Status Report

NASA Hubble Space Telescope Daily Report #3954

By SpaceRef Editor
September 28, 2005
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT      # 3954

PERIOD COVERED: UT September 27, 2005 (DOY 270)


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.


A Search for Debris Disks in the Coeval Beta Pictoris Moving Group

Resolved observations of debris disks present us with the opportunity of studying planetary evolution in other solar systems. We propose to search for debris disks in the Beta Pictoris moving group {8-20 Myrs, 10-50 pc away} , which provides a coeval sample of multiple spectral types, and it has already produced two magnificent resolved debris disks: AU Mic and Beta Pic. Such coeval sample will provide us with a snapshop of the crucial time in disk evolution in which the disk makes the transition from optically thick to optically thin, and it will be useful to study the stellar mass dependence of the disk evolution.

ACS/WFC 10497

Cepheid Calibrations of the Luminosity of Two Reliable Type Ia Supernovae and a Re- determination of the Hubble Constant

We propose to determine the luminosity of two type Ia supernovae {SNe Ia}, 1995al in NGC 3021 and SN 2002fk in NGC 1309, by observing Cepheids in their spiral hosts. Modern CCD photometry yields an extremely tight Hubble diagram for SNe Ia with a precisely determined intercept {i.e., Delta H_0/H_0}. Yet, the measurement of the true Hubble constant via SNe Ia is limited by the calibration derived from problematic and unreliable SN data. Most of the SNe Ia calibrated by HST to date are significantly compromised by the systematics of photographic photometry, high reddening and SN peculiarity, and by the photometric anomolies associated with WFPC2. The extended reach of ACS now provides opportunities to more reliably calibrate SNe Ia and H_0. Our Cepheid calibration of a reliable SN Ia dataset, SN 1994ae, using ACS in Cycle 11 resulted in a 15% increase in H_0 from the value derived by the HST SN Ia Calibration Program. Yet, there remains a terribly small sample of reliable SN Ia data sets on which to base such a crucial cosmological result. SN 1995al and SN 2002fk are two of the best observed SNe Ia both with little reddening. They provide two opportunities to use ACS for placing the calibration of H_0 via SN Ia on firmer footing and potentially improve its precision.

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 10620

Massive Star Formation and the Proper Motions of the OMC-1 Molecular Hydrogen Fingers

The Orion Molecular Cloud OMC-1 is by far the nearest region of massive star formation, and as such provides a laboratory for studying massive star formation with unprecedented detail. Using NICMOS, eight years ago our group discovered unique molecular hydrogen ‘fingers’ emanating from the IRc2 area. We propose new NICMOS imaging of the same region to compare with our earlier results. This will determine spatial motions to ~3 AU/year. Using the two data sets, we will: 1} bound the age range of the features and thus address whether all the molecular hydrogen features were produced in a single event – such as an explosion or a stellar merger – or in multiple events/steady outflow; 2} limit the location of the outflow source{s}, which remain to be identified despite sub-arcsecond imaging at thermal infrared wavelengths; and 3} characterize inhomogeneities on the 100 AU scale. Together these findings will significantly constrain how massive star formation proceeds in OMC-1. NICMOS achieves the highest quality, near-infrared images for diffuse objects in crowded regions. Because of the complexity of the OMC-1 region, and the difficulty in using Adaptive Optics to measure small position shifts for diffuse, low contrast objects, these high precision proper motion measurements require the stable PSF, high Strehl ratio, and low response in the PSF wings which HST/NICMOS uniquely provides.

NIC3 10616

Gotcha! Using Swift GRBs to Pinpoint the Highest Redshift Galaxies

While there is convincing evidence that the Universe was re-ionized between redshifts of 6.5 and 15, the role of galaxies in this process is still not understood. Several star-forming galaxies at z~6 have been identified in recent deep, narrow-field surveys, but the expensive observations along with cosmic variance and contamination make it difficult to assess their contribution to re-ionization. Moreover, the detection of galaxies at z>7 is exceedingly difficult even with the Hubble UDF or cluster lensing. Significant progress can be made using gamma-ray bursts {GRBs} localized with the now-operational Swift satellite, which is capable of detecting bursts out to z>10. GRBs have the advantage of being an uncontaminated signpost for star- formation, and their afterglows are sufficiently bright even at z>6 to allow photometric selection {via the Ly-alpha drop out technique} with 2-5 meter telescopes. Using our approved TOO programs at an extensive range of facilities {from 1-m robotic telescopes to Keck/Magellan}, we can rapidly find afterglows at z>6 and easily distinguish them from dusty low redshift bursts. This approach is highly efficient compared to current techniques, especially at z>7. Here we request imaging with NICMOS {z>6}, ACS {z~6}, and Spitzer/IRAC to characterize the properties {SFR, age, morphology} of up to five galaxies located in this manner, and begin to address their role in re-ionization. These observations are requested as >2 month TOOs, allowing flexibility of scheduling and at the same time taking a unique and timely advantage of the exquisite performance of three of NASA’s premier missions.


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


9963 – OBAD Failed Identification @ 271/03:06:27z Upon AOS at 271/03:23:01 two 486 ESB messages 1902 (OBAD Failed Identification)   were observed.  Total RSS error was 81830.80 arcseconds (22.7 degrees). Vehicle was in fine lock on FGS 1 and 3 at AOS. Mnemonic GOBSTAT shows “AttDTerr” at AOS. Two OBAD’s at 04:17:06 and 04:35:46 were successful with small errors.



                             SCHEDULED     SUCCESSFUL       FAILURE TIMES 
 Gsacq                   08                     08 

 Reacq                    07                     07 
 OBAD with 
 Maneuver      30                     27                271/03:06:27z (HSTAR 
 # 9963) 
 (HSTAR # 9963) 
 (HSTAR # 9963) 


SpaceRef staff editor.