Status Report

NASA Hubble Space Telescope Daily Report # 3662

By SpaceRef Editor
July 29, 2004
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




ACS/HRC 9974

Mid-Ultraviolet Spectral Templates for Old Stellar Systems

We propose a three-year program to provide both observational and
theoretical mid-ultraviolet {2300A — 3100A} spectral templates for
interpreting the age and metallicity of globular clusters and
elliptical galaxies from spectra of their integrated light. The mid-UV
is the region most directly influenced by stellar age, and is observed
directly in optical and infrared studies of high-redshift quiescent
systems. The reliability of age and metallicity determinations remains
questionable until non-solar metallicities and abundance ratios are
considered, and stars spanning the color-magnitude diagram are
included, as we propose here. With archival HST STIS spectra we have
improved the list of mid-UV atomic line parameters, then calculated
spectra from first principles which match observed spectra of standard
stars up to one- fourth solar metallicity. We will extend both
observations and calculations to stars of solar metallicity and
beyond, and to those in short-lived stages hotter than the
main-sequence turnoff, stars not currently well-represented in
empirical libraries. The necessary line-list improvements will come
from new high-resolution mid-UV spectra of nine field stars. A key
application of the results of this program will be to the old systems
now being discovered as `Extremely Red Objects’ at high redshifts.
Reliable age-dating of these places constraints on the epoch when
large structures first formed in the universe.


AALs in Quasars: Diagnostics of the Environment

Associated absorption lines {AALs} in quasar spectra carry a wealth of
information on the gas-phase kinematics, ionization states, column
densities, outflow masses, and elemental abundances near the quasars.
Most of the existing UV spectra have low spectral resolution, which
hampers efforts to accurately determine these properties at low
redshifts. We propose medium-resolution FUV and NUV STIS spectroscopy,
more than an order of magnitude improvement in spectral resolution
over previous studies, to observe a sample of AAL quasars at redshifts
and luminosities intermediate between the nearby Seyferts and the
bright, high-z quasars. Our aim is to determine basic physical
parameters for the absorbers, measure the abundances, search for AAL
variability, and constrain the location of the absorbers relative to
the central quasars. A unique aspect of our z~0.2 sample is the
ability to get both UV and X-ray diagnostics, thus allowing us to
perform a joint analysis of our STIS data with X-ray observations to
further constrain the full range of ionizations and column densities
of the UV/X-ray absorbing gas.

NIC3 9846

The Origins of Sub-stellar Masses: Searching for the End of the IMF

Is there a preferred scale that defines the end of the IMF? We propose
to test this hypothesis by conducting a deep spectroscopic survey of
extremely low mass objects in the embedded young cluster associated
with NGC1333. At a distance of only 300pc, this cluster is one of the
nearest examples of a dense young cluster. We will be able to obtain
R=200 spectra and photometry for 40-60 cluster members with masses
between 5-40 Jupiter masses at an age of 1 Myr observed through
A{v}<10 mag. This will enable us to estimate temperatures and
luminosities for all sources detected in the survey. We will compare
their positions in an H-R diagram to PMS evolutionary tracks in order
to estimate their ages and masses. For a solar metallicity cloud at a
temperature of 10 K, the minimum mass for fragmentation is thought to
be 10 Jupiter masses. A statistically significant sample of objects
detected below this limit would challenge the role of hierarchical
fragmentation in limiting substellar masses. The proximity of this
cluster combined with the unique sensitivity, wavelength coverage, and
multi-object spectroscopic capability of NICMOS on HST make this
experiment possible.

ACS/WFC 9842

A Snapshot Search for Halo Very-Low-Mass Binaries

We propose a snapshot search for binary M subdwarf stars. These nearby
stars have high velocities and low metallicies that identify them as
members of the old Galactic halo {Population II}. ACS imaging is
requested to search for secondary companions. This supplements a
previous snapshot program that only obtained 10 observations. The
observed binary fraction will be compared to the disk M dwarf fraction
to look for differences in star formation. It is likely that a system
suitable for orbital mass determinations will be found. In this case,
future HST observations could determine the first masses for
very-low-mass, low-metallicity stars.

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.


Probing Outflowing Winds from the Galactic Center

We propose to use two extragalactic sightlines to probe our own
Galaxy’s "starburst" wind emanating from the Galactic Center. While
new infrared imaging and spectroscopy have detected massive stars and
very recent {<3×10^6 yrs} star formation in the Galactic Center
region, only indirect evidence {e.g., radio loops and arcs, bi-conical
cavity edges seen in the mid-IR} exists for a wind. However, these
winds are routinely detected from starbursts in other galaxies. Far-UV
STIS echelle spectroscopy {E140M} of two targets on either side of the
Galactic Center at {l, b}={350,-33} and {349, 55} will allow us to map
the kinematics of outflowing gas in high ionization species of N V, Si
IV and C IV. Similar spectra of distant {1.5-5 kpc}, bright B stars in
the same regions of the sky will allow us to remove foreground
contaminating components due to the Sco-Cen OB associations. Lower
resolution STIS first-order and FUSE spectra show highly redshifted
gas in N V and O VI respectively along these sightlines; these new
observations will provide three times better spectral resolution {7-10
km/s in the 1185-1580A region} so that the kinematic signature of the
outflow can definitely be detected. The foreground stars will allow us
to determine whether the outflow is from the Galactic Center or the
Sco-Cen OB associations. Absorption line column densities will be used
to estimate the outflowing mass and energy by assuming a metallicity
and ionizing source for the gas.


A morphological study of EROs and sub-mm sources in a unique deep field

We propose a deep I-band ACS WFC survey in a unique deep field,
focusing on two classes of high-redshift galaxy which are believed to
be the progenitors of today’s massive ellipticals: {1} our
recently-studied deep sample of 158 "extremely red objects" {EROs};
{2} a complete flux-limited sample of 14 SCUBA sub-mm sources, which
may represent the formation episode of the most massive galaxies at
high redshift. The basic goals are to go deep enough to obtain
morphological parameters for this large sample {e.g. scale-lengths and
shape parameters} to investigate whether, for example, the EROs have
sizes comparable to present day elliptical galaxies. Likewise, what
are the typical size scales and morphologies for the SCUBA sources?
Can we visualize their formation from smaller fragments? We can
achieve both goals in a single contiguous field with a mosaic of 8
deep ACS WFC fields, requiring 16 orbits.


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.

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 10228

Multi-color HST imaging of the GJ 803 debris disk

We propose to conduct a comprehensive high angular resolution study of
the newly discovered debris disk around GJ 803. This nearby, young
star has an estimated age of 8-20 Myr, a critical epoch in disk
evolution and planet formation. By virtue of its proximity {10 pc} and
nearly edge-on orientation, GJ 803’s disk has an exceptional surface
brightness and angular size relative to other disks resolved in
scattered light thus far. Hence, this system offers an exciting new
opportunity to study debris disks. Our proposed ACS and NICMOS imaging
will elucidate the disk morphology, ascertain the grain properties as
a function of radius, and search for fine dynamical structure
indicative of the presence of planets. ACS WFC and NICMOS
coronagraphic imaging will explore the inner disk, which includes the
~17 AU inner disk hole inferred from the star’s spectral energy
distribution. Complementary ACS WFC imaging will probe the outer disk
{>70 AU}; at such large distances around GJ 803, dust evolutionary
timescales are longer than the stellar age, and hence we can study the
composition of primordial circumstellar material. The combined dataset
will provide the most comprehensive study to date of a debris disk
from ~7 AU to ~200 AU radius.

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.

ACS/WFC 10120

The Formation Histories and Dynamical Roles of X-ray Binaries in
Globular Clusters

Close binaries are fundamental to the dynamical stability and
evolution of globular clusters, but large populations have been
extremely difficult to identify. Chandra X-ray images provide a
revolutionary resource, revealing a few to dozens of low-luminosity
X-ray sources in every cluster deeply examined; our own Chandra
programs uniformly study these ubiquitous X-ray sources {close
binaries and their progeny} in 11 clusters. However, definitive
understanding of the nature of the various X-ray subpopulations
requires the identification of optical counterparts, and HST is the
demonstrated key in these crowded environments. We thus propose a
proven, efficient, and uniform, HST multicolor imaging program for
optical identifications in 6 of our clusters with Chandra data
on-hand, but which lack adequate optical images in the HST archive.
The proposed ACS images will permit statistical classifications into
the various subtypes: CVs, qLMXBs, BY Dra’s/RS CVn’s {and MSPs}. A
unique aspect of our program is that our clusters span a range of
physical properties such as central concentration, cluster size, and
mass–essential ingredients in the formation, evolution, and dynamical
roles of cluster binaries. Exploiting this range of properties, we
have identified a relation that provides the first compelling link
between the number of X-ray sources and the predicted stellar
encounter frequency in globular cluster cores. But further progress in
understanding the details implicit in this relationship {e.g., whether
CVs and qLMXBs formed primarily via stellar encounters, while BY
Dra’s/RS CVn’s are mainly primordial binaries} demands uniform optical
identifications for multiple clusters, spanning the full range
physical properties.

FGS 10103

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

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.

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 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.


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.

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.

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
investigated.) None


17230-2 Off-line +B SPA Trim Relay @ 209/16:10z

17231-0 Increase Battery 5 VTFE @ 209/16:18z


1246-0 Battery 5 Capacity Test Ground Limits @ 208/19:10z

1253-0 Battery 5 Pres Limit Changes Post Batt Capacity @ 208/19:15z

                        SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq             22                          22
FGS REacq             10                          10
FHST Update          30                          30


Successfully off-lined +B SPA Trim Relay at first opportunity
209/16:10Z (OR 17230-2 with attached script). A complement of SA 3
strings is being kept off-line to optimize the battery full charge
rate. The +DD SPA (4-string, Battery 1) has been kept off-line since
Day 147 for this purpose. Since Battery 1 will undergo a capacity test
in the next few weeks, need to reconfigure the charge-optimization
configuration to avoid complexity in the Battery 1 Capacity Test
script and promote recovery of Battery 1 following the discharge.
Brought the +DD SPA (4-string, Batter 1) back on-line and took the +B
SPA (4-string, Battery 4) off-line.

Successfully increased Battery 5 VTFE Curve @ 209/16:18Z (OR 17231
with attached script).

Following the uplinks, EPS SE monitored the power system operations
from the console in the MOR for two orbits to verify nominal operation
of TRSWCC (+B SPA Trim Relay disconnected, commanded relay order upon
Trickle Charge initiation, Battery 5 VTFE cut-off, etc.). The
batteries experienced Trickle Charge durations during the first and
second orbits of 37 minutes and 42 minutes, respectively. EPS SEs
continued to closely monitor the power system performance, especially
battery temperatures and pressures, to assess the effect of these

SpaceRef staff editor.