we will be able to study these sources’ spatially resolved stellar populations (modulo extinction) in the rest-frame optical. SMGs’ large luminosities appear to be due largely to merger-triggered starbursts; high-resolution NICMOS imaging will help us understand the stellar masses, mass ratios, and other properties of the merger progenitors, valuable information in the effort to model the mass assembly history of the universe.

ACS/WFC3 11138

The Physics of the Jets of Powerful Radio Galaxies and Quasars

We propose to obtain HST polarimetry of the jets of the quasars 1150+497 and PKS 1136-135. Our goal is to solve the riddle of their high-energy emission mechanism, and tackle issues such as particle acceleration and jet dynamics. Our targets are the optically brightest quasar jets, and they span the range of luminosities and beaming parameters seen in these objects. Recent observations with Spitzer, HST and Chandra have shed new light on the spectral morphology of quasar jets, throwing wide open the question of the nature of their optical and X-ray emission. Three mechanisms are possible, including synchrotron emission as well as two Comptonization processes. Polarimetry can uniquely determine which of these mechanisms operates in the optical. We will compare the optical polarimetry to in-hand radio polarimetry as well as in-hand and new Spitzer, HST and Chandra imaging to gain new insights on the structure of these jets, as well as particle acceleration mechanisms and jet dynamics.


Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)


#12138 GSAcq(1,2,1) @352/22:59:07z and REAcq(1,2,1) @353/00:33:15z, 353/02:09:07z & 353/03:45:01z failed to gyro control due to search radius limit exceeded on FGS-1

Observations affected: STIS #31-37 Proposal #11572; WFC3 #159-161 Proposal #11905


#18783-0 CONTINGENCY: Continuous FGS Loss of Lock Looping – updated (Generic) 352/23:18z


FGS GSAcq 27 26
FGS REAcq 15 12
OBAD with Maneuver 20 20


Final Gyro 3 Reconfiguration to Backup Heater Flash Report:

The Gyro 3 heater controller was switched to the backup controller at 350/21:45. Initial biases measurements up to 351/01:50 were nominal, however the GS acquisition at 351/02:57 failed to Loss of Lock (LOL) looping which was indicative of a bias issue. Subsequent biases appeared to increase in the V2 and V3 axes and acquisitions between 06:07 and 10:27 failed due to search radius limit exceeds (SRLEX) or LOL looping while efforts were made to correct the bias. The GS acquisition at 12:01 was successful and performed an onboard bias update. The GS acquisition at 13:05 failed due to a dim star. The full GS acquisition at 19:01 was successful and subsequent successful acquisitions confirm that the EOD transition signature has been reduced back to a typical nominal gyro observer bias signature and that the bias has stabilized. The transients across the EOD crossings are less than 10 arcsec/hr and the bias subsequently returns to its pre-EOD trend after the EOD crossing.

SpaceRef staff editor.