Status Report

NASA Hubble Space Telescope Daily Report #3955

By SpaceRef Editor
September 29, 2005
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT       # 3955

PERIOD COVERED: UT September 28, 2005 (DOY 271)


ACS/HRC 10549

SAINTS – Supernova 1987A INTensive Survey

SAINTS is a program to observe SN 1987A, the brightest supernova in 384 years, as it morphs into the youngest supernova remnant at age 18. HST is the unique and perfect tool for spatially- resolved observations of the many physical components of SN 1987A. A violent encounter is underway between the fastest-moving debris and the circumstellar ring, exciting hotspots seen with HST that are suddenly lighting up. The optical and X-ray flux from the ring are both rising rapidly: HST and Chandra observations taken together are needed to understand the physics of these shocked regions. In Cycle14, the hotspots may fuse as the shock fully enters the ring. Photons from these shocks may excite previously hidden gas outside the ring, revealing the true extent of the mass loss that preceded the explosion. The inner debris of the explosion itself, still excited by radioactive isotopes produced in the explosion, is now well resolved by ACS and seen to be aspherical, providing direct clues to the mechanism of the explosion. Our search for a compact remnant is beginning to eliminate some theoretical possibilities and we have the opportunity in Cycle 14 to place much more stringent limits with NICMOS. Many questions about SN 1987A remain unanswered. How did the enigmatic three rings form in the late stages of Sanduleak -69 202? Precisely what took place in the center during the core collapse and bounce? Is a black hole or a neutron star left behind in the debris? SAINTS has been a continuous program since HST was launched– we propose to extend this rich and deep data set for present use and future reference to answer these central questions in the science of supernovae.


ACS CCDs daily monitor – Cycle 13 – Part 2

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 program will be for the entire lifetime of ACS.


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.

NIC2/NIC1 10419

An in-depth analysis of a prototypical giant H II region: NGC 604

NGC 604 is, together with 30 Doradus, the extragalactic prototype giant H II region. Its stellar content and mass {~200 O+WR stars, ~10**5 M_Sun}, age {~3.5 Myr}, proximity {840 kpc}, and low foreground extinction {E{B-V} <= 0.1} make it an ideal object to study the massive stellar population of a scaled OB association, its interaction with the surrounding medium, and the effects caused by the strong differential extinction. We propose new HST observations which, combined with existent ones, will provide the most thorough multi-wavelength study of NGC 604 from the FUV to the NIR. We will obtain spectral classifications for ~200 stars, measure their spectral energy distributions from 1300 A to 2.2 microns, identify embedded very-young stellar populations hidden inside dust clouds, measure the extinction law and its possible variations as a function of environmental conditions, and analyze the relationship between the hot stars and the surrounding gas. The new data we are proposing is divided into three parts: {a} slitless objective-prism FUV spectroscopy using ACS/SBC, {b} multi-filter {6 broad-band and 2 narrow- band} NUV-optical imaging using ACS/HRC, and {c} HST/NICMOS broadband imaging. Our final goal is to analyze in detail a well-resolved giant H II region in order to understand the properties of similar but unresolved objects located at cosmological distances.


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

HSTARS: (None)



                               SCHEDULED     SUCCESSFUL 
 Gsacq                      9                      9 
 Reacq                      5                      5 
 OBAD with Maneuver       28                    28 


SpaceRef staff editor.