NASA Hubble Space Telescope Daily Report #4481
Notice: Due to the conversion of some ACS WFC or HRC observations into WFPC2, or NICMOS observations after the loss of ACS CCD science capability in January, there may be an occasional discrepancy between a proposal’s listed (and correct) instrument usage and the abstract that follows it.
HUBBLE SPACE TELESCOPE DAILY REPORT #4481
– Continuing to collect World Class Science
PERIOD COVERED: UT November 01, 2007 (DOY 305)
OBSERVATIONS SCHEDULED
FGS 11213
Distances to Eclipsing M Dwarf Binaries
We propose HST FGS observations to measure accurate distances of 5 nearby M dwarf eclipsing binary systems, from which model-independent luminosities can be calculated. These objects have either poor or no existing parallax measurements. FGS parallax determinations for these systems, with their existing dynamic masses determined to better than 0.5%, would serve as model-independent anchor points for the low-mass end of the mass-luminosity diagram.
NIC1/NIC2/NIC3 11330
NICMOS Cycle 16 Extended Dark
This takes a series of Darks in parallel to other instruments.
NIC1/NIC2/NIC3 8794
NICMOS Post-SAA calibration – CR Persistence Part 5
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 USEAFTER 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.
S/C 11163
Accreting Pulsating White Dwarfs in Cataclysmic Variables
Recent ground-based observations have increased the number of known pulsating white dwarfs in close binaries with active mass transfer {cataclysmic variables} from 5 to 11 systems. Our past Cycles 8 and 11 STIS observations of the first 2 known, followed by our Cycle 13 SBC observations of the next 3 discovered, revealed the clear presence of the white dwarf and increased amplitude of the pulsations in the UV compared to the optical. The temperatures derived from the UV spectra show 4 systems are much hotter than non- interacting pulsating white dwarfs. A larger sample is needed to sort out the nature of the instability strip in accreting pulsators i.e. whether effects of composition and rotation due to accretion result in a well-defined instability strip as a function of Teff.
WFPC2 11027
Visible Earth Flats
This proposal monitors flatfield stability. This proposal obtains sequences of Earth streak flats to construct high quality flat fields for the WFPC2 filter set. These flat fields will allow mapping of the OTA illumination pattern and will be used in conjunction with previous internal and external flats to generate new pipeline superflats. These Earth flats will complement the Earth flat data obtained during cycles 4-14.
WFPC2 11029
WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation Anomaly Monitor
Intflat observations will be taken to provide a linearity check: the linearity test consists of a series of intflats in F555W, in each gain and each shutter. A combination of intflats, visflats, and earthflats will be used to check the repeatability of filter wheel motions. {Intflat sequences tied to decons, visits 1-18 in prop 10363, have been moved to the cycle 15 decon proposal xxxx for easier scheduling.} Note: long-exposure WFPC2 intflats must be scheduled during ACS anneals to prevent stray light fromthe WFPC2 lamps from contaminating long ACS external exposures.
WFPC2 11103
A Snapshot Survey of The Most Massive Clusters of Galaxies
We propose the continuation of our highly successful SNAPshot survey of a sample of 125 very X-ray luminous clusters in the redshift range 0.3-0.7. As demonstrated by the 25 snapshots obtained so far in Cycle14 and Cycle15 these systems frequently exhibit strong gravitational lensing as well as spectacular examples of violent galaxy interactions. The proposed observations will provide important constraints on the cluster mass distributions, the physical nature of galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set of optically bright, lensed galaxies for further 8-10m spectroscopy. All of our primary science goals require only the detection and characterization of high-surface-brightness features and are thus achievable even at the reduced sensitivity of WFPC2. Because of their high redshift and thus compact angular scale our target clusters are less adversely affected by the smaller field of view of WFPC2 than more nearby systems. Acknowledging the broad community interest in this sample we waive our data rights for these observations. Due to a clerical error at STScI our approved Cycle15 SNAP program was barred from execution for 3 months and only 6 observations have been performed to date – reinstating this SNAP at Cycle16 priority is of paramount importance to reach meaningful statistics.
WFPC2 11124
The Origin of QSO Absorption Lines from QSOs
We propose using WFPC2 to image the fields of 10 redshift z ~ 0.7 foreground {FG} QSOs which lie within ~29-151 kpc of the sightlines to high-z background {BG} QSOs. A surprisingly high fraction of the BG QSO spectra show strong MgII {2796,2803} absorption lines at precisely the same redshifts as the FG QSOs. The high resolution capabilities of WFPC2 are needed to understand the origin of these absorption systems, in two ways. First, we wish to explore the FG QSO environment as close as possible to the position of the BG QSO, to search for interloping group or cluster galaxies which might be responsible for the absorption, or irregularly shaped post-merger debris between the FG and BG QSO which may indicate the presence of large amount of disrupted gas along a sightline. Similarly, high resolution images are needed to search for signs of tidal interactions between any galaxies which might be found close to the FG QSO. Such features might provide evidence of young merging events causing the start of QSO duty cycles and producing outflows from the central AGN. Such winds may be responsible for the observed absorption lines. Second, we seek to measure the intrinsic parameters of the FG QSO host galaxy, such as luminosity and morphology, to correlate with the properties of the MgII absorption lines. We wish to observe each field through the F814W filter, close to the rest-frame B-band of the FG QSO. These blue data can reveal enhanced star formation regions close to the nucleus of the host galaxy, which may be indicative of galaxy mergers with the FG QSO host. The FG QSO environment offers quite a different set of phenomena which might be responsible for MgII absorption, providing an important comparison to studies of MgII absorption from regular field galaxies.
WFPC2 11167
A Unique High Resolution Window to Two Strongly Lensed Lyman Break Galaxies
On rare occasions, the otherwise very faint Lyman Break Galaxies {LBGs} are magnified by gravitational lensing to provide exceptional targets for detailed spectroscopic and imaging studies. We propose HST WFPC2 and NICMOS imaging of two strongly lensed Lyman Break Galaxies {LBGs} that were recently discovered by members of our team. These two LBGs — the “8 O’Clock Arc” and the “SDSS J1206+5142 Arc” — are currently the brightest known LBGs, roughly 3 times brighter than the former record-holder, MS1512-cB58 {a.k.a. “cB58”}. The z=2.73 “8 O’Clock Arc” extends ~10 arcsec in length and is magnified by a factor of 12. The z=2.00 “SDSS J1206+5142 Arc” also extends ~10 arcsec in length and is magnified by a factor of 30. Due to their brightness and magnification, these two strongly lensed LBGs offer an unprecedented opportunity for the very detailed investigation of two individual galaxies at high redshift. We are currently pursuing a vigorous ground-based campaign to obtain multi-wavelength {UV, optical, NIR, radio} observations of these two LBGs, but our campaign currently lacks a means of obtaining high-resolution optical/NIR imaging — a lack that currently only HST can address. Our prime objective for this proposal is to obtain high resolution HST images of these two systems with two-orbit WFPC2 images in the BVI bands and two-orbit NICMOS/NIC2 images in the J and H bands. These data will allow us to construct detailed lensing models, probe the mass and light profiles of the lenses and their environments, and constrain the star formation histories and rest-frame UV/optical spectral energy distributions of the LBGs.
WFPC2 11312
The Local Cluster Substructure Survey {LoCuSS}: Deep Strong Lensing Observations with WFPC2
LoCuSS is a systematic and detailed investigation of the mass, substructure, and thermodynamics of 100 X-ray luminous galaxy clusters at 0.15< z<0.3. The primary goal is to test our recent suggestion that this population is dominated by dynamically immature disturbed clusters, and that the observed mass-temperature relation suffers strong structural segregation. If confirmed, this would represent a paradigm shift in our observational understanding of clusters, that were hitherto believed to be dominated by mature, undisturbed systems. We propose to complete our successful Cycle 15 program {SNAP:10881} which prior to premature termination had delivered robust weak-lensing detections in 17 clusters, and candidate strongly-lensed arcs in 11 of these 17. These strong and weak lensing signals will give an accurate measure of the total mass and structure of the dark matter distribution that we will subsequently compare with X-ray and Sunyaev Zeldovich Effect observables. The broader applications of our project include 1} the calibration of mass-temperature and mass-SZE scaling relations which will be critical for the calibration of proposed dark energy experiments, and 2} the low redshift baseline study of the demographics of massive clusters to aid interpretation of future high redshift {z>1} cluster samples. To complete the all-important high resolution imaging component of our survey, we request deep WFPC2 observations of 20 clusters through the F606W filter, for which wide-field weak-lensing data are already available from our Subaru imaging program. The combination of deep WFPC2 and Subaru data for these 20 clusters will enable us to achieve the science program approved by the Cycle 15 TAC.
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: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL FGS GSacq 06 06 FGS REacq 09 09 OBAD with Maneuver 30 30
SIGNIFICANT EVENTS: (None)
