Status Report

NASA Space Telescope Daily Report # 3618

By SpaceRef Editor
May 25, 2004
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




NIC1/NIC2/NIC3 9995

Photometric Stability

This NICMOS calibration proposal carries out photometric monitoring
observations during Cycle 12. The format of the program is identical
to that of the Cycle 11 program 9639, except that the frequency has
been reduced to bimonthly.


Gravitational Microlensing in the NGC 3314A-B Galaxy Pair

Determining the composition of the dark matter that dominates the
masses of galaxies is an important unsolved problem, and the results
of the MACHO Collaboration suggest that some of Milky Way’s dark
matter may be in the form of very old white dwarfs. However, some have
argued that the excess of microlensing events seen by MACHO are due to
a larger than expected microlensing rate for lens stars in the LMC
itself or its tidal debris. We propose to address this question by
detecting microlensing events in the line-of-sight galaxy pair NGC
3314 A & B. The large line-of-sight distance between these galaxies
gives an optical depth that is 3-4 orders of magnitude larger than if
the source stars and lenses were in the same galaxy, and the fact that
the background galaxy is a spiral ensures that there will be a
sufficient number of bright, non-variable source stars. Our proposed
observations should have the sensitivity to detect microlensing by
both ordinary stars and dark matter in NGC 3314A {the foreground
galaxy}. If there are dark matter microlensing events to be found,
they can be clearly distinguished from stellar microlensing events
because they will occur outside the visible disk of NGC 3314A. If
baryonic dark matter is detected in NGC 3314A, we will be able to map
its radial density variation.

FGS 9972

Calibrating the Mass-Luminosity Relation at the End of the Main Sequence

We propose to use HST-FGS1R to calibrate the mass-luminosity relation
{MLR} for stars less massive than 0.2 Msun, with special emphasis on
objects near the stellar/brown dwarf border. Our goals are to
determine M_V values to 0.05 magnitude, masses to 5 than double the
number of objects with masses determined to be less than 0.20 Msun.
This program uses the combination of HST-FGS3/FGS1R at optical
wavelengths and ground-based infrared interferometry to examine
nearby, subarcsecond binary systems. As a result of these
measurements, we are deriving high quality luminosities and masses for
the components in the observed systems, and characterizing their
spectral energy distributions from 0.5 to 2.2 Mum. Several of the
objects included have M < 0.1 Msun, placing them at the very end of
the stellar main sequence. Three of the targets are brown dwarf
candidates, including the current low mass record holder, GJ 1245C,
with a mass of 0.062 +/- 0.004 Msun. The payoff of this proposal is
high because all 10 of the systems selected have already been resolved
with HST- FGS3/FGS1R during Cycles 5–10 and contain most of the
reddest objects for which masses can be determined.


Probing IGM Phases, Metals, and the Cosmic Web with New SDSS QSOs

We propose STIS G140L SNAPSHOT observations of 100 new z < 1 QSOs from
the Sloan Digital Sky Survey for studies of the IGM. These targets
will be chosen to simultaneously maximize IGM pathlength and to form
closely spaced groups of 2-8 QSO sightlines within 1 h^-1 Mpc of a
foreground galaxy. These observations will, in the long term, provide
a rich database of target QSOs for detailed study by COS of the IGM
phases, metallicity, and relationship to the large scale structure. In
the near term, these observations will detect up to 10 Lyman alpha
clouds with N_HI > 10^14 and 3 clouds with N_HI > 10^15, per target.
Thus they will provide an immediate test of filamentary structure in
the "cosmic web" within 1 h^-1 Mpc of galaxies. We ask for 22 minute
exposures for each target with STIS/G140L to obtain S/N = 5-16 for
these V = 16 – 18 QSOs. These observations will be sensitive to Lyman
alpha equivalent widths ranging from 300 mA for the brighter sources
to 600 mA at the fainter end. These targets represent a Deltaz
pathlength of 17 {at 50% yield}, with Deltaz = 10 in the range where
Lya, Lyb, and O VI lie in the HST band. These observations will also
refine predictions of the FUV flux of QSOs based on the larger SDSS
sample and will estimate the degree to which such factors as intrinsic
and Galactic extinction, variability, and intervening absorption can
be controlled. If successful, this technique could make
UV-prequalification SNAPs of QSOs obsolete, at a significant savings
of HST time. Our observations lie at the median duration for SNAPs,
and in the range most likely to be executed. Our program accomplishes
both near- and long-term goals at a relatively low investment of time,
and thus is ideally suited for a SNAP proposal. To ensure maximum
scientific return for our own purposes and for additional science
{HVCs, Galactic halo} we waive the right to a proprietary data period.

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.

ACS/WFC 9860

ESSENCE: Measuring the Dark Energy Equation of State

The accelerating universe appears to be dominated by a dark energy
with a significant negative pressure. The ratio of the pressure to
density of this mysterious energy {its equation of state} is an
observable which can differentiate between the proliferating candidate
theories. We propose to estimate the dark energy equation of state by
observing Type Ia supernovae at redshifts near z=0.7 with HST in
concert with the on-going ESSENCE NOAO Survey program that is
discovering and studying supernovae between 0.3<z<0.8. We show that an
interesting constraint on the equation of state can be made with
supernovae observed at modest redshifts given the current knowledge of
the matter density. We will follow 10 Type Ia supernovae discovered
from the ground and passed to HST without disrupting its schedule. The
full data set will constrain the equation of state to 10% and strictly
limit the range of possible dark energy models. In keeping with the
ESSENCE policy, these observations will available to the community

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.


UV extinction by dust in unexplored LMC environments

The ensemble of results from studies of the UV extinction in the Milky
Way, Magellanic Clouds {MC}, M31 and M33, indicates a complex
dependence of the dust properties with environment, where starburst
activity and metallicity are relevant factors. Work in the LMC to
date, based on IUE data, has several drawbacks: a} only supergiants
could be used, b} they all have moderate extinction, c} the IUE S/N is
limited, d} the large IUE slit may include light from other sources,
such as scattered light from dust or faint companion stars, e} studies
are confined to few {extreme} environments. We propose to obtain UV
extinction curves more accurate than previous ones {from STIS spectra
of main sequence stars with higher reddening}, sampling four
environments in the LMC with different levels of star formation
activity, including the general field, hitherto unexplored. The
results will characterize the properties of dust in different
conditions, at the LMC metallicity, which is useful to intepret
integrated properties of distant galaxies, as well as GALEX upcoming
UV surveys. A complementary study is under way with FUSE in the far-UV
range. The combined results will provide insight on the properties of
small grains.

NIC3 9824

NIC3 SNAPs of nearby galaxies imaged in the mid-UV: the remarkable
cool stellar population in late-type galaxies.

We propose a NIC3 H-band {F160W} SNAPshot survey of 48 nearby mid- to
late-type galaxies covering all inclinations. In Cycle 9 and 10, we
imaged ~100 galaxies in the mid-UV {F300W/F255W} and I-band {F814W}
with WFPC2, and obtained UBVR CCD surface photometry from the ground.
Early-mid-type galaxies show the usual small radial color-gradients,
where disks become somewhat bluer at larger radii. But, remarkably,
the majority of {lower luminosity, smaller and rounder} late-type
galaxies shows the opposite trend and becomes redder outwards in all
filters. While young UV/blue-bright stellar populations dominate their
inner morphology, most late-type galaxies must have a significant halo
or thick disk of older stars. Combining our proposed NIC3 H-band with
existing WFPC2 images will span the wavelength range 0.29-1.6 micron
at resolutions of 0.04-0.16" {FWHM}. This Panchromatic Nearby Galaxy
Atlas will be applicable to a wide range of problems, and will be made
public immediately. Our NIC3/F160W science goals are to: {1} Establish
the nature of the old outer stellar population. All target galaxies
have z<0.005, allowing us to resolve any luminous, cool supergiant
population. NIC3 is essential to make a pixel-to-pixel color-magnitude
study of the nature, distribution and uniformity of the outer stellar
populations, which will constrain dwarf galaxy formation theories. {2}
Determine galaxy structure at 5-20 pc resolution, tracing the old
stellar population and mass distribution compared to the star-forming
regions seen in the mid-UV. A range of inclinations is needed to
distinguish between old thick disks or halos in late-type galaxies.
{3} Make a multi-wavelength pixel-to-pixel decomposition to help
delineate the effects of dust, age, and metallicity. Since we must
cover a range of inclinations, NIC3 H-band is essential to map the
effects from dust, and see how these may affect the studies of {1} and

ACS/WFC 9788

A Narrow-band Snapshot Survey of Nearby Galaxies

We propose to use ACS/WFC to conduct the first comprehensive HST
narrow-band {H-alpha + [N II]} imaging survey of the central regions
of nearby bulge-dominated disk {S0 to Sbc} galaxies. This survey will
cover, at high angular resolution extending over a large field, an
unprecedented number of galaxies representing many different
environments. It will have important applications for many
astrophysical problems of current interest, and it will be an
invaluable addition to the HST legacy. The observations will be
conducted in snapshot mode, drawing targets from a complete sample of
145 galaxies selected from the Palomar spectroscopic survey of nearby
galaxies. Our group will use the data for two primary applications.
First, we will search for nuclear emission-line disks suitable for
future kinematic measurements with STIS, in order to better constrain
the recently discovered relations between black hole mass and bulge
properties. Preliminary imaging of the type proposed here must be
done, sooner or later, if we are to make progress in this exciting new
field. Second, we will investigate a number of issues related to
extragalactic star formation. Specifically, we will systematically
characterize the properties of H II regions and super star clusters on
all galactic scales, from circumnuclear regions to the large-scale

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.


Calibrating the Black Hole Mass Scale for Quasars

We propose to obtain ACS/WFC imaging of all 17 low-redshift quasars
that have black hole masses measured from reverberation mapping. This
is a key sample since all secondary methods to estimate black hole
mass in quasars depend on this local reverberation-mapped sample for
their calibration. The best external check on reverberation mapping is
whether it gives results that are consistent with the black hole mass-
host galaxy correlations of nearby galaxies. For local Seyfert
galaxies the reverberation masses appear consistent with the M-sigma
correlation, but it is not known whether this also holds true for
quasars because the stellar velocity dispersions of quasar hosts are
virtually impossible to measure. We will use the ACS data to measure
accurate bulge parameters {luminosity and effective radius} for the
host galaxies of the reverberation-mapped quasars. From the
fundamental plane or the Faber-Jackson relation, we can estimate the
host galaxy velocity dispersion and test whether the reverberation
masses follow the M-sigma relation even for objects with quasar
luminosities. This is a crucial test if we are to trust the
reverberation masses as the lowest rung on a "distance ladder" of
black hole mass estimators for quasars, so that quasars can be used to
trace the cosmological growth history of black holes. {Note added in
Phase II: the TAC awarded us 8 orbits to observe 7 quasars and a PSF


Tracing the History of Cosmic Expansion to z~2 with Type Ia Supernovae

Type Ia supernovae {SNe Ia} provide the only direct evidence for an
accelerating universe, an extraordinary result that needs the most
rigorous test. The case for cosmic acceleration rests on the
observation that SNe Ia at z = 0.5 are about 0.25 mag fainter than
they would be in a universe without acceleration. A powerful and
straightforward way to assess the reliability of the SN Ia measurement
and the conceptual framework of its interpretation is to look for
cosmic deceleration at z > 1. This would be a clear signature of a
mixed dark-matter and dark-energy universe. Systematic errors in the
SNe Ia result attributed to grey dust or cosmic evolution of the SN Ia
peak luminosity would not show this change of sign. We have obtained a
toehold on this putative “epoch of deceleration” with SN 1997ff at z
= 1.7, and 3 more at z > 1 from our Cycle 11 program, all found and
followed by HST. However, this is too important a test to rest on just
a few objects, anyone of which could be subject to a lensed
line-of-sight or misidentification. Here we propose to extend our
measurement with observations of twelve SNe Ia in the range 1.0 < z <
1.5 or 6 such SNe Ia and 1 ultradistant SN Ia at z = 2, that will be
discovered as a byproduct from proposed Treasury and DD programs.
These objects will provide a much firmer foundation for a conclusion
that touches on important questions of fundamental physics.

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.


The Origin of Gamma-Ray Bursts

The rapid and accurate localization of gamma-ray bursts {GRBs}
promised by a working HETE-2 during the coming year may well
revolutionize our ability to study these enigmatic, highly luminous
transients. We propose a program of HST and Chandra observations to
capitalize on this extraordinary opportunity. We will perform some of
the most stringent tests yet of the standard model, in which GRBs
represent collimated relativistic outflows from collapsing massive
stars. NICMOS imaging and STIS CCD spectroscopy will detect broad
atomic features of supernovae underlying GRB optical transients, at
luminosities more than three times fainter than SN 1998bw. UV,
optical, and X-ray spectroscopy will be used to study the local ISM
around the GRB. Chandra spectroscopy will investigate whether the GRB
X-ray lines are from metals freshly ripped from the stellar core by
the GRB. HST and CTIO infra-red imaging of the GRBs and their hosts
will be used to determine whether `dark’ bursts are the product of
unusually strong local extinction; imaging studies may for the first
time locate the hosts of `short’ GRBs. Our early polarimetry and
late-time broadband imaging will further test physical models of the
relativistic blast wave that produces the bright GRB afterglow, and
will provide unique insight into the influence of the GRB environment
on the afterglow.

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.

NIC3 10337

The COSMOS 2-Degree ACS Survey NICMOS Parallels

The COSMOS 2-Degree ACS Survey NICMOS Parallels. This program is a
companion to program 10092.


The COSMOS 2-Degree ACS Survey

We will undertake a 2 square degree imaging survey {Cosmic Evolution
Survey — COSMOS} with ACS in the I {F814W} band of the VIMOS
equatorial field. This wide field survey is essential to understand
the interplay between Large Scale Structure {LSS} evolution and the
formation of galaxies, dark matter and AGNs and is the one region of
parameter space completely unexplored at present by HST. The
equatorial field was selected for its accessibility to all
ground-based telescopes and low IR background and because it will
eventually contain ~100, 000 galaxy spectra from the VLT-VIMOS
instrument. The imaging will detect over 2 million objects with I> 27
mag {AB, 10 sigma}, over 35, 000 Lyman Break Galaxies {LBGs} and
extremely red galaxies out to z ~ 5. COSMOS is the only HST project
specifically designed to probe the formation and evolution of
structures ranging from galaxies up to Coma-size clusters in the epoch
of peak galaxy, AGN, star and cluster formation {z ~0.5 to 3}. The
size of the largest structures necessitate the 2 degree field. Our
team is committed to the assembly of several public ancillary datasets
including the optical spectra, deep XMM and VLA imaging, ground-based
optical/IR imaging, UV imaging from GALEX and IR data from SIRTF.
Combining the full-spectrum multiwavelength imaging and spectroscopic
coverage with ACS sub-kpc resolution, COSMOS will be Hubble’s ultimate
legacy for understanding the evolution of both the visible and dark

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


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 10046

CCD Hot Pixel Annealing

Hot pixel annealing will be performed once every 4 weeks. The CCD TECs
will be turned off and heaters will be activated to bring the detector
temperatures to about +20C. This state will be held for approximately
12 hours, after which the heaters are turned off, the TECs turned on,
and the CCDs returned to normal operating condition. To assess the
effectiveness of this procedure, a bias and two dark images will be
taken after the annealing procedure for both WFC and HRC. The HRC
darks are taken in parallel with the WFC darks.

STIS/CCD 10037

STIS Cycle 12 Faint Standard Extension: FASTEX

WD 1657+343 is the faintest of four pure hydrogen WD stars that
comprised the original FASTEX program and has been observed thrice in
2000 and once in 2002 to firmly establish the absolute flux levels.
Annual revisits of one orbit should occur to monitor our predictions
of the CTE correction, which is increasing with time on orbit. G430L
at both the standard and E1 aperture position are required at the
exposure times already established as standard. The remaining time in
the orbit will be spent extending the wavelength coverage using G750L.
To date, HST has not provided any faint solar analog stars to
compliment the three V=12-13.5 mag solar analogs provided by M. Rieke
for NICMOS calibration. As instrumentation in space and on the ground
becomes more sensitive, fainter flux standards are required. A solar
analog in a field with low reddening is an excellent choice for a
fainter standard, because unreddened pure hydrogen WDs are rare beyond
V=16, because Solar absolute fluxes are well measured at all
wavelengths, and because the fluxes do not fall off as fast as the hot
WDs at longer wavelengths. A 16.5 G star may not be faint enough for
most JWST modes but will provide a significant step in the right
direction. The SNAP program requires such a spectrophotometric
standard, which lies at the bright limit of its spectroscopy mode.
NICMOS grism observation of this standard are planned for cycle 12 and
STIS spectra are required to establish the standard over the full
range from 0.3-2 microns.

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 10018

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.


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

HSTAR 9421: GS Acquisition (1,2,1) @ 142/22:24:24Z ended in FL backup
on FGS 1 due to SSLE on FGS 2 @ 142/22:28:31Z. Under investigation.

HSTAR 9422: During ZOE, GS Acquisition (2,1,1) scheduled @
143/10:39:19Z resulted in FL backup on FGS 2. At AOS @ 143/10:53:34Z,
there were no flags, however, only FGS 2 resulted in FL. Previous
FHST FM Updates @ 143/10:22Z and 10:25Z both succeeded with low
vehicle errors. Following FHST Map @ 143/11:17:01Z showed axis errors
of 2.275, 5.927, and 1.199 arcsec. Under investigation.

HSTAR 9423: GS Reacquisition (1,2,2) @ 144/12:03:38Z required two
attempts to reach FL due to SSLE on FGS 2. Under investigation.



  • 1234-0 TDW Cross-support tracking (T77 CODE)(Closed)
  • 1236-0 Change Limits MAMA1 Threshold Voltage @ 143/0621z (closed)
  • 1224-2 Bay 5 Web Temp Limit Changed @143/1151z (closed)

                            SCHEDULED     SUCCESSFUL    FAILURE TIMES
GSacq                33                           33 

FGS REacq 15 15 FHST Update 53 53 LOSS of LOCK


Gyro Scale Factor modification SMS SA145. Modified value is:
rga_scale_error = ¼"/degree.

SpaceRef staff editor.