Status Report

NASA Hubble Space Telescope Daily Report #4779

By SpaceRef Editor
January 29, 2009
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HUBBLE SPACE TELESCOPE DAILY REPORT #4779

Continuing to collect World Class Science

PERIOD COVERED: 5am January 27 – 5am January 28, 2009 (DOY 027/1000z-028/1000z)

OBSERVATIONS SCHEDULED

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 11566

Imaging Saturn’s Equinoctal Auroras

Auroral emissions provide an indispensable diagnostic tool for the energetic processes occurring in planetary magnetospheres. In 2009 Saturn will reach equinox for the first time since the advent of high-sensitivity planetary ultraviolet (UV) auroral imaging, offering a unique, transient opportunity to observe both polar auroral regions simultaneously. The observations proposed here will not only provide the best images to date of Saturn’s northern auroras, they will address three fundamental issues: (1) Are Saturn’s auroras similar in the north and south? This will reveal the nature of the processes that cause the northern auroras, and verify the multipole nature of Saturns internal magnetic field. (2) Is the location of the northern auroral emission symmetric with to the south? This will indicate why the southern auroral oval is displaced a few degrees toward midnight from the spin pole. It will also reveal whether the oscillation observed in the location of the southern auroral oval is similarly observed in the north, illuminating the nature of near-planetary period oscillations observed throughout the magnetosphere and potentially providing a value for the elusive rotation period of the deep interior. (3) What is the influence of equinox on the magnetosphere? The unique orientation of the planetary spin axis at equinox will reveal whether the auroras are influenced by the direction of the interplanetary magnetic field, and whether the Sun’s effect on Saturn’s magnetosphere changes throughout the planet’s seasons. The Hubble Space Telescope is the only instrument capable of providing global instantaneous coverage of Saturn’s UV auroras, and since Saturn’s orbital period is ~30 years, Cycle 17 is the only opportunity to make these observations.

FGS 11943/11944

Binaries at the Extremes of the H-R Diagram

We propose to use HST/Fine Guidance Sensor 1r to survey for binaries among some of the most massive, least massive, and oldest stars in our part of the Galaxy. FGS allows us to spatially resolve binary systems that are too faint for ground-based, speckle or optical long baseline interferometry, and too close to resolve with AO. We propose a SNAP-style program of single orbit FGS TRANS mode observations of very massive stars in the cluster NGC 3603, luminous blue variables, nearby low mass main sequence stars, cool subdwarf stars, and white dwarfs. These observations will help us to (1) identify systems suitable for follow up studies for mass determination, (2) study the role of binaries in stellar birth and in advanced evolutionary states, (3) explore the fundamental properties of stars near the main sequence-brown dwarf boundary, (4) understand the role of binaries for X-ray bright systems, (5) find binaries among ancient and nearby subdwarf stars, and (6) help calibrate the white dwarf mass – radius relation.

WFPC2 11103

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful SNAPshot survey of a sample of 125 very X-ray luminous clusters in the redshift range 0.3-0.7. As demonstrated by the 25 snapshots obtained so far in Cycle14 and Cycle15 these systems frequently exhibit strong gravitational lensing as well as spectacular examples of violent galaxy interactions. The proposed observations will provide important constraints on the cluster mass distributions, the physical nature of galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set of optically bright, lensed galaxies for further 8-10m spectroscopy. All of our primary science goals require only the detection and characterization of high-surface-brightness features and are thus achievable even at the reduced sensitivity of WFPC2. Because of their high redshift and thus compact angular scale our target clusters are less adversely affected by the smaller field of view of WFPC2 than more nearby systems. Acknowledging the broad community interest in this sample we waive our data rights for these observations.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11650 – GSAcq (1,2,2) scheduled from 027/12:44:20 – 027/12:51:27 failed at 12:48:20 due to QF1STOPF and QSTOP flags on FGS-1.

Observations affected: WFPC 38 – 41, Proposal# 10877.

COMPLETED OPS REQUEST:

18394-3 – Uplink new FHST Alignments

COMPLETED OPS NOTES: (None)

                          SCHEDULED      SUCCESSFUL
FGS GSacq                12                   11
FGS REacq                00                   00
OBAD with Maneuver       24                   24

SIGNIFICANT EVENTS:

Flash Reports:

Ops Request 18394 was successfully executed approximately 027/13:55 – 13:52 to update the T2G Database for the FHST Alignments.

SpaceRef staff editor.