HST Daily Report # 3264
HUBBLE SPACE TELESCOPE
DAILY REPORT # 3264
PERIOD COVERED: DOYs 347-349
OBSERVATIONS SCHEDULED
ACS 9472
A Snapshot Survey for Gravitational Lenses among z >= 4.0 Quasars
Over the last few years, the Sloan Digital Sky Survey has revolutionized the
study of high-redshift quasars by discovering over 200 objects with redshift
greater than 4.0, more than doubling the number known in this redshift
interval.
The sample includes eight of the ten highest redshift quasars known. We propose
a snapshot imaging survey of a well-defined sample of 250 z > 4.0 quasars in
order to find objects which are gravitationally lensed. Lensing models
including
magnification bias predict that at least 4% of quasars in a flux-limited sample
at z > 4 will be multiply lensed. Therefore this survey should find of order 10
lensed quasars at high redshift; only one gravitationally lensed quasar is
currently known at z > 4. This survey will provide by far the best sample to
date of high-redshift gravitational lenses. The observed fraction of lenses can
put strong constraints on cosmological models, in particular on the
cosmological
constant Lambda. In addition, magnification bias can significantly bias
estimates of the luminosity function of quasars and the evolution thereof; this
work will constrain how important an effect this is, and thereby give us a
better understanding of the evolution of quasars and black holes at early
epochs, as well as constrain models for black hole formation.
ACS 9658
ACS Earth Flats
This program will obtain sequences of flat field images by observing the bright
Earth. Several UV filters from the interim calibration program {9564} require
additional exposures to obtain the required illumination. A few UV filters from
this program will be repeated to monitor for changes in the flat fields and to
verify the interim results. Since no streaks are observed in the UV, the
wavelength coverage is extended to longer wavelengths in order to explore the
severity of streaks in the flats from clouds in the FOV. We have added
exposures
for the HRC in the visible filters to verify the results derived from the
L-flat
campaign and to explore the severity of streaks. We have also added
exposures on
WFC using the minimum exposure time and using filters which will not saturate
the brightest WFC pixel by more than 10 times the full well.
ACS 9655
ACS Post-SMOV UV Contamination Monitor
A standard star field {NGC6681} is observed about once a month through all the
ACS broad band UV filters. NGC6681 hosts several UV spectro – photometric
standard stars for which accurate spectra have been {and will continue to be}
measured with STIS. The target cannot be observed for three months from mid
November through to mid February, so the standard star GRW+70 will be observed
twice in its stead. This programme continues the UV sensitivity monitoring
campaign {ACS SMOV proposal 9010} of the HRC and SBC after the end of the SMOV
period. An SBC dark current measurement is taken as the last exposure of each
SBC sequence.
ACS 9482
ACS Pure Parallel Lyman-Alpha Emission Survey {APPLES}
Ly-alpha line emission is an efficient tool for identifying young galaxies at
high redshift, because it is strong in galaxies with young stars and little or
no dust — properties expected in galaxies undergoing their first burst of
star- formation. Slitless spectroscopy with the ACS Wide-Field Camera and G800L
grism allows an unmatched search efficiency for such objects over the
uninterrupted range 4 <~ z <~ 7. We propose the ACS Pure Parallel Ly-alpha
Emission Survey {“APPLES”}, to exploit this unique HST capability and so
obtain the largest and most uniform sample of high redshift Ly-alpha emitters
yet. Parallel observations will allow this survey to be conducted with minimal
impact on HST resources, and we will place reduced images and extracted spectra
in the public domain within three months of observation. We aim to find ~ 1000
Ly-alpha emitters, 5 times the biggest current sample of Ly-alpha emitters.
This
unprecedented sample will provide robust statistics on the populations and
evolution of Ly-alpha emitters between redshifts 4–7; a robust measurement of
the reionization redshift completely independent of the Gunn-Peterson trough;
spatial clustering information for Ly-alpha emitters which would let us probe
their bias function and hence halo mass as a function of redshift; many
galaxies
at redshift exceeding 6; and lower redshift serendipitous discoveries.
ACS 9463
Are OH/IR stars the youngest post-AGB stars? An ACS SNAPshot imaging survey
Essentially all well-characterized preplanetary nebulae {PPNs}– objects in
transition between the AGB and planetary nebula evolutionary phases – are
bipolar, whereas the mass-loss envelopes of AGB stars are strikingly spherical.
In order to understand the processes leading to bipolar mass-ejection, we need
to know at what stage of stellar evolution does bipolarity in the mass-loss
first manifest itself? We have recently hypothesized that most OH/IR stars
{evolved mass- losing stars with OH maser emission} are very young PPNe. We
propose an ACS/SNAPshot imaging survey of a large, morphologically unbiased
sample of these objects, selected using their IRAS 12-to-25micron colors. Our
ground-based imaging study of OH/IR stars has revealed a few compact bipolar
objects, supporting our hypothesis. However since most objects remain
unresolved, HST observations are needed to determine how and when the bipolar
geometry asserts itself. Our complementary program of interferometric
mapping of
the OH maser emission in our sources is yielding kinematic information with
spatial resolution comparable to that in the HST images. The HST/radio data
will
provide crucial input for theories of post-AGB stellar evolution. In addition,
these data will also indicate whether the multiple concentric rings,
“searchlight beams”, and truncated equatorial disks recently discovered with
HST in a few PPNs, are common or rare phenomena.
ACS 9647
CCD Daily Monitor Part I
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 9480
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 ideal.
ACS 9288
Stars in Extended HI Disk Galaxies
Half of gas rich galaxies have HI disks extending well beyond their optical
extents. This gas is a significant potential fuel repository for future star
formation. How can galaxies can store such quantities of ISM without any
apparent star formation? These extended gas disks have well maintained velocity
dispersions and dynamical structure. What is keeping them warm? Perhaps
there is
star formation, but at such low levels it is not readily apparent. We will test
this hypothesis with WFC images deep enough to detect all main sequence stars
that can become type II supernova {i.e. O and B stars}. This will directly
constrain the disk heating rate from stellar populations. The target NGC2915
{DDO154 as a reserve orbit candidate} has one of the most spectacular HI disks;
it extends over five times the optical {Holmberg} radius and displays HI spiral
arms. Recently we discovered three faint HII regions slightly beyond the
optical
radius, indicating some outer disk star formation. Parallel HRC observations
will image one of these HII regions to determine if it is ionized by a cluster
or single star {only one star is needed to produce the ionizing flux}.
Observations of an extended faint young outer stellar population, if found,
will
also [1] constrain IMF parameters {upper mass limit, slope}; [2] imply that the
ISM is not primordial; [3] imply that the target is not as dark matter
dominated
as previously measured.
ACS 9453
The Age of the Andromeda Halo
With the advent of the ACS, we can cross a critical threshold in the study of
galaxy formation: For the first time, we can resolve the old main sequence
stars
in the Andromeda halo, and thus directly determine the ages of the halo
stars in
a giant galaxy other than our own. As the nearest giant galaxy, Andromeda
offers
the best testing ground for understanding galaxy formation and evolution.
Resolution of its halo will tell us about its spread in age and metallicity,
thus providing a formation history. Via extensive simulations, we demonstrate
that we can unambiguously characterize the halo population via a deep
F606W/F814W color-magnitude diagram reaching below the main sequence turnoff.
The data will distinguish whether the halo formed quickly or through protracted
infall and merging episodes, and would detect even a few percent trace of
intermediate age stars. Our field was carefully chosen to meet two criteria: an
optimal stellar density ensuring adequate statistics while avoiding
overcrowding, and the inclusion of an Andromeda globular cluster matched to the
peak halo metallicity. We also propose very brief observations in the same two
bands of five Galactic globular clusters spanning a wide metallicity range,
thus
establishing population templates in the ACS photometric system that will be
used to calibrate and interpret the Andromeda data.
ACS/WFPC2 9488
Cosmic Shear – with ACS Pure Parallel Observations
The ACS, with greater sensitivity and sky coverage, will extend our ability to
measure the weak gravitational lensing of galaxy images caused by the large
scale distribution of dark matter. We propose to use the ACS in pure parallel
{non- proprietary} mode, following the guidelines of the ACS Default Pure
Parallel Program. Using the HST Medium Deep Survey WFPC2 database we have
measured cosmic shear at arc-min angular scales. The MDS image parameters, in
particular the galaxy orientations and axis ratios, are such that any residual
corrections due to errors in the PSF or jitter are much smaller than the
measured signal. This situation is in stark contrast with ground-based
observations. We have also developed a statistical analysis procedure to derive
unbiased estimates of cosmic shear from a large number of fields, each of which
has a very small number of galaxies. We have therefore set the stage for
measurements with the ACS at fainter apparent magnitudes and smaller, 10
arc-second scales corresponding to larger cosmological distances. We will adapt
existing MDS WFPC2 maximum likelihood galaxy image analysis algorithms to work
with the ACS. The analysis would also yield an online database similar to that
in archive.stsci.edu/mds/
FGS 9338
FGS Parallaxes of Cataclysmic Variables: Understanding Their Peculiar Secondary
Stars
We have recently completed an HST FGS program that measured high-precision {+/-
0.5 mas} parallaxes for three dwarf novae. The true distances for all three
objects turned out to be substantially larger than predicted. The results
for SS
Cyg alone, will challenge existing models to explain its large accretion
luminosity. As part of that program we obtained infrared spectra to examine the
spectral types of the secondary stars. The combination of the parallaxes, the
spectra, and existing optical/IR photometry has revealed that the secondary
stars of cataclysmic variables {CVs} are peculiar, and are clearly affected by
close-binary star evolution. We propose a program to measure precise parallaxes
for three additional CVs {WZ Sge, RU Peg, and YZ Cnc}, whose orbital periods
span a much larger range than explored in our previous program. This will allow
us to examine how the accretion luminosity and secondary star change with
orbital period. To do this will require 18 total HST orbits over two separate
cycles. Twelve orbits in Cycle 10 {four per object}, and six orbits in Cycle 11
{two per object}. Only the FGS on HST is capable of providing timely,
high-precision parallaxes on CVs of particular astrophysical interest.
GO 9508
A binary system in the Kuiper Belt: 1998_WW31
1998_WW31 is the first Kuiper Belt Object, outside the pair Pluto/Charon, to be
discovered as a binary object. Though only preliminary results are available
from two orbits of HST DDT observation when this proposal is submitted, the
pair
exhibits a very high eccentricity {larger than 0.5} and a period of 570 days.
The purpose of this proposal is to complete the monitoring of the pair on a
full
orbit, up to February 2003. Monitoring will then have to cease {Sun too close}.
The binarity of an asteroid allows the determination of the total mass of the
system and provides important information on the past Kuiper Belt environment
{formation/collisions/capture processes}. If size can be obtained from albedo
determination, the mass will give the density, a key parameter for any study of
the origin and evolution of the Kuiper Belt. Hubble’s unparalleled resolution
provides the unique way to acquire observations of the pair good enough to
access the physical characteristics of this system with a high degree of
confidence, as the high eccentricity of the orbit keeps the two components less
than 1 arc-second apart for most of the orbit. The observations would be made
public immediately to allow the continuation of the education program offering
to follow the pair on a regular basis to illustrate the prediction/verification
iterative process of science and the direct use of simple laws for the
determination of key parameters.
NICMOS 9702
NICMOS Parallel Thermal Background
NICMOS Camera 2 pure parallel exposures in the F222M and F237M filters to
establish the stability of the HST+NCS+Instrument thermal emission. This data
will be compared against the already available Camera 3 measurements in F222M
which show an increased thermal background.
NICMOS 8790
NICMOS Post-SAA calibration – CR Persistence Part 1.
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.
NICMOS 9639
Photometric Stability
This NICMOS calibration proposal carries out photometric monitoring
observations
during cycle 11.
NICMOS 9484
The NICMOS Parallel Observing Program
We propose to manage the default set of pure parallels with NICMOS. Our
experience with both our GO NICMOS parallel program and the public parallel
NICMOS programs in cycle 7 prepared us to make optimal use of the parallel
opportunities. The NICMOS G141 grism remains the most powerful survey tool for
HAlpha emission-line galaxies at cosmologically interesting redshifts. It is
particularly well suited to addressing two key uncertainties regarding the
global history of star formation: the peak rate of star formation in the
relatively unexplored but critical 1<= z <= 2 epoch, and the amount of star
formation missing from UV continuum-based estimates due to high extinction. Our
proposed deep G141 exposures will increase the sample of known HAlpha emission-
line objects at z ~ 1.3 by roughly an order of magnitude. We will also obtain a
mix of F110W and F160W images along random sight-lines to examine the space
density and morphologies of the reddest galaxies. The nature of the extremely
red galaxies remains unclear and our program of imaging and grism spectroscopy
provides unique information regarding both the incidence of obscured star
bursts
and the build up of stellar mass at intermediate redshifts. In addition to
carrying
out the parallel program we will populate a public database with calibrated
spectra
and images, and provide limited ground- based optical and near-IR data for the
deepest parallel fields.
SNAP/STIS 9434
A SNAPSHOT Survey of the Hot Interstellar Medium
We propose to obtain SNAPSHOT STIS echelle observations of key tracers of hot
interstellar gas {CIV, NV and SiIV} for selected FUSE Team OVI survey targets
with known UV fluxes. By taking advantage of the SNAPSHOT observing mode we
will
efficiently obtain a large number of spectra suitable for the study of the
highly ionized hot component of the interstellar medium {ISM}. Our goals are to
explore the physical conditions in and distribution of such gas, as well as to
explore the nature of the interfaces between the hot ISM and the other
interstellar gas phases. Using inter–comparisons of the various ionic ratios
for CIV, NV, OVI and SiIV, we will be able to discriminate between the various
models for the production of the highly ionized gas in the Galactic ISM. The
survey will also enable detailed studies of regions already known to
contain hot
gas through X-ray emission measurements {e.g., SNRs and radio loops}. The
proposed SNAPSHOT observations will extend our previous Cycle 9 survey {which
was compromised by the STIS side 1 failure}, and should roughly double the
number of stars for which high quality STIS observations of the important hot
gas tracers are available, enabling us to derive a truly global view of the hot
ISM.
STIS 9607
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 9605
CCD Dark Monitor-Part 1
Monitor the darks for the STIS CCD
STIS 9095
Simultaneous HST, Chandra and FUSE Observations of Intrinsic Absorbers in AGN
Photoionized, warm absorbing gas is an important component of the nuclear
structure of AGN. Approximately half of all low-z AGN show high-ionization UV
absorption lines and X-ray warm absorbers, but the relationship of the
UV-absorbing gas to the even higher ionization X-ray absorbing material is not
yet understood. Only a handful of high-spectral-resolution observations with
HST, Chandra or FUSE currently exist {NGC 4151, NGC 3516, NGC 3783, NGC 5548,
Mrk 509}. These show a diversity of kinematic structure and ionization
states in
the absorbers. We propose to increase significantly the sample of low-redshift
AGN studied at high spectral resolution in the UV and the X-ray by obtaining
simultaneous HST, Chandra, and FUSE spectra of NGC 7469 and Mrk 279. Both are
bright AGN with O vi absorption resolved in recent FUSE observations. The new
simultaneous observations will resolve the kinematics and ionization state of
both the UV and X-ray absorbers. This will permit a definitive assessment of
their relationship and give clues to their location in the nuclear region.
Using
the variety of ionization states and the multiple absorbing components, we will
also reconstruct the ionizing spectrum. Understanding the absorbing gas and its
influence on the radiation escaping from AGN has important implications for the
radiative input to the IGM and the origins of the X-ray background.
STIS 9633
STIS parallel archive proposal – Nearby Galaxies – Imaging and Spectroscopy
Using parallel opportunities with STIS which were not allocated by the TAC, we
propose to obtain deep STIS imagery with both the Clear {50CCD} and Long-Pass
{F28X50LP} filters in order to make color-magnitude diagrams and luminosity
functions for nearby galaxies. For local group galaxies, we also include G750L
slitless spectroscopy to search for e.g., Carbon stars, late M giants and
S-type
stars. This survey will be useful to study the star formation histories,
chemical evolution, and distances to these galaxies. These data will be placed
immediately into the Hubble Data Archive.
STIS 9692
STIS Pure Parallel Imaging Program: Cycle 10
This is the default archival pure parallel program for STIS during cycle 10.
STIS/CCD 9074
The Origin and Physics of Gamma-Ray Bursts.
The Space Telescope Imaging Spectrograph (CCD) was used to make observations
that will provide the most stringent tests yet performed of the hypothesis that
GRBs are powered by the collapse of massive stars. STIS CCD spectroscopy
will be
used to detect broad atomic features of supernovae underlying GRB optical
transients, at flux levels more than a factor of three fainter than SN 1998bw.
WFPC2 9699
POMS Test Proposal: WFII backup parallel archive proposal
This is a POMS test proposal designed to simulate scientific plans.
WFPC2 9676
POMS Test Proposal: 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.
WFPC2 9341
Saturn’s Rings and Small Moons
We propose to continue our long-term survey of Saturn’s rings, using the unique
capabilities of the WFPC2, to obtain a coherent set of high resolution,
multi-color images of the Saturnian ring system over the full range of ring
tilt
and phase angles accessible from the Earth over the course of 1/4 Saturn
year {7
Earth years}. Our Cycle 6 {program 6806} and long-term Cycle 7 {7427} and Cycle
8 {8398} observations explored the rings from their nearly edge-on aspect, just
after the most recent ring plane crossings, to their current moderate
inclination. Here, we propose to complete our survey during the next three
Saturn oppositions {Cycles 9–11}, as the rings gradually approach their most
open configuration, shortly before the arrival of the Cassini spacecraft at
Saturn. Our key goals are to investigate the composition, structure, and
particle properties of the rings from variations of ring brightness and color
with radius, tilt and phase angle, to measure the azimuthal asymmetry of the A
ring and the temporal variability of the clumpy F ring, to follow the enigmatic
behavior of the renegade satellites Prometheus and Pandora, and to observe the
south polar region of Saturn.
WFPC2 9593
WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt1/3
This dark calibration program obtains 3 dark frames every day to provide data
for monitoring and characterizing the evolution of hot pixels.
WFPC2/PC1 9663
Focus Monitoring
The HST focus is monitored using WFPC2/PC1. In principle ACS/HRC should provide
superior capability for monitoring the HST focus. Since most of the HST science
will shift to ACS in Cycle 11 trending observations are continued with this
program to establish the focus of WFPC2/PC1 {and hence HST} and ACS/HRC
{and WFC
to a lessor degree} using exposures over full orbits that are taken in
parallel.
With parallel exposures breathing cancels out for the relative camera offset.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of
potential non-nominal performance that will be investigated.)
HSTAR 8880: GS Re-acquisition (3,1,3) @ 347/21:26:30Z resulted in SSLE on
FGS 1 on first and second attempts. Third attempt
was successful.
Exact time of SCI INIT is undetermined due to
LOS. D4MRFGS was still
at CFObsrvr @ 347/21:32:14Z (LOS time). Under
investigation.
COMPLETED OPS REQs:
16885-0 Configure DIU Reader for GYRO#3 Motor Current Sampling @ 347/17:29:29z
OPS NOTES EXECUTED:
1059-0 Change Limits MAMA1 Threshold Voltage @ 347/1938z
1058-0 Post-FSW 2.2A Installation Cleanup @ 347/2020z
1059-0 Change Limits MAMA1 Threshold Voltage @ 349/0859z
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 22 22
FGS REacq 29 27 See Hstar #
8880
FHST Update 42 42
LOSS of LOCK
SIGNIFICANT EVENTS: None
