NASA Hubble Space Telescope Daily Report #5060

HUBBLE SPACE TELESCOPE DAILY REPORT #5060

Continuing to Collect World Class Science

PERIOD COVERED: 5am March 24 – 5am March 25, 2010 (DOY 083/09:00z-084/09:00z)

OBSERVATIONS SCHEDULED

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.

S/C 11550

COS-GTO: X-Ray Binaries

This is a program to obtain UV spectra of soft X-ray transients (SXTs) in their quiescent states. The target, A0620-00, is an interacting binary system with a K7V donor star and a 9.7 M_solar black hole accretor. Our observations will use the COS G140L and STIS G230L modes to obtain low spectral resolution (R= 1000-2000), broadband (1230-3200 A) spectra of A0620-00. We will also obtain contemporaneous optical spectra of the system, which varies on time scales of days. The data will be used to establish the broadband SED of the system and to measure emission line strengths and widths in the UV. The dereddened SED will be modeled to determine the structure and temperature of the accretion disk. The FUV region of the spectrum, which has not been observed before, will be a key parameter in constraining the temperature and inner truncation radius of the disk, which is believed to transition to an advection-dominated accretion flow (ADAF) at large distances from the black hole in quiescent SXTs. The UV line spectrum, and in particular the NV 1240 and CIV 1550 transitions, will show whether C depletions, which have been seen in the NIR spectrum of the donor star, are present in the accretion disk and whether enhanced N abundances are also seen, indicative of CNO processing of material during the evolutionary history of the binary. Comparison of emission line velocities between the optical HI emission and the ionized UV metal transitions will also be used to constrain the relative extents of the photoionized disk chromosphere and the bulk of the disk in quiescent black hole binaries.

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 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 11849

STIS CCD Hot Pixel Annealing

This purpose of this activity is to repair radiation induced hot pixel damage to the STIS CCD by warming the CCD to the ambient instrument temperature and annealing radiation-damaged pixels.

Radiation damage creates hot pixels in the STIS CCD Detector. Many of these hot pixels can be repaired by warming the CCD from its normal operating temperature near -83 deg. C to the ambient instrument temperature (~ +5 deg. C) for several hours. The number of hot pixels repaired is a function of annealing temperature. The effectiveness of the CCD hot pixel annealing process is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects.

WFC3/IR 11666

Chilly Pairs: A Search for the Latest-type Brown Dwarf Binaries and the Prototype Y Dwarf

We propose to use HST/NICMOS to image a sample of 27 of the nearest (< 20 pc) and lowest luminosity T-type brown dwarfs in order to identify and characterize new very low mass binary systems. Only 3 late-type T dwarf binaries have been found to date, despite that fact that these systems are critical benchmarks for evolutionary and atmospheric models at the lowest masses. They are also the most likely systems to harbor Y dwarf companions, an as yet unpopulated putative class of very cold (T < 600 K) brown dwarfs. Our proposed program will more than double the number of T5-T9 dwarfs imaged at high resolution, with an anticipated yield of ~5 new binaries with initial characterization of component spectral types. We will be able to probe separations sufficient to identify systems suitable for astrometric orbit and dynamical mass measurements. We also expect one of our discoveries to contain the first Y-type brown dwarf. Our proposed program complements and augments ongoing ground-based adaptive optics surveys and provides pathway science for JWST. WFC3/IR 11928 WFC3/IR Low-Frequency Flat and Geometric Distortion Multiple observations of globular cluster Omega Cen at multiple infrared wavelengths of IR detector will be used to derive filter dependency of low-frequency sensitivity (L_flat fields) across of IR detector and its time variation. Additionally, the same data will be also used to derive filter-dependant geometric distortion of the detector and its time-dependency. WFC3/IR/ACS/WFC 11663 Formation and Evolution of Massive Galaxies in the Richest Environments at 1.5 < z < 2.0 We propose to image seven 1.55 arcsec radius. Deep, saturated full field images will also be obtained at each field point to permit evaluation of the wings at larger radii. The images will also permit examination of potential straylight effects, image persistence and electronic cross-talk.

WFC3/UVIS 11732

The Temperature Profiles of Quasar Accretion Disks

We can now routinely measure the size of quasar accretion disks using gravitational microlensing of lensed quasars. At optical wavelengths we observe a size and scaling with black hole mass roughly consistent with thin disk theory but the sizes are larger than expected from the observed optical fluxes. One solution would be to use a flatter temperature profile, which we can study by measuring the wavelength dependence of the disk size over the largest possible wavelength baseline. Thus, to understand the size discrepancy and to probe closer to the inner edge of the disk we need to extend our measurements to UV wavelengths, and this can only be done with HST. For example, in the UV we should see significant changes in the optical/UV size ratio with black hole mass. We propose monitoring 5 lenses spanning a broad range of black hole masses with well-sampled ground based light curves, optical disk size measurements and known GALEX UV fluxes during Cycles 17 and 18 to expand from our current sample of two lenses. We would obtain 5 observations of each target in each Cycle, similar to our successful strategy for the first two targets.

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:

#12228 GSAcq(1,2,1) @083/20:27:16z and REAcqs @ 083/22:03:30z, 083/23:39:22z, 084/01:15:13z and 084/02:51:05z failed to fine lock backup on FGS 1.

Observations possibly affected: STIS #31-54 Proposal #11550

COMPLETED OPS REQUEST:

#18834-1 Clear GENSLEW Slot-12 for STIS proposal 11550 @ 083/17:08z

COMPLETED OPS NOTES: (None)

SIGNIFICANT EVENTS: (None)