NASA Hubble Space Telescope Daily Report #4220

Status Report From: Space Telescope Science Institute
Posted: Tuesday, October 17, 2006



- Continuing to collect World Class Science

PERIOD COVERED: UT October 16, 2006 (DOY 289)



ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. The files, biases and dark will be used to create reference files for science calibration. This programme will be for the entire lifetime of ACS. Changes from cycle 13:- The default gain for WFC is 2 e-/DN. As before bias frames will be collected for both gain 1 and gain 2. Dark frames are acquired using the default gain {2}. This program cover the period May, 31 2006- Oct, 1-2006. The first half of the program has a different proposal number: 10729.

ACS/WFC 10769

X-Ray Sources in Starburst Galaxies

We propose to observe a sample of nearby, M82-like, starburst galaxies with high star formation rates. The data will be used to better understand the correlation between the X-ray point population in a galaxy and its star formation rate, to measure the high end of X-ray point source luminosity function to verify or refute the cutoff reported at high luminosities, and, using joint NICMOS and ACS/WFC observations, to study the spatial relation between X-ray source and star forming regions.

ACS/WFC 10816

The Formation History of Andromeda's Extended Metal-Poor Halo

We propose deep ACS imaging in the outer spheroid of the Andromeda galaxy, in order to measure the star formation history of its true halo. For the past 20 years, nearly all studies of the Andromeda "halo" were focused on the spheroid within 30 kpc of the galaxy's center, a region now known to host significant substructure and populations with high metallicity and intermediate ages. However, two groups have recently discovered an extended metal-poor halo beyond 30 kpc; this population is distinct in its surface-brightness profile, abundance distribution, and kinematics. In earlier cycles, we obtained deep images of the inner spheroid {11 kpc on the minor axis}, outer disk {25 kpc on the major axis}, and giant tidal stream, yielding the complete star formation history in each field. We now propose deep ACS imaging of 4 fields bracketing this 30 kpc transition point in the spheroid, so that the inner spheroid and the extended halo populations can be disentangled, enabling a reconstruction of the star formation history in the halo. A wide age distribution in the halo, as found in the inner spheroid, would imply the halo was assembled through ongoing accretion of satellite galaxies, while a uniformly old population would be a strong indication that the halo was formed during the early rapid collapse of the Andromeda proto-galaxy.

ACS/WFC 10875

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful Cycle14 snapshot survey of a sample of 123 very X-ray luminous clusters in the redshift range 0.3-0.7. As demonstrated by the 21 snapshots obtained so far in Cycle14 these systems frequently exhibit strong gravitational lensing as well as spectacular examples of violent galaxy evolution. 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. Acknowledging the broad community interest in this sample we waive our data rights for these observations.

NIC1 11061

NICMOS Imaging of Grism Spectrophotometric Standards

In this program we will take imaging observations with all 3 cameras with a range of filters of a significant number of stars that are part of the spectroscopic standard star project. These stars will form the fainter reference star backbone for programs as JWST, Sophia, and SNAP. With this program we will: 1. Accurately calibrate relative brightness of standard stars, which can be done more accurately with photometry than with spectroscopy. This has been proven to be vary valuable to straighten out the problems in the spectroscopic data reduction and calibrations so far. 2. Increase the number of stars over a large magnitude range to provide a more accurate cross check of our count rate dependent non-linearity correction 3. Include stars with radically different {very red} spectra to investigate whether the filter curves as measured before flight are still valid by comparing the throughput estimates from these stars to those used for the standard calibration. 4. Repeat a few standard star observations from cycle 7 and post-NCS installation SMOV, to increase the accuracy in the change in sensitivity measurement with just a few observations thanks to the long baseline.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration - CR Persistence Part 4

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 DARKSs. 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.

WFPC2 10744

WFPC2 Cycle 14 Decontaminations and Associated Observations

This proposal is for the WFPC2 decontamination. Also included are instrument monitors tied to decontamination: photometric stability check, focus monitor, pre- and post-decontamination internals {bias, intflats, kspots, & darks}, UV throughput check, VISFLAT sweep, and internal UV flat check.

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 from the WFPC2 lamps from contaminating long ACS external exposures.


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

HSTARS: (None)


                          SCHEDULED      SUCCESSFUL 
FGS GSacq                06                      06 
FGS REacq                08                      08 
OBAD with Maneuver   28                      28 


HRC Flash_Report

The HRC detector was initialized and the ASPC2 +35 (JHAS2P35) FSW limit was return to its nominal range by stored commanding 289/00:12. The first HRC image (part of the daily monitor program) was obtained at 289/00:30 and all telemetry voltages and temperatures are within their expected range.

Flash Report: ACS HRC Biases and Darks look good

Everything looks nominal. The frames are clean. The CCD appears to have annealed well, and the C-amplifier readnoise is at the expected (historical) level. The bias levels in these first images are just a bit above the historical averages (a few % high), but this is expected for biases obtained soon after the HRC is configured for science operations. We expect the bias levels to drop to the nominal values within a few hours, and this return to the historical average should be evident in the next set obtained on Wednesday. Looks like we have another terrific ACS camera back on line and operating well.

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