HST Daily Report # 3318
HUBBLE SPACE TELESCOPE
DAILY REPORT # 3318
PERIOD COVERED: DOY 71
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.
GO 9172
Molecular Hydrogen in the Damped LyAlpha Absorber of Q1331+170
We wish to search for the Lyman and Werner absorption lines of molecular
hydrogen {rest LambdaLambda = 1104 to 911 Angstrom} associated with the
well-studied damped LyAlpha and 21-cm absorber at z=1.776 in Q1331+170.
The
rare
detection of C I absorption in this system make this a promising
candidate
for a
search. After detecting H_2, we plan to measure the relative population
in the
individual rotation states. The J = 0, 1, 2, 3 states will yield the
kinetic
temperature of the gas, while the weak J = 4 and higher states will
measure {or
limit} the local UV radiation field and hydrogen density. The detection
of
C I^*
has been used to measure the cosmic microwave background temperature at
z=1.776,
and test the validity of the Big Bang model. The observed population of
the
fine
structure levels of C I can be explained entirely by the expected CMB
radiation,
with surprisingly strong limits on local sources of excitation. The H_2
spectrum
will enable us to check this result, by allowing us to make an
independent
estimate of the rate of UV and collisional pumping of the C I^* levels.
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.
ACS 9381
The Birth of a Dwarf Galaxy: The Star Formation History of the Tidal Arm
near
NGC 3077
The extended tidal arm of neutral gas near NGC 3077 {member of the M 81
triplet,
D~3.8 Mpc} is one of the most dramatic features of its kind seen in the
local
universe; it was created by an interaction with M 81 some 3*10^8 yr ago.
It is
one of the few tidal systems where atomic {HI} and molecular {CO} gas as
well as
low–level star formation {HAlpha} is detected over an area of several
kpc^2.
This tidal complex is believed to be in the process of forming a tidal
dwarf
galaxy. Using the unique resolving capability of the Hubble Space
Telescope
{HST} and the wide–field imaging capabilities of the ACS, we propose to
perform
a stellar population study of this tidally created system. By combining
various
methods to recover the star formation history {e.g., using the luminosity
function of the core Helium burning stars} we will 1} measure the SF
history
since closest encounter with M 81, 2} determine whether older stars are
present
in the tidal feature or not and 3} investigate propagation of star
formation
across the tidal feature. This can be done with F435W, F555W, and F814W
imaging
using HST’s ACS with only 8 orbits. We will, for the first time, recover
the
star formation history and the distribution of stars within a tidally
created
system. This study will also shed light on the creation and evolution of
other
tidal dwarf galaxies which are typically much further away.
ACS 9454
The Nature of the UV Continuum in LINERs: A Variability Test
LINERs may be the most common AGNs, and the signposts of accretion onto
the
massive black holes present in most galaxies. However, the LINER spectrum
is the
result of UV excitation, and, in at least some LINERs, a nuclear cluster
of hot
stars, rather than an AGN, dominates the energetics in the UV. Thus, it
is
still
unknown if the UV continuum, or the optical emission lines it excites,
have
anything to do with an AGN. The demographics and accretion physics of
low-luminosity AGNs hinge on this question. We propose to search for
variability
in a sample of 17 LINERs with compact UV nuclei. Variability can reveal
an AGN
component in the UV continuum, even when its light is not dominant. We
will
test
systematically the handful of non-definitive reports of UV variability,
and
potentially quantify the AGN contribution to the UV emission. Variability
in all
or most objects will be strong evidence that LINERs mark dormant AGNs in
most
galaxies. Alternatively, a general null detection of variability will
suggest
that, even in LINERs with additional AGN signatures, the UV continuum is
stellar
in origin. Contemporaneous monitoring with the VLA/VLBA of 11 objects
which
have
radio cores {five of which we already know are radio-variable} will
reveal the
relations between UV and radio variations. The UV-variable objects will
be
targeted for future, better-sampled, monitoring.
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 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.
ACS/WFC 9584
ACS Default {Archival} Pure Parallel Program II.
The Advanced Camera for Surveys (WFC) was used to test ACS pure
parallels.
WFPC2 9589
WFPC2 Decontaminations and Associated Observations Pt. 1/3
This proposal is for the monthly WFPC2 decons. Also included are
instrument
monitors tied to decons: photometric stability check, focus monitor, pre-
and
post-decon internals {bias, intflats, kspots, & darks}, UV throughput
check,
VISFLAT sweep, and internal UV flat check.
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
WFPC2 9598
Earth Flats
This proposal monitors flatfield stability. This proposal obtains
sequences of
Earth streak flats to construct high quality flat fields for the WFPC2
filter
set. These flat fields will allow mapping of the OTA illumination pattern
and
will be used in conjunction with previous internal and external flats to
generate new pipeline superflats. These Earth flats will complement the
Earth
flat data obtained during cycles 4-10.
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.
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
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.) None
COMPLETED OPS REQs: None
OPS NOTES EXECUTED:
0911-0 Limit Management During WFPC2 Decontamination (M001) @ 071/1314z
0911-0 Limit Management During WFPC2 Decontamination (M001) @ 071/2327z
1084-2 Restore DB Limits @ 071/1930z
0900-1 COMMAND PROBLEM @ 072/0647z
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 06 06
FGS REacq 06 06
FHST Update 11 11
LOSS of LOCK
SIGNIFICANT EVENTS: None
