HST Daily Report # 3317
DAILY REPORT # 3317
PERIOD COVERED: DOY 70
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.
ACS 9352
The Deceleration Test from Treasury Type Ia Supernovae at Redshifts 1.2 to
1.6
Type Ia supernovae {SNe Ia} provide the only direct evidence for an
accelerating
universe, an extraordinary result that needs a rigorous test. The case for
cosmic acceleration rests on the observation that SNe Ia at z ~ 0.5 are ~
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 SN Ia result attributed
to
grey dust or cosmic evolution of the SN Ia peak luminosity would not show
this
change of sign. We have demonstrated proof of this concept with a single SN
Ia,
SN 1997ff at z = 1.7, found and followed by HST. The results suggest an
early
epoch of deceleration, but this is too important a conclusion to rest on
just
one object. Here we propose to use HST for observations of six SNe Ia in the
range 1.2 <= z <= 1.6, that will be discovered as a byproduct from proposed
Treasury programs for high-latitude ACS surveys. Six objects will provide a
much
firmer foundation for a conclusion that touches on important questions of
fundamental physics.
NICMOS 9360
Paschen-alpha Imaging of a SIRTF-Selected Nearby Galaxy Sample
We propose to carry out a NICMOS snapshot survey in the Paschen-alpha
{PAlpha}
emission line and H-band of the sample of galaxies being observed at 3.5 —
160
microns as part of SIRTF Nearby Galaxies Survey {SINGS} and a related
guaranteed
time survey of starburst galaxies. The PAlpha images, accessible only from
HST,
will be combined with groundbased HAlpha imaging to measure the extinction
in
the star-forming centers of these galaxies, and obtain robust, extinction-
corrected maps of the massive star formation rate {SFR}. The PAlpha data by
themselves will provide reliable `extinction- free’ SFRs, and a
cross-calibration of the {dust–affected} HAlpha– and UV–based SFRs. The
PAlpha–based SFR measurements will extend the SFR-vs.-gas density law
{Schmidt–law} to surface densities at least 30 times higher than what is
accessible using HAlpha–based SFR measurements alone, bridging the gap
between
normal galaxies and IR–luminous starbursts. Furthermore, the combination
of the
HST PAlpha images with the SIRTF images and spectra, as well as ancillary
ground–based UBVRIJHK images and GALEX UV images being obtained as part of
the
SINGS project, will provide a definitive study of the radiative transfer of
starlight and dust heating in star–forming galaxies. The processed NICMOS
images will be incorporated into the public SINGS Legacy Data Archive, to
enable
scores of follow-up studies by the astronomical community at large.
ACS 9450
The lensing galaxy of JVAS B0218+357: determination of H_0
Much effort has been devoted to estimating Hubble’s constant H_0 using
observations of very nearby objects. Gravitational lensing time delays offer
potentially the most accurate method for determining H_0 using observations
on
cosmological scales; it is a very clean method in that little complicated
astrophysics is involved, and it is a single–step method compared to the
traditional multi–step distance ladder. The major problem with most such
determinations in the past has been systematic errors due to uncertainties
in
the lens mass model, leading to 20 Einstein-ring lens system, is the one
system
for which these systematic uncertainties can be reduced very substantially,
and
in particular is unique in that the modeling systematics can be reduced to
the
level of the uncertainties in the measurement of the time delay. The only
requirement left is to be able accurately to locate the center of the
lensing
galaxy. We propose an extremely deep ACS image in I-band of this system for
this
purpose; the prize is a robust 5 {lens mass model}. We have conducted
simulations to estimate the necessary S:N ratio in an ACS observation in
order
to be able to achieve a successful deconvolution of the lens galaxy and
lensed
images with the required accuracy.
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/WFPC2 9481
Pure Parallel Near-UV Observations with WFPC2 within High-Latitude ACS
Survey
Fields
In anticipation of the allocation of ACS high-latitude imaging survey{s}, we
request a modification of the default pure parallel program for those WFPC2
parallels that fall within the ACS survey field. Rather than duplicate the
red
bands which will be done much better with ACS, we propose to observe in the
near-ultraviolet F300W filter. These data will enable study of the
rest-frame
ultraviolet morphology of galaxies at 0<z<1. We will determine the
morphological
k-correction, and the location of star formation within galaxies, using a
sample
that is likely to be nearly complete with multi-wavelength photometry and
spectroscopic redshifts. The results can be used to interpret observations
of
higher redshift galaxies by ACS.
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
CAL/WF2 9597
Intflat Sweep, Visflat Sweep, and Filter Anomaly Check
No abstract available.
WFPC2 9599
WFPC2 Cycle 11 UV Earth Flats
Monitor flat field stability. This proposal obtains sequences of earth
streak
flats to improve the quality of pipeline flat fields for the WFPC2 UV filter
set. These Earth flats will complement the UV earth flat data obtained
during
cycles 8-10.
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 9615
Cycle 11 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.
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 9673
CCD Daily Monitor
for any source of noise in ACS CCD detectors. This programme will be
executed
once a day for the entire lifetime of ACS
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.
STIS 9706
STIS Pure Parallel Imaging Program: Cycle 10
This is the default archival pure parallel program for STIS during cycle 10.
WFPC2 9713
The Origin of Short-Period Comets
none supplied
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of
potential non-nominal performance that will be investigated.)
HSTAR 8955: Gsacq (3,1,1) results to Finelock Backup (3,0,3). The
GSACQ(3,1,1) scheduled at 071/08:47:09 – 08:54:33
resulted to finelock
(3,0,3) using FGS#3 due to scan step limit exceeded
on FGS#1. Possible
observations affected: STIS 41,42 ACS 86 NICMOS
18. For additional
details see SERS system. The guide star acquisition
for this observation
was non-nominal, further analysis will determine if
a repeat observation
is required.
COMPLETED OPS REQs:
16918-0 Null Genslews For Proposal 9713 (slots 1-11) (NOT REQUIRED)
OPS NOTES EXECUTED: NONE
SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 15 15 FGS REacq 0 0 FHST Update 17 17 LOSS of LOCK
SIGNIFICANT EVENTS: None
