Notice: For the foreseeable future, the daily reports may
contain
apparent discrepancies between some proposal descriptions
and the listed
instrument usage. This is due to the conversion of
previously approved
ACS WFC or HRC observations into WFPC2, or NICMOS
observations
subsequent to the loss of ACS CCD science capability in
late January.
HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT # 4396
PERIOD COVERED: UT June 02, 2007 (DOY 183)
OBSERVATIONS SCHEDULED
WFPC2 11024
WFPC2 CYCLE 15 INTERNAL MONITOR
This calibration proposal is the Cycle 15 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 {both
gain 7 and
gain 15 -- to test stability of gains and bias levels}, a
test for
quantum efficiency in the CCDs, and a monitor for possible
buildup of
contaminants on the CCD windows. These also provide raw
data for
generating annual super-bias reference files for the
calibration
pipeline.
FGS 11212
Filling the Period Gap for Massive Binaries
The current census of binaries among the massive O-type
stars is
seriously incomplete for systems in the period range from
years to
millennia because the radial velocity variations are too
small and the
angular separations too close for easy detection. Here we
propose to
discover binaries in this observational gap through a
Faint Guidance
Sensor SNAP survey of relatively bright targets listed in
the Galactic O
Star Catalog. Our primary goal is to determine the binary
frequency
among those in the cluster/association, field, and runaway
groups. The
results will help us assess the role of binaries in
massive star
formation and in the processes that lead to the ejection
of massive
stars from their natal clusters. The program will also
lead to the
identification of new, close binaries that will be targets
of long term
spectroscopic and high angular resolution observations to
determine
their masses and distances. The results will also be
important for the
interpretation of the spectra of suspected and newly
identified binary
and multiple systems.
NIC1/NIC2/NIC3 8794
NICMOS Post-SAA calibration - CR Persistence Part 5
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 11101
The Relevance of Mergers for Fueling AGNs: Answers from
QSO Host
Galaxies
The majority of QSOs are known to reside in centers of
galaxies that
look like ellipticals. Numerical simulations have shown
that remnants of
galaxy mergers often closely resemble elliptical galaxies.
However, it
is still strongly debated whether the majority of QSO host
galaxies are
indeed the result of relatively recent mergers or whether
they are
completely analogous to inactive ellipticals to which
nothing
interesting has happened recently. To address this
question, we recently
obtained deep HST ACS images for five QSO host galaxies
that were
classified morphologically as ellipticals {GO-10421}. This
pilot study
revealed striking signs of tidal interactions such as
ripples, tidal
tails, and warped disks that were not detected in previous
studies. Our
observations show that at least some
"elliptical" QSO host galaxies are
the products of relatively recent merger events rather
than old galaxies
formed at high redshift. However, the question remains
whether the host
galaxies of classical QSOs are truly distinct from
inactive ellipticals
and whether there is a connection between the merger
events we detect
and the current nuclear activity. We must therefore place
our results
into a larger statistical context. We are currently
conducting an HST
archival study of inactive elliptical galaxies {AR-10941}
to form a
control sample. We now propose to obtain deep HST/WFPC2
images of 13
QSOs whose host galaxies are classified as normal
ellipticals. Comparing
the results for both samples will help us determine
whether classical
QSOs reside in normal elliptical galaxies or not. Our recent
pilot study
of five QSOs indicates that we can expect exciting results
and deep
insights into the host galaxy morphology also for this
larger sample of
QSOs. A statistically meaningful sample will help us
determine the true
fraction of QSO hosts that suffered strong tidal
interactions and thus,
whether a merger is indeed a requirement to trigger
nuclear activity in
the most luminous AGNs. In addition to our primary science
observations
with WFPC2, we will obtain NICMOS3 parallel observations
with the
overall goal to select and characterize galaxy populations
at high
redshifts. The imaging will be among the deepest NICMOS
images: These
NICMOS images are expected to go to a limit a little over
1 magnitude
brighter than HUDF-NICMOS data, but over 13 widely
separated fields,
with a total area about 1.5 times larger than HUDF-NICMOS.
This
separation means that the survey will tend to average out
effects of
cosmic variance. The NICMOS3 images will have sufficient
resolution for
an initial characterization of galaxy morphologies, which
is currently
one of the most active and promising areas in approaching
the problem of
the formation of the first massive galaxies. The depth and
area coverage
of our proposed NICMOS observations will also allow a
careful study of
the mass function of galaxies at these redshifts. This
provides a large
and unbiased sample, selected in terms of stellar mass and
unaffected by
cosmic variance, to study the on-going star formation
activity as a
function of mass {i.e. integrated star formation} at this
very important
epoch.
NIC3 11062
NICMOS non-linearity tests
This program incorporates a number of tests to analyze the
count rate
dependent non- linearity seen in NICMOS
spectro-photometric
observations. We will observe a field with stars of a
range in
luminosity in NGC3603 with NICMOS in NIC1: F090M, F110W,
F140W, F160W
NIC2: F110W, F160W, F187W, F205W, and F222M NIC3: F110W,
F150W, F160W,
F175W, and F222M. We will repeat the observations with
flatfield lamp
on, creating artificially high count-rates, allowing tests
of NICMOS
linearity as function of count rate. We first take
exposures with the
lamp off, then exposures with the lamp on, and repeat at
the end with
lamp off. Finally, we continue with taking darks during
occultation. We
will furthermore observe spectro-photometric standard
P041C using the
G096, G141, and G206 grisms in NIC3, and repeat the lamp
off/on/off test
to artificially create a high background.
WFPC2 11023
WFPC2 CYCLE 15 Standard Darks - part 1
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.
WFPC2 11029
WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation
Anomaly
Monitor
Intflat observations will be taken to provide a linearity
check: the
linearity test consists of a series of intflats in F555W,
in each gain
and each shutter. A combination of intflats, visflats, and
earthflats
will be used to check the repeatability of filter wheel
motions.
{Intflat sequences tied to decons, visits 1-18 in prop
10363, have been
moved to the cycle 15 decon proposal xxxx for easier
scheduling.} Note:
long-exposure WFPC2 intflats must be scheduled during ACS
anneals to
prevent stray light from the WFPC2 lamps from
contaminating long ACS
external exposures.
WFPC2 11175
UV Imaging to Determine the Location of Residual Star
Formation in
Galaxies Recently Arrived on the Red Sequence
We have identified a sample of low-redshift {z = 0.04 -
0.10} galaxies
that are candidates for recent arrival on the red
sequence. They have
red optical colors indicative of old stellar populations,
but blue
UV-optical colors that could indicate the presence of a
small quantity
of continuing or very recent star formation. However,
their spectra lack
the emission lines that characterize star-forming
galaxies. We propose
to use ACS/SBC to obtain high- resolution imaging of the
UV flux in
these galaxies, in order to determine the spatial
distribution of the
last episode of star formation. WFPC2 imaging will provide
B, V, and I
photometry to measure the main stellar light distribution
of the galaxy
for comparison with the UV imaging, as well as to measure
color
gradients and the distribution of interstellar dust. This
detailed
morphological information will allow us to investigate the
hypothesis
that these galaxies have recently stopped forming stars and
to compare
the observed distribution of the last star formation with
predictions
for several different mechanisms that may quench star
formation in
galaxies.
WFPC2 11178
Probing Solar System History with Orbits, Masses, and
Colors of
Transneptunian Binaries
The recent discovery of numerous transneptunian binaries
{TNBs} opens a
window into dynamical conditions in the protoplanetary
disk where they
formed as well as the history of subsequent events which
sculpted the
outer Solar System and emplaced them onto their present
day heliocentric
orbits. To date, at least 47 TNBs have been discovered,
but only about a
dozen have had their mutual orbits and separate colors
determined,
frustrating their use to investigate numerous important
scientific
questions. The current shortage of data especially
cripples scientific
investigations requiring statistical comparisons among the
ensemble
characteristics. We propose to obtain sufficient
astrometry and
photometry of 23 TNBs to compute their mutual orbits and
system masses
and to determine separate primary and secondary colors,
roughly tripling
the sample for which this information is known, as well as
extending it
to include systems of two near-equal size bodies. To make
the most
efficient possible use of HST, we will use a
optimally schedule our observations.
WFPC2 11201
Systemic and Internal motions of the Magellanic Clouds:
Third Epoch
Images
In Cycles 11 and 13 we obtained two epochs of ACS/HRC data
for fields in
the Magellanic Clouds centered on background quasars. We
used these data
to determine the proper motions of the LMC and SMC to
better than 5% and
15% respectively. These are by far the best determinations
of the proper
motions of these two galaxies. The results have a number
of unexpected
implications for the Milky Way-LMC-SMC system. The implied
three-dimensional velocities are larger than previously
believed, and
are not much less than the escape velocity in a standard
10^12 solar
mass Milky Way dark halo. Orbit calculations suggest the
Clouds may not
be bound to the Milky Way or may just be on their first
passage, both of
which would be unexpected in view of traditional
interpretations of the
Magellanic Stream. Alternatively, the Milky Way dark halo
may be a
factor of two more massive than previously believed, which
would be
surprising in view of other observational constraints.
Also, the
relative velocity between the LMC and SMC is larger than
expected,
leaving open the possibility that the Clouds may not be
bound to each
other. To further verify and refine our results we now
request an epoch
of WFPC2/PC data for the fields centered on 40 quasars
that have at
least one epoch of ACS imaging. We request execution in
snapshot mode,
as in our previous programs, to ensure the most efficient
use of HST
resources. A third epoch of data of these fields will
provide crucial
information to verify that there are no residual
systematic effects in
our previous measurements. More importantly, it will
increase the time
baseline from 2 to 5 yrs and will increase the number of
fields with at
least two epochs of data. This will reduce our
uncertainties
correspondingly, so that we can better address whether the
Clouds are
indeed bound to each other and to the Milky Way. It will
also allow us
to constrain the internal motions of various populations
within the
Clouds, and will allow us to determine a distance to the
LMC using
rotational parallax.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS: (None)
COMPLETED OPS REQUEST: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 6 6
FGS REacq 7 7
OBAD with Maneuver 26
26
COMPLETED OPS NOTES: (None)
SIGNIFICANT EVENTS: (None)