NASA Hubble Space Telescope Daily Report #4943
HUBBLE SPACE TELESCOPE DAILY REPORT #4943
Continuing to Collect World Class Science
PERIOD COVERED: 5am October 1 – 5am October 2, 2009 (DOY 274/09:00z-275/09:00z)
OBSERVATIONS SCHEDULED
ACS/WFC3 11882
CCD Hot Pixel Annealing
All the data for this program is acquired using internal targets (lamps) only, so all of the exposures should be taken during Earth occultation time (but not during SAA passages). This program emulates the ACS pre-flight ground calibration and post launch SMOV testing (program 8948), so that results from each epoch can be directly compared. Extended Pixel Edge Response (EPER) and First Pixel Response (FPR) data will be obtained over a range of signal levels for the Wide Field Channel (WFC). The High Resolution Channel (HRC) visits have been removed since it could not be repaired during SM4.
COS/NUV 11899
NUV Imaging Sensitivity, Cycle 17
The purpose of this proposal is to test NUV imaging sensitivity for a range of target spectral energy distributions. All targets have wide-slit STIS spectra in the HST Archive. We use eleven horizontal branch stars in the globular cluster NGC 6681 covering a range of effective temperatures, plus a solar-analog standard star.
NIC1/NIC2/NIC3 11947
Extended Dark Monitoring
This program takes a series of darks to obtain darks (including amplifier glow, dark current, and shading profiles) for all three cameras in the read-out sequences used in Cycle 17. A set of 12 orbits will be observed every two months for a total of 72 orbits for a 12 month Cycle 17. This is a continuation of Cycle 16 program 11330 scaled down by ~80%.
The first orbit (Visit A0) should be scheduled in the NICMOS SMOV after the DC Transfer Test (11406) and at least 36h before the Filter Wheel Test (11407). Data download using fast track.
The following 28 orbits (visit A1-N2) should be scheduled AFTER the SMOV Proposal 11407 (Filter Wheel Test). This is done in order to monitor the dark current following an adjustment of the NCS set-point. These visits should be executed until the final temperature is reached during SMOV.
NIC1/NIC2/NIC3 8795
NICMOS Post-SAA Calibration – CR Persistence Part 6
This is a new procedure proposed to alleviate the CR-persistence problem of NICMOS. Dark frames will be obtained immediately upon exiting the SAA contour 23, and every time a NICMOS exposure is scheduled within 50 minutes of coming out of the SAA. The darks will be obtained in parallel in all three NICMOS cameras. The post-SAA darks will be non-standard reference files available to users with a ‘Use After’ date/time mark. The keyword ‘UseAfter=date/time’ will also be added to the header of each post-SAA dark frame. The keyword must be populated with the time, in addition to the date, because HST crosses the SAA ~8 times per day, so each post-SAA dark will need to have the appropriate time specified, for users to identify the ones they need. Both the raw and processed images will be archived as post-SAA darks. Generally we expect that all NICMOS science/calibration observations started within 50 minutes of leaving an SAA will need such MAPs to remove the CR persistence from the science images. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.
STIS/CCD 11844
CCD Dark Monitor Part 1
The purpose of this proposal is to monitor the darks for the STIS CCD.
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/MA1 11525
COS-GTO: STIS High Resolution Observations of the Local ISM
We shall use bright early-type B stars located within 150pc of the Sun to probe the absorption properties of the interstellar gas associated with the local cavity. By utilizing the high sensitivity and high spectral resolution of the HST-STIS spectrograph we shall be able to place new detection limits on absorption occurring in any highly ionized gas associated with the lines of NV, SiIV and CIV that may be present along these sight-lines within the local cavity. These data will be used to test current theoretical models that generally predict far higher absorption column densities than have been previously found. Also, the high spectral resolution will enable far stricter limits to be placed on the thermal widths of such highly ionized absorption lines, which previous observations towards the Loop I region have suggested anomalously narrow profiles consistent with their formation by either photo ionization or highly non-equilibrium processes.
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/ACS/IR 11359
Panchromatic WFC3 Survey of Galaxies at Intermediate z: Early Release Science Program for Wide Field Camera 3
The unique panchromatic capabilities of WFC3 will be used to survey the structure and evolution of galaxies at the peak of the galaxy assembly epoch. Deep ultraviolet and near-IR imaging and slitless spectroscopy of existing deep multi-color ACS fields will be used to gauge star-formation and the growth of stellar mass as a function of morphology, structure and surrounding density in the critical epoch 1 < z < 4. Images in the F225W, F275W, and F336W filters will identify galaxies at z < 1.5 from their UV continuum breaks, and provide star-formation indicators tied directly to both local and z > 3 populations. Deep near-IR (F125W and F160W) images will probe the stellar mass function well below 10^9 Msun for mass-complete samples. Lastly, the WFC3 slitless UV and near-IR grisms will be used to measure redshifts and star-formation rates from H- alpha and rest-frame UV continuum slope. This WFC3 ERS program will survey one 4 x 2 mosaic for a total area of 50 square arcminutes to 5-sigma depths of m_AB = 27 in most filters from the mid-UV through the near-IR.
This multicolor high spatial resolution data set will allow the user to gauge the growth of galaxies through star-formation and merging. High precision photometric and low- resolution spectroscopic redshifts will allow accurate determinations of the faint-end of the luminosity and mass functions, and will shed light on merging and tidal disruption of stellar and gaseous disks. The WFC3 images will also allow detailed studies of the internal structure of galaxies, and the distribution of young and old stellar populations. This program will demonstrate the unique power of WFC3 by applying its many diverse modes and full panchromatic capability to a forefront problem in astrophysics.
WFC3/ACS/IR 11584
Resolving the Smallest Galaxies with ACS
An order of magnitude more dwarf galaxies are expected to inhabit the Local Group, based on currently accepted galaxy formation models, than have been observed. This discrepancy has been noted in environments ranging from the field to rich clusters, with evidence emerging that lower density regions contain fewer dwarfs per giant than higher density regions, in further contrast to model predictions. However, there is no complete census of the faintest dwarf galaxies in any environment. The discovery of the smallest and faintest dwarfs is hampered by the limitations in detecting such compact or low surface brightness galaxies, and this is compounded by the great difficulty in determining accurate distances to, or ascertaining group membership for, such faint objects. The M81 group provides a powerful means for establishing membership for faint galaxies in a low density region. With a distance modulus of 27.8, the tip of the red giant branch (TRGB) appears at I ~ 24, just within the reach of ground based surveys. We have completed a 65 square degree survey in the region around M81 with the CFHT/MegaCam. Half of our survey was completed before Cycle 16 and we were awarded time with WFPC2 to observe 15 new candidate dwarf galaxy group members in F606W and F814W bands in order to construct color-magnitude diagrams from which to measure accurate TRGB distances and determine star formation and metallicity histories. The data obtained show that 8 – 9 of these objects are galaxies at the same distance as M81. In completing our survey, we have discovered an additional 8 candidate galaxies we propose to image with ACS in order to measure TRGB distances and establish membership. We also wish to re-observe our smallest candidate group member and a tidal dwarf candidate with deeper observations made possible with ACS. Once membership has been established for this second set of candidates, we will have a complete census of the dwarf galaxy population in the M8 group to M_r ~ -10, allowing us to obtain a firm measurement of the luminosity function faint-end slope, and, combined with previous HST data, to provide a complete inventory of the age and abundance properties for the collapsed core of the M81 group.
WFC3/IR 11838
Completing a Flux-limited Survey for X-ray Emission from Radio Jets
We will measure the changing flow speeds, magnetic fields, and energy fluxes in well- resolved quasar jets found in our short-exposure Chandra survey by combining new, deep Chandra data with radio and optical imaging. We will image each jet with sufficient sensitivity to estimate beaming factors and magnetic fields in several distinct regions, and so map the variations in these parameters down the jets. HST observations will help diagnose the role of synchrotron emission in the overall SED, and may reveal condensations on scales less than 0.1 arcsec.
WFC3/IR 11915
IR Internal Flat Fields
This program is the same as 11433 (SMOV) and depends on the completion of the IR initial alignment (Program 11425). This version contains three instances of 37 internal orbits: to be scheduled early, middle, and near the end of Cycle 17, in order to use the entire 110-orbit allocation.
In this test, we will study the stability and structure of the IR channel flat field images through all filter elements in the WFC3-IR channel. Flats will be monitored, i.e. to capture any temporal trends in the flat fields and delta flats produced. High signal observations will provide a map of the pixel-to-pixel flat field structure, as well as identify the positions of any dust particles.
WFC3/IR 11926
IR Zero Points
We will measure and monitor the zeropoints through the IR filters using observations of the white dwarf standard stars, GD153, GD71 and GD191B2B and the solar analog standard star, P330E. Data will be taken monthly during Cycle 17. Observations of the star cluster, NGC 104, are made twice to check color transformations. We expect an accuracy of 2% in the wide filter zeropoints relative to the HST photometric system, and 5% in the medium- and narrow-band filters.
WFC3/UVIS 11657
The Population of Compact Planetary Nebulae in the Galactic Disk
We propose to secure narrow- and broad-band images of compact planetary nebulae (PNe) in the Galactic Disk to study the missing link of the early phases of post-AGB evolution. Ejected AGB envelopes become PNe when the gas is ionized. PNe expand, and, when large enough, can be studied in detail from the ground. In the interim, only the HST capabilities can resolve their size, morphology, and central stars. Our proposed observations will be the basis for a systematic study of the onset of morphology. Dust properties of the proposed targets will be available through approved Spitzer/IRS spectra, and so will the abundances of the alpha-elements. We will be able thus to explore the interconnection of morphology, dust grains, stellar evolution, and populations. The target selection is suitable to explore the nebular and stellar properties across the galactic disk, and to set constraints on the galactic evolutionary models through the analysis of metallicity and population gradients.
WFC3/UVIS 11707
Detecting Isolated Black Holes through Astrometric Microlensing
This proposal aims to make the first detection of isolated stellar-mass black holes (BHs) in the Milky Way, and to determine their masses. Until now, the only directly measured BH masses have come from radial-velocity measurements of X-ray binaries. Our proposed method uses the astrometric shifts that occur when a galactic-bulge microlensing event is caused by a BH lens. Out of the hundreds of bulge microlensing events found annually by the OGLE and MOA surveys, a few are found to have very long durations (>200 days). It is generally believed that the majority of these long- duration events are caused by lenses that are isolated BHs.
To test this hypothesis, we will carry out high-precision astrometry of 5 long-duration events, using the ACS/HRC camera. The expected astrometric signal from a BH lens is >1.4 mas, at least 7 times the demonstrated astrometric precision attainable with the HRC.
This proposal will thus potentially lead to the first unambiguous detection of isolated stellar-mass BHs, and the first direct mass measurement for isolated stellar-mass BHs through any technique. Detection of several BHs will provide information on the frequency of BHs in the galaxy, with implications for the slope of the IMF at high masses, the minimum mass of progenitors that produce BHs, and constraints on theoretical models of BH formation.
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).
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
12028 – GSAcq(2,1,1) at 274/17:57z failed due search radius exceeded flag on FGS2.
Observation affected: ACS 78-82 Proposal ID# 11882 and WFC3 95-96 Proposal ID# 11657 and 11915.
12030 – REAcq(1, 2, 1) scheduled for 274/20:30:09z failed to RGA HOLD.
Observation affected: STIS 55-59 Proposals ID# 11525, 11857.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSAcq 07 06
FGS REAcq 10 09
OBAD with Maneuver 06 06
SIGNIFICANT EVENTS: (None)
