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 # 4459
PERIOD
COVERED: UT October 01, 2007 (DOY 274)
OBSERVATIONS
SCHEDULED
WFPC2
10909
Exploring
the diversity of cosmic explosions: The supernovae of
gamma-ray
bursts
While
the connection between gamma-ray bursts {GRBs} and supernovae
{SNe}
is now clearly established, there is a large variety of
observational
properties among these SNe and the physical parameters of
these
explosions are poorly known. As part of a comprehensive program,
we
propose to use HST in order to obtain basic information about the
supernovae
associated with gamma-ray bursts. HST offers the means to
cleanly
separate the light curves of the GRB afterglow from the
supernova,
and to remove the contamination from the host galaxy, opening
a
clear route to the fundamental parameters of the SN. From these
observations,
we will determine the absolute magnitude at maximum, the
shape
of the spectral energy distribution, and any change over time of
the
energy distribution. We will also measure the rate of decay of the
exponential
tail. Merged with the ground-based data that we will obtain
for
each event, we will be able to compare our data set to models and
constrain
the energy of the explosion, the mass of the ejecta and the
mass
of Nickel synthesized during the explosion. These results will shed
light
on the apparent variety of supernovae associated with gamma-ray
bursts
and X-ray flashes, and on the relation between these SNe and
other,
more common varieties of core-collapse explosions.
ACS/SBC
11151
Evaluating
the Role of Photoevaporation of Protoplanetary Disk Dispersal
Emission
produced by accretion onto the central star leads to
photoevaporation,
which may play a fundamental role in disk dispersal.
Models
of disk photoevaporation by the central star are challenged by
two
potential problems: the emission produced by accretion will be
substantially
weaker for low-mass stars, and photoevaporation must
continue
as accretion slows. Existing FUV spectra of CTTSs are biased to
solar-mass
stars with high accretion rates, and are therefore
insufficient
to address these problems. We propose use HST/ACS SBC
PR130L
to obtain FUV spectra of WTTSs and of CTTSs at low masses and
mass
accretion rates to provide crucial data to evaluate
photoevaporation
models. We will estimate the FUV and EUV luminosities
of
low-mass CTTSs with small mass accretion rates, CTTSs with transition
disks
and slowed accretion, and of magnetically-active WTTSs.
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.
NIC1/NIC2/NIC3
8795
NICMOS
Post-SAA calibration - CR Persistence Part 6
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 i
mages.
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
11107
Imaging
of Local Lyman Break Galaxy Analogs: New Clues to Galaxy
Formation
in the Early Universe
We
have used the ultraviolet all-sky imaging survey currently being
conducted
by the Galaxy Evolution Explorer {GALEX} to identify for the
first
time a rare population of low- redshift starbursts with properties
remarkably
similar to high-redshift Lyman Break Galaxies {LBGs}. These
"compact
UV luminous galaxies" {UVLGs} resemble LBGs in terms of size,
SFR,
surface brightness, mass, metallicity, kinematics, dust, and color.
The
UVLG sample offers the unique opportunity of investigating some very
important
properties of LBGs that have remained virtually inaccessible
at
high redshift: their morphology and the mechanism that drives their
star
formation. Therefore, in Cycle 15 we have imaged 7 UVLGs using ACS
in order
to 1} characterize their morphology and look for signs of
interactions
and mergers, and 2} probe their star formation histories
over
a variety of timescales. The images show a striking trend of
small-scale
mergers turning large amounts of gas into vigorous
starbursts
{a process referred to as dissipational or "wet" merging}.
Here,
we propose to complete our sample of 31 LBG analogs using the
ACS/SBC
F150LP {FUV} and WFPC2 F606W {R} filters in order to create a
statistical
sample to study the mechanism that triggers star formation
in
UVLGs and its implications for the nature of LBGs. Specifically, we
will
1} study the trend between galaxy merging and SFR in UVLGs, 2}
artificially
redshift the FUV images to z=1-4 and compare morphologies
with
those in similarly sized samples of LBGs at the same rest-frame
wavelengths
in e.g. GOODS, UDF, and COSMOS, 3} determine the presence
and
morphology of significant stellar mass in "pre-burst" stars, and 4}
study
their immediate environment. Together with our Spitzer
{IRAC+MIPS},
GALEX, SDSS and radio data, the HST observations will form
a
unique union of data that may for the first time shed light on how the
earliest
major episodes of star formation in high redshift galaxies came
about.
This proposal was adapted from an ACS HRC+WFC proposal to meet
the
new Cycle 16 observing constraints, and can be carried out using the
ACS/SBC
and WFPC2 without compromising our original science goals.
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
11027
Visible
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
4-14.
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.
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
11010
- REACQ(1,0,1) early loss of lock
REACQ(1,0,1) at 06:03:06 acquired fine lock at 06:08:08 but never
achieved "Sci Init", and subsequently lost fine lock at
06:21:14, TERM
EXP was not expected until 06:44:25
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL FAILURE TIMES
FGS
GSacq
04
04
FGS
REacq
10
09
OBAD
with Maneuver
28
28
LOSS
of
LOCK
275/0621z
SIGNIFICANT
EVENTS: (None)