Status Report

NASA Hubble Space Telescope Daily Report #4264

By SpaceRef Editor
December 21, 2006
Filed under , ,
NASA Hubble Space Telescope Daily Report #4264


– Continuing to collect World Class Science

PERIOD COVERED: UT December 20, 2006 (DOY 3354)


ACS/HRC 10800

Kuiper Belt Binaries: Probes of Early Solar System Evolution

Binaries in the Kuiper Belt are a scientific windfall: in them we have relatively fragile test particles which can be used as tracers of the early dynamical evolution of the outer Solar System. We propose to continue a Snapshot program using the ACS/HRC that has a demonstrated discovery potential an order of magnitude higher than the HST observations that have already discovered the majority of known transneptunian binaries. With this continuation we seek to reach the original goals of this project: to accumulate a sufficiently large sample in each of the distinct populations collected in the Kuiper Belt to be able to measure, with statistical significance, how the fraction of binaries varies as a function of their particular dynamical paths into the Kuiper Belt. Today’s Kuiper Belt bears the imprints of the final stages of giant-planet building and migration; binaries may offer some of the best preserved evidence of that long-ago era.

ACS/HRC 11041

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. For cycle 15 the program will cover 18 months 12.1.06->05.31.08 and it has been divied into three different proposal each covering six months. The three proposals are 11041-11042-11043.

ACS/HRC 11051

CCD Stability Monitor

This program will verify that the low frequency flat fielding, the photometry, and the geometric distortion are stable in time and across the field of view of the CCD arrays.

ACS/WFC 10829

Secular Evolution at the End of the Hubble Sequence

The bulgeless disk galaxies at the end of the Hubble Sequence evolve at a glacial pace relative to their more violent, earlier-type cousins. The causes of their internal, or secular evolution are important because secular evolution represents the future fate of all galaxies in our accelerating Universe and is a key ingredient to understanding galaxy evolution in lower-density environments at present. The rate of secular evolution is largely determined by the stability of the cold ISM against collapse, star formation, and the buildup of a central bulge. Key diagnostics of the ISM’s stability are the presence of compact molecular clouds and narrow dust lanes. Surprisingly, edge-on, pure disk galaxies with circular velocities below 120 km/s do not appear to contain such dust lanes. We propose to obtain ACS/WFC F606W images of a well-selected sample of extremely late-type disk galaxies to measure the characteristic scale size of the cold ISM and determine if they possess the unstable, cold ISM necessary to drive secular evolution. Our sample has been carefully constructed to include disk galaxies above and below the critical circular velocity of 120 km/s where the dust properties of edge-on disks change so remarkably. We will then use surface brightness profiles to search for nuclear star clusters and pseudobulges, which are early indicators that secular evolution is at work, as well as measure the pitch angle of the dust lanes as a function of radius to estimate the central mass concentrations.

ACS/WFC 10835

Probing The Globular Cluster / Low Mass X-ray Binary Connection in Early-type Galaxies At Low X-ray

Combined high-resolution imaging from Hubble and Chandra {CXO} has revolutionized our understanding of extragalactic low-mass X-ray binaries {LMXBs} and globular clusters {GCs}, yet their connection in early-type galaxies has remained unstudied at the luminosities of the Galactic LMXBs in GCs. NGC 4278 and 3379 will be the first two prototypical elliptical galaxies with deep CXO observations enabling the study of LMXBs at lower luminosities. We propose mosaic ACS observations of both galaxies {5 fields per galaxy} that will provide the most comprehensive view into the connection between GCs and LMXBs in early-type galaxies. We will detect ~860 and ~270 GCs in all of NGC 4278 and NGC 3379, respectively. These two galaxies will have among the greatest number of detected GC-LMXBs to date {~130 & 50} and will include the faintest GC-LMXBs in a normal early-type galaxy. We will measure the fraction of GCs which contain LMXBs, as a function of X-ray luminosity, galactocentric distance, color, and GC half-light radius. Using the radial profiles of optical light, GCs, and LMXBs, we will determine the percentage of field LMXBs which may have originated in GCs. We will use the measured GC properties over the entire extent of both galaxies to constrain theories of GC formation and evolution.

ACS/WFC 10917

Afterglows and Environments of Short-Hard Gamma-Ray Bursts

Discovery of the first afterglows of short-hard bursts {SHBs} has led to a revolution in our understanding of these events, strongly suggesting that they originate in the mergers of compact-object binaries. Capitalizing on this progress, we propose to pursue the next generation of SHB observations with HST, tracking the decay of all accessible SHB afterglows to late times and pinpointing the location of several more within the context of their host galaxies. These observations will allow quantitative analysis of progenitor lifetimes and short burst environments, enable direct confrontation with population synthesis models, and provide updated event rate estimates for the LIGO and VIRGO gravitational-wave detectors that are now coming on-line.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration – CR Persistence Part 5

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, ACS/WFC 10802

SHOES-Supernovae, HO, for the Equation of State of Dark energy

The present uncertainty in the value of the Hubble constant {resulting in an uncertainty in Omega_M} and the paucity of Type Ia supernovae at redshifts exceeding 1 are now the leading obstacles to determining the nature of dark energy. We propose a single, integrated set of observations for Cycle 15 that will provide a 40% improvement in constraints on dark energy. This program will observe known Cepheids in six reliable hosts of Type Ia supernovae with NICMOS, reducing the uncertainty in H_0 by a factor of two because of the smaller dispersion along the instability strip, the diminished extinction, and the weaker metallicity dependence in the infrared. In parallel with ACS, at the same time the NICMOS observations are underway, we will discover and follow a sample of Type Ia supernovae at z > 1. Together, these measurements, along with prior constraints from WMAP, will provide a great improvement in HST’s ability to distinguish between a static, cosmological constant and dynamical dark energy. The Hubble Space Telescope is the only instrument in the world that can make these IR measurements of Cepheids beyond the Local Group, and it is the only telescope in the world that can be used to find and follow supernovae at z > 1. Our program exploits both of these unique capabilities of HST to learn more about one of the greatest mysteries in science.


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


10565 – GSacq(1,3,1) failed to RGA control At AOS 354/16:41:51 flags indicated that the GSacq(1,3,1) scheduled at 354/16:11:14 failed due to search radius limit exceeded on FGS 3. The Map at 16:18:24 showed errors of V1=2.70, V2=9.52, V3=0.18 and RSS=9.90.

10566 – GSAcq(2,1,2) failed to RGA Hold (Gyro Control) The GSAcq(2,1,2) scheduled at 354/22:33:45 – 22:41:50 failed to RGA Hold due to (QF2STOPF) stop flag indication on FGS-2. Pre-acquisition OBADs showed (RSS) attitude correction values of 2643.66 and 5.33 arcseconds. Post-acquisition OBAD/MAP had 3-axis (RSS) error value of 1.48 arcseconds.


17975-0 – Adjust Battery 3 VTFE Curve to K1L4-50mV

17982-0 – Remove VTFE SSPC Branch Command from SMAC00


                        SCHEDULED      SUCCESSFUL
FGS GSacq               09                    07
FGS REacq               05                    05
OBAD with Maneuver  28                    28


Battery 3 VTFE Curve & SMAC00 Adjustment Flash Report:

On DOY 2006/354 at 13:15 GMT, Ops Request 17975 was successfully executed to increase the Battery 3 VTFE curve to K1L4-50mV. This change was implemented to account for the discrepancy with the Battery 3 calibration curve. EPS SEs will continue to closely monitor and evaluate the system performance over the next few days. Follow-up reports will be provided.

In addition, Ops Request 17982 was successfully executed to remove the VTFE curve reset special branch command from SMAC00 such that the VTFE curves will not be reset to K1L4 upon safemode entry.

SpaceRef staff editor.