Status Report

NASA Hubble Space Telescope Daily Report # 3554

By SpaceRef Editor
February 20, 2004
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




ACS 9984

Cosmic Shear With ACS Pure Parallels

Small distortions in the shapes of background galaxies by foreground
mass provide a powerful method of directly measuring the amount and
distribution of dark matter. Several groups have recently detected
this weak lensing by large-scale structure, also called cosmic shear.
The high resolution and sensitivity of HST/ACS provide a unique
opportunity to measure cosmic shear accurately on small scales. Using
260 parallel orbits in Sloan textiti {F775W} we will measure for the
first time: beginlistosetlength sep0cm setlengthemsep0cm setlength
opsep0cm em the cosmic shear variance on scales <0.7 arcmin, em the
skewness of the shear distribution, and em the magnification effect.
endlist Our measurements will determine the amplitude of the mass
power spectrum sigma_8Omega_m^0.5, with signal-to-noise {s/n} ~ 20,
and the mass density Omega_m with s/n=4. They will be done at small
angular scales where non-linear effects dominate the power spectrum,
providing a test of the gravitational instability paradigm for
structure formation. Measurements on these scales are not possible
from the ground, because of the systematic effects induced by PSF
smearing from seeing. Having many independent lines of sight reduces
the uncertainty due to cosmic variance, making parallel observations

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.


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 9701

ACS Default {Archival} Pure Parallel Program II

The proposal is designed to test ACS pure parallels in POMS.

ACS/WFC 9765

The Dusty ISM Substructure in Nearby Spiral Galaxies

We propose an ACS V&I imaging snapshot survey of all nearby edge-on
spiral galaxies in order to measure the small scale structures in
their dust extinction down to the 10pc scale. Dust and molecular gas
are tightly coupled and therefore HST high resolution reddening maps
can reveal information about the cold ISM phase on a scale
inaccessible from the groundby any other means. We have recently
discovered a sudden change in dust lane properties using ground-based
data; all galaxies with rotation speeds in access of 120km/s show dust
lanes, but none of the slower rotators does. This transition may be
caused by a sudden change in the state of the multiphase ISM, and HST
resolution imaging is needed to fully quantify this effect. Analysis
will consist of full radiative transfer modeling of dust extinction
with realistic, fractal like substructure and power spectrum analysis
of the structure from the global to the 10pc scale. By observing a
sample of galaxies with a range in structural parameters we can
quantify how the cold ISM structure changes as function of radius,
rotation speed, local surface density, et cetera. This information is
duly needed with SIRTF soon providing a wealth of information on dust
absorption, but lacking the resolution to determine the small scale
distribution of the dust.


A tailored survey of proplyds with the ACS

While our specific understanding of the proto-planetary disks in Orion
is increasing, our general knowledge of what promotes and hinders
their birth and longevity is hampered by having good observations in
only this one region. Observations of proplyds in other regions with
different conditions of ultraviolet irradiation and age can provide
more stringent tests of our present models. We have therefore designed
an ACS/WFC and parallel WFC2 survey of open clusters embedded in H II
regions that, with a small number of orbits, maximizes the probability
of successfully finding proplyds there. Our observing strategy will
additionally afford a quantitative study of the detected proplyds, as
well as the derivation of a correlation between those characteristics
and the clusters’ stellar population. ACS gives us an unprecedented
opportunity to kick start the mass discovery of proplyds in many
environments, an obvious way in which progress can be made in this
field. This small tailored survey, gives us an excellent chance to
obtain a huge return at low cost.

FGS 10012

F583W/F5ND Cross Filter Calibration FGS1r Off Center

This proposal calibrates the shift of a star’s position when observed
through the F550 filter and F5ND attenuator relative to the F583W
filter at locations off center in the FGS1r FOV. This calibration is
necessary to support ongoing multi-cycle FGS astrometry proposals
{extrasolar planet astrometry and the Cepheid distance scale in

FGS 9969

FGS Astrometry of the Extrasolar Planet of Epsilon Eridani

We propose observations with HST/FGS in Position Mode to determine the
astrometric elements {perturbation orbit semimajor axis and
inclination} of the candidate extra-solar planet around the K2 V star
Epsilon Eridani that has been detected by Doppler spectroscopy. These
observations will also permit us to determine the actual mass of the
planet by providing the sin{i} factor which can not be determined with
the radial velocity method. High precision radial velocity {RV}
measurements spanning the years 1980.8–2000.0 for the nearby {3.22
pc} star Epsilon Eri show convincing variations with a period of ~ 7
yrs. These data represent a combination of six independent data sets
taken with four different telescopes. A least squares orbital solution
using robust estimation yields orbital parameters of period, P = 6.9
yrs, velocity K- amplitude = 19 m/s, eccentricity e = 0.6, projected
companion mass M_B sin{i} = 0.83 M_Jupiter. An estimate of the
inclination yields a perturbation semi-major axis, Alpha = 0arcs0022,
easily within the reach of HST/FGS astrometry.

FGS 9971

FGS Astrometry of a Star Hosting an Extrasolar Planet: The Mass of
Upsilon Andromedae d

We propose observations with HST/FGS to determine the astrometric
elements {perturbation orbit semimajor axis and inclination} produced
by the outermost extra-solar planet orbiting the F8V star Upsilon
Andromedae. These observations will permit us to determine the actual
mass of the planet by providing the presently unknown sin i factor
intrinsic to the radial velocity method which discovered this object.
An inclination, i = 30degrees, within the range of one very low
precision determination using reanalyzed HIPPARCOS intermediate data
products, would produce the observed radial velocity amplitude, K = 66
ms with a companion mass of ~8 M_Jupiter. Such a mass would induce in
Upsilon Andromedae a perturbation semi-major axis, Alpha = 0arcs0012,
easily within the reach of HST/FGS fringe tracking astrometry. The
proposed observations will yield a planetary mass, rather than, as
previous investigations have done, only suggest a planetary mass

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.

NIC2 9834

Finding Planets in the Stellar Graveyard: A Faint Companion Search of
White Dwarfs with NICMOS

We propose to do a deep search for substellar objects in orbit around
white dwarfs with the newly refurbished NICMOS camera as part of the
PI’s doctoral thesis work. Direct imaging of planets around main
sequence stars is difficult due to the large contrast ratio, a problem
which is much less severe for companions to white dwarfs. White dwarfs
are not usually considered in planet searches but recent theoretical
work and observations are motivating new searches for planetary
systems and dust disks around DAZ white dwarfs. We propose to conduct
the search with the NIC2 coronagraph to find resolved companions and
do photometry to search for unresolved companions through Near-IR
excesses. We estimate that the survey will be sensitive to brown
dwarfs, high mass jovian planets, and dust disks. By probing a wide
range of orbital separations and companion masses, this survey will
help to answer questions about the brown dwarf desert, common envelope
evolution, and planet formation. HST and NICMOS provide a unique
capability to do this search, as no ground based observatory with AO
can adequately search for faint companions as close and with such high

NIC3 10014

Spectrophotometry of FAINT IR STANDARDS

Faint spectrophotometric standard stars required for COS and the SBC
channel on ACS have been established via the STIS FASTEX program that
has executed over the last three cycles. 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 defocussing the OTA. The primary Sloan standard BD+17d4708 at
V=9.9 is safely fainter than this Nicmos limit.


NICMOS Post-SAA calibration – CR Persistence Part 2

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 10033

MAMA Sensitivity and Focus Monitor Cycle 12

Monitor sensitivity of each MAMA grating mode to detect any change due
to contamination or other causes. Also monitor the STIS focus in a
spectroscopic and an imaging mode.

STIS 9786

The Next Generation Spectral Library

We propose to continue the Cycle 10 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] lt
-1.5}, low {[Fe/H] -1.5 to -0.5}, near-solar {[Fe/H] -0.3 to 0.1}, and
super-solar {[Fe/H] gt 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 10017

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD.

STIS/CCD 10019

CCD Bias Monitor – Part 1

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 10085

STIS Pure Parallel Imaging Program: Cycle 12

This is the default archival pure parallel program for STIS during
cycle 12.

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

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

WFPC2 10084

WFII parallel archive proposal

This is the 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 2002 Parallels
Working Group.


Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.) None


1201-0 – Change Limits MAMA2 Threshold Voltage (closed) @ 049/1252z

                           SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq               8                          8
FGS REacq               8                          8
FHST Update             19                        19


Science Planning and Scheduling System (SPSS), Version 46.1 went into
operation on Monday, February 16, 2004. This release includes new
features to display Two Gyro mode activities and scheduling event
windows. It also includes some routine maintenance items. SPSS Build
46.2 went into the test phase on the same day. This build includes
code portability updates to allow code sharing of the complex Earth
Avoidance software with the PASS software system.

SpaceRef staff editor.