Status Report

Hubble Space Telescope Daily Report #2900 25 June 2001

By SpaceRef Editor

June 25, 2001

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

HUBBLE SPACE TELESCOPE

DAILY REPORT #2900

PERIOD COVERED: 0000Z (UTC) 06/22/01 – 0000Z (UTC) 06/25/01

Daily Status Report as of 176/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 Completed Six 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 WF/PC-2 8177 (Investigating Type Ia Supernovae and an
Accelerating Universe)

The WF/PC-2 was used to obtain rest frame U and B photometry for
four z~ 0.85 Supernova (SN) Ia. These observations will be coupled to
ground-based rest frame V photometry and spectra. These data, combined
with previous samples, will extend the D_L vs. z diagram for SN Ia to
z~0.85, and allow us to discriminate the redshift dependence of supernova
magnitudes in an accelerating Universe from that expected to result from
systematic effects such as age of the stellar population, chemical
evolution, a drift in the properties of dust, and weak gravitational
lensing. The proposal completed with no reported problems.

1.3 Completed WF/PC-2 9085 (Measuring The Masses Of High-Z Quasar Host
Galaxies)

The WF/PC-2 was used to investigate the close link between
black-hole mass and spheroid mass in both quiescent and active galaxies in
the local universe. Consequently black-hole and spheroid formation/growth
are now viewed as intimately related processes, and establishing the mass
of quasar host galaxies as a function of redshift is now seen as a key
measurement in observational cosmology. From the Cycle 7 NICMOS program,
the best estimate to date of the mass evolution of the hosts of both
radio-quiet and radio-loud quasars out to z ~eq 2 has been derived. Under
the assumption of passive stellar-population evolution our results are
consistent with the black-hole/spheroid population being unchanged out to z
~eq 2. However, the crucial assumption of passive evolution needs to be
tested. All observations competed nominally.

1.4 Completed Two Sets of 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.

1.5 Completed Three Sets of WF/PC-2 8583 (Imaging Snapshots of Asteroids)

The WF/PC-2 was used to obtain images of the fifty largest main
belt asteroids that have favorable apparitions during cycle 9. The images
will be searched for companion bodies, as well as mineralogical variegation
on the resolved main bodies. There were no reported problems.

1.6 Completed Two Sets of 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.

1.7 Completed Two Sets of WF/PC-2 8592 (Pixel Microlensing of M87)

The WF/PC-2 was used to undertake a pixel microlensing study of M87
in order to: 1} probe the lower end of the M87 IMF via star-star lensing,
2} possibly obtain the first evidence of Massive Compact Objects (MACHOs)
in the halo of a galaxy other than our own, and 3} search for intracluster
MACHOs. The proposal completed nominally.

1.8 Completed WF/PC-2 9122 (The Physics of X-Ray/Optical Jets)

The WF/PC-2 was used to perform an important new probe of the
physics of large-scale radio jets that is possible with the discovery of
resolved X-ray/optical jets. The optical emission comes from high energy
electrons, which have short radiative lifetimes and so pinpoint particle
acceleration sites. Spectral energy distributions of knots in two jets
suggest the X-rays come from lower energy electrons inverse-Compton
scattering the {beamed} cosmic microwave background. This requires the jet
to be still relativistic on kiloparsec scales {out to ~1 Mpc for the
high-redshift jets.}. This model robustly constrains both the bulk
relativistic speed and the minimum electron energy in the jet, which
together determine the total jet power. To probe jet energetics and
physics generally, and to test the “Compton/CMB” interpretation
specifically, it is proposed to execute deep HST imaging of three
X-ray/optical jets {PKS 1127–145, PKS 0637–752, 3C 371} and one optical
jet {PKS 2201+044}, plus Chandra observations of the latter two. The
proposal completed with no reported problems.

1.9 Completed Two 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.

1.10 Completed Three Sets of WF/PC-2 9086 (Investigating the Formation
History of Spiral Galaxy Halos)

The WF/PC-2 was used to make observations in order to constrain the
origin of spiral galaxy halos by studying stellar populations near the tip
of the red giant branch. This will be the first systematic study of this
population in external galaxies and will quadruple the sample of normal
spiral galaxies for which the halo metallicity distribution function is
measured. This larger sample will permit study of the relationship between
the bulge, disk, and halo components and between halos and globular
systems. Such correlations will in turn provide indications as to whether
the halo, bulge, and globular cluster systems built up nearly
simultaneously in the early universe or were accreted over time through
different kinds of merging events. The proposal completed nominally.

1.11 Completed WF/PC-2 9107 (The Fundamental Plane for Nuclear Black Holes)

The WF/PC-2 was used to conduct more in-depth searches for
supermassive black holes in galaxy centers. Previous work has led to the
discoveries that {1} most or all hot galaxies contain massive dark objects
at their centers, presumably black holes; {2} there is a remarkably tight
correlation between the black-hole mass and the luminosity-weighted
velocity dispersion of the hot component of the galaxy. This mbh-Sigma
relation has a scatter which is <0.3 dex in mbh and consistent with zero. This 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. The goal of this proposal is to investigate the scatter in the mbh-Sigma relation and the role of possible second parameters, by examining a sample of galaxies at fixed velocity dispersion Sigma=200+/- 20 kms. This approach decouples the effects of a second parameter from uncertainties in the shape of the mbh-Sigma relation, and minimizes spurious correlations because all of the galaxies will be studied using the same well-tested observational and modeling techniques. No anomalous activity occurred.

1.12 Completed WF/PC-2 9267 (Supernova Search)

The WF/PC-2 was used to search for high-redshift supernovae in
GO-observed fields, taking advantage of good first-epoch observations and
of the scheduling opportunities available because STIS is not currently
observing. No anomalous activity was reported.

1.13 Completed WF/PC-2 8773 (Expansion Parallax Distances to Planetary
Nebulae)

The WF/PC-2 was used to observe planetary nebulae {PNe} for which
the lack of reliable distances is especially troubling. Acquired by
generalized statistical methods in all but a handful of cases, individual
PNe distances are often uncertain by factors of two or more. The
observations completed nominally.

1.14 Completed WF/PC-2 8604 (Stellar Populations Across the Small
Magellanic Cloud (SMC) : History and Structure)

The WF/PC-2 was to be used investigate the structure and
evolutionary history of the SMC by obtaining a series of 50 three-color
snapshots of selected SMC regions. As detailed in HSTAR 8248 and 2.1, the
acquisition for this proposal failed and three observations were lost.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 19

Successful: 18

Per HSTAR 8247, the acquisition at 175/2247Z failed when the search radius
limit was exceeded. The proposal detailed in 1.14 was affected.

Scheduled Re-acquisitions: 26

Successful: 26

2.2 FHST Updates:

Scheduled: 41

Successful: 41

2.3 Operations Notes:

The STIS instrument remains in safe mode.