Status Report

Hubble Space Telescope Daily Report #2772 12/19/00

By SpaceRef Editor
December 19, 2000
Filed under ,

PERIOD COVERED:  0000Z (UTC) 12/18/00 – 0000Z (UTC) 12/19/00
Daily Status Report as of 354/0000Z
    1.1 Completed Three Sets of WF/PC-2 8827 (Cycle 9 Supplemental Darks pt2/3)
        The WF/PC-2 was used to obtain three dark frames every day to provide data for monitoring and characterizing the evolution of hot pixels.  The proposal completed nominally.
    1.2 Completed WF/PC-2 8720 (Masses and Multiplicity of Nearby Free- floating Methane and L Dwarfs)
        The WF/PC-2 was used to observe 50 very-low-mass objects in the solar neighborhood with spectral types of L0 and later {including several dwarfs with Methane absorption bands in their atmospheres}.  These objects will be observed in two filter bands with the aim to identify close companions, measure their colors, and to obtain first epoch data of the newly discovered binaries.  The observations completed nominally.
    1.3 Completed STIS/CCD 8562 (Probing the Large Scale Structure: Cosmic Shear Observations)
        The Space Telescope Imaging Spectrograph (CCD) was used to probe the distortion of light bundles from distant galaxies, looking at the statistical properties of the intervening inhomogeneous {dark} matter distribution.  The proposal completed nominally.
    1.4 Completed WF/PC-2 8645 (A Survey of Mid-UV Morphology of Nearby Galaxies: Galaxy Structure and Faint Galaxy)
        The WF/PC-2 was used to investigate the relation between star formation and the global physical characteristics of galaxies to interpret the morphologies of distant galaxies in terms of their evolutionary status.  The observations completed nominally.
    1.5 Completed Two Sets of STIS/CCD 8260 (Searching for the Hydrogen Reionization Edge of the Universe at 5HST)
        The Space Telescope Imaging Spectrograph (CCD) was used to observe one of 36 parallel orbits {4–5 fields of 5–8 orbits each} to constrain the H Lyman-edge in emission that marks the transition from a neutral to a fully ionized IGM at a predicted zion~eq5–15.  This edge is due to recombination from the H Lyman series and Lyman continuum, and can be used to constrain zion, one of the most important unknown quantities in large scale structure and cosmology.  The proposal completed nominally.
    1.6 Completed Two Sets of WF/PC-2 8815 (Cycle 9 Earth Flats)
        The WF/PC-2 was used to monitor flatfield stability.  This proposal obtains sequences of Earth streak flats to construct high quality flat fields for the WF/PC-2 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.  The proposal completed nominally.
    1.7 Completed Two Sets of STIS/CCD 8837 (CCD Dark Monitor-Part 1)
        The Space Telescope Imaging Spectrograph (CCD) was used to monitor the darks.  The proposal completed with no reported problems.
    1.8 Completed STIS/CCD 8841 (Hot Pixel Annealing C9)
        The Space Telescope Imaging Spectrograph (CCD) was used to improve the effectiveness of the CCD hot pixel annealing process.  This is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects.  In addition CTE performance is examined by looking for traps in a low signal level flat.  The observations completed with no reported problems.
    1.9 Completed WF/PC-2 7407 (Continuation of Temporal Monitoring of the Crab Synchrotron Nebula)
        The WF/PC-2 was used to observe the synchrotron nebula surrounding the Crab pulsar that has been the subject of intensive study for decades.  It is generally accepted that the structure and activity in this region are due to wave phenomena near the termination shock of the pulsar wind, observations of which hold unique promise of leading to more complete models of the pulsar and its magnetosphere.  Unfortunately, this promise has not been fulfilled, largely because of the low spatial resolution and uneven temporal coverage of existing studies.  Recent WF/PC-2 observations of the Crab synchrotron nebula offer new hope in this quest.  These data, which reach the natural size scale defined by the Larmor radius of energetic electrons, resolve the majority of the known features in the Crab.  For the first time it is possible to reliably establish the physical conditions {e.g., emissivities, equipartition fields, and pressures} of features associated with the wind and its termination shock.  The observations completed as planned.
    1.10 Completed Six Sets of WF/PC-2 8811 (Cycle 9 Standard Darks)
        The WF/PC-2 was used to obtain 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.  The proposal completed with no reported problems.
    1.11 Completed STIS/CCD/MA2 8770 (The Nucleosynthesis of Boron – Benchmarks for the Galactic Disk)
        The Space Telescope Imaging Spectrograph (CCD and MA2) was used to determine boron (B) abundance.  In spite of several HST cycles of B abundance determinations, we do not know the true, ambient, present-day abundance of B.  Only two stars {with undepleted Li and Be} have been observed to derive the Population I true B abundance.  Past cycles have focused on {1} halo stars with low metallicity and {2} solar-type stars with Li and/or Be deficiencies.  In this proposal, the stellar abundances of B will be determined, measured from the B I 2497 Angstrom line from STIS echelle spectra, of main sequence F-G stars that have retained their full initial abundances of boron.  Our target stars are those for which ground-based observations show that beryllium is undepleted.  These new abundances will map evolution of the B abundance in the Galactic disk in the metallicity range from one-third solar up to solar.  Then the B, and previously determined Li and Be abundances, will be used to improve understanding of the nucleosynthesis of B.  There were no reported anomalies.
    1.12 Completed STIS/MA1 8657 (Jovian Auroral Variability Due to the Solar Wind/Magnetosphere Interaction)
        The Space Telescope Imaging Spectrograph (MA1) was used to observe Jupiter, covering nearly complete Jupiter rotations, permitting the observers to perform several known key measurements of the auroral emissions, and also to study uniquely the effects of solar wind variations on the auroral morphology.  The proposal completed nominally.
    1.13 Completed WF/PC-2 8812 (Cycle 9 Internal Monitor)
        The WF/PC-2 was used to obtain routine internal monitors for WFPC2 in order 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 {gain 7 and gain 15}, a test for quantum efficiency in the CCDs, and a monitor for possible buildup of contaminants on the CCD windows.  There were no reported problems.
    1.14 Completed STIS/CCD 8838 (Bias Monitor – Part 1)
        The Space Telescope Imaging Spectrograph (CCD) was used 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.  The proposal completed nominally.
    1.15 Completed STIS/CCD 8572 (Identifying Normal Galaxies at 1.3 < z < 2.5)
        The Space Telescope Imaging Spectrograph (CCD) was used to perform studies of faint, distant galaxies.  It is now possible to observe hundreds of galaxies out to z=1 and in the range 3 < z < 4.5, yet the redshift range 1 < z <3 remains largely unexplored.  No problems were noted.
    1.16 Completed WF/PC-2 8587 (Stroemgren Photometry of Globular Clusters in M87: Breaking the Age- Metallicity Degeneracy)
        The WF/PC-2 was used to further demonstrate that the globular cluster {GC} systems of most, and possibly all, luminous galaxies show bimodal distributions in broadband color and, by implication, age and/or metallicity.  Whatever its origin, this bimodality {which is observed in giant galaxies that span a wide range in Hubble Type and local environment} must hold a fundamental clue to the process of galaxy formation.  The technique of this proposal hinges on the ability of Stroemgren photometry to decouple the effects of age and metallicity for large samples of GCs, and will provide the first strong constraints on the various galaxy formation models.  There were no reported problems.
    1.17 Completed STIS/CCD 8836 (Performance Monitor {Cycle 9})
        The Space Telescope Imaging Spectrograph (CCD) was used to measure the baseline performance and commandability of the CCD subsystem.  Only primary amplifier D was used.  Bias and Flat Field
exposures were taken in order to measure read noise, CTE, and
gain.  Numerous bias frames were taken to permit construction of "superbias" frames in which the effects of read noise have been rendered negligible.  Full frame and binned observations were made, with binning factors of 2 x 1, 1 x 2, 2 x 2, 4 x 1, and 4 x 2.  Dark images were taken in 2×2 binning mode; 1×1 binning darks are being taken in the nominal CCD Dark Monitor.  The exercise completed nominally.
    2.1 Guide Star Acquisitions:
      Scheduled Acquisitions:  8
                Successful:  8
    Scheduled Re-acquisitions:  7
                Successful:  7
    2.2 FHST Updates:
                  Scheduled: 23
                Successful: 23
    2.3 Operations Notes:
        Using ROP SR-1A, the SSR EDAC error counter was cleared three times.
        The engineering status buffer limits were adjusted at 353/1259Z per ROP DF-18A.
        The ephemeris table was uplinked at 354/0522Z as directed by ROP DF-07A.
        Continuation of normal science observations and calibrations.

SpaceRef staff editor.