Status Report

NASA Hubble Space Telescope Daily Report # 3621

By SpaceRef Editor
May 28, 2004
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT # 3621

PERIOD COVERED: DOY 147

OBSERVATIONS SCHEDULED

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 coronographic
monitoring is required to assess the changing position of the spots.

ACS/HRC 9746

Binary systems in the Kuiper Belt

The properties of the orbits of Kuiper belt object {KBO} satellites
hold keys to fundamental insight into masses and densities of KBOs,
the interaction history of the early solar system, the internal
structure of distant ice-rock bodies, and even the genesis of the
Pluto-Charon binary. Within the past 18 months, 9 KBO satellite
systems have been discovered, allowing for the first time the
possibility of characterizing a sample of KBO satellite orbital
properties. We propose HRC observations to determine satellite orbits
in the 6 best cases. We have carefully devised a strategy for each of
these 6 systems to make maximum use of ground-based observations,
previous HST observations, and the smallest possible number of new HST
observations. Our proposed observations will efficiently provide
highly reliable orbital solutions which are critical to achieving the
scientific promise available from the study of these systems. Our
strategy relies heavily on extensive Monte Carlo simulations to define
optimal times of observing such that each new point obtained gives
maximum leverage for refining the orbital solution. We find that with
this strategy we can provide mass solutions for all 6 systems to an
accuracy of better than 10% using only 25 new HST observations. This
highly efficient program provides extreme scientific output with
optimal use of scarce resources.

ACS/HRC/WFC 10060

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/HRC/WFC 9731

Kepler’s Supernova Remnant: an Imaging Study of the Blast Wave –
Circumstellar Medium Interaction

Kepler’s SNR {SN 1604 AD} is the prime example of a young Galactic SNR
where the blast wave is running into the wind of the progenitor star.
The interaction between the blast wave and the inhomogeneous
circumstellar medium gives rise to knots, evolving on a time scale of
years, that dominate the optical emission from the remnant. Also
visible in the optical are fainter Balmer line filaments that exhibit
a range of geometries – from normal sheet-like filaments to more
diffuse clumps of emission, the latter unique to this remnant. We
propose to image Kepler’s SNR through several narrowband filters using
ACS/WFC and WFPC2. The morphology and ionization structure of the
knots will be obtained from H-alpha, [S II], and [O III] images. We
will also obtain a [N II] image, which is known to be strong and
spatially variable in the remnant. The proposed H-alpha images will be
deep enough so that the physical scales and structure of the Balmer
dominated non-radiative shocks can be investigated. Our data will be a
critical part of multiwavelength studies of Kepler’s SNR. They will
complement Chandra and XMM X-ray data and VLA radio data, and provide
a significant advance in understanding the processes of magnetic field
amplification and cosmic ray acceleration in SNRs as well as the
evolution and dynamics of the blast wave – circumstellar medium
interaction.

ACS/WFC 10002

Detailed Study of X-ray Jets from a Complete Survey

We propose deep followup HST and Chandra observations of two X-ray
jets, which are the X-ray brightest discovered in our Chandra survey
of quasars with known radio jets. With these data, we will compare
their X-ray, optical and radio morphologies. We will also obtain X-ray
and optical spectral indices, and spatially resolved SEDs from the
radio through the X-rays. This will allow us to determine the X-ray
emission mechanism at each point in these jets, and test critical
predictions made by each mechanism. We will also be able to track any
changes in physical conditions {including magnetic field and bulk
Lorentz factor} that are present in the observed 90 degree bends.

NIC/NIC3 9865

The NICMOS Parallel Observing Program

We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency of
our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at
0.7<z<1.9, which provides an excellent measure of current star
formation rate. We will also detect star-forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial–but poorly observed–redshift range where
galaxies appear to have assembled most of their stellar mass. This key
process of galaxy evolution needs to be studied with IR data; we found
that observations at shorter wavelengths appear to have missed a large
fraction of the star-formation in galaxies, due to dust reddening. We
will also obtain deep F110W and F160W images, to examine the space
densities and morphologies of faint red galaxies. In addition to
carrying out the public parallels, we will make the fully reduced and
calibrated images and spectra available on-line, with some
ground-based data for the deepest parallel fields included.

NIC1 9833

T Dwarf Companions: Searching for the Coldest Brown Dwarfs

Faint companions to known stars have historically led to the discovery
of new classes of stellar and substellar objects. Because these
discoveries are typically limited by the flux ratio of the components
in the system, the intrinsically faintest companions are most
effectively identified around the intrinsically faintest primaries. We
propose to use NICMOS to image a sample of 22 of the coolest known
{T-type} brown dwarfs in the Solar Neighborhood in order to search for
fainter and cooler brown dwarf companions. The high spatial resolution
of the NIC 1 detector enables us to distinguish binary systems with
apparent separations greater than 0"08, or physical separations
greater than 1.2 AU at the nominal distances of the objects in our
sample. Furthermore, the substantial sensitivity of NICMOS imaging
allows us to probe companion masses of 5-50 Jupiter masses and
companion effective temperatures of 250-1300 K in a maximally
efficient manner. Based on work to date, we expect that roughly 20% of
the objects in our sample will be binary, and that one or two of these
will likely harbor a significantly fainter secondary. Hence, we expect
to find a companion cooler than any currently known brown dwarf, a
potential prototype for the next spectral class. In addition, our
investigation will add substantially to the sample of known binary
brown dwarfs, allowing improved statistical analyses of the binary
fraction, separation distribution, and mass ratio distribution of
these systems, key quantities for probing brown dwarf formation. We
will also identify optimal substellar systems for astrometric mass
measurements, a critical check for theoretical models of brown dwarfs
and extrasolar planets.

NIC1/NIC2/NIC3 8792

NICMOS Post-SAA calibration – CR Persistence Part 3

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.

STIS/CCD/MA1 9754

Intergalactic O VI absorption at redshift <0.004

Simulations of the formation of large-scale structure in the universe
predict that at the present time a large fraction of the baryons in
the intergalactic medium {IGM} is in a warm/hot phase, with
T=10^5-10^7 K. The warm phase has been detected with HST in absorption
through the OVI 1031.926, 1037.671 doublet at redshifts ~0.15-0.3. In
a sample of 100 extra-galactic objects observed with FUSE, we find 12
detections of OVI at redshifts z=0.0008-0.004 {v=250 to 1200 km/s}.
Many of these occur within 400 kpc and 50 km/s of a nearby galaxy,
making it much easier to understand the relation between the OVI
absorbers and galaxies. Our sample allows a comparison of the
properties of nearby vs more distant OVI absorbers. However, modeling
the physical conditions in the gas requires measurements of HI, OVI,
CIV, NV and CIII. High velocity resolution is required to resolve the
HI, CIV and NV lines in order to discriminate between collisional and
photoionization. We propose to obtain improved HI data, as well as the
CIV and NV measurements for two absorbers at z<0.004. One appears to
represent collisional ionization {Mrk 876}, while the other probably
represents a case of a photoionized system {Ton S180}. Understanding
the ionization of the warm IGM is essential for determining elemental
abundance and the baryonic content of the gas.

WFPC2 10067

WFPC2 Cycle 12 Decontaminations and Associated Observations

This proposal is for the monthly WFPC2 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.

WFPC2 10070

WFPC2 CYCLE 12 Supplemental Darks Part 2/3

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

FLIGHT OPERATIONS SUMMARY:

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

HSTAR 9427: GS Acquisition (2,1,2) @ 148/03:17:34Z resulted in FL
backup on FGS 2 due to SSLE on FGS 1. Prior FHST FM Updates @
148/03:12:04Z and 03:14:49Z showed good attitude error vector. FHST
Map @ 148/03:25:50Z showed 3-axis (RSS) error value of ~ 8.00 arcsec.
Subsequent GS Reacquisition (2,1,2) @ 148/04:02:13Z resulted in FL
backup. Under investigation.

COMPLETED OPS REQs:
17166-0 Off-line the +DD SPA @147/13:00z

OPS NOTES EXECUTED:
1115-0 CCC IPCONFIG Connnection 147/13:08z

                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq              08                           08
FGS REacq              08                           08
FHST Update           12                           12
LOSS of LOCK

SIGNIFICANT EVENTS:

Successfully completed EPS Reconfiguration (offline +DD SPA), 5 to 4
Strings Offline during first uplink opportunity @ 147/13:00:11Z (OR
17166 with attached IP-057 and IP-062 procedures. EPS monitored power
system operations for the MOR for two orbits to verify nominal
operations of TRSWCC (+DD SPA Trim Relay disconnected and commanded
relay order upon Trickle Charge initiation). Batteries experienced
Trickle Charge durations of 31 minutes during both the first and
second orbits. EPS SE continued close monitoring of the power system
performance, especially battery temperatures and pressure, to assess
the effects of this change.

Successfully completed second round of OBAD Data Collections, Sections
J through M 147/23:52Z – 01:45Z, adding four more scheduled OBAD/Rate
Control combinations to the seven collected yesterday. See Ops
Request 17169 with attached OBAD Data Collection procedure.

Additional OBAD data collection periods are necessary for further
analysis of the process in support of future TGS efforts. OBAD data
collection series scheduled as follows:

  • 148/01:25:00 – 148/02:03:00 (HN)
  • 148/16:02:30 – 148/16:22:00 (HN)
  • 148/23:43:00 – 149/00:25:00 (PN)

One of these periods involves a transition to PN format in order to
capture FHST position and intensity data at a higher rate. All
commanding relating to the OBAD data collection is on a NIB with
routine spacecraft activities. See Ops Request 17169 with attached
OBAD Data Collection script for details.

SpaceRef staff editor.