Status Report

NASA Hubble Space Telescope Daily Report #4185

By SpaceRef Editor
August 25, 2006
Filed under , ,
NASA Hubble Space Telescope Daily Report #4185
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT # 4185

PERIOD COVERED: UT August 24, 2006 (DOY 236)

OBSERVATIONS SCHEDULED

ACS/HRC 10805

ACS Imaging of Uranus’ Atmosphere Near Equinox

Uranus’ 97-degree spin axis inclination results in the largest fractional seasonal variation of solar insolation in the solar system. Uranus is now close to its 7 December 2007 equinox, and we can now see most of the northern hemisphere, which was in darkness when Voyager provided our first detailed view of the planet in 1986. If Uranus’ seasonal response has the large phase shift expected from its long radiative time constant, it should now exhibit nearly maximal hemispheric contrast. Although the long time constant also suggests a small physical response, significant hemispheric asymmetries in cloud structure and dynamics are becoming apparent. We propose a detailed characterization of Uranus’ current response to this forcing with a 10-orbit program consisting of 4 orbits of WFC imaging with narrowband ramp filters and 6 orbits of HRC imaging using both broadband and narrowband filters. Nine narrow-band filters between 0.62 and 0.955 microns will provide vertical sensing depths scanning through the pressure range where the putative methane and deeper H2S clouds might plausibly exist and provide strong constraints on their optical properties and parent gas mixing ratios. The high resolution HRC images will characterize the dynamics of discrete features at the 15-30 hour time scale unavailable from the ground. Short wavelength HRC images will enable a characterization of the stratospheric haze. These observations have unique combinations of spectral range and resolution with needed temporal and spatial resolution not available from groundbased observations.

ACS/HRC 10833

Host Galaxies of Reverberation Mapped AGNs

We propose to obtain unsaturated high-resolution images of 17 reverberation-mapped active galactic nuclei in order to remove the point-like nuclear light from each image, thus yielding a “nucleus-free” image of the host galaxy. This will allow investigation of host galaxy properties: our particular interest is determination of the host-galaxy starlight contribution to the reverberation-mapping observations. This is necessary {1} for accurate determination of the relationship between the AGN nuclear continuum flux and the size of the broad Balmer-line emitting regions of AGNs, which is important in estimating black hole masses for large samples of QSOs, and {2} for accurate determination of the bolometric luminosity of the AGN proper. Through observations in Cycles 12 and 14, we have obtained or will obtain images of 18 of the 35 objects in the reverberation-mapping compilation of Peterson et al. {2004}. These observations revealed that the host-galaxy contribution, even in the higher-luminosity AGNs, is higher than expected and that all of the reverberation-mapped AGNs will have to be observed, not just the lower-luminosity sources; each source is different, and each source is important. Therefore we request time to observe the 17 remaining reverberation-mapped AGNs.

ACS/HRC 10909

Exploring the diversity of cosmic explosions: The supernovae of gamma-ray bursts

While the connection between gamma-ray bursts {GRBs} and supernovae {SNe} is now clearly established, there is a large variety of observational properties among these SNe and the physical parameters of these explosions are poorly known. As part of a comprehensive program, we propose to use HST in order to obtain basic information about the supernovae associated with gamma-ray bursts. HST offers the means to cleanly separate the light curves of the GRB afterglow from the supernova, and to remove the contamination from the host galaxy, opening a clear route to the fundamental parameters of the SN. From these observations, we will determine the absolute magnitude at maximum, the shape of the spectral energy distribution, and any change over time of the energy distribution. We will also measure the rate of decay of the exponential tail. Merged with the ground-based data that we will obtain for each event, we will be able to compare our data set to models and constrain the energy of the explosion, the mass of the ejecta and the mass of Nickel synthesized during the explosion. These results will shed light on the apparent variety of supernovae associated with gamma-ray bursts and X-ray flashes, and on the relation between these SNe and other, more common varieties of core- collapse explosions.

ACS/WFC 10258

Tracing the Emergence of the Hubble Sequence Among the Most Luminous and Massive Galaxies

There is mounting evidence that the redshift range 1 < z < 2 was an important era when massive galaxies assembled their stellar content and assumed their present--day morphologies. Despite extensive HST imaging surveys, however, there is very little data in the optical rest frame {i.e., observed near--infrared} on the morphologies of the most luminous galaxies at these redshifts. We propose to image a carefully selected set of 20 of the most luminous, K--band selected GOODS galaxies at 1.3 < z < 2, using NICMOS camera 2. This offers diffraction--limited, critically sampled imaging at 1.6 microns to ensure the best angular resolution for comparison to ACS. The galaxies are chosen to span a simple 4--fold parameter space of morphological and spectral type, in order to provide the most information about the variety of massive galaxy properties in this redshift range. We will investigate the emergence of large scale--length disks, stable spiral structure, mature bulges with red stellar populations, central bar structures, the incidence of disturbed morphology, the existence {or lack thereof} of blue ellipticals, and other questions that concern the evolution and maturation of the brightest, largest, and most massive ordinary galaxies in this critical redshift range.

ACS/WFC 10886

The Sloan Lens ACS Survey: Towards 100 New Strong Lenses

As a continuation of the highly successful Sloan Lens ACS {SLACS} Survey for new strong gravitational lenses, we propose one orbit of ACS-WFC F814W imaging for each of 50 high- probability strong galaxy-galaxy lens candidates. These observations will confirm new lens systems and permit immediate and accurate photometry, shape measurement, and mass modeling of the lens galaxies. The lenses delivered by the SLACS Survey all show extended source structure, furnishing more constraints on the projected lens potential than lensed-quasar image positions. In addition, SLACS lenses have lens galaxies that are much brighter than their lensed sources, facilitating detailed photometric and dynamical observation of the former. When confirmed lenses from this proposal are combined with lenses discovered by SLACS in Cycles 13 and 14, we expect the final SLACS lens sample to number 80–100: an approximate doubling of the number of known galaxy-scale strong gravitational lenses and an order-of-magnitude increase in the number of optical Einstein rings. By virtue of its homogeneous selection and sheer size, the SLACS sample will allow an unprecedented exploration of the mass structure of the early-type galaxy population as a function of all other observable quantities. This new sample will be a valuable resource to the astronomical community by enabling qualitatively new strong lensing science, and as such we will waive all but a short {3-month} proprietary period on the observations.

ACS/WFC/NIC3 10632

Searching for galaxies at z>6.5 in the Hubble Ultra Deep Field

We propose to obtain deep ACS {F606W, F775W, F850LP} imaging in the area of the original Hubble Ultra Deep Field NICMOS parallel fields and – through simultaneous parallel observations – deep NICMOS {F110W, F160W} imaging of the ACS UDF area. Matching the extreme imaging depth in the optical and near-IR bands will result in seven fields with sufficiently sensitive multiband data to detect the expected typical galaxies at z=7 and 8. Presently no such a field exist. Our combined optical and near-IR ultradeep fields will be in three areas separated by about 20 comoving Mpc at z=7. This will allow us to give a first assessment of the degree of cosmic variance. If reionization is a process extending over a large redshift interval and the luminosity function doesn’t evolve strongly beyond z=6, these data will allow us to identify of the order of a dozen galaxies at 6.5 < z < 8.5 - using the Lyman break technique - and to place a first constrain on the luminosity function at z>6.5. Conversely, finding fewer objects would be an indication that the bulk of reionization is done by galaxies at z=6. By spending 204 orbits of prime HST time we will capitalize on the investment of 544 prime orbits already made on the Hubble Ultra Deep Field {UDF}. We have verified that the program as proposed is schedulable and that it will remain so even if forced to execute in the 2-gyro mode. The data will be non-proprietary and the reduced images will be made public within 2 months from the completion of the observations.

FGS 10989

Astrometric Masses of Extrasolar Planets and Brown Dwarfs

We propose observations with HST/FGS to estimate the astrometric elements {perturbation orbit semi-major axis and inclination} of extra-solar planets orbiting six stars. These companions were originally detected by radial velocity techniques. We have demonstrated that FGS astrometry of even a short segment of reflex motion, when combined with extensive radial velocity information, can yield useful inclination information {McArthur et al. 2004}, allowing us to determine companion masses. Extrasolar planet masses assist in two ongoing research frontiers. First, they provide useful boundary conditions for models of planetary formation and evolution of planetary systems. Second, knowing that a star in fact has a plantary mass companion, increases the value of that system to future extrasolar planet observation missions such as SIM PlanetQuest, TPF, and GAIA.

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.

WFPC2 10744

WFPC2 Cycle 14 Decontaminations and Associated Observations

This proposal is for the WFPC2 decontamination. Also included are instrument monitors tied to decontamination: photometric stability check, focus monitor, pre- and post-decontamination internals {bias, intflats, kspots, & darks}, UV throughput check, VISFLAT sweep, and internal UV flat check.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10409 – FHST OBAD Failure @ 236/23:14:05z

FHST OBAD (With Maneuver) failed during los. At AOS 23:22:30, we received an 486 STB message 1904 (OBAD Too Many Angle Checks)

10410 – REacq(2,1,2) failed to RGA control @ 236/23:22:30z

The REacq(2,1,2) failed due to search radius limit exceeded on FGS 1. The OBAD at 23:06:19 showed errors of V1=-3.05, V2=24.28, V3=4.10, and RSS=24.81.

COMPLETED OPS REQUEST:

17898-0 – Battery 4 Capacity Test Script & 5 Battery Pressure Limit COP (Thru step 39) @ 236/2106z

COMPLETED OPS NOTES:

1523-1 – Transfer TRTT Macro load to CMD Que

                         SCHEDULED      SUCCESSFUL 
FGS GSacq               11                     11 
FGS REacq               04                      03 
OBAD with Maneuver  30                     29 

SIGNIFICANT EVENTS:

1. Battery 4 Capacity Test Flash Report #3 The Battery 4 discharge terminated at 2006/236 13:41 GMT (9:41 am local) and the battery was placed back on-line in hardware at 14:57 GMT (10:57 am local). The recovery period began at approximately 15:18 GMT (11:18 am local) with the batteries charging at the K1L4 equivalent. During the 1st two recovery orbit day cycles, only 3 batteries reached charge cut-off, thus BRT = 4 was not satisfied. During the 3rd recovery orbit, BRT was satisfied with 4 batteries reaching charge cut-off. As such, the ROC Trickle Charge Elapse Timer limit was restored to a nominal 4 orbits at 21:05 GMT (5:05 pm local). Battery temperatures continue to cycle below 1.0 deg C. Battery 4 is still scheduled to be placed back on-line in FSW on 237/1320 GMT (08/25 at 9:20 am).

2. Flash Report: TRTT Macro Installation and Execution FRR (Summary Extract) – The Flight Readiness Review for the Transient Rate Trending Test (TRTT) Macro Installation and Execution was held on August 24, 2006 and authority to proceed was given. The 1st commanding opportunity for the Macro installation begins on Wednesday August 30th at ~14h01m UTC, and the subsequent TRTT Macro executions are planned for Thursday August 31st between ~11h32m UTC and ~13h54m UTC. OTA will monitor the initial GSAcq (1,3,1) at ~15h03m, after the 2nd TRTT Macro execution is complete.

SpaceRef staff editor.