Date: April 3rd 2010

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  • Daily Report #5065 - 1 messages, 1 author http://groups google com/group/sci astro hubble/t/a41c37b2a4c29570?hl=en
  • Daily Report #5066 - 1 messages, 1 author http://groups google com/group/sci astro hubble/t/cf245c0967c4a43f?hl=en

============================================================================== TOPIC: Daily Report #5065

http://groups google com/group/sci astro hubble/t/a41c37b2a4c29570?hl=en

== 1 of 1 == Date: Thurs, Apr 1 2010 6:37 am From: "Bassford, Lynn"

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5065

PERIOD COVERED: 5am March 31 - 5am April 1, 2010 (DOY 090/09:00z-091/09:00z)

OBSERVATIONS SCHEDULED

ACS/WFC 11715

The Luminous Galactic Cepheid RS Puppis: A Geometric Distance from its Nested Light Echoes

RS Puppis is one of the most luminous Cepheids in the Milky Way (P = 41 4 days) and an analog of the bright Cepheids used to measure extragalactic distances An accurate distance would help anchor the zero-point of the bright end of the period-luminosity relation, but at a distance of about 2 kpc it is too far away for a trigonometric parallax with existing instrumentation

RS Pup is unique in being surrounded by a reflection nebula, whose brightness varies as pulses of light from the Cepheid propagate outwards Members of our team have used ground-based imaging of the nebula to derive phase lags in the light variations of individual features in the nebula, and have inferred a seemingly very precise geometric distance to the star However, there is an unavoidable ambiguity involving the cycle counts, which was resolved by assuming that the features lie in the plane of the sky If this assumption is incorrect, a large systematic error would be introduced into the distance measurement

We show that polarimetric imaging using the high spatial resolution of ACS/WFC and its ability to image close to the star can resolve this ambiguity and yield a reliable geometric distance to RS Pup We will also obtain a wide-field multicolor image of the nebula, in order to study its morphology and the mass-loss history of the Cepheid

ACS/WFC 11995

CCD Daily Monitor (Part 2)

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 320 orbits (20 weeks) from 1 February 2010 to 20 June 2010

ACS/WFC3 11599

Distances of Planetary Nebulae from SNAPshots of Resolved Companions

Reliable distances to individual planetary nebulae (PNe) in the Milky Way are needed to advance our understanding of their spatial distribution, birthrates, influence on galactic chemistry, and the luminosities and evolutionary states of their central stars (CSPN) Few PNe have good distances, however One of the best ways to remedy this problem is to find resolved physical companions to the CSPN and measure their distances by photometric main-sequence fitting We have previously used HST to identify and measure probable companions to 10 CSPN, based on angular separations and statistical arguments only We now propose to use HST to re-observe 48 PNe from that program for which additional companions are possibly present We then can use the added criterion of common proper motion to confirm our original candidate companions and identify new ones in cases that could not confidently be studied before We will image the region around each CSPN in the V and I bands, and in some cases in the B band Field stars that appear close to the CSPN by chance will be revealed by their relative proper motion during the 13+ years since our original survey, leaving only genuine physical companions in our improved and enlarged sample This study will increase the number of Galactic PNe with reliable distances by 50 percent and improve the distances to PNe with previously known companions

COS/FUV 11897

FUV Spectroscopic Sensitivity Monitoring

The purpose of this proposal is to monitor sensitivity in each FUV grating mode to detect any changes due to contamination or other causes

COS/NUV 11561

An Intensive COS Spectroscopic Study of the Planetary Debris Disks Around two Warm White Dwarfs

It is very likely that the gas giants in our Solar system will survive the evolution of the Sun into a white dwarf, and the same is thought to be generally true for Jovian planets around solar-like stars if their initial orbits are wider than ~3AU Despite this prediction, no unambiguous detection of a planet around a white dwarf has been announced so far However, over the past few years, about a dozen white dwarfs have been identified which host metal-rich debris disks that are thought to stem from the tidal disruption of asteroids In most cases the debris disks are observed in the form of an infrared flux excess, and offer relatively little diagnostic potential for the study of their structure We have discovered three warm (T~20000K) white dwarfs with metal-rich debris disks in a gaseous phase which display strong double-peaked CaII emission lines in the I-band and weak Fe 5169A emission The line profiles can be modeled in terms of Keplerian disks with an extension of ~1Rsun around the white dwarfs Photospheric MgII 4481A absorption demonstrates that the white dwarfs are accreting from the debris disks Besides these spectral features, the optical wavelength range is devoid of other useful metal transitions Here, we propose an intensive spectroscopic ultraviolet study of these systems, which will provide (a) ~1000 photospheric absorption lines of 15 chemical elements, allowing an accurate abundance study of the material accreted from the debris disks, and (b) ~2 dozen additional emission lines of Mg, Cr, Ti, and Fe that will provide detailed insight into the dynamical, thermal, and density structure of these exo-planetary debris disks

COS/NUV 11894

NUV Detector Dark Monitor

The purpose of this proposal is to measure the NUV detector dark rate by taking long science exposures with no light on the detector The detector dark rate and spatial distribution of counts will be compared to pre-launch and SMOV data in order to verify the nominal operation of the detector Variations of count rate as a function of orbital position will be analyzed to find dependence of dark rate on proximity to the SAA Dependence of dark rate as function of time will also be tracked

COS/NUV/FUV/WFC3/UVIS/IR 11520

COS-GTO: QSO Absorbers, Galaxies and Large-Scale Structures in the Local Universe

This is a program to probe the large scale structure of baryons in the universe, including addressing questions of baryon fraction, physical conditions and relationships between absorbers and large-scale structures of galaxies Besides these specific goals, this proposed GTO program also probes a large enough total path length in Ly alpha and OVI to add significantly to what STIS/FUSE has already observed Several Galactic High Velocity Cloud Complexes also are probed by these sightlines, particularly the M Complex The total path length of this proposed program for Ly alpha large-scale structure surveys is delta_z~5 5

We have selected a variety of targets to address these questions, under the following subcategories:

  1. Target 8 bright BL Lac objects to search for low contrast Ly alpha absorbers from the warm- hot interstellar medium (WHIM)

  2. Ly alpha cloud sizes: The targets are a bright AGN pair which yield tangential distance separations of 100--500 kpc at z=0 01--0 05, where galaxy surveys are excellent This pair has two filaments and two voids in this distance range

  3. Probes of starburst outflows: The targets are bright AGN, <= 100 kpc in projection out of the minor axis of nearby starburst galaxies

  4. A large galaxy's gaseous halo: Three probes of the kinematics and metallicity of a single L* galaxy halo These observations includes G130M, G160M exposures at SNR~20 and G285M at 2850A and SNR~10 for MgII The 2L* galaxy, ESO 157-G049 (cz=1678 km/s), being probed by these sightlines has an available H I 21cm map from ATCA, H alpha imaging from CTIO and long- slit spectra from MSSSO

  5. Dwarf galaxy winds: These targets probe the kinematics and metallicities of outflows from active and inactive (in terms of star formation) dwarfs

STIS/CC 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD

STIS/CC 11847

CCD Bias Monitor-Part 2

Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns

STIS/CC/MA 11516

COS-GTO: Cold ISM

With the COS, we will be able to observe interstellar spectra in a new regime, translucent clouds, for atomic, ionic, and molecular lines and bands, and extinction curves The COS will allow us to observe stars with total visual extinctions up to 10 magnitudes, and the grain size indicator Rv up to 4 5 In translucent clouds we expect to see the transition from neutral and ionized carbon to mostly C I, and then from there, we should expect to see carbon increasingly locked up in molecular form, as CO Other species are expected to make similar transitions, so we should find detectable abundances of molecules such as H2O, OH, CS, CH2, SiO, and others; also, lower ionization fractions of the metallic elements - and higher depletions of those elements as well Given that we expect to find higher depletions, we should see an altered grain size distribution, which may show up in the extinction curves, probably as lower far-UV extinction than in diffuse clouds Finally, we will search for neutral PAHs in absorption, as diffuse bands in the UV, paralleling the optical DIBs (which are thought by some scientists to be formed by singly-ionized PAHs) In translucent clouds, models show that the PAHs will be neutral, not in cationic form

STIS/CCD/MA2 11568

A SNAPSHOT Survey of the Local Interstellar Medium: New NUV Observations of Stars with Archived FUV Observations

We propose to obtain high-resolution STIS E230H SNAP observations of MgII and FeII interstellar absorption lines toward stars within 100 parsecs that already have moderate or high-resolution far-UV (FUV), 900-1700 A, observations available in the MAST Archive Fundamental properties, such as temperature, turbulence, ionization, abundances, and depletions of gas in the local interstellar medium (LISM) can be measured by coupling such observations Due to the wide spectral range of STIS, observations to study nearby stars also contain important data about the LISM embedded within their spectra However, unlocking this information from the intrinsically broad and often saturated FUV absorption lines of low-mass ions, (DI, CII, NI, OI), requires first understanding the kinematic structure of the gas along the line of sight This can be achieved with high resolution spectra of high-mass ions, (FeII, MgII), which have narrow absorption lines, and can resolve each individual velocity component (interstellar cloud) By obtaining short (~10 minute) E230H observations of FeII and MgII, for stars that already have moderate or high- resolution FUV spectra, we can increase the sample of LISM measurements, and thereby expand our knowledge of the physical properties of the gas in our galactic neighborhood STIS is the only instrument capable of obtaining the required high resolution data now or in the foreseeable future

STIS/MA1/MA2 11857

STIS Cycle 17 MAMA Dark Monitor

This proposal monitors the behavior of the dark current in each of the MAMA detectors

The basic monitor takes two 1380s ACCUM darks each week with each detector However, starting Oct 5, pairs are only included for weeks that the LRP has external MAMA observations planned The weekly pairs of exposures for each detector are linked so that they are taken at opposite ends of the same SAA free interval This pairing of exposures will make it easier to separate long and short term temporal variability from temperature dependent changes

For both detectors, additional blocks of exposures are taken once every six months These are groups of five 1314s FUV-MAMA Time-Tag darks or five 3x315s NUV ACCUM darks distributed over a single SAA-free interval This will give more information on the brightness of the FUV MAMA dark current as a function of the amount of time that the HV has been on, and for the NUV MAMA will give a better measure of the short term temperature dependence

WFC3/UVIS/IR 11909

UVIS Hot Pixel Anneal

The on-orbit radiation environment of WFC3 will continually generate new hot pixels This proposal performs the procedure required for repairing those hot pixels in the UVIS CCDs During an anneal, the two-stage thermo-electric cooler (TEC) is turned off and the four-stage TEC is used as a heater to bring the UVIS CCDs up to ~20 deg C As a result of the CCD warmup, a majority of the hot pixels will be fixed; previous instruments such as WFPC2 and ACS have seen repair rates of about 80% Internal UVIS exposures are taken before and after each anneal, to allow an assessment of the procedure's effectiveness in WFC3, provide a check of bias, global dark current, and hot pixel levels, as well as support hysteresis (bowtie) monitoring and CDBS reference file generation One IR dark is taken after each anneal, to provide a check of the IR detector

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

12234 ? OBAD(1,3) at 091/07:56:38z failed due to too few stars on FHST#1 GSAcq(1,2,1) at 091/08:02:11z was successful

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                  SCHEDULED SUCCESSFUL

FGS GSAcq 9 9 FGS REAcq 7 7 OBAD with Maneuver 5 4

SIGNIFICANT EVENTS: (None)

============================================================================== TOPIC: Daily Report #5066

http://groups google com/group/sci astro hubble/t/cf245c0967c4a43f?hl=en

== 1 of 1 == Date: Fri, Apr 2 2010 8:42 am From: "Cooper, Joe"

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5066

PERIOD COVERED: 5am April 1 - 5am April 2, 2010 (DOY 091/09:00z-092/09:00z)

OBSERVATIONS SCHEDULED

ACS/WFC 11679

Probing The Globular Cluster / Low Mass X-ray Binary Connection in Early-type Galaxies At Low X-ray Luminosities

Combined high-resolution images from Hubble and Chandra (CXO) have revolutionized our understanding of extragalactic low-mass X-ray binaries (LMXBs) and globular clusters (GCs), yet their connection in early-type galaxies has remained unstudied at the luminosities of the Galactic LMXBs in GCs NGC 3379 and NGC 4278 are be the first prototypical elliptical galaxies with complete, deep CXO observations enabling the study of LMXBs at lower luminosities We propose completing mosaic ACS observations of both galaxies (5 fields per galaxy) that will provide the most comprehensive view into the connection between GCs and LMXBs in early-type galaxies We will detect ~860 and ~270 GCs in all of NGC 4278 and NGC 3379, respectively These two galaxies will have among the greatest number of detected GC-LMXBs to date (~130 & 50) and will include the faintest GC-LMXBs in a normal early-type galaxy We will measure the fraction of GCs which contain LMXBs, as a function of X-ray luminosity, galactocentric distance, color, and GC half-light radius Using the radial profiles of optical light, GCs, and LMXBs, we will determine the percentage of field LMXBs which may have originated in GCs We will use the measured GC properties over the entire extent of both galaxies to constrain theories of GC formation and evolution This is a resubmission of an approved Cycle 15 program (10835) which was only partially completed

COS/FUV 11897

FUV Spectroscopic Sensitivity Monitoring

The purpose of this proposal is to monitor sensitivity in each FUV grating mode to detect any changes due to contamination or other causes

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

COS/NUV 11561

An Intensive COS Spectroscopic Study of the Planetary Debris Disks Around two Warm White Dwarfs

It is very likely that the gas giants in our Solar system will survive the evolution of the Sun into a white dwarf, and the same is thought to be generally true for Jovian planets around solar-like stars if their initial orbits are wider than ~3AU Despite this prediction, no unambiguous detection of a planet around a white dwarf has been announced so far However, over the past few years, about a dozen white dwarfs have been identified which host metal-rich debris disks that are thought to stem from the tidal disruption of asteroids In most cases the debris disks are observed in the form of an infrared flux excess, and offer relatively little diagnostic potential for the study of their structure We have discovered three warm (T~20000K) white dwarfs with metal-rich debris disks in a gaseous phase which display strong double-peaked CaII emission lines in the I-band and weak Fe 5169A emission The line profiles can be modeled in terms of Keplerian disks with an extension of ~1Rsun around the white dwarfs Photospheric MgII 4481A absorption demonstrates that the white dwarfs are accreting from the debris disks Besides these spectral features, the optical wavelength range is devoid of other useful metal transitions Here, we propose an intensive spectroscopic ultraviolet study of these systems, which will provide (a) ~1000 photospheric absorption lines of 15 chemical elements, allowing an accurate abundance study of the material accreted from the debris disks, and (b) ~2 dozen additional emission lines of Mg, Cr, Ti, and Fe that will provide detailed insight into the dynamical, thermal, and density structure of these exo-planetary debris disks

COS/NUV 11894

NUV Detector Dark Monitor

The purpose of this proposal is to measure the NUV detector dark rate by taking long science exposures with no light on the detector The detector dark rate and spatial distribution of counts will be compared to pre-launch and SMOV data in order to verify the nominal operation of the detector Variations of count rate as a function of orbital position will be analyzed to find dependence of dark rate on proximity to the SAA Dependence of dark rate as function of time will also be tracked

FGS 11704

The Ages of Globular Clusters and the Population II Distance Scale

Globular clusters are the oldest objects in the universe whose age can be accurately determined The dominant error in globular cluster age determinations is the uncertain Population II distance scale We propose to use FGS 1R to obtain parallaxes with an accuracy of 0 2 milliarcsecond for 9 main sequence stars with [Fe/H] < -1 5 This will determine the absolute magnitude of these stars with accuracies of 0 04 to 0 06mag This data will be used to determine the distance to 24 metal-poor globular clusters using main sequence fitting These distances (with errors of 0 05 mag) will be used to determine the ages of globular clusters using the luminosity of the subgiant branch as an age indicator This will yield absolute ages with an accuracy of 5%, about a factor of two improvement over current estimates Coupled with existing parallaxes for more metal-rich stars, we will be able to accurately determine the age for globular clusters over a wide range of metallicities in order to study the early formation history of the Milky Way and provide an independent estimate of the age of the universe

The Hipparcos database contains only 1 star with [Fe/H] < -1 4 and an absolute magnitude error less than 0 18 mag which is suitable for use in main sequence fitting Previous attempts at main sequence fitting to metal-poor globular clusters have had to rely on theoretical calibrations of the color of the main sequence Our HST parallax program will remove this source of possible systematic error and yield distances to metal-poor globular clusters which are significantly more accurate than possible with the current parallax data The HST parallax data will have errors which are 10 times smaller than the current parallax data Using the HST parallaxes, we will obtain main sequence fitting distances to 11 globular clusters which contain over 500 RR Lyrae stars This will allow us to calibrate the absolute magnitude of RR Lyrae stars, a commonly used Population II distance indicator

STIS/CC 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD

STIS/CC 11847

CCD Bias Monitor-Part 2

Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns

STIS/MA1/MA2 11857

STIS Cycle 17 MAMA Dark Monitor

This proposal monitors the behavior of the dark current in each of the MAMA detectors

The basic monitor takes two 1380s ACCUM darks each week with each detector However, starting Oct 5, pairs are only included for weeks that the LRP has external MAMA observations planned The weekly pairs of exposures for each detector are linked so that they are taken at opposite ends of the same SAA free interval This pairing of exposures will make it easier to separate long and short term temporal variability from temperature dependent changes

For both detectors, additional blocks of exposures are taken once every six months These are groups of five 1314s FUV-MAMA Time-Tag darks or five 3x315s NUV ACCUM darks distributed over a single SAA-free interval This will give more information on the brightness of the FUV MAMA dark current as a function of the amount of time that the HV has been on, and for the NUV MAMA will give a better measure of the short term temperature dependence

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

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

WFC3/IR/S/C 12097

Additional IR Subarray Dark Current Measurements (in support of GO programs 11205, 11580)

This proposal will produce IR dark images necessary to calibrate GO science observations (already taken, see proposals 11205 and 11580) that use observing modes not supported by the existing IR dark current monitor (proposal 11929) These modes are as follows: SQ256SUB/SPARS100, SQ256SUB/SPARS200, SQ512SUB/SPARS10, SQ512SUB/SPARS100, and SQ512SUB/SPARS200

WFC3/UV/IR 11709

Stretching the Diversity of Cosmic Explosions: The Supernovae of Gamma-ray Bursts

While the association between gamma-ray bursts (GRBs) and massive stars is robust, there is a large diversity of properties among supernovae (SNe) associated with GRBs The converse is also true: Several recent events show that there is a large brightness range among high energy transients associated with SNe As part of a comprehensive program, we propose to use HST in order to search for and characterize the SNe associated with GRB

HST offers the means to cleanly separate the light curve of the GRB afterglow from the supernova, and to remove the contamination from the host galaxy, opening a clear path to the fundamental parameters of the SN, and thence to the progenitor From these observations, we will determine the absolute magnitude at maximum, the shape of the spectral energy distribution, and any change over time of the energy distribution We will also measure the rate of decay of the exponential tail

Merged with the ground-based data that we will obtain for each event, we will be able to compare our data set to models and constrain the energy of the explosion, the mass of the ejecta and the mass of Nickel synthesized during the explosion These results will shed light on the apparent variety of supernovae associated with gamma-ray bursts and X-ray flashes, and on the relation between these SNe and other, more common, types of core-collapse explosions

WFC3/UVIS 11594

A WFC3 Grism Survey for Lyman Limit Absorption at z=2

We propose to conduct a spectroscopic survey of Lyman limit absorbers at redshifts 1 8 < z < 2 5, using WFC3 and the G280 grism This proposal intends to complete an approved Cycle 15 SNAP program (10878), which was cut short due to the ACS failure We have selected 64 quasars at 2 3 < z < 2 6 from the Sloan Digital Sky Survey Spectroscopic Quasar Sample, for which no BAL signature is found at the QSO redshift and no strong metal absorption lines are present at z

2 3 along the lines of sight The survey has three main observational goals First, we will determine the redshift frequency dn/dz of the LLS over the column density range 16 0 < log(NHI) < 20 3 cm^-2 Second, we will measure the column density frequency distribution f(N) for the partial Lyman limit systems (PLLS) over the column density range 16 0 < log(NHI) < 17 5 cm^-2 Third, we will identify those sightlines which could provide a measurement of the primordial D/H ratio By carrying out this survey, we can also help place meaningful constraints on two key quantities of cosmological relevance First, we will estimate the amount of metals in the LLS using the f(N), and ground based observations of metal line transitions Second, by determining f(N) of the PLLS, we can constrain the amplitude of the ionizing UV background at z~2 to a greater precision This survey is ideal for a snapshot observing program, because the on-object integration times are all well below 30 minutes, and follow-up observations from the ground require minimal telescope time due to the QSO sample being bright

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)

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 3x3 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/IR 11909

UVIS Hot Pixel Anneal

The on-orbit radiation environment of WFC3 will continually generate new hot pixels This proposal performs the procedure required for repairing those hot pixels in the UVIS CCDs During an anneal, the two-stage thermo-electric cooler (TEC) is turned off and the four-stage TEC is used as a heater to bring the UVIS CCDs up to ~20 deg C As a result of the CCD warm up, a majority of the hot pixels will be fixed; previous instruments such as WFPC2 and ACS have seen repair rates of about 80% Internal UVIS exposures are taken before and after each anneal, to allow an assessment of the procedure's effectiveness in WFC3, provide a check of bias, global dark current, and hot pixel levels, as well as support hysteresis (bowtie) monitoring and CDBS reference file generation One IR dark is taken after each anneal, to provide a check of the IR detector

WFC3/UV 12077

Monitoring the Aftermath of an Asteroid Impact Event

Our Director's Discretionary program (GO-12053) to image the newly discovered object P/2010 A2 executed successfully on 2010 Jan 25 and 29 with spectacular results Hubble has apparently borne witness to the first detection of a collision in the asteroid belt Hubble imaging with the WFC3 has revealed an object unlike anything ever seen before and with details impossible to detect with any other facility We request 6 more orbits of Hubble time (1 orbit every 20 days over the next few months, until the object enters Hubble's solar exclusion zone in late-June 2010) to monitor the evolution of this remarkable object and further clarify the nature of this event These observations may usher in a new era of searching for and characterizing collisional events within the asteroid belt

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST:

18837-0 - Null Genslew for proposal 12077 - slot 13 @ 091/1345z

COMPLETED OPS NOTES: (None)

                   SCHEDULED  SUCCESSFUL

FGS GSAcq 10 10 FGS REAcq 5 5 OBAD with Maneuver 4 4

SIGNIFICANT EVENTS: (None)

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