Status Report

NASA Hubble Space Telescope Daily Report #4369

By SpaceRef Editor
May 25, 2007
Filed under , ,
NASA Hubble Space Telescope Daily Report #4369

Notice: For the foreseeable future, the daily reports may contain apparent discrepancies between some proposal descriptions and the listed instrument usage. This is due to the conversion of previously approved ACS WFC or HRC observations into WFPC2, or NICMOS observations subsequent to the loss of ACS CCD science capability in late January.


– Continuing to collect World Class Science

PERIOD COVERED: UT May 23, 2007 (DOY 143)


WFPC2 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.

WFPC2 10877

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for supernovae {SNe}, most notably our Lick Observatory Supernova Search {LOSS}, have found hundreds of SNe, many of them in quite nearby galaxies {cz < 4000 km/s}. Most of the objects were discovered before maximum brightness, and have follow-up photometry and spectroscopy; they include some of the best-studied SNe to date. We propose to conduct a snapshot imaging survey of the sites of some of these nearby objects, to obtain late-time photometry that {through the shape of the light and color curves} will help reveal the origin of their lingering energy. The images will also provide high-resolution information on the local environments of SNe that are far superior to what we can procure from the ground. For example, we will obtain color-color and color-magnitude diagrams of stars in these SN sites, to determine the SN progenitor masses and constraints on the reddening. Recovery of the SNe in the new HST images will also allow us to actually pinpoint their progenitor stars in cases where pre- explosion images exist in the HST archive. This proposal is an extension of our successful Cycle 13 snapshot survey with ACS. It is complementary to our Cycle 15 archival proposal, which is a continuation of our long-standing program to use existing HST images to glean information about SN environments.

ACS/SBC 10862

Comprehensive Auroral Imaging of Jupiter and Saturn during the International Heliophysical Year

A comprehensive set of observations of the auroral emissions from Jupiter and Saturn is proposed for the International Heliophysical Year in 2007, a unique period of especially concentrated measurements of space physics phenomena throughout the solar system. We propose to determine the physical relationship of the various auroral processes at Jupiter and Saturn with conditions in the solar wind at each planet. This can be accomplished with campaigns of observations, with a sampling interval not to exceed one day, covering at least one solar rotation. The solar wind plasma density approaching Jupiter will be measured by the New Horizons spacecraft, and a separate campaign near opposition in May 2007 will determine the effect of large-scale variations in the interplanetary magnetic field {IMF} on the Jovian aurora by extrapolation from near-Earth solar wind measurements. A similar Saturn campaign near opposition in Jan. 2007 will combine extrapolated solar wind data with measurements from a wide range of locations within the Saturn magnetosphere by Cassini. In the course of making these observations, it will be possible to fully map the auroral footprints of Io and the other satellites to determine both the local magnetic field geometry and the controlling factors in the electromagnetic interaction of each satellite with the corotating magnetic field and plasma density. Also in the course of making these observations, the auroral emission properties will be compared with the properties of the near-IR ionospheric emissions {from ground- based observations} and non thermal radio emissions, from ground-based observations for Jupiter?s decametric radiation and Cassini plasma wave measurements of the Saturn Kilometric Radiation {SKR}.

WFPC2 10826

Galaxy Evolution During Half the Age of the Universe: ACS imaging of rich galaxy clusters

Detailed studies of nearby galaxies {z<0.05} show that galaxies have very complex histories of formation and evolution involving mergers, bursts of star formation, and morphological changes. Even so, the global properties of the galaxies {radii, luminosities, rotation velocities, velocity dispersions, and absorption line strengths} follow a number of very tight {empirical} scaling relations, e.g. the Tully-Fisher relation and the Fundamental Plane {FP}. We use the scaling relations plus quantative morphological measures for galaxy clusters up to z=1 to constrain models for galaxy evolution. Here we request 24 orbits to obtain ACS imaging of the remaining three clusters in our sample at z~0.7-1.0. High resolution imaging of the clusters is critical for our study of star formation histories and structural evolution in dense environments since z<1. We have previously obtained deep spectroscopic observations of the clusters with Gemini. The data will provide samples large enough to establish the slope of the FP for each cluster. With multiple clusters at similar redshifts, we can probe evolutionary differences within a single epoch in order to decouple changes due to different environments. Our two other high-z clusters exhibit different chemical enrichment histories, which we argue are due to the different merging histories of these clusters.

NIC2 10858

NICMOS Imaging of the z ~ 2 Spitzer Spectroscopic Sample of Ultraluminous Infrared Galaxies

We propose to obtain NICMOS images of the first large sample of high-z ultra-luminous infrared galaxies {ULIRGs} whose redshifts and physical states have been determined with Spitzer mid-IR spectra. The detection of strong silicate absorption and/or PAH emission lines suggest that the these sources are a mixture of highly obscured starbursts, AGNs and composite systems at z=2. Although some of the spectra show PAH emission similar to local starburst ULIRGs, their bolometric luminosities are roughly an order of magnitude higher. One important question is if major mergers, which are the trigger for 95% of local ULIRGs, also drive this enormous energy output observed in our z=2 sample. The NICMOS images will allow us to {1} measure surface brightness profiles of z~2 ULIRGs and establish if major mergers could be common among our luminous sources at these early epochs, {2} determine if starbursts and AGNs classified based on their mid-IR spetra would have different morphological signatures, thus different dynamic state; {3} make comparisons with the similar studies of ULIRGs at z ~ 0 – 1, thus infer any evolutionary connections between high-z ULIRGs and the formation of normal, massive galaxies and quasars observed today. FGS 11019 Monitoring FGS1r’s Interferometric Response as a Function of Spectral Color This proosal uses FGS1r in Transfer mode to observe standard single stars of a variety of spectral types to obtain point source interferograms for the Transfer mode calibration library. In specific cases, the calibration star will also be observed in POS mode multiple times with the F583W and F5ND elements to provide the data to verify the stabiligy of the cross filter calibration.

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.

WFPC2 10888

Complexity in the Smallest Galaxies: Star Formation History of the Sculptor Dwarf Spheroidal

The Sculptor dwarf spheroidal galaxy {Scl dSph} is one of the most luminous of the Milky Way dSph satellites, suffers virtually no foreground confusion or reddening because of its high galactic latitude, and is nearby at 80 kpc from the Sun. It is of great interest to astronomy to understand the detailed histories of dSph galaxies because they may be survivors of the hierarchical merging process that created giant galaxies like our own. Despite this, the age distribution of stars in Scl dSph remains remarkably poorly constrained because of a dearth of high-quality color-magnitude diagrams {CMDs} of its central regions. Scl dSph is known to be complex on the basis of shallower photometry, radial velocity studies, and investigations of the metallicity; however, the age range of significant star-formation and the proportion of stars older and younger than 10 Gyr is still completely unknown. The age of the centrally concentrated, metal-rich population has never been measured. We propose to obtain deep optical images of the core of Scl dSph with WFPC2 in order to measure the temporal evolution of its star-formation rate over its entire lifetime. The ONLY way to reliably measure the variation in star-formation rate on Gyr timescales at ages of 10-13 Gyr is with photometry of a large number of stars at and below the oldest main-sequence turnoffs to magnitudes of {B,I} = {25.1, 24.5}. Because of the high stellar density and resulting image crowding, it is impossible to achieve the required level of photometric precision except with diffraction-limited imaging. These data will permit the first reliable measurement of the star-formation history of the main body of Scl dSph; limited inferences from WFPC2 data in an outer field have been made, but they were hindered not only by small number statistics but by the subsequent revelation of extremely strong population gradients in Scl dSph, such that the stars in the existing WFPC2 field are not representative of the galaxy as a whole. Our proposed program will shed strong new light on the formation processes of the smallest galaxies. Only by measuring the detailed early histories of galaxies like Scl dSph can we evaluate the impact of outside influences like ram-pressure stripping, tidal stirring, and photoionization feedback on the evolution of small galaxies.


Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: (None from today)

10828 [May 15. 2007 (UT)] – Reacq(1,2,1) failed due to Search Radius Limit Exceeded @ 135/23:32:54z

During the PTAS data review it was noted that the Reacq (1,2,1) at 135/23:32 had failed due to a Search Radius Limit Exceeded Error. The entire acquisition and guiding period were in a ZOE. Previous acquisition at 135/22:05 on the same stars had succeeded and no problems were seen with either star.


18089-0 – MSS Only Converged & Add Gyro1 Tests#21 & #25 for day 143

18092-0 – PCS KF OOT Support.

18054-0 – Preview KF Sun Vector Data via Telemetry Diags,


                       SCHEDULED      SUCCESSFUL 
FGS GSacq               08                  08 
FGS REacq               05                  05 
OBAD with Maneuver      26                  26 


Evaluation of Universal Kalman Filter performance continued. Multiple text segments were executed, all of them successfully. Details follow. Background Kalman Filter Operation:

The Gyro1 sensor input was added to the KF at 143/19:38 (OR 18089-0). The filter was already converged with only the MSS sensor input enabled. The Gyro1 input was added during an M2G period, with the vehicle inertially fixed and during orbit day. All UKF parameters showed nominal operation. The test was to monitor the addition of the Gyro1 sensor input to an already converged filter (M_G1_RNF, Test #21). The Gyro1 sensor input was left enabled to support the execution of the subsequent KF convergence test at 21:17.

The Gyro1 sensor input was removed from the KF at 143/21:17 (OR 18089-0). The filter was already converged with the MSS and Gyro1 sensor inputs enabled. The Gyro1 input was removed during an M2G guiding interval, with the vehicle inertially fixed and during orbit day. All UKF parmeters showed nominal operation. The test was to monitor the removal of the Gyro1 sensor input from the converged filter (M_G1_HNF, Test #25). The removal of the Gyro1 sensor input left the KF in the currently desired configuration with only the MSS sensor input enabled.

SpaceRef staff editor.