Status Report

Hubble Space Telescope Daily Report #2914 16 Jul 2001

By SpaceRef Editor

July 16, 2001

Filed under Hubble Space Telescope, Space Telescope Science Institute, US

HUBBLE SPACE TELESCOPE

DAILY REPORT #2914

PERIOD COVERED: 0000Z (UTC) 07/13/01 – 0000Z (UTC) 07/16/01

Daily Status Report as of 197/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 Completed Eight Sets of WF/PC-2 8828 (Cycle 9 Supplemental Darks pt3/3)

The WF/PC-2 was used to obtain three dark frames every day to
provide data for monitoring and characterizing the evolution of hot
pixels. The proposal completed with no reported problems.

1.2 Completed Three Sets of WF/PC-2/STIS/CCD 9266 (STIS Recovery
Proposal 2)

The WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD) were
used to measure the STIS aperture position after the switch to Side 2
electronics. The lack of CCD temperature control on Side 2 implies that a
check of position and plate scale stability should be obtained. The field
in 47 Tuc previously observed provides a well calibrated reference for
which any deviations in x, y position and plate scale can be accurately
tracked. The sensitivity in both CLEAR and Longpass filters will also be
verified. There will be 3 one orbit visits separated by about 5 orbits
each, intended to sample different thermal environments. Exposures will be
taken in parallel with WFPC2 to allow precise tracking of results with
respect to previous nominal behavior. There were no reported problems.

1.3 Completed Four Sets of STIS/CCD 8864 (CCD Dark Monitor-Part 2)

The Space Telescope Imaging Spectrograph (CCD) was used to monitor
the darks for the CCD. The proposal completed nominally.

1.4 Completed Three Sets of WF/PC-2 9235 (The Asymmetric Atmosphere of
Uranus)

The WF/PC-2 was used to image Uranus as the planet plunges toward
equinox in 2007. Recent HST images during this unique epoch have revealed:
{i} strongly wavelength-dependent latitudinal structure, {ii} the presence
of numerous visible-wavelength cloud features in the northern hemisphere,
{iii} zonal winds which may deviate from the smooth profile implied by the
Voyager observations in 1986, and, {iv} in the near-IR, discrete features
northward of +25 degs that have the highest contrast ever seen for a
Uranian. Specific scientific issues that were addressed with these
observations are: whether the northern features are indicative of intrinsic
change or result simply from a change of viewing angle; the shape and
stability of the zonal wind profile; and the source of the as-yet
unexplained variations of the atmospheric reflectivity. No problems were
reported.

1.5 Completed Three Sets of STIS/CCD 8865 (Bias Monitor-Part 2)

The Space Telescope Imaging Spectrograph (CCD) was used 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. The proposal completed with no anomalous activity.

1.6 Completed Three Sets of WF/PC-2 8632 (A UV Atlas of Nearby Galaxies)

The WF/PC-2 was used to perform a snapshot survey of local galaxies
at UV wavelengths with the F300W filter. The aim of the project is to
build a reference UV Atlas of normal galaxies, whose optical images are
well known, with the highest possible degree of information, covering all
the morphological types and luminosity classes. The proposal completed
normally.

1.7 Completed WF/PC-2 8597 (The Fueling of Active Nuclei: Why are
Active Galaxies Active?)

The WF/PC-2 was used to investigate the accretion onto massive
black holes that are believed to be the energy source for AGN. However,
evidence for black holes in quiescent galaxies has also been reported. Why
are these galaxies inactive? One possibility is that active galaxies are
better at providing fuel to the nuclear region than quiescent
galaxies. Other possible fueling mechanisms such as “bars-within-bars”
or nuclear spirals cannot be investigated from the ground because they are
relatively small features in the ISM. The observations were completed as
planned.

1.8 Completed WF/PC-2 9160 (Disks and Envelopes of Nearby Nebulous
Young Stellar Objects: A Snapshot Survey)

The WF/PC-2 was used to perform a snapshot survey of nearby
nebulous young stellar objects to study the detailed morphology of the
their disks and envelopes and probe the effect of inclination on the
infrared spectral energy distribution of disk/envelope systems. The
proposal completed as planned.

1.9 Completed Four Sets of WF/PC-2 9244 (POMS Test Proposal: WFII
Parallel Archive Proposal Continuation)

The WF/PC-2 was used to perform a generic target version of the
Archival Pure Parallel program. The program will be used to take parallel
images of random areas of the sky, following the recommendations of the
Parallels Working Group. The observations completed with no anomalous
activity.

1.10 Completed FGS/1 9168 (The Distances to AM CVn Stars)

Fine Guidance Sensor (FGS) #1 was used to determine the parallaxes
and proper motions of the five brightest of the seven known AM CVn systems
using the HST FGSs. AM CVn systems are binaries where mass is transferred
from a completely hydrogen-deficient, degenerate mass donor to a white
dwarf primary through a helium accretion disk. A better understanding of
these systems is crucial for a number of reasons: (1) to study the late
stages of binary evolution, (2) to study the effect of chemical composition
on the physics of accretion discs, (3) to estimate their contribution to
the Supernovae Ia rate, and (4) to estimate their contribution to the
gravitational radiation background. All observations completed with no
reported problems.

1.11 Completed WF/PC-2 8698 (Identification of the Galaxy’s Missing Mass)

The WF/PC-2 was used to observe the nature of dark matter that is
one of the key astrophysical questions of the day. The existence of dark
matter and its dynamical dominance in the outer parts of our Galaxy and
spiral galaxies with flat rotation curves is well established. The MACHO
project has identified ~half of the Milky Way’s dark matter with stellar
objects of ~0.5 M_sun, probably white dwarfs. But the location of the
microlensing in the halo is disputed. Several have detected two candidate
halo white dwarfs of L/L_sun ~ 10^-5 in the Hubble Deep Field with 25 +/- 5
mas/year proper motions. The observations completed with no reported problems.

1.12 Completed Two Sets of STIS/CCD 9265
(Wavelength-Dependent-Sensitivity Of CCD At Different Temperatures)

The Space Telescope Imaging Spectrograph (CCD) was used to monitor
the wavelength-dependent-sensitivity of CCD at different temperatures. The
proposals uses standard stars at extreme beta-angles to maximize the
expected range of CCD temperatures. In addition, the proposals use the SAA
constraints to further enhance the range of CCD operating
temperatures. There were no reported problems.

1.13 Completed WF/PC-2 8820 (Wavelength Stability of Narrow Band and
Linear Ramp Filters)

The WF/PC-2 was used to verify the mapping of wavelength as a
function of CCD position on linear ramp filters and to check for changes in
central wavelengths of the narrow band filters. The proposal completed
nominally.

1.14 Completed WF/PC-2 8825 (Decontaminations and Associated
Observations 4/4)

The WF/PC-2 was used to perform the monthly decontaminations
(decons). Also included are instrument monitors tied to decons:
photometric stability check, focus monitor, pre- and post-decon internals
{bias, intflats, kspots, & darks}, UV throughput check, VISFLAT sweep, and
internal UV flat check. The proposal completed with no reported problems.

1.15 Completed WF/PC-2 8599 (A Census of Nuclear Star Clusters in
Late-Type Spiral Galaxies)

The WF/PC-2 was used to conduct an I-band snapshot survey of a
well-defined sample of nearby, face-on spiral galaxies of type Scd or
later. The proposal completed nominally.

1.16 Completed STIS/CCD 9106 (The Biggest Black Holes)

The Space Telescope Imaging Spectrograph (CCD) was used to perform
searches for supermassive black holes in galaxy centers that have led to
the discoveries that {1} most or all hot galaxies contain massive dark
objects at their centers, presumably black holes; and {2} there is a tight
correlation between the black-hole mass and the luminosity-weighted
velocity dispersion of the hot component of the galaxy. This remarkable
relationship suggests a strong link between black-hole formation, AGN
activity, and galaxy formation, and once it is understood this link should
advance our understanding of all three processes. There were no reported
problems.

1.17 Completed WF/PC-2 8701 (Multiplicity among Very-Low Mass Stars and
Brown Dwarfs in Alpha Persei and the Pleiades)

The WF/PC-2 was used to observe open clusters which provide
excellent hunting grounds for brown dwarf {BD} searches. The AlphaPer and
Pleiades clusters are young, nearby and have low extinction. They are
considered to be the best-suited places to study the Substellar Mass. A
dozen of cool faint AlphaPer and Pleiades members have been confirmed as
“bona-fide” BDs with the lithium test. By comparison with those, about
60 very good cluster BD candidates are currently known. The Pleiades SMF
obtained using the most recent deep large CCD surveys indicates that BDs
are quite numerous but do not make a significant contribution to the total
cluster mass. The observations completed with no reported problems.

1.18 Completed WF/PC-2 8581 (A Search For Low-Mass Companions To
Ultracool Dwarfs)

The WF/PC-2 was used to search for very low-mass {VLM} companions
to a complete sample of 120 late-M and L dwarfs, drawn mainly from the
2MASS and SDSS surveys. The primary goal is to determine the multiplicity
of M less than 0.1 M_odot dwarfs. In particular, we aim to identify binary systems
suitable for long-term astrometric monitoring and mass measurement, and
systems with cool, sub-1000K companions. The proposal completed with no
reported problems.

1.19 Completed WF/PC-2 9043 (Cepheid Distances to Early-type Galaxies)

The WF/PC-2 was used to continue observations in the HST Key
Project on the Extragalactic Distance Scale and the HST project on the
“Calibration of Nearby Type Ia Supernovae” that have greatly improved our
knowledge of the Hubble Constant by providing a solid zero point for the
Tully- Fisher {TF} relation and Type Ia Supernovae {SNIa}. However, severe
inconsistencies remain for distance estimators to early-type galaxies such
as surface brightness fluctuations {SBF}, the planetary nebula luminosity
function {PNLF}, the fundamental plane {FP}, and the globular cluster
luminosity function {GCLF}. As a result, the distance to the Virgo cluster
core remains uncertain by as much as 20 determination is directly affected
by a lingering 0.1 mag {5 uncertainty in the photometric calibration of the
WFPC2. Resolving these issues is essential not only to firm up the
extragalactic distance scale, but also to understand the mass and velocity
structure of the local universe. SBF in particular is emerging as the
method of choice for mapping local velocity fields to 10, 000 kms because
it offers an order of magnitude less Malmquist bias than TF, and SNIa are
too rare to study large scale flows effectively. This project will tighten
the photometric calibration of the WFPC2, and provide a solid Cepheid
calibration for SBF and PNLF. The observations completed nominally.

1.20 Completed WF/PC-2 8602 (A Snapshot Survey of the Sites of Recent,
Nearby Supernovae)

The WF/PC-2 was used to conduct a snapshot survey in V and I of the
sites of the nearby SNe, which have precisely known positions, to obtain
high-resolution information on their local environment. The proposal
completed with no reported problems.

1.21 Completed Two Sets of WF/PC-2 9149 (The Nature Of The Most
Luminous Star- Forming Galaxies In The Redshift Range 0.4 To 1.5)

The WF/PC-2 was used to perform additional ISO deep surveys that have
previously uncovered a population of galaxies which are making stars at the
fantastic rate of greater than 100 M_odotyr^-1 in the redshift range from 0.4 to
1.5. However this population evolves rapidly and luminous star-forming
galaxies are 5 to 10 times more numerous at z=1 than today. Combination of
ISO data with radio {VLA}, sub-mm {SCUBA} and optical data shows that they
contribute a major fraction {30-50$ representing only a few percent of the
field galaxy population. HST imaging of a small subsample of these
galaxies indicates that most of them are disks showing disrupted
morphologies or possessing companions, emphasizing the role of merging in
their star formation history. The proposal completed without incident.

1.22 Completed WF/PC-2 8683 (Imaging Of Brightest Cluster Galaxies: The
High End Of The Black Hole Mass Distribution)

The WF/PC-2 was used to make kinematic black hole detections in
galaxies to decide whether they indicate that the mass correlates with both
optical luminosity and radio power. The observation completed with no
reported problems.

1.23 Completed Two Sets of FGS/1 9034 (The Masses and Luminosities of
Population II Stars)

Fine Guidance Sensor #1 was used to observe the mass-luminosity
relation {MLR} of Population II stars of which very little is currently
known. With the advent of the Hipparcos Catalogue, improved distances to
many spectroscopic binaries known to be Pop II systems are now
available. After surveying the literature and making reasonable estimates
of the secondary masses, we find 13 systems whose minimum separation should
be larger than the resolution limit of FGS #1. The observations completed
nominally.

1.24 Completed WF/PC-2 9050 (Outflow Collimation in Bipolar Symbiotic
Nebulae)

The WF/PC-2 was used to observe flow collimation in evolved stars
that is neither expected nor understood. Classical theories of stellar
evolution do not predict and cannot explain this bipolarity. More exotic
concepts {binary interactions, spun-up atmospheres, poloidal or toroidal
magnetized winds} have been proposed, but observations are yet to verify or
falsify any of their predictions. This proposal will probe the
near-nuclear morphology and kinematics of four bright, low-extinction
targets whose large-scale structure is highly bipolar. The goal is to
provide a detailed description of the circumnuclear outflows, to uncover
the physical structure and nature of the collimator, and to evaluate the
speculative collimation mechanisms. The bright nucleus has hampered
efforts to explore the nebular collimators that lie close to the star, so
we’ll use STIS to disperse the nuclear light and, thus, to avoid its
glare. A secondary goal is to obtain second-epoch WFPC2 images of all
targets. There were no reported problems.

1.25 Completed WF/PC-2 9045 (The Relationship Between Radio Luminosity
and Radio-Loud AGN Host Galaxy Properties)

The WF/PC-2 was used to determine the relationship between the
properties of the host galaxies of radio-loud AGN and their radio
luminosities. Previous studies in this area with the HST have concentrated
on the 3C sample which shows a tight correlation between luminosity and
redshift, such that evolutionary effects cannot be distinguished from those
depending upon radio luminosity. Our sample of 46 radio galaxies at z ~
0.5 comes from four complete, low-frequency-selected samples of radio
sources with differing flux limits. Thus the total sample spans an
unprecedented three orders of magnitude in radio luminosity at a fixed
redshift interval. The proposal completed with no reported problems.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 28

Successful: 28

Scheduled Re-acquisitions: 20

Successful: 20

2.2 FHST Updates:

Scheduled: 61

Successful: 61

2.3 Operations Notes:

Using ROP SR-1A, the SSR EDAC error counter was cleared seven times.

The engineering status buffer limits were adjusted once per ROP DF-18A.