Hubble Space Telescope Daily Report #2883 – 31 May 2001

HUBBLE SPACE TELESCOPE

DAILY REPORT #2883

PERIOD COVERED: 0000Z (UTC) 05/30/01 – 0000Z (UTC) 05/31/01

Daily Status Report as of 151/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 Completed 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 9132 (Resolving the Puzzling Dark Mass
Concentration in Abell 1942)

The WF/PC-2 was used to make observations that will significantly
improve the precision and localized position of a puzzling
signal. Independent lensing analyses of two optical datasets reveal a
striking mass concentration south of the cluster center with no obvious
visible source counterpart. Placed at the redshift of the cluster the
implied mass would be M{0.5h^-1mboxMpc} >= 1* 10^14M_odot. The absence of
an obvious excess of faint sources in suitably deep infrared images makes
it highly unlikely that such a strong lensing signal can be caused by a
projected background cluster of galaxies. No anomalous activity was
reported.

1.3 Completed 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.

1.4 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.

1.5 Completed Two Sets of 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.

1.6 Completed Two Sets of 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 < 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.

1.7 Completed WF/PC-2 8677 (Extragalactic Novae: the Maximum Magnitude
– Rate of Decline Relation in NGC 4472)

The WF/PC-2 was used to accomplish two goals: {1} to provide the
first homogeneous observational constraints on theoretical models for novae
outbursts; and {2} to assess the reliability of novae as standard candles
by using WFPC2 to collect well sampled light curves for 20-50 novae in the
supergiant elliptical galaxy NGC 4472, the brightest galaxy within 30
Mpc. Both the length of the observing window and the temporal sampling of
the observations are specifically designed to ensure that the novae peak
magnitudes and decline rates are measured accurately. These data will be
used to construct the first `Maximum Magnitude versus Rate of Decline’
{MMRD} relation for a galaxy beyond the Local Group. This relation is not
only a potentially powerful standard candle, but its shape and dispersion
are directly linked to physical parameters which govern the physics of
novae outbursts such as the white dwarf mass, temperature and mass
accretion rate. The proposal completed with no reported problems.

1.8 Completed WF/PC-2 8601 (A Snapshot Survey of Probable Nearby
Galaxies)

The WF/PC-2 was used to continue the very successful snapshot
survey in order to use the high spatial resolution of HST to determine
whether selected galaxies are nearby on the basis of resolution into stars,
and the magnitudes and colors of the brightest stars. There were no
reported problems.

1.9 Completed Two 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.

1.10 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.

1.11 Completed FGS/1 9240 (Astrometric Mass Determination of an
Extrasolar Planet Candidate)

Fine Guidance Sensor-1R was used to perform astrometric
observations that will allow a quick measure of the sky-plane motion of 55
Cancri, a G star with an Msin{i} = 0.9 MJ radial velocity companion with a
14 day period. By using 7 pairs of visits, where each visit within a pair
has the same parallax factor, we will be able to accurately determine the
stars’s proper motion. The reflex motion of the star, due to its orbit
about the star-companion barycenter, will manifest itself as a systematic
residual to the measured proper motion if the companion is sufficiently
massive. There were no reported problems.

1.12 Completed Three 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.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 16

Successful: 16

Per HSTAR 8329, the acquisition at 157/071141Z defaulted to fine
lock on FGS-2 only when the scan step limit was exceeded on FGS-1. One
proposal, WF/PC-2 9133 which occurs during the period of the next report,
may have been affected.

Scheduled Re-acquisitions: 2

Successful: 2

2.2 FHST Updates:

Scheduled: 35

Successful: 35

2.3 Operations Notes:

The STIS instrument remains in safe mode.

The SSR EDAC error counter was cleared twice per ROP SR-1A.

The NSSC-1 status buffer was dumped and reset at 150/0949Z, using
ROP NS-3.

3.0 SIGNIFICANT FORTHCOMING EVENTS:

Continuation of normal science observations and calibrations.