Status Report

NASA Hubble Space Telescope Daily Report #4965

By SpaceRef Editor
November 5, 2009
Filed under , ,


Continuing to Collect World Class Science

PERIOD COVERED: 5am November 3 – 5am November 4, 2009 (DOY 307/10:00z-308/10:00z)


ACS/WFC 11782

Measuring the Shape and Orientation of the Galactic Dark-Matter Halo using Hypervelocity Stars

We propose to obtain high-resolution images of five hypervelocity stars in the Galactic halo in order to establish the first-epoch astrometric frame for them, as a part of a long-term program to measure precise proper motions. The origin of these recently discovered stars, all with positive radial velocities above 540 km/s, is consistent only with being ejected from the deep potential well of the massive black hole at the Galactic center. The deviations of their space motions from purely radial trajectories probe the departures from spherical symmetry of the Galactic potential, mainly due to the triaxiality of the dark-matter halo. Reconstructing the full three-dimensional space motion of the hypervelocity stars, through astrometric proper motions, provides a unique opportunity to measure the shape and orientation of the dark halo. The hypervelocity stars allow measurement of the potential up to 75 kpc from the center, independently of and at larger distances than are afforded by tidal streams of satellite galaxies such as the Sagittarius dSph galaxy. HVS3 may be associated with the LMC, rather then the Galactic center, and would therefore present a case for a supermassive black hole at the center of the LMC. We request one orbit with ACS/WFC for each of the five hypervelocity stars to establish their current positions relative to background galaxies. We will request a repeated observation of these stars in Cycle 17, which will conclusively measure the astrometric proper motions.

COS/NUV 11896

NUV Spectroscopic Sensitivity Monitoring

The purpose of this proposal is to monitor sensitivity of each NUV grating mode to detect any changes due to contamination or other causes.

STIS/CCD 11844

CCD Dark Monitor Part 1

The purpose of this proposal is to monitor the darks for the STIS CCD.

STIS/CCD 11846

CCD Bias Monitor-Part 1

The purpose of this proposal is to monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns.

STIS/CCD 11848

CCD Read Noise Monitor

This proposal measures the read noise of all the amplifiers (A, B, C, D) on the STIS CCD using pairs of bias frames. Full-frame and binned observations are made in both Gain 1 and Gain 4, with binning factors of 1×1, 1×2, 2×1, and 2×2. All exposures are internals. Pairs of visits are scheduled monthly for the first four months and then bi-monthly after that.


Galaxies at z~7-10 in the Reionization Epoch: Luminosity Functions to <0.2L* from Deep IR Imaging of the HUDF and HUDF05 Fields The first generations of galaxies were assembled around redshifts z~7-10+, just 500-800 Myr after recombination, in the heart of the reionization of the universe. We know very little about galaxies in this period. Despite great effort with HST and other telescopes, less than ~15 galaxies have been reliably detected so far at z>7, contrasting with the ~1000 galaxies detected to date at z~6, just 200-400 Myr later, near the end of the reionization epoch. WFC3 IR can dramatically change this situation, enabling derivation of the galaxy luminosity function and its shape at z~7-8 to well below L*, measurement of the UV luminosity density at z~7-8 and z~8-9, and estimates of the contribution of galaxies to reionization at these epochs, as well as characterization of their properties (sizes, structure, colors). A quantitative leap in our understanding of early galaxies, and the timescales of their buildup, requires a total sample of ~100 galaxies at z~7-8 to ~29 AB mag. We can achieve this with 192 WFC3 IR orbits on three disjoint fields (minimizing cosmic variance): the HUDF and the two nearby deep fields of the HUDF05. Our program uses three WFC3 IR filters, and leverages over 600 orbits of existing ACS data, to identify, with low contamination, a large sample of over 100 objects at z~7-8, a very useful sample of ~23 at z~8-9, and limits at z~10. By careful placement of the WFC3 IR and parallel ACS pointings, we also enhance the optical ACS imaging on the HUDF and a HUDF05 field. We stress (1) the need to go deep, which is paramount to define L*, the shape, and the slope alpha of the luminosity function (LF) at these high redshifts; and (2) the far superior performance of our strategy, compared with the use of strong lensing clusters, in detecting significant samples of faint z~7-8 galaxies to derive their luminosity function and UV ionizing flux. Our recent z~7.4 NICMOS results show that wide-area IR surveys, even of GOODS-like depth, simply do not reach faint enough at z~7-9 to meet the LF and UV flux objectives. In the spirit of the HDF and the HUDF, we will waive any proprietary period, and will also deliver the reduced data to STScI. The proposed data will provide a Legacy resource of great value for a wide range of archival science investigations of galaxies at redshifts z~2-9. The data are likely to remain the deepest IR/optical images until JWST is launched, and will provide sources for spectroscopic followup by JWST, ALMA and EVLA.

WFC3/IR 11929

IR Dark Current Monitor

Analyses of ground test data showed that dark current signals are more reliably removed from science data using darks taken with the same exposure sequences as the science data, than with a single dark current image scaled by desired exposure time. Therefore, dark current images must be collected using all sample sequences that will be used in science observations. These observations will be used to monitor changes in the dark current of the WFC3-IR channel on a day-to-day basis, and to build calibration dark current ramps for each of the sample sequences to be used by GOs in Cycle 17. For each sample sequence/array size combination, a median ramp will be created and delivered to the calibration database system (CDBS).

WFC3/UV 12045

Evolution of the 2009 Single Impact on Jupiter

The 19 July 2009 impact on Jupiter captured worldwide attention, and sparked a highly successful WFC3 imaging program during SMOV, with the last Hubble image acquired on 8 August. Continuing ground-based observations have revealed significant differences between this event and the Shoemaker-Levy 9 impacts in 1994: a single impact event offers a chance to study the longer-term evolution of the impact debris field without confusion due to overlapping aerosol debris clouds, and this debris field evolved more slowly than the SL9 sites. Initial analysis of our first data set reveals possible curved streamlines that correspond to no known tropospheric vortex. To constrain the stratospheric velocity field traced by the impact-generated aerosols, we request 10-hour separated data (a temporal sampling rate which we could not obtain during SMOV) that are crucial for tracking coherent albedo features. We also requested (but were not granted) a single orbit of high-resolution near-infrared images. These data would have provided the sharpest visible and near-infrared images of the site, providing context for the ongoing worldwide campaign of lower-resolution ground-based observations.

WFC3/UV 11588

Galaxy-Scale Strong Lenses from the CFHTLS Survey

We aim to investigate the origin and evolution of early-type galaxies using gravitational lensing, modeling the mass profiles of objects over a wide range of redshifts. The low redshift (z = 0.2) sample is already in place following the successful HST SLACS survey; we now propose to build up and analyze a sample of comparable size (~50 systems) at high redshift (0.4 < z < 0.9) using HST WFC3 Snapshot observations of lens systems identified by the SL2S collaboration in the CFHT legacy survey. WFC3/UV 11657 The Population of Compact Planetary Nebulae in the Galactic Disk We propose to secure narrow- and broad-band images of compact planetary nebulae (PNe) in the Galactic Disk to study the missing link of the early phases of post-AGB evolution. Ejected AGB envelopes become PNe when the gas is ionized. PNe expand, and, when large enough, can be studied in detail from the ground. In the interim, only the HST capabilities can resolve their size, morphology, and central stars. Our proposed observations will be the basis for a systematic study of the onset of morphology. Dust properties of the proposed targets will be available through approved Spitzer/IRS spectra, and so will the abundances of the alpha- elements. We will be able thus to explore the interconnection of morphology, dust grains, stellar evolution, and populations. The target selection is suitable to explore the nebular and stellar properties across the galactic disk, and to set constraints on the galactic evolutionary models through the analysis of metallicity and population gradients. WFC3/UV 11905 WFC3 UVIS CCD Daily Monitor The behavior of the WFC3 UVIS CCD will be monitored daily with a set of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K subarray biases are acquired at less frequent intervals throughout the cycle to support subarray science observations. The internals from this proposal, along with those from the anneal procedure (Proposal 11909), will be used to generate the necessary superbias and superdark reference files for the calibration pipeline (CDBS). FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: 12065 – SIC&DH safed during LOS at 307/18:37:42z due to failure of SIC&DH Pit toggle test. COMPLETED OPS REQUEST: 18743-1 – Recover NICMOS to SAA Operate with FPA Temp Sensor (skip steps 3-5) @ 307/1538z
18735-1 – Adjust NCS CPL Setpoint @ 307/1550z, 307/1714z
18744-1 – Recover SICDH @ 307/2238z
18745-0 – Execute Safemode Recovery @ 307/2242z
18749-3 – Recover SICDH to normal mode @ 308/0010z
18747-0 – Re-enable ACR to Reset S1 MEB @ 308/0012z
18746-0 – Re-enable NSSC-1 HV Protect Function @ 308/0020z
18751-0 – Recover WFC3 to Operate @ 308/0050z
18750-0 – Recover the ESMNCSCPL PCE @ 308/0127z


FGS GSAcq 10 10
FGS REAcq 06 06
OBAD with Maneuver 05 05


At 307/15:37z, Ops Request 18743 was successfully completed to transition NICMOS from safe to SAA Operate.

At 307/19:10:17z, AOS telemetry indicates the SIC&DH safed during LOS.

Ops request 18744 to power cycle the CDH2, perform SI memory dumps and safe all the payload elements was successfully completed at 307/22:38z.

Ops request 18749-3 to recovery CDH2 to normal was successfully completed at 308/00:08. Ops request 18746 to re-enable NSSC-1 HV protection was completed at 308/00:21. WFC3 was recovered to operate without power cycling the TECs at 308/00:50 via ops request 18751.

Ops Request 18750 was successfully completed at 308/01:30 UTC, recovering the ESM up to its Operate mode, placing the NCS CPL in its Standby state at a reservoir setpoint of -34 degC, and re-enabling the PCE to restore visibility into various NCC telemetry.

SpaceRef staff editor.