Status Report

NASA Hubble Space Telescope Daily Report # 3648

By SpaceRef Editor
July 7, 2004
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science


PERIOD COVERED: DOY 188 (partial- due to safemode entry @188:16:28:48z)


ACS/HRC 10050

ACS Earth Flats

High signal sky flats will be obtained by observing the bright Earth
with the HRC and WFC. These observations will be used to verify the
accuracy of the flats currently used by the pipeline and will provide
a comparison with flats derived via other techniques: L-flats from
stellar observations, sky flats from stacked GO observations, and
internal flats using the calibration lamps. Weekly coronagraphic
monitoring is required to assess the changing position of the spots.

ACS/HRC 10272

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 environment 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
their 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. Use of ACS rather than WFPC2 will make our snapshot
survey even more valuable than our Cycle 9 survey. This Proposal is
complementary to our Cycle 13 archival proposal, in which we outline a
plan for using existing HST images to glean information about SN


CCD Daily Monitor

This program consists of basic tests to monitor, the read noise, the
development of hot pixels and test for any source of noise in ACS CCD
detectors. This programme will be executed once a day for the entire
lifetime of ACS.

ACS/WFC 10229

Space Motions for the Draco and Sextans Dwarf Spheroidal Galaxies

We will use the powerful astrometric capabilities of HST to measure
proper motions for the Draco and Sextans dwarf spheroidal galaxies
that will yield tangential velocities accurate to about 30 km/s. These
two galaxies are the last inside a galactocentric radius of 200~kpc
without measured proper motions. Knowing their orbits is critical for
our understanding of the low-luminosity satellites of the Milky Way.
In particular they are critical for understanding why Ursa Minor has
survived tidal disruption on its plunging orbit and how Carina formed
a large intermediate-age stellar population despite its small mass.

ACS/WFC 9777

The environment of QSOs at the reionization epoch

Our goal is to elucidate the role of QSOs and galaxies at the tail end
of reionization by identifying z~6 galaxies near SDSS z>6 QSOs through
their red i-z colors. A similar technique was used by the SDSS to
identify the QSOs themselves. Based on our understanding of the growth
of structure in the Universe and on observations at z ~= 4, we expect
z~6 QSOs to be associated to the high peaks in the matter density
distribution. Therefore, they should be surrounded by an excess of
objects – as compared to random fields – unless the ionizing radiation
from the QSOs themselves is inhibiting star formation. We will
concentrate on 5 QSOs discovered by the SDSS at z>~6 and spend 7
orbits with ACS on each of the QSO fields {2.5 in F775W – i – and 4.5
in F850LP – z}, for a total of 35 orbits. The exposures are optimized
for the detection of objects with i-z> 2. The reference properties of
the field population will be provided by GOODS which is reaching the
same depth. The proposed observations will be capable of revealing the
dominant effect between galaxy suppression by the QSO ionizing flux
and number density excess due to clustering. We will test whether the
balance between suppression and enhancement evolves with redshift. We
will also be able to estimate for these fields the ionizing continuum
contribution by galaxies and compare it with that of the QSOs. If
galaxies are found to be comparably important to QSOs in these
selected fields, the idea that hydrogen reionization is primarily due
to stellar radiation would be significantly strengthened.

NIC/NIC3 10266

Origins of the Highly Ionized Gas toward the X-ray Bright BL Lac
Object Mrk 421

The X-ray bright BL Lac object Mrk 421 is one of the small number of
extragalactic objects for which it is possible to study the highly
ionized gas in the ISM and Local Group using the full diagnostic power
of UV, far-UV and X-ray observatories. High quality far-UV
observations of OVI and other ions have been obtained by FUSE, whereas
Chandra and XMM-Newton have provided X-ray measurements of extremely
strong OVII and OVIII absorption at redshift zero. It has been
proposed that the OVI, OVII, and OVIII originate together in the
warm-hot intergalactic medium, of the kind predicted by numerical
simulations to contain a substantial fraction of the baryons at z=0.
However, the properties of the high-ion absorption are also consistent
with an origin in an extended Galactic Corona. Data for other species
such as SiIII, SiIV, and CIV will be essential to determine whether or
not a Local Group WHIM filament has been detected. These species are
not expected to be seen in a hot {T > 10^6 K} medium and their
detection at the same velocity as OVI would suggest that the OVI
samples a different phase of the gas than the OVII and OVIII. We
propose to obtain a high quality 7 km/s resolution STIS UV spectrum of
Mrk 421 from 1150 to 1700 A. The STIS measurements of CII, CIV, SiIII,
SiIV, and other species will allow us to evaluate the ionization
conditions in the absorbing gas in the Galactic thick disk and in an
anomalous high positive velocity absorption wing currently only traced
by OVI and CIII. The ionic ratios among these species will provide
critical tests of the ionization mechanisms affecting the OVI

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration – CR Persistence Part 4

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.

STIS/CCD 10018

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

STIS/CCD 10020

CCD Bias Monitor – Part 2

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.

WFPC2 10071

WFPC2 CYCLE 12 Supplemental Darks Part 3/3

This dark calibration program obtains 3 dark frames every day to
provide data for monitoring and characterizing the evolution of hot


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

HSTAR 9470: After completing Ops Request 17208 RGA Scale
Factor/Alignment and Bias Offset, spacecraft entered ZGSP safemode @
188/16:28:48Z. Under investigation.


  • 17208-0 RGA Scale Factor/Alignment & Bias Offset Calibration @188/1629z
  • 17210-0 Dump ESBs @ 188/2016z
  • 17214-0 Full Memory Dump @ 188/2122z
  • 17211-0 GEA’s Turn On After Safemode @ 188/2127z
  • 17209-1 Transition NICMOS to SAAOPER @ 188/2130z


                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq              01                           01
FGS REacq              03                           03
FHST Update           02                           02


Rerun of TGS Target Reacquisition test was executed from SMS
187/03:38Z – 05:27Z. OTA SEs monitored the test and confirmed there
were no error flags seen during either of the acquisitions for the
test. OTA SEs will be analyzing the quaternion data and will present
the results at a later time.

Uplinked RGA Scale Factor/Alignment and Bias Offset @ 188/16:29Z (OR
17208 with attached script, ROP DF-15A, COP 3.52, and ROP DF-01A).
Following a memory dump of the RGA Scale Factor/Alignment Table, 107
miscompares were noted in the compare best estimate verification
process. Sixty five seconds after initiating a T2 slew @
188/16:27:42Z, vehicle entered Zero Gyro Sun Point (ZGSP) Safemode.
HST entered ZGSP Safemode @ 188/16:28:47Z after accumulating 40 Gyro
Disparity counts, causing the Two Gyro configuration safemode test to
fail. See HSTAR 9470.

HST entered Zero Gyro Sun Point (ZGSP) Safemode @ 188/16:28:47Z after
accumulating 40 Gyro Disparity counts, causing the Two Gyro
configuration safemode test to fail. See HSTAR 9470.

At the time of issuance of this report, the safemode recovery
procedures have begun, with the Health & Safety (H&S) load anticipated
to begin at 190:04:00z. The 18-hour H&S load will permit generation
and review of the science intercept Science Mission Specification

SpaceRef staff editor.