Notice:
Due to the conversion of some ACS WFC or HRC observations into
WFPC2,
or NICMOS observations after the loss of ACS CCD science
capability
in January, there may be an occasional discrepancy between a
proposal's
listed (and correct) instrument usage and the abstract that
follows
it.
HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT # 4421
PERIOD
COVERED: UT August 07, 2007 (DOY 219)
OBSERVATIONS
SCHEDULED
ACS/SBC
11225
The
Wavelength Dependence of Accretion Disk Structure
We
can now routinely measure the size of quasar accretion disks using
gravitational
microlensing of lensed quasars. The next step to testing
accretion
disk models is to measure the size of accretion disks as a
function
of wavelength, particularly at the UV and X-ray wavelengths
that
should probe the inner, strong gravity regime. Here we focus on two
four-image
quasar lenses that already have optical {R band} and X-ray
size
measurements using microlensing. We will combine the HST
observations
with ground-based monitoring to measure the disk size as a
function
of wavelength from the near-IR to the UV. We require HST to
measure
the image flux ratios in the ultraviolet continuum near the
Lyman
limit of the quasars. The selected targets have estimated black
hole
masses that differ by an order of magnitude, and we should find
wavelength
scalings for the two systems that are very different because
the
Blue/UV wavelengths should correspond to parts of the disk near the
inner
edge for the high mass system but not in the low mass system. The
results
will be modeled using a combination of simple thin disk models
and
complete relativistic disk models. While requiring only 18 orbits,
success
for one system requires observations in both Cycles 16 and 17.
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 DARKs. 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.
WFPC2
11124
The
Origin of QSO Absorption Lines from QSOs
We
propose using WFPC2 to image the fields of 10 redshift z ~ 0.7
foreground
{FG} QSOs which lie within ~29-151 kpc of the sightlines to
high-z
background {BG} QSOs. A surprisingly high fraction of the BG QSO
spectra
show strong MgII {2796,2803} absorption lines at precisely the
same
redshifts as the FG QSOs. The high resolution capabilities of WFPC2
are
needed to understand the origin of these absorption systems, in two
ways.
First, we wish to explore the FG QSO environment as close as
possible
to the position of the BG QSO, to search for interloping group
or
cluster galaxies which might be responsible for the absorption, or
irregularly
shaped post-merger debris between the FG and BG QSO which
may
indicate the presence of large amount of disrupted gas along a
sightline.
Similarly, high resolution images are needed to search for
signs
of tidal interactions between any galaxies which might be found
close
to the FG QSO. Such features might provide evidence of young
merging
events causing the start of QSO duty cycles and producing
outflows
from the central AGN. Such winds may be responsible for the
observed
absorption lines. Second, we seek to measure the intrinsic
parameters
of the FG QSO host galaxy, such as luminosity and morphology,
to
correlate with the properties of the MgII absorption lines. We wish
to
observe each field through the F814W filter, close to the rest-frame
B-band
of the FG QSO. These blue data can reveal enhanced star formation
regions
close to the nucleus of the host galaxy, which may be indicative
of
galaxy mergers with the FG QSO host. The FG QSO environment offers
quite
a different set of phenomena which might be responsible for MgII
absorption,
providing an important comparison to studies of MgII
absorption
from regular field 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
11307
Completing
the ACS Nearby Galaxy Survey with WFPC2
We
are requesting 25 orbits of Director's Discretionary Time to complete
the
primary science goals of our highly-ranked ACS Nearby Galaxy Survey
Treasury
program {ANGST}. Our program lost ~2/3 of its orbits due to the
ACS
failure. Roughly half of these were restored as a result of an
appeal
to the Telescope Time Review Board which re-scoped the program.
The
Board's response to our appeal was explicit in terms of which
targets
were to be observed and how. We were directed to request
Director's
discretionary time for the components of the appeal which
were
not granted by the Review Board, but which were vital to the
success
of the program. The observing strategy for ANGST is two-fold: to
obtain
one deep field per galaxy which enables derivation of an accurate
ancient
star formation history, and to obtain radial tilings sufficient
for
recovering the full star formation history. The Review Board granted
WFPC2
observations for deep fields in 7 galaxies, but no time for radial
tilings.
However, recovering the full star formation history of a galaxy
is
not possible without additional radial coverage. We have searched the
archives
for observations which may be used in place of the tilings
{conceding
some of the Treasury goals, but providing significant
constraints
on the full star formation history}, and have identified
suitable
observations for all but two of the galaxies. Here we request
DD
time for radial tilings for those last two galaxies.
WFPC2/ACS/SBC
11020
Cycle
15 Focus Monitor
The
focus of HST is measured primarily with ACS/HRC over full CVZ orbits
to
obtain accurate mean focus values via a well sampled breathing curve.
Coma
and astigmatism are also determined from the same data in order to
further
understand orbital effects on image quality and optical
alignments.
To monitor the stability of ACS to WFPC2 relative focii,
we've
carried over from previous focus monitor programs parallel
observations
taken with the two cameras at suitable orientations of
previously
observed targets, and interspersed them with the HRC CVZ
visits.
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)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
06
06
FGS
REacq
08
08
OBAD
with Maneuver
30
30
SIGNIFICANT
EVENTS: (None)