HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #4958
PERIOD
COVERED: 5am October 23 - 5am October 26, 2009 (DOY 296/09:00z-299/09:00z)
OBSERVATIONS
SCHEDULED
WFC3/IR/S/C
11929
IR
Dark Current Monitor
Analyses
of ground test data showed that dark current signals are more
reliably
removed from science data using darks taken with the same
exposure
sequences as the science data, than with a single dark current
image
scaled by desired exposure time. Therefore, dark current images
must
be collected using all sample sequences that will be used in
science
observations. These observations will be used to monitor changes
in
the dark current of the WFC3-IR channel on a day-to-day basis, and to
build
calibration dark current ramps for each of the sample sequences to
be
used by GOs in Cycle 17. For each sample sequence/array size
combination,
a median ramp will be created and delivered to the
calibration
database system (CDBS).
WFC3/UVIS
11924
WFC3/UVIS
External and Internal CTE Monitor
CCD
detector Charge Transfer Inefficiency (CTI)-induced losses in
photometry
and astrometry will be measured using observations of the
rich
open cluster NGC6791 and with the EPER (Extended Pixel Edge
Response)
method using tungsten lamp flat field exposures. Although we
do
not expect to see CTE effects at the outset of Cycle 17, this CTE
monitoring
program is the first of a multi-cycle program to monitor and
establish
CTE-induced losses with time. We expect to measure CTE effects
with
a precision comparable to the ACS measurements.
WFC3/UVIS
11908
Cycle
17: UVIS Bowtie Monitor
Ground
testing revealed an intermittent hysteresis type effect in the
UVIS
detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially
found via an unexpected bowtie-shaped feature in flatfield
ratios,
subsequent lab tests on similar e2v devices have since shown
that
it is also present as simply an overall offset across the entire
CCD,
i.e., a QE offset without any discernable pattern. These lab tests
have
further revealed that overexposing the detector to count levels
several
times full well fills the traps and effectively neutralizes the
bowtie.
Each visit in this proposal acquires a set of three 3x3 binned
internal
flatfields: the first unsaturated image will be used to detect
any
bowtie, the second, highly exposed image will neutralize the bowtie
if
it is present, and the final image will allow for verification that
the
bowtie is gone.
WFC3/UVIS
11905
WFC3
UVIS CCD Daily Monitor
The
behavior of the WFC3 UVIS CCD will be monitored daily with a set of
full-frame,
four-amp bias and dark frames. A smaller set of 2Kx4K
subarray
biases are acquired at less frequent intervals throughout the
cycle
to support subarray science observations. The internals from this
proposal,
along with those from the anneal procedure (Proposal 11909),
will
be used to generate the necessary superbias and superdark reference
files
for the calibration pipeline (CDBS).
ACS/WFC3
11879
CCD
Daily Monitor (Part 1)
This
program comprises basic tests for measuring the read noise and dark
current
of the ACS WFC and for tracking the growth of hot pixels. The
recorded
frames are used to create bias and dark reference images for
science
data reduction and calibration. This program will be executed
four
days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To
facilitate
scheduling, this program is split into three proposals. This
proposal
covers 352 orbits (22 weeks) from 31 August 2009 to 31 January
2010.
STIS/CCD
11846
CCD
Bias Monitor-Part 1
The
purpose of this proposal is to monitor the bias in the 1x1, 1x2,
2x1,
and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up
high-S/N
superbiases and track the evolution of hot columns.
STIS/CCD
11844
CCD
Dark Monitor Part 1
The
purpose of this proposal is to monitor the darks for the STIS CCD.
ACS/SBC
11791
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.
WFC3/UV
11730
Continued
Proper Motions of the Magellanic Clouds: Orbits, Internal
Kinematics,
and Distance
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. The results had a number of unexpected implications
for
the Milky Way-LMC-SMC system and received considerable attention in
the
literature and in the press. The implied three-dimensional
velocities
are larger than previously believed and close to the escape
velocity
in a standard 10^12 solar mass Milky Way dark halo. Our orbit
calculations
suggest the Clouds may not be bound to the Milky Way or may
just
be on their first passage, both of which are unexpected in view of
traditional
interpretations of the Magellanic Stream. Alternatively, the
Milky
Way dark halo may be a factor 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 was
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
requested
an additional epoch data in Cycle 16 which is being executed
with
WFPC2/PC due to the failure of ACS. A detailed analysis of one LMC
field
shows that the field proper motion using all three epochs of data
is
consistent within 1-sigma with the two-epoch data, thus verifying
that
there are no major systematic effects in our previous measurements.
The
random errors, however, are only smaller by a factor of 1.4 because
of
the relatively large errors in the WFPC2 data. A prediction for a
fourth
epoch with measurement errors similar to epochs 1 and 2 shows
that
the uncertainties will improve by a factor of 3. This will allow us
to
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 to determine a
distance
to the LMC using rotational parallax. Continuation of this
highly
successful program is therefore likely to provide important
additional
insights. Execution in SNAPshot mode guarantees maximally
efficient
use of HST resources.
WFC3/UVIS
11657
The
Population of Compact Planetary Nebulae in the Galactic Disk
We
propose to secure narrow- and broad-band images of compact planetary
nebulae
(PNe) in the Galactic Disk to study the missing link of the
early
phases of post-AGB evolution. Ejected AGB envelopes become PNe
when
the gas is ionized. PNe expand, and, when large enough, can be
studied
in detail from the ground. In the interim, only the HST
capabilities
can resolve their size, morphology, and central stars. Our
proposed
observations will be the basis for a systematic study of the
onset
of morphology. Dust properties of the proposed targets will be
available
through approved Spitzer/IRS spectra, and so will the
abundances
of the alpha- elements. We will be able thus to explore the
interconnection
of morphology, dust grains, stellar evolution, and
populations.
The target selection is suitable to explore the nebular and
stellar
properties across the galactic disk, and to set constraints on
the
galactic evolutionary models through the analysis of metallicity and
population
gradients.
COS/NUV
11601
UV
Spectroscopy of the Hot Bare Stellar Core H1504+65
H1504+65
is the hottest known white dwarf (Teff=200, 000 K). It has an
extraordinary
surface composition. The surface is devoid of hydrogen and
helium.
It is mainly composed of carbon and oxygen (by equal amounts)
and
neon (2%). We obviously see the exposed core of a former red giant.
The
evolutionary history of this unique object is unknown. We have
identified
magnesium absorption lines in the soft X-ray photospheric
Chandra
spectrum, which suggests that H1504+65 may be an O-Ne-Mg white
dwarf.
We will test this hypothesis by abundance determinations of Mg
and
Na. If confirmed, then H1504+65 would be the most compelling case
for
the existence of single O-Ne-Mg white dwarfs.
ACS/WFC3
11564
Optical
and Ultraviolet Photometry of Isolated Neutron Stars
We
propose ultraviolet and B-band observations of 5 nearby, thermally
emitting
neutron stars. These data will measure the Rayleigh-Jeans tails
of
their spectra, providing a vital complement to X-ray spectroscopy and
helping
to constrain atmospheric models, working toward the ultimate
goal
of unraveling the physics of neutron stars. With these data we will
have
good-quality optical and UV data for the full sample of these
objects,
allowing detailed comparisons between them. Finally, the data
should
allow us to measure proper motions for one or two objects, and
will
serve as the reference data for the remaining objects; such proper
motions
allow ages to be determined for these objects by tracing them
back
to likely birth locations.
COS/NUV/FUV
11531
COS-GTO:
Brown Dwarf Activity
COS
will obtain ultraviolet spectra of a representative sample of brown
dwarfs
to study such questions as: (1) Is the hot gas in the outer
atmospheres
of young brown dwarfs heated by accretion? (2) Is the
molecular
hydrogen emission due to Lyman-alpha fluorescence or
collisional
excitation? (3) Are the older brown dwarfs without disks low
mass
analogs of active M dwarfs with flares and transient heating? (4)
Are
young brown dwarfs with disks low mass analogs of classical T Tauri
stars?
COS/NUV/FUV
11522
COS-GTO:
STAR FORMATION/LYMAN-ALPHA
A
sample of 20 star-forming galaxies will be observed with COS G130M.
The
galaxies were selected from the Kitt Peak International
Spectroscopic
Survey (KISSR) data release and cover a broad range of
luminosity,
oxygen abundance, and reddening. The goal of the program is
to
characterize the Lyman-alpha properties and establish correlations
with
fundamental galaxy properties. Each galaxy will be observed for one
orbit.
NIC
11417
NICMOS
Detector Read noise and Dark Current
The
NICMOS detector characteristics will be monitored during the entire
extent
of the SMOV4 through a set of dark exposures. This will also
allow
a determination of the detector temperature from bias
measurements.
The data should be obtained in SAA-free orbits,
approximately
every 24 hours. In addition, the detector read noise and
the
detector shading profiles will be measured once a week.
WFC3/ACS/UVIS
11360
Star
Formation in Nearby Galaxies
Star
formation is a fundamental astrophysical process; it controls
phenomena
ranging from the evolution of galaxies and nucleosynthesis to
the
origins of planetary systems and abodes for life. The WFC3,
optimized
at both UV and IR wavelengths and equipped with an extensive
array
of narrow-band filters, brings unique capabilities to this area of
study.
The WFC3 Scientific Oversight Committee (SOC) proposes an
integrated
program on star formation in the nearby universe which will
fully
exploit these new abilities. Our targets range from the
well-resolved
R136 in 30 Dor in the LMC (the nearest super star cluster)
and
M82 (the nearest starbursting galaxy) to about half a dozen other
nearby
galaxies that sample a wide range of star-formation rates and
environments.
Our program consists of broad band multiwavelength imaging
over
the entire range from the UV to the near-IR, aimed at studying the
ages
and metallicities of stellar populations, revealing young stars
that
are still hidden by dust at optical wavelengths, and showing the
integrated
properties of star clusters. Narrow-band imaging of the same
environments
will allow us to measure star-formation rates, gas
pressure,
chemical abundances, extinction, and shock morphologies. The
primary
scientific issues to be addressed are: (1) What triggers star
formation?
(2) How do the properties of star-forming regions vary among
different
types of galaxies and environments of different gas densities
and
compositions? (3) How do these different environments affect the
history
of star formation? (4) Is the stellar initial mass function
universal
or determined by local conditions?
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:
18734-1
- NCS CPL Restart (23 October 09) @ 296/2124z
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSAcq
22
21
FGS
REAcq
20
20
OBAD
with Maneuver
17
17
SIGNIFICANT
EVENTS:
Flash
Report: NCS CPL Restart
Ops
Request 18734-1 to restart the NCS CPL has been successfully
completed.
The
PCE was nominally commanded off at 296/14:29z UTC. The CPL was
transitioned
from Standby to Pressure Prime at a reservoir setpoint of
+5
degC at 296/14:30z UTC. After achieving stability at the pressure
prime
setpoint, the CPL was transitioned from Pressure Prime to Startup
at
296/16:41z UTC, enabling the 50 W Startup heater.
At
this time, the +5 degC setpoint will be maintained until stable
operation
at that temperature is confirmed.
Flash
Report: SIs Recovered
ACS,
STIS, COS, and WFC3 have all been recovered to their Operate states
via
the intercept SMS, with WFC3 being the last to complete at 297/1329z.
ACS
and COS have resumed observations. WFC3 will spend until ~297/2033z
UTC
going through its detector cooldowns with its first observation
beginning
at 297/2203z.