Status Report

NASA Hubble Space Telescope Status Update #4802

By SpaceRef Editor
March 5, 2009
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HUBBLE SPACE TELESCOPE DAILY REPORT #4802

Continuing to collect World Class Science

PERIOD COVERED: 5am March 2 – 5am March 3, 2009 (DOY 061/1000z-062/1000z)

OBSERVATIONS SCHEDULED

ACS/SBC 11980

Deep FUV Imaging of Cooling Flow Clusters

We propose to take deep ACS FUV images of a carefully selected sample of 19 bright central galaxies in nearby galaxy clusters. This program is the last critical element of a comprehensive investigation of the impact of stellar and AGN feedback on the local galaxy cluster environment. The HST images will complement new, high-resolution, Halpha images obtained with the recently commissioned Maryland-Magellan Tunable Filter (MMTF) on the Baade 6.5m telescope, archival Chandra, VLA, and GALEX data, and on-going H2/NIR observations. The MMTF data have revealed unsuspected filamentary complexes in several systems. The GALEX data often show hints of extended NUV and FUV emission on a similar scale, but their poor spatial resolution prevents meaningful comparison with the MMTF data. The HST data will provide this much needed gain in resolution. The combined radio-H2-Halpha-FUV-X-ray dataset will allow us to derive with unprecedented precision the role of the AGN, hot stars, shocks, and relativistic particles on the excitation and thermodynamics of the multi-phase intracluster and interstellar media in these systems. This is an important question since the formation and evolution of most cluster galaxies have likely been affected by these processes.

ACS/SBC 11982

Spanning the Reionization History of IGM Helium: a Large and Efficient HST Spectral Survey of Far-UV-Bright Quasars

The reionization of IGM helium is thought to have occurred at redshifts of z=3 to 4. Detailed studies of HeII Lyman-alpha absorption toward a handful of QSOs at 2.72.8 SDSS DR7 (and other) quasars with GALEX GR4 UV sources to obtain 550 new, high confidence, sightlines potentially useful for HST HeII studies; and in cycle 15-16 trials we demonstrated the efficacy of our SDSS/GALEX selection approach identifying 9 new HeII quasars at unprecedented 67% efficiency. We propose the first far-UV-bright HeII quasar survey that is both large in scale and also efficient, via 2-orbit reconnaissance ACS/SBC prism spectra toward a highly select subset of 40 new SDSS/GALEX quasars at 3.14), enabling superb post-SM4 follow-up spectra with COS or STIS. But simultaneously and independent of any SM4 uncertainties, we will hereby directly obtain 10-orbit UV spectral stacks from the 5 HeII quasars in each of the 8 redshift bins to trace the reionization history of IGM helium over at least 3.1

WFPC2 11302

WFPC2 CYCLE 16 Standard Darks – Part III

This dark calibration program obtains dark frames every week in order to provide data for the ongoing calibration of the CCD dark current rate, and to monitor and characterize the evolution of hot pixels. Over an extended period these data will also provide a monitor of radiation damage to the CCDs.

WFPC2 11793

WFPC2 Cycle 16 Internal Monitor

This calibration proposal is the Cycle 15 routine internal monitor for WFPC2, to be run weekly to monitor the health of the cameras. A variety of internal exposures are obtained in order to provide a monitor of the integrity of the CCD camera electronics in both bays (both gain 7 and gain 15 — to test stability of gains and bias levels), a test for quantum efficiency in the CCDs, and a monitor for possible buildup of contaminants on the CCD windows. These also provide raw data for generating annual super-bias reference files for the calibration pipeline.

WFPC2 11972

Investigating the Early Solar System with Distant Comet Nuclei

We propose 85 orbits of imaging observations with the WFPC2 to get nucleus size estimates for 8 well observed dynamically new and long-period comets at large distances from the sun when their activity levels are low. This will increase the sample of these nucleus sizes by nearly 50%, but will more than double the selection of comets for which we can run thermal models. Small icy bodies are the best preserved remnants of planet formation, and we have recently found that observationally constrained thermal models can distinguish differences in microphysical properties of comet nuclei. The new HST data will enable the first exploration of physical conditions in different regions of the early solar nebula.

WFPC2 11978

Luminous and Dark Matter in Disk Galaxies from Strong Lensing and Stellar Kinematics

The formation of realistic disk galaxies within the LCDM paradigm is still an unsolved problem. Theory is only now beginning to make predictions for how dark matter halos respond to galaxy formation and for the properties of disk galaxies. Measuring the density profiles of dark matter halos on galaxy scales is therefore a strong test for the standard paradigm of galaxy formation, offering great potential for discovery. However, from an observational point of view, the degeneracy between the stellar and dark matter contributions to galaxy rotation curves remains a major road block. Strong gravitational lensing, when coupled to spatially-resolved kinematics and stellar population models, can solve this long-standing problem. Unfortunately, this joint methodology could not be exploited so far due to the paucity of known edge-on spiral lenses. Exploiting the full SDSS-DR7 archive we have identified a new sample of exactly these systems. We propose multi-color HST imaging to confirm and measure a sample of twenty spiral lenses, covering a range of bulge to disk ratios. By combining dynamical lensing and stellar population information for this unique sample we will deliver the first statistical constraints on halos and disk properties, and a new stringent test of disk galaxy formation theories.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11703 – GSAcq(1,2,2) at 061/15:10z as well as REAcqs at 18:21z and 21:33z failed with FGS2 stop flag.

061/16:46z and 19:59z REAcqs were successful.

Observations affected: WFPC #31-34, #39-42 & 47-50, Proposal ID#11972.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                        SCHEDULED      SUCCESSFUL

FGS GSAcq                03                  02
FGS REAcq                11                  09
OBAD with Maneuver       22                  22

SIGNIFICANT EVENTS: (None)

SpaceRef staff editor.