HST Daily Report # 3309
DAILY REPORT††††††† # 3309
PERIOD COVERED: DOY 58
OBSERVATIONS SCHEDULED
NICMOS 8791
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/CCD/MA1 9357
Towards a global understanding of accretion physics –, Clues from an UV
spectroscopic survey of cataclysmic variables
Accretion inflows and outflows are fundamental phenomena in a wide
variety of
astrophysical environments, such as Young Stellar Objects, galactic
binaries,
and AGN. Observationally, cataclysmic variables {CVs} are particularly
well
suited for the study of accretion processes. We propose to carry out a
STIS UV
spectroscopic snapshot survey of CVs that fully exploits the diagnostic
potential of these objects for our understanding of accretion physics.
This
survey will provide an homogenous database of accretion disc and wind
outflow
spectra covering a wide range of mass transfer rates and binary
inclinations. We
will analyse these spectra with state-of-the-art accretion disc model
spectra
{SYNDISK}, testing our current knowledge of the accretion disc structure,
and,
thereby, providing new insight into the so far not well understood
process of
viscous dissipation. We will use our parameterised wind model PYTHON for
the
analysis of the radiation driven accretion disc wind spectra, assessing
the
fundamental question whether the mass loss rate correlates with the disc
luminosity. In addition, our survey data will identify a number of
systems in
which the white dwarf significantly contributes to the UV flux,
permitting an
analysis of the impact of mass accretion on the evolution of these
compact
stars. This survey will at least double, if not triple, the number of
high-quality accretion disc / wind outflow / accreting white dwarf
spectra, and
we waive our proprietary rights to permit a timely use of this database.
ACS 9411
Morphologies and faint neighbors of z=4.5 Lyman Alpha Emitting Galaxies
We propose to image one ACS field containing four spectroscopically
confirmed
Ly-alpha emitters at z=4.5 in restframe UV and a narrowband filter
containing
the Ly-alpha line. These observations will {A} Reveal the morphology of
the
four
spectroscopically confirmed sources. The high equivalent widths of the
Ly-alpha
line in these four galaxies in particular and this population in general
cannot
be explained without invoking one or more of: extreme youth of the
stellar
population, zero metallicity, energetic winds or type II quasars.
Comparison of
morphologies in the line and continuum would help favor or rule out some
of
these possibilties. This would also tell us whether the star-formation is
uniformly distributed or centrally concentrated or concentrated but in
many
clumps? Proximity of these galaxies {average projected physical
separation of
200 kpc, with one pair 30 kpc apart} also makes interactions likely. {B}
Extend
the luminosity function of Ly-alpha sources by 2.5 magnitudes due to
better
spatial resolution of HST and sensitivity of ACS. We will be able to
detect
sources with line flux of ~eq 2 * 10^-18 ergcm2s over 11.5 sq-arcmins {~
100
sources}. This complements the LALA {Large Area Lyman Alpha} survey which
covers
1/3 square-degree to a line sensitivity of ~eq 2 * 10^- 17. Thus we get a
picture of this patch of young universe in two ways: statistics of faint
galaxies and morphologies of relatively bright ones.
ACS/STIS 9451
ACS Imaging and STIS Spectroscopy of Binary Brown Dwarfs
We have compiled a sample of 9 spatially resolved binary brown dwarfs {18
objects}, and now propose ACS imaging and STIS spectroscopic follow-up
observations. While theoretical models on the interplay of chemical and
physical
processes governing brown dwarf atmospheres have reached a high level of
sophistication, interpretation of observational data remains difficult.
As
brown
dwarfs never stabilize themselves on the hydrogen main sequence, there is
always
an ambiguity between the temperature or luminosity of any brown dwarf and
its
mass or age. The individual components of brown dwarf binaries, however,
are
expected to be coeval and have the same underlying chemical composition.
This
provides crucial constraints on any model, thus greatly reducing the
number of
the free parameters. The aim is to obtain photometric and spectroscopic
data to
probe the physical and chemical properties of the brown dwarf
atmospheres, as
well as second epoch astrometric data to characterize th e orbital
motion. The
study will provide important feedback on theoretical model atmospheres
and
evolutionary tracks for brown dwarfs. As such, it will be an important
step
towards a better understanding of objects with spectral properties
intermediate
between those of giant planets and late-type stars.
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 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 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.
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.
NICMOS 9485
Completing A Near-Infrared Search for Very Low Mass Companions to Stars
within
10 pc of the Sun
Most stars are fainter and less massive than the Sun. Nevertheless, our
knowledge of very low mass {VLM} red dwarfs and their brown dwarf cousins
is
quite limited. Unknown are the true luminosity function {LF},
multiplicity
fraction, mass function, and mass-luminosity relation for red and brown
dwarfs,
though they dominate the Galaxy in both numbers and total mass. The best
way to
constrain these relations is a search for faint companions to nearby
stars.
Such
a search has several advantages over field surveys, including greater
sensitivity to VLM objects and the availability of precise parallaxes
from
which
luminosities and masses can be derived. We propose to complete our
four-filter
NICMOS snapshot search for companions to stars within 10 pc. With a 10
sigma
detection limit of M_J ~ 20 at 10 pc, we can detect companions between 10
and
100 AU that are at least 9 mag fainter than the empirical end of the main
sequence and at least 6.5 mag fainter than the brown dwarf Gl 229B. When
completed, our search will be the largest, most sensitive, volume-limited
search
for VLM companions ever undertaken. Our four-filter search will permit
unambiguous identification of VLM-companion candidates for follow-up
observation. Together with IR speckle and deep imaging surveys, our
program
will
firmly establish the LF for VLM companions at separations of 1-1000 AU
and the
multiplicity fraction of all stars within 10 pc.
WFPC2 9594
WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt2/3
This dark calibration program obtains 3 dark frames every day to provide
data
for monitoring and characterizing the evolution of hot pixels
STIS 9605
CCD Dark Monitor-Part 1
Monitor the darks for the STIS CCD
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 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.
ACS 9656
Stability of the ACS CCD: geometry, flat fielding, photometry
A moderately crowded stellar field, located ~6′ West of the centre of the
cluster 47 Tuc, is observed repeatedly {every three weeks with the WFC,
every
other month with the HRC} in various filters, spending 1 orbit per epoch.
Different filters will be used every time, so that over the course of the
year
all filters will have been employed at least twice. The most common
filters
will
be checked more frequently. The same field has been observed in the
course of
the SMOV phase and the positions and magnitudes of the most prominent
stars
have
been accurately measured. Although the field is neither a proper
astrometric nor
a proper photometric standard one, the positions and magnitudes of the
objects
in it can be used to monitor any local and large scale variations in the
platescale and sensitivity of the detectors. It should be noted that for
the
filters which have already been used during the SMOV phase it will be
sufficient
to take one single image, without CR-SPLIT, since the exposure time is
always
short {20-30 sec} and there will be so many stars that the few of them
which are
affected by cosmic rays can be discarded as outliers in the photometry.
For
narrow and medium band filters not exercised on this target in the SMOV
phase,
however, a baseline will have to be set. This expenditure of time will
apply to
the current cycle only. At variance with the approach used in SMOV, there
is no
need for large telescope slews to place the same objects on opposite
sides of
the detectors, thence allowing the programme to remain compact and
efficient.
All exposure level parameters are set to their default values, except for
the
amplifier gain of the WFC exposures in the F606W band, which will be
collected
with the gain value of 2 for the WFC for compatibility with the SMOV
observations. The exposure time is typically 30 seconds for the WFC, 60
sec for
the HRC. No attempt will be made to attain a predefined or the same
orientation
on the sky amongst different epochs. Typically, for the WFC, five
exposures
will
be accommodated in one orbit. For the HRC, about 10 exposures can be
fitted
within one orbit
ACS 9673
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
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.
STIS 9706
STIS Pure Parallel Imaging Program: Cycle 10
This is the default archival pure parallel program for STIS during cycle
10.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.) None
†††††††††††††††††††††††† SCHEDULED†††† SUCCESSFUL††† FAILURE TIMES FGS GSacq†††††††††††† 06††††††††††††††††††††††† 06 †††† ††††††† FGS REacq†††††††††††† 10††††††††††††††††††††††† 10 FHST Update†††††††††† 11††††††††††††††††††††††† 11††††† LOSS of LOCKSIGNIFICANT EVENTS: None
