Status Report

NASA hubble Space Telescope Daily Report # 3666

By SpaceRef Editor
August 4, 2004
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




ACS/HRC 10255

A Never Before Explored Phase Space: Resolving Close White Dwarf / Red
Dwarf Binaries

We propose an ACS Snapshot imaging survey to resolve a well-defined
sample of highly probable white dwarf plus red dwarf close binaries.
These candidates were selected from a search for white dwarfs with
infrared excess from the 2MASS database. They represent unresolved
systems {separations less than approximately 2" in the 2MASS images}
and are distributed over the whole sky. Our HST+ACS observations will
be sensitive to a separation range {1-20 AU} never before probed by
any means. The proposed study will be the first empirical test of
binary star parameters in the post-AGB phase, and cannot be
accomplished from the ground. By resolving as few as 20 of our ~100
targets with HST, we will be able to characterize the distribution of
orbital semi-major axes and secondary star masses.

ACS/HRC 9862

ACS detection of sub-stellar companions around Vega, Fomalhaut and
beta Pic via parallax & proper motion

The first visible light coronagraph on HST provides high contrast
ratios near very bright stars. Vega, Fomalhaut and Beta Pictoris have
dusty debris disks with structure thought to originate from the
presence of yet-undetected, substellar companions. The detection of
substellar companions is possible with the ACS HRC coronagraph if
observations are made in two epochs. Here we propose to image Vega in
two epochs within Cycle 12. We argue that in a few months interval,
the sky plane motion of any companions due to parallax and proper
motion is large relative to the HRC astrometric uncertainties.
Likewise, we propose to obtain a second epoch image of Beta Pic and
Fomalhaut within Cycle 12 to complement the single epoch imaging of
the GTO program. Because Vega, Fomalhaut and Beta Pictoris are young
and nearby, this imaging campaign will be sensitive to brown dwarfs
and massive extrasolar giant planets at their predicted locations
40-60 AU projected radius from each star. Either positive or negative
results for each system will be used to constrain the physical
characteristics of massive objects hypothesized to cause the observed
disk asymmetries.


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/WFC 10260

The Most Massive Star Clusters: Supermassive Globular Clusters or
Dwarf Galaxy Nuclei?

Evidence is mounting that the most massive globular clusters, such as
Omega Centauri and M31-G1, may be related to the recently discovered
"Ultra-Compact Dwarfs" and the dense nuclei of dE, N galaxies.
However, no systematic imaging investigation of these supermassive
globular clusters — at the level of Omega Cen and beyond — has been
done, and we do not know what fraction of them might bear the
signatures {such as large effective radii or tidal tails} of having
originated as dE nuclei. We propose to use the ACS/WFC to obtain deep
images of 18 such clusters in NGC 5128 and M31, the two nearest rich
globular cluster systems. These globulars are the richest star
clusters that can be found in nature, the biggest of them reaching
10^7 Solar masses, and they are likely to represent the results of
star formation under the densest and most extreme conditions known.
Using the profiles of the clusters including their faint outer
envelopes, we will carry out state-of-the-art dynamical modelling of
their structures, and look for any clear evidence which would indicate
that they are associated with stripped satellites. This study will
build on our previous work with STIS and WFPC2 imaging designed to
study the ‘Fundamental Plane’ of globular clusters. When our new work
is combined with Archival WFPC2, STIS, and ACS material, we will also
be able to construct the definitive mapping of the Fundamental Plane
of globular clusters at its uppermost mass range, and confirm whether
or not the UCD and dE, N objects occupy a different structural
parameter space.

NIC/NIC3 10226

The NICMOS Grism Parallel Survey

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/NIC2/NIC3 8793

NICMOS Post-SAA calibration – CR Persistence Part 4

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.

NIC2 9768

Enabling Coronagraphic Polarimetry with NICMOS

We propose to enable a new mode on NICMOS that combines the powerful
diffracted light rejection of the coronagraph with the diagnostic
power of polarimetry. This new capability will open a new regime in
high contrast imaging that has not been possible before. We will
enable this capability by observing calibration targets with the
coronagraph and the NIC2 polarizers in place. The enabled science
includes, but is not limited to, detection and imaging of
circumstellar debris in polarized light, the polarized emission
surrounding bright planetary nebulae, and the extended structure
around bright active galaxies.

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 10222

The Next Generation Spectral Library

We propose to complete our snapshot program to produce a Next
Generation Spectral Library of 600 stars for use in modeling the
integrated light of galaxies and clusters. This program is using the
low dispersion UV and optical gratings of STIS. The library will be
roughly equally divided among four metallicities, very low {[Fe/H] <
-1.5}, low {-1.5 < [Fe/H] < -0.5}, near-solar {-0.3 < [Fe/H] < 0.1},
and super-solar {[Fe/H] > 0.2}, well-sampling the entire HR-diagram in
each bin. Such a library will surpass all extant compilations and have
lasting archival value, well into the Next Generation Space Telescope
era. Because of the universal utility and community-broad nature of
this venture, we waive the entire proprietary period.

STIS/CCD 10249

Mass Distributions of z ~ 1 Galaxies: Probing Substructure and
Dynamical Evidence for Bulges in Velocity Profiles

We propose to use the unique resolving capabilities of STIS to conduct
a pilot study of the internal kinematics, structure, and star
formation properties of five spiral galaxies at redshifts z ~ 1. Our
aim is to determine if these large, rapidly rotating disks have bulges
in place at this epoch, and hence can be viewed as direct precursors
to their local counterparts. STIS provides a unique opportunity to
study the detailed kinematics of distant galaxies, and to probe
evolution in the shape of the mass distribution. We have selected
targets from a high redshift sample containing 100+ Keck+LRIS
major-axis, optical rotation curves for which the [OII]3727A optical
emission line has high S/N across the disk. STIS spectroscopy will be
combined with existing LRIS spectroscopy and WFPC2, NICMOS and
ground-based photometry to derive fundamental structural parameters
{rotation velocity profile, stellar mass, mass concentration, disk
scale length}, luminosities and star formation rates, and compare them
with local counterparts. This will provide a stringent test of current
scenarios for the formation of galactic disks and bulges.


Integrated Absorption- and Emission-Line Analysis of Nebulae

Serious discrepancies have arisen in CNONe abundance determinations
for galactic nebulae in the past ten years depending upon which type
of emission lines are used in the analysis: forbidden vs. permitted
lines. The cause of the discrepancies, which can exceed an order of
magnitude for some PNe, has been studied intensively but is still
unknown. Emission line abundances cannot be considered reliable until
the nature of these contradictory results is understood. We have
developed a technique for integrating absorption lines into emission
analyses for diffuse nebulae that provides an independent check on the
validity of emission-line analyses. It requires high resolution
observations of UV resonance absorption produced by the nebular gas in
imbedded or background stars together with optical spectra of the
nebulae. We propose to obtain UV spectra of four PNe central stars
with STIS that will provide data necessary to exploit the new
technique of integrated abundance determination that combines both
emission and absorption lines.

STIS/MA1 10034

Cycle 12 MAMA Dark Monitor

This test performs the routine monitoring of the MAMA detector dark
noise. This proposal will provide the primary means of checking on
health of the MAMA detectors systems through frequent monitoring of
the background count rate. The purpose is to look for evidence of
change in dark indicative of detector problem developing.

WFPC2 10068

WFPC2 CYCLE 12 Standard Darks

This dark calibration program obtains dark frames every week in order
to provide data for the ongoing calibration of the CCD dark current
rate, and to monitor and characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

WFPC2 10071

WFPC2 CYCLE 12 Supplemental Darks Part 3/3

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

WFPC2 10072


This calibration proposal is the Cycle 12 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A
variety of internal exposures are obtained in order to provide a
monitor of the integrity of the CCD camera electronics in both bays
{gain 7 and gain 15}, a test for quantum efficiency in the CCDs, and a
monitor for possible buildup of contaminants on the CCD windows.


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

HSTAR 9496: FHST Roll Delay Update (U1,2RD) @ 215/10:02:00Z failed
with Error Box indicating "2 FAILED" for mnemonics QEBSTFG0, QEBSTFG1,
and QEBSTFG2 @ 215/10:02:49Z. FHST 2 failed to locate the Reference
Star (ID 20440003, or eta Indi) of magnitude 4.52 Mv. Under

HSTAR 9499: Upon AOS @ 216/07:41:02Z, a single 486 Status Buffer
message "a05" was observed, indicating "FGS coarse track failed, SRLE"
during the primary GS acquisition (1,2,2) @ 216/07:25:04Z. Vehicle
was in FL on FGS 1 and 2 at AOS, no observations affected. Further
analysis after engineering recorder dump scheduled for 216/23:28Z.
Upon AOS @ 216/09:06:00Z, a second 486 Status Buffer message "a05" was
observed, and vehicle was operating on gyro control only. GS
Reacquisition (1,2,2) @ 216/08:57:58Z failed to reacquire GSs.
Real-time FHST Map @ 216/09:30Z showed attitude errors of -0.901,
14.808, and 11.332 arcsec, no attitude problem was apparent. Under


1251-0 Adjust Recharge Ratio Limits for High Sun DOY 2004/203-215 @ 215/1201z

                            SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq                09                        09
FGS REacq                05                        05
Update              15                        14               215/10:02:49z


SpaceRef staff editor.