Status Report

NASA Hubble Space Telescope Daily Report #3932

By SpaceRef Editor
August 29, 2005
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science


PERIOD COVERED: UT August 25, 2005 (DOY 237)


ACS/HRC 10525

Characterizing the Near-UV Environment of M Dwarfs: Implications for Extrasolar Planetary Searches and Astrobiology

We propose SNAP observations with the ACS HRC PR200L prism, designed to measure the near ultraviolet emission in a sample of 107 nearby M dwarfs. The sample spans the mass range from 0.1 – 0.6 solar masses {temperature range 2200K – 4000K} where the UV energy distributions vary widely between active and inactive stars. The strength and distribution of this UV emission can have critical consequences for the atmospheres of attendant planets. Our proposed observations will provide desperately needed constraints on models of the habitability zone and the atmospheres of possible terrestrial planets orbiting M dwarf hosts, and will be used to sharpen TPF target selection. In addition, the NUV data will be used in conjunction with existing optical, FUV and X-ray data to constrain a new generation of M dwarf atmospheric models, and to explore unanswered questions regarding the dynamo generation and magnetic heating in these low-mass stars.

ACS/HRC 10627

A Snapshot Survey of Post-AGB Objects and Proto-Planetary Nebulae

We propose an ACS/HRC snapshot survey of 50 post-AGB sources, objects which have evolved from the AGB but may or may not become planetary nebulae {PNe}. This survey will complement existing HST images of proto-planetary nebulae {PPNe} and PNe in addressing circumstellar envelope morphology as a function of: 1} the progenitor star mass; 2} the chemical composition; and 3} evolutionary stage. We will connect the observed diversity of nebualar shapes with the main physical and chemical conditions characterizing post-AGB objects, to identify the mechanism that breaks the symmetry of AGB mass loss. To our knowledge, no previous HST projects have been specifically designed to address this issue. From our database of 360 post-AGB candidates, we have selected approximately 50 targets, none of which have been or are being observed with HST, to sample different central star masses, chemical compositions, and evolutionary stages, uniformly across the sky. These new data will also provide important constraints to a quantitative analysis of Spitzer Space Telescope {SST} observations planned for a similar sample of objects. We will model the HST images and SST spectra using our axisymmetric dust code 2-Dust, to derive dust density distributions, pole to equator density ratios, dust shell masses, inclination angles as well as dust composition.

ACS/WFC 10368

External CTE Monitor

Monitor CTE changes during cycle 11. Determine CTE.


Probing Evolution And Reionization Spectroscopically {PEARS}

While imaging with HST has gone deep enough to probe the highest redshifts, e.g. the GOODS survey and the Ultra Deep Field, spectroscopic identifications have not kept up. We propose an ACS grism survey to get slitless spectra of all sources in a wide survey region {8 ACS fields} up to z =27.0 magnitude, and an ultradeep field in the HUDF reaching sources up to z =28 magnitude. The PEARS survey will: {1} Find and spectrocopically confirm all galaxies between z=4-7. {2} Probe the reionization epoch by robustly determining the luminosity function of galaxies and low luminosity AGNs at z = 4 – 6. With known redshifts, we can get a local measure of star formation and ionization rate in case reionization is inhomogeneous. {3} Study galaxy formation and evolution by finding galaxies in a contiguous redshift range between 4 < z < 7, and black hole evolution through a census of low-luminosity AGNs. {4} Get a robust census of galaxies with old stellar populations at 1 < z < 2.5, invaluable for checking consistency with heirarchical models of galaxy formation. Fitting these galaxies' spectra will yield age and metallicity estimates. {5} Study star-formation and galaxy assembly at its peak at 1< z < 2 by identifying emission lines in star-forming galaxies, old populations showing the 4000A break, and any combination of the two. {6} Constrain faint white dwarfs in the Galactic halo and thus measure their contribution to the dark matter halo. {7} Derive spectro-photometric redshifts by using the grism spectra along with broadband data. This will be the deepest unbiased spectroscopy yet, and will enhance the value of the multiwavelength data in UDF and the GOODS fields to the astronomical community. To this end we will deliver reduced spectra to the HST archives.

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.

NIC3 10406

NICMOS Imaging of Massive Galaxies at z ~ 2

We propose NICMOS F160W imaging of a sample of massive red galaxies from the Gemini Deep Deep Survey. These galaxies dominate the stellar mass density at 1.5< z < 2 and are our best link to early galaxy formation. The NICMOS images will be used in conjunction with our ACS images and deep Gemini spectra to examine the formation and early evolution of massive ellpitcal galaxy progenitors. We waive all propretary rights to the data and wil make them available on our web site as we have done with the Gemini Deep Deep Survey spectra, catalogs and ACS images.


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


9925 – GSACQ(2,1,2) failed, search radius limit exceeded on FGS 2 @ 238/03:43:30z

GSACQ(2,1,2) at 238/03:36:42 failed due to Search Radius Limit Exceeded on FGS 2 at 03:43:30 and 03:47:34. Full Maneuver Updates prior to GSACQ had nominal errors of 76.950, -49.946, 16.069 for first update, 1.764, -0.086, 3.836 for second update. REACQ(2,1,2) at 04:04:11 was successful with saved FGS error null bias (QSFGENB0) of -1329.876. FHST map at 04:44:00 showed attitude errors of 4.337, -4.773, -3.682. Four 486 status buffer messages were received indicating FGS coarse mode angle check failed (A0C) at 03:41:05 and 03:45:08, and FGS coarse track failed (A05) at 03:43:30 and 03:47:34.



                           SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS Gsacq                08                        07             238/03:43:30z
FGS Reacq                10                        10
FHST Update              14                        14


The switch of Gyro 4 from primary to backup temperature control heater was successfully performed 237/06:50. A bias shift of approximately 60 as/hr was observed in the QDVTHEJ1 telemetry, and the bias update at 07:03 corresponded to this value. The subsequent Acquisitions (07:45, 09:20, and 10:55) were all nominal.

Uplink of the gyro bias computation patches was accomplished at 05:36 and restoration to nominal configuration (20 min bias update averaging & 75 as/hr data check) was accomplished at 07:22.

Preliminary analysis indicates that both the G4 heater power transient duration and the AOA EON signatures have been significantly reduced.

SpaceRef staff editor.