Status Report

Hubble Space Telescope Daily Report #2806 12 Feb 2001

By SpaceRef Editor

February 12, 2001

Filed under Space Telescope Science Institute, US

HUBBLE SPACE TELESCOPE

DAILY REPORT #2806

PERIOD COVERED: 0000Z (UTC) 02/09/01 – 0000Z (UTC) 02/12/01

Daily Status Report as of 043/0000Z

1.0 OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

1.1 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.

1.2 Completed Seven Sets of STIS/CCD 8562 (Probing the Large Scale
Structure: Cosmic Shear Observations)

The Space Telescope Imaging Spectrograph (CCD) was used to probe
the distortion of light bundles from distant galaxies, looking at the
statistical properties of the intervening inhomogeneous {dark} matter
distribution. The proposal completed nominally.

1.3 Completed Six Sets of STIS/CCD 8837 (CCD Dark Monitor-Part 1)

The Space Telescope Imaging Spectrograph (CCD) was used to monitor
the darks. The proposal completed with no reported problems.

1.4 Completed STIS/CCD/MA2 8627 (Testing Theories Of Wind/Jet
Production In YSOs)

The Space Telescope Imaging Spectrograph (CCD and MA2) was used to
test theories of jet/wind production from the accretion disks of low-mass
young stellar objects, providing new insight into disk physics, accretion
energy balance, and jet collimation. Observations of the Fe II ultraviolet
lines in absorption will probe lower-density and lower-temperature material
than optical forbidden and permitted emission lines, and thus provide
unique information on jet/wind launching and
acceleration. Velocity-resolved spectra will distinguish between X-wind
models, in which all the mass ejection occurs from the inner disk edge, and
disk wind models, where the flow originates from a much larger area of the
disk. The proposal completed nominally.

1.5 Completed Six Sets of WF/PC-2 8805 (POMS Test Proposal: WFII
Parallel Archive Proposal Continuation)

The WF/PC-2 was used to perform a generic target version of the
WFPC2 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 proposal completed with no reported
problems.

1.6 Completed Three Sets of WF/PC-2 8816 (Cycle 9 UV Earthflats)

The WF/PC-2 was used to obtain sequences of Earth streak flats to
improve the quality of pipeline flat fields for the WFPC2 UV filter set and
in order to monitor flat field stability. There were no reported problems.

1.7 Completed Three Sets of WF/PC-2 8815 (Cycle 9 Earth Flats)

The WF/PC-2 was used to monitor flatfield stability. This proposal
obtains sequences of Earth streak flats to construct high quality flat
fields for the WF/PC-2 filter set. These flat fields will allow mapping of
the OTA illumination pattern and will be used in conjunction with previous
internal and external flats to generate new pipeline superflats. The
proposal completed nominally.

1.8 Completed Two Sets of WF/PC-2 8587 (Stroemgren Photometry of
Globular Clusters in M87: Breaking the Age- Metallicity Degeneracy)

The WF/PC-2 was used to further demonstrate that the globular
cluster {GC} systems of most, and possibly all, luminous galaxies show
bimodal distributions in broadband color and, by implication, age and/or
metallicity. Whatever its origin, this bimodality {which is observed in
giant galaxies that span a wide range in Hubble Type and local environment}
must hold a fundamental clue to the process of galaxy formation. The
technique of this proposal hinges on the ability of Stroemgren photometry
to decouple the effects of age and metallicity for large samples of GCs,
and will provide the first strong constraints on the various galaxy
formation models. There were no reported problems.

1.9 Completed Three Sets of STIS/CCD 8841 (Hot Pixel Annealing C9)

The Space Telescope Imaging Spectrograph (CCD) was used to improve
the effectiveness of the CCD hot pixel annealing process. This is assessed
by measuring the dark current behavior before and after annealing and by
searching for any window contamination effects. In addition CTE
performance is examined by looking for traps in a low signal level
flat. The observations completed with no reported problems.

1.10 Completed Three Sets of STIS/CCD 8838 (Bias Monitor – Part 1)

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 nominally.

1.11 Completed STIS/CCD 8881 (An Unbiased Survey of X-Ray and Optical
Emission From Extended Radio Jets in AGN)

The Space Telescope Imaging Spectrograph (CCD) was used to an X-ray
bright jet in the distant quasar PKS 1510-089 that shows that X-rays can be
energetically dominant in relativistic jets. The observations completed
nominally.

1.12 Completed 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.

1.13 Completed Two Sets of WF/PC-2/STIS/CCD 8679 (Constraining the Age
of the Oldest Stars from the White Dwarf Cooling Sequence in M4)

The WF/PC-2 and the Space Telescope Imaging Spectrograph (CCD) were
used to search for the oldest and hence coolest white dwarfs {WDs} in M4,
the nearest Galactic globular cluster to the Sun. New models for cooling
hydrogen white dwarfs predict that their colors should become bluer, rather
than redder, with increasing age. The goal is to test these models and at
the same time constrain the age of M4. The proposal completed with no
problems.

1.14 Completed Six Sets of WF/PC-2 8827 (Cycle 9 Supplemental Darks pt2/3)

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 nominally.

1.15 Completed STIS/CCD/MA2 8628 (High Density {~ 10^9 Cm^-3} Gas In
The Jet Formation Region Of T Tauri Stars)

The Space Telescope Imaging Spectrograph (CCD and MA2) was used to
investigate the ubiquitous outflow that occurs during star formation for
which the driving mechanism is still unknown. The proposal intends to
compare the kinematics of the UV line formation region with that of the
optical forbidden lines and to determine the physical characteristics of
the jet formation region. There were no reported problems.

1.16 Completed STIS/CCD/MA2 8569 (A New Survey for Low-Redshift Damped
Lyman-Alpha Lines in QSO MgII Systems)

The Space Telescope Imaging Spectrograph (CCD and MA2) was used to
support studies which have shown that most of the observable neutral gas
mass in the Universe resides in QSO damped LyAlpha {DLA} systems. However,
at low redshift , DLA can only be found by searching in the UV with
HST. By boot-strapping from the MgII statistics, we will be able to
further improve the determination of the low- redshift statistical
properties of DLA {their incidence and cosmological mass density} and open
up new opportunities for studies at low redshift. The observations
completed nominally.

1.17 Completed WF/PC-2 8771 (Development And Evolution Of Yso Outflows
And Jets, Cycle 9)

The WF/PC-2 was used to observe XZ Tauri, HL Tauri, and HH 30 which
are three young stars which can be observed simultaneously in a single
WFPC2 pointing. Broad-band HST imaging has revealed that the XZ Tauri
binary is the source of an elongated bubble of emission nebulosity nearly
5″ long. In new images of these objects, it was discovered that the XZ Tau
bubble had expanded significantly and had become markedly limb-brightened
since 1995. This behavior suggests that we are witnessing, for the first
time, the earliest stages of development of a Herbig-Haro bowshock, perhaps
the initial formation of its post-shock cooling zone. It is proposed to
test this hypothesis with emission line imaging and temporal monitoring of
the bubble’s size and brightness. Simultaneously with the XZ Tau study, we
will observe the jets and reflection nebulosities of HH 30 and HL
Tauri. Monitoring of HH 30 is particularly important, as our 1998 imaging
also revealed that a very large reflected light asymmetry has developed in
this prototype young stellar object accretion disk system. There were no
anomalies.

1.18 Completed WF/PC-2 7407 (Continuation of Temporal Monitoring of the
Crab Synchrotron Nebula)

The WF/PC-2 was used to observe the synchrotron nebula surrounding
the Crab pulsar that has been the subject of intensive study for
decades. It is generally accepted that the structure and activity in this
region are due to wave phenomena near the termination shock of the pulsar
wind, observations of which hold unique promise of leading to more complete
models of the pulsar and its magnetosphere. Unfortunately, this promise
has not been fulfilled, largely because of the low spatial resolution and
uneven temporal coverage of existing studies. Recent WF/PC-2 observations
of the Crab synchrotron nebula offer new hope in this quest. These data,
which reach the natural size scale defined by the Larmor radius of
energetic electrons, resolve the majority of the known features in the
Crab. For the first time it is possible to reliably establish the physical
conditions {e.g., emissivities, equipartition fields, and pressures} of
features associated with the wind and its termination shock. The
observations completed as planned.

1.19 Completed WF/PC-2 8829 (Observatory Focus Monitor)

The WF/PC-2 was used to analyze the HST focus which drifts slowly
and shows evidence of undergoing slips of a few microns at random
times. The rate of the WFPC2 monitoring program is insufficient to track
and/or understand OTA behavior in order to request timely and appropriate
secondary mirror corrections. This 14-orbit program obtains a large amount
of high signal to noise focus data, sometimes in two Science Instruments at
once, and will be sufficient to more accurately define the HST
focus. There were no reported problems.

1.20 Completed STIS/CCD/MA1 8603 (Secular Changes In The Temperatures
And Radii Of Extreme Helium Stars)

The Space Telescope Imaging Spectrograph (CCD and MA1) was used to
make observations of 15 extreme helium stars (EHEs_ which, together with
IUE data, will give a 20-year baseline of ultraviolet
spectrophotometry. EHEs are luminous stellar remnants evolving rapidly to
become white dwarfs. They represent an important stage in the evolution of
at least some low-mass stars, and are closely related to the R Coronae
Borealis variables. Models do not agree about their origin, nor about what
fraction of normal stars pass through this phase, in which the stars have
been completely stripped of their outer layers. The models do predict that
EHEs are contracting and provide rate predictions and evolutionary
lifetimes. The observations completed with no reported problems.

1.21 Completed Two Sets of STIS/CCD/MA2 8684 (Emission Lines from
Photoionized Accretion Disks and Winds in AGNs)

The Space Telescope Imaging Spectrograph (CCD and MA2) was used to
observe the origin and dynamics of the gas that produces the broad optical
and ultraviolet emission lines in AGNs, a fundamental gap that remains in
our knowledge of AGNs. The proposal completed with no reported problems.

1.24 Completed WF/PC-2 8887 (Heritage Observations of IC 2944)

The WF/PC-2 was used to observe IC 2944 as part of the Hubble
Heritage Project. The aim of the Heritage Project is to provide
spectacular HST color images for public release, outreach, and
education. We are supplementing existing archival data to produce a
three-color image. No problems were noted.

1.23 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.

1.24 Completed STIS/CCD 8664 (Structural Measurement of Globular
Clusters in M31 and NGC 5128: Stalking the Fundamental Plane)

The Space Telescope Imaging Spectrograph (CCD) was used to observe
in the snapshot mode to image a wide selection of individual globular
clusters in two other large galaxies {M31 and NGC 5128} for measurement of
their structural parameters {r_c, c, central surface brightness}. We will
use these to compute their binding energies and define the FP in these two
galaxies. Comparison with the Milky Way will then give us powerful new
information on just how “universal” the cluster formation process was in
the early protogalaxies. The observations completed with no reported problems.

1.25 Completed STIS/CCD 8189 (The Source of Gamma Ray Bursts and the
Nature of their Hosts)

The Space Telescope Imaging Spectrograph (CCD) was used to make
high resolution optical and ultraviolet observations of the Gamma Ray
Burster (GRB) 990123 and its host galaxy. This comprehensive set of
observations will provide new insights into the astrophysics of GRBs and
their high redshift host galaxies. The observations were completed as
planned, and no problems were reported.

1.26 Completed WF/PC-2 8821 (Cycle 9 CTE Monitor)

The WF/PC-2 was used to monitor CTE changes during cycle 9. It is
expected to determine CTE and zero points by comparison to ground based
observations of clusters. The observations completed nominally.

2.0 FLIGHT OPERATIONS SUMMARY:

2.1 Guide Star Acquisitions:

Scheduled Acquisitions: 23

Successful: 23

Scheduled Re-acquisitions: 25

Successful: 25

2.2 FHST Updates:

Scheduled: 53

Successful: 53

2.3 Operations Notes:

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

On two occasions, the engineering status buffer limits were
adjusted per ROP DF-18A.