Status Report

NASA Hubble Space Telescope Daily Report # 3657

By SpaceRef Editor
July 21, 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.


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 9727

Exploration of the SN Ia Hubble Diagram at z > 1.2

In the spirit of a Treasury proposal, we propose to organize, and
deliver to the astronomical community, non-proprietary follow-up
observations of ~10 Type Ia supernovae at 1<z<1.7 that are expected to
be discovered in a Cycle 12 Treasury proposal. Together with the
currently available sample, this would provide a Hubble diagram with
over 20 SNe Ia in this redshift range, where it is possible to test
the current cosmological model in the epoch of deceleration: If z ~
0.5 SNe Ia are fainter due to evolution rather than an accelerating
expansion, they should continue to get fainter at even higher
redshifts. This size sample will show trends and outliers, and permit
a more rigorous treatment of the asymmetric amplification distribution
from gravitational lensing. This is a key redshift range for the
studies of dark energy that will be done with future surveys; this
dataset will lay the ground-work for these studies by establishing the
simple properties of the supernovae in this redshift range, including
magnitudes, colors, and timescales. If considered more appropriate,
this proposal could be treated as a part of a Treasury or Director’s
Discretionary program, since the data would be available to everybody
immediately, and we would welcome others who would want to work with
us on it.

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 9845

NICMOS Confirmation of a Young Planetary-Mass Companion

We have recently discovered a strong candidate for a planetary-mass
{~10 Mjup} companion to a young Sun-like star, based on near-IR
imaging and spectroscopy with the Keck and Subaru adaptive optics {AO}
systems. While the ground-based data strongly suggest that the
candidate has a very low effective temperature, and hence a very low
mass, they are not definitive. We propose to obtain NICMOS
coronagraphy to measure the companion’s 1.9um water-band absorption.
This feature is a distinct signature of very cool objects and is
unobservable from the ground. The combined ground-based and
space-based data set will determine whether the companion has a very
low temperature, and hence if it is the lowest mass companion found to
date by direct imaging.

NIC2 9875

The Fundamental Plane of Massive Gas-Rich Mergers

We propose deep NICMOS H-band imaging of a carefully selected sample
of 33 luminous, late-stage galactic mergers. This program is part of a
comprehensive investigation of the most luminous mergers in the nearby
universe, the ultraluminous infrared galaxies {ULIGs}. The
high-resolution HST images will complement an extensive set of
ground-based data that include long-slit NIR spectra from a recently
approved Large VLT Programme. This unique dataset will allow us to
derive with unprecedented precision structural -and- kinematic
parameters for a large unbiased sample of objects spanning the entire
ULIG luminosity function. These data will refine the fundamental plane
of massive gas-rich mergers and enable us to answer the following
questions: {1} Do ultraluminous mergers form elliptical galaxies, and
in particular, giant ellipticals? {2} Do ULIGs evolve into optically
bright QSOs? The results from this detailed study of massive mergers
in the local universe will be relevant to understanding galaxy
formation and evolution at earlier epochs, and in particular, the
dusty sub-mm population that accounts for more than half of the star
formation at z > 1.

NIC3 10014

Spectrophotometry of FAINT IR STANDARDS

Cycle 12 is an especially opportune time to establish companion faint
IR standards for WFC3, because the NICMOS proposal 9998 includes
observations in cycle 12 of all 6 of the primary standard stars in
order to establish the absolute flux calibration of the three grism
modes to 1%. In addition to WFC3, these new faint secondary IR
standards will be a significant step towards establishing flux
standards for JWST, as well as for SNAP, SIRTF, and SOFIA. The 6
primary standards included in Propid=9998 are in the range of V=11-13
and include three hot pure hydrogen WDs and 3 solar analogs. We
propose to establish new IR faint standards in the 15-17 mag range.
Appropriate spectral types for faint IR standards are solar analogs
and hotter WDs. Many M type and cooler stars are variable, so that
long term monitoring is required before committing HST time to such
cool stars. A few G type and WD faint stars will provide a set of
faint IR standards with minimal sky and color coverage. Existing HST
images of any candidates can provide verification that there are no
contaminating stars above the 1% level within 2-3arcsec. However, the
ACS calibration field in 47 Tuc is too crowded for linking to ground
based observations. If the other candidates are selected from SDSS or
other ground based data, then the NICMOS and STIS acquisition images
can provide this verification, as well as correction factors for
arbitrary photometric size apertures. The SNAP team is providing the
northern faint stars using unreleased SDSS data. In addition, the
extreme coolest types such as L and T stars have proven essential to
sorting out the long wavelength QE of ACS; both the ACS and eventually
WFC3 calibrations could be improved with knowledge of L and T SEDs in
the region beyond 0.95 microns. In addition to the primary purpose of
ACS QE vs. wavelength and broad band F814W and F850LP calibrations,
these three stars in C.} below are at the flux level required for WFC3
grism calibration. The brighter M, L, and T standard stars will each
require a NICMOS orbit, while each faint standard requires two NICMOS
orbits and one STIS orbit for complete wavelength coverage. The STIS
spectra of the M and L stars are done as ACS calibrations in cycles 12
and 11, respectively. An additional faint WD has already been proposed
for 2 NICMOS and 4 STIS orbits in their cycle 12 programs already. See
Table 1 for a summary of the 18 orbit allocation for this program
10014. Bright stars in the V=0-6 mag range would be useful for direct
comparisons to NIST calibrated lamps. This comparison would offer the
opportunity to compare two fundamentally different realms of physics:
pure hydrogen stellar models and laboratory black body physics.
Unfortunately, the NICMOS bright limit is V=~8 for a solar analog and
a 1s exposure without defocusing the OTA. The primary Sloan standard
BD+17d4708 at V=9.9 is safely fainter than this NICMOS limit.

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/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
investigated.) None



                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq              09                           09
FGS REacq              07                            07
FHST Update           13                           13


SpaceRef staff editor.