Status Report

NASA Hubble Space Telescope Daily Report #4085

By SpaceRef Editor
April 5, 2006
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NASA Hubble Space Telescope Daily Report #4085

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science


PERIOD COVERED: UT April 04, 2006 (DOY 094)


ACS/HRC 10474

Shooting Stars: Looking for Direct Evidence of Massive Central Black Holes in Globular Clusters

We propose to make observations that directly test the proposition that globular clusters contain massive black holes. Our targets are the bulge globular clusters NGC 6388 and NGC 6441. These are probably among the most massive in the galaxy, but are understudied compared to more familiar objects such as M15. Our analysis suggests that these two clusters are the most likely to show unambiguous evidence for a central massive black hole if such things exist in globular clusters. The observations proposed will give us the first thorough kinematic and photometric studies of these two clusters. The combination of the two epochs will give us proper motions good to of order 6 km/s. In addition, they will provide us with the first good, deep, color-magnitude diagrams for these clusters. These diagrams will be used to investigate the make up of the stellar population in the clusters, to more firmly establish their distances, ages, and metallicities, and to search for a binary sequence.

ACS/WFC 10496

Decelerating and Dustfree: Efficient Dark Energy Studies with Supernovae and Clusters

We propose a novel HST approach to obtain a dramatically more useful “dust free” Type Ia supernovae {SNe Ia} dataset than available with the previous GOODS searches. Moreover, this approach provides a strikingly more efficient search-and-follow-up that is primarily pre- scheduled. The resulting dark energy measurements do not share the major systematic uncertainty at these redshifts, that of the extinction correction with a prior. By targeting massive galaxy clusters at z > 1 we obtain a five-times higher efficiency in detection of Type Ia supernovae in ellipticals, providing a well-understood host galaxy environment. These same deep cluster images then also yield fundamental calibrations required for future weak lensing and Sunyaev-Zel’dovich measurements of dark energy, as well as an entire program of cluster studies. The data will make possible a factor of two improvement on supernova constraints on dark energy time variation, and much larger improvement in systematic uncertainty. They will provide both a cluster dataset and a SN Ia dataset that will be a longstanding scientific resource.

ACS/WFC 10573

Globular Clusters in the Direction of the Inner Galaxy

The age, chemical and kinematic distributions of stellar populations provide powerful constraints on models of the formation and evolution of the Milky Way. The globular clusters constitute an especially useful case because the stars within individual clusters are coeval and spatially distinct. But a serious limitation in the study of many globular clusters — especially those located near the Galactic Center — has been the existence of large absolute and differential extinction by foreground dust. We propose to use the ACS to map the differential extinction and remove their effects in a large sample of globular clusters located in the direction of the inner Galaxy using a technique refined recently by von Braun and Mateo {2001}. These observations and their analyses will let us produce high quality color-magnitude diagrams of these poorly studied clusters that will allow us to determine these clusters’ relative ages, distances and chemistry and to address important questions about the formation and the evolution of the inner Galaxy. Our aim for these ACS observations is to obtain data for the most crowded clusters in the inner Galaxy where the excellent spatial resolution of the ACS is most necessary.

ACS/WFC 10592

An ACS Survey of a Complete Sample of Luminous Infrared Galaxies in the Local Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared selected galaxies exceeds that of optically selected galaxies. These `luminous infrared galaxies’ {LIRGs} are primarily interacting or merging disk galaxies undergoing enhanced star formation and Active Galactic Nuclei {AGN} activity, possibly triggered as the objects transform into massive S0 and elliptical merger remnants. We propose ACS/WFC imaging of a complete sample of 88 L_IR > 10^11.4 L_sun luminous infrared galaxies in the IRAS Revised Bright Galaxy Sample {RBGS: i.e., 60 micron flux density > 5.24 Jy}. This sample is ideal not only in its completeness and sample size, but also in the proximity and brightness of the galaxies. The superb sensitivity, resolution, and field of view of ACS/WFC on HST enables a unique opportunity to study the detailed structure of galaxies that sample all stages of the merger process. Imaging will be done with the F439W and F814W filters {B and I-band} to examine as a function of both luminosity and merger state {i} the evidence at optical wavelengths of star formation and AGN activity and the manner in which instabilities {bars and bridges} in the galaxies may funnel material to these active regions, {ii} the relationship between star formation and AGN activity, and {iii} the structural properties {AGN, bulge, and disk components} and fundamental parameters {effective radius and surface brightness} of LIRGs and their similarity with putative evolutionary byproducts {elliptical, S0 and classical AGN host galaxies}. This HST survey will also bridge the wavelength gap between a Spitzer imaging survey {covering seven bands in the 3.6-160 micron range} and a GALEX UV imaging survey of these galaxies, but will resolve complexes of star clusters and multiple nuclei at resolutions well beyond the capabilities of either Spitzer or GALEX. The combined datasets will result in the most comprehensive multiwavelength study of interacting and merging galaxies to date.

S/C 10718

The Exosphere of a Newly Discovered Transiting Planet

We propose to use HST to directly detect the atmosphere and extended envelope {exosphere} of a recently discovered planet that transits the relatively bright star HD 149026. Absorption of background stellar Lyman-alpha emission is an extremely sensitive exospheric diagnostic that only HST can measure. If the HD 149026 planet is evaporating, then hydrogen in the exosphere should fill or overfill the Roche lobe, which has a size 4 times the diameter of Jupiter. If we do not detect a decrease in Lyman-alpha flux during several transits, then the hydrogen exosphere does not fill the Roche lobe of the planet and significant evaporation is unlikely. This would be a surprise, given that Vidal-Madjar et al. {2003} detected the exosphere of the planet that transits HD 209458, and the models of Lecavelier des Etangs et al. {2004} predict an order of magnitude more evaporation for the planet around HD 149026, due to its lower mass and smaller orbital distance. The newly discovered planet has 3 times the mean density and at least 3 times the core mass of the planet that transits HD 209458, which is consistent with significant exospheric evaporation in the past. We will also use ACS/PR200L observations to measure stellar limb darkening in the NUV, to detect Mg in the lower atmosphere of the planet, and to search for evidence of a moon or planetary rings.

WFPC2 10745


This calibration proposal is the Cycle 14 routine internal monitor for WFPC2, to be run weekly to monitor the health of the cameras. A variety of internal exposures are obtained in order to provide a monitor of the integrity of the CCD camera electronics in both bays {both gain 7 and gain 15 — to test stability of gains and bias levels}, a test for quantum efficiency in the CCDs, and a monitor for possible buildup of contaminants on the CCD windows. These also provide raw data for generating annual super-bias reference files for the calibration pipeline.


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


10197 – GSAcq (1,2,1) failed due to search radius limit exceeded on FGS- @ 094/12:01:30z

GSAcq (1,2,1) scheduled at 094/11:56:22-12:03:11 failed due to search radius limit exceeded on FGS-1. At 094/11:59:01 received ESB “1805”(x3)(Moving target detected) and later received ESB “a05” (Exceeded SRL).

OBAD #1: V1 -321.53, V2 -1306.23, V3 -569.31, RSS 1460.73.

OBAD #2: V1 5.41, V2 -6.58, V3 -3.56, RSS 9.23

OBAD MAP: V1 -0.67, V2 75.62, V3 -0.27, RSS 75.63

10199 – GSAcq(2,1,2) requires two attempts to achieve CT-DV @ 089/21:51:32z

GSAcq(2,1,2) scheduled for 2006/089 21:51:32 required two attempts to achieve CT-DV on FGS2. The acquisition was successful.


17689-0 – Battery 6 Capacity Test Script & Battery Pressure Limit COP (Step thru 17)

17693-0 – Genslew for proposal 10695 – slot 7 @ 094/18:53z

17694-0 – Genslew for proposal 10695 – slot 8 @ 094/18:55z


                         SCHEDULED      SUCCESSFUL      FAILURE TIMES
FGS GSacq               12                    11                  Hstar # 10197
FGS REacq               03                    03
OBAD with Maneuver  30                    30


Commanding for the Battery 6 Capacity Test started as scheduled at DOY 094/1155 GMT (4/4 at 7:55 am) with setting the Battery Pressure Test for a 5-battery system. Battery 6 was taken off-line and battery discharge was begun at 1353 GMT (4/4 at 9:53 am).

Battery 6 switched from the High-rate to Low-rate discharge resistor at approximately 095/0011 GMT (4/4 at 08:11 pm).

Following completion of the discharge, which is expected to occur around 096/1600 GMT (4/06 at 12:00 noon), Battery 6 will be placed back on-line in hardware during orbit night. On the orbit night pass following battery back to section switch, the Elevated VTFE Macro will be executed. On 097/1200 GMT (4/07 at 8:00 am), Battery 6 is scheduled to be placed back on-line in FSW.

As of 095/0045 GMT (4/4 at 08:41 pm local), the battery 6 discharge continues nominally.

SpaceRef staff editor.