HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT # 4549
PERIOD
COVERED: UT April 21, 2008 (DOY 112)
OBSERVATIONS
SCHEDULED
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
11148
High
Contrast Imaging of Dusty White Dwarfs
For
the past 18 years, only one white dwarf with a circumstellar dust
disk
was known to exist. In the last two years, six new disks have been
discovered.
Since all material inwards of a few AU should be scoured
clean
during post main sequence evolution, the primary explanation is
the
presence of a planetary system that is perturbing relic
planetesimals
into the tidal disruption radius of the white dwarf. Dusty
disks
around white dwarfs should be markers for planets and we propose
to
use high contrast imaging to search for faint companions down to 6
M_$J$
that may be feeding the disks. White dwarfs are uniquely suited
for
planet searches, where the planet/white dwarf contrast is less than
for
main sequence stars.
NIC2/WFPC2
11142
Revealing
the Physical Nature of Infrared Luminous Galaxies at 0.3<z<2.7
Using
HST and Spitzer
We
aim to determine physical properties of IR luminous galaxies at
0.3<z<2.7
by requesting coordinated HST/NIC2 and MIPS 70um observations
of
a unique, 24um flux-limited sample with complete Spitzer mid-IR
spectroscopy.
The 150 sources investigated in this program have S{24um}
>
0.8mJy and their mid-IR spectra have already provided the majority
targets
with spectroscopic redshifts {0.3<z<2.7}. The proposed
150~orbits
of NIC2 and 66~hours of MIPS 70um will provide the physical
measurements
of the light distribution at the rest-frame ~8000A and
better
estimates of the bolometric luminosity. Combining these
parameters
together with the rich suite of spectral diagnostics from the
mid-IR
spectra, we will {1} measure how common mergers are among LIRGs
and
ULIRGs at 0.3<z<2.7, and establish if major mergers are the drivers
of
z>1 ULIRGs, as in the local Universe. {2} study the co-evolution of
star
formation and blackhole accretion by investigating the relations
between
the fraction of starburst/AGN measured from mid-IR spectra vs.
HST
morphologies, L{bol} and z. {3} obtain the current best estimates of
the
far-IR emission, thus L{bol} for this sample, and establish if the
relative
contribution of mid-to-far IR dust emission is correlated with
morphology
{resolved vs. unresolved}.
WFPC2
11070
WFPC2
CYCLE 15 Standard Darks - part II
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
11185
Search
for H-poor/He-rich Inclusions and a Solution to the Abundance,
Temperature
Problems
Our
recent abundance survey of a large sample of Galactic planetary
nebulae
(PNe) has led to the discovery of a group of super-metal-rich
nebulae
whose spectra are characterized by prominent optical
recombination
lines (ORLs) from C, N, O, & Ne ions and a large Balmer
discontinuity
jump. The heavy element abundances derived from ORLs for
several
PNe are more than an order of magnitude higher than those
derived
from the traditional method based on collisionally excited lines
(CELs),
while the Balmer jump yields electron temperatures (Te)
significantly
lower than values derived from the [O III] 5007/4363 CEL
line
ratio. A proposition that aspires to explain both the nebular
abundance
and Te problems is one according to which these nebulae
contain
(at least) two distinct emission regions - one of "normal" Te (~
10000
K) and chemical composition (~solar) and another of very low Te
that
is H- deficient, thus having high helium and metal abundances
relative
to hydrogen. The latter component emits strong He and heavy
element
ORLs but essentially no CELs. The consistent picture that
emerges
from fitting a 2-component photoionization model to the
spectroscopic
data is that the H-poor component is in high-density
inclusions,
which provide only a minor fraction of the total nebular
mass.
We propose to directly detect these inclusions in the planetary
nebula
M 1-42 using WFPC2 (PC) to make a high spatial resolution image
in the
He I 5876 A ORL and ratio it to Halpha. With NICMOS (NIC1), we
plan
to observe the He I 10830 A line, which is substantially
collisionally
excited, along with Palpha 18760 A. The ratio image of He
I
10830 to Palpha is expected to be less likely to show the inclusions,
thus
serving as an important control to the optical imaging. M 1-42 is
one
of the most extreme cases of the abundance and Te problem; it is
reasonably
bright and compact. This program has the potential to resolve
a
serious challenge to our current understanding of nebular
astrophysics.
WFPC2
11222
Direct
Detection and Mapping of Star Forming Regions in Nearby, Luminous
Quasars
We
propose to carry out narrow-band emission line imaging observations
of
8 quasars at z=0.05-0.15 with the WFPC2 ramp filters and with the
NICMOS
narrow-band filters. We will obtain images in the [O II], [O
III],
H-beta, and Pa-alpha emission line bands to carry out a series of
diagnostic
tests aimed at detecting and mapping out star-forming regions
in
the quasar host galaxies. This direct detection of star-forming
regions
will confirm indirect indications for star formation in quasar
host
galaxies. It will provide a crucial test for models of quasar and
galaxy
evolution, that predict the co-existence of starbursts and
"monsters"
and will solve the puzzle of why different indicators of star
formation
give contradictory results. A secondary science goal is to
assess
suggested correlations between quasar luminosity and the size of
the
narrow-line region.
WFPC2
11312
The
Local Cluster Substructure Survey {LoCuSS}: Deep Strong Lensing
Observations
with WFPC2
LoCuSS
is a systematic and detailed investigation of the mass,
substructure,
and thermodynamics of 100 X-ray luminous galaxy clusters
at
0.15<z<0.3. The primary goal is to test our recent suggestion that
this
population is dominated by dynamically immature disturbed clusters,
and
that the observed mass-temperature relation suffers strong
structural
segregation. If confirmed, this would represent a paradigm
shift
in our observational understanding of clusters, that were hitherto
believed
to be dominated by mature, undisturbed systems. We propose to
complete
our successful Cycle 15 program {SNAP:10881} which prior to
premature
termination had delivered robust weak-lensing detections in 17
clusters,
and candidate strongly-lensed arcs in 11 of these 17. These
strong
and weak lensing signals will give an accurate measure of the
total
mass and structure of the dark matter distribution that we will
subsequently
compare with X-ray and Sunyaev Zeldovich Effect
observables.
The broader applications of our project include 1} the
calibration
of mass-temperature and mass-SZE scaling relations which
will
be critical for the calibration of proposed dark energy
experiments,
and 2} the low redshift baseline study of the demographics
of
massive clusters to aid interpretation of future high redshift {z>1}
cluster
samples. To complete the all-important high resolution imaging
component
of our survey, we request deep WFPC2 observations of 20
clusters
through the F606W filter, for which wide-field weak-lensing
data
are already available from our Subaru imaging program. The
combination
of deep WFPC2 and Subaru data for these 20 clusters will
enable
us to achieve the science program approved by the Cycle 15 TAC.
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
11262
- GSAcq (1,2,1) failed due to QSTOP flag on FGS 1
At 112/10:33:46 GSAcq (1,2,1) scheduled from 10:30:47-10:38:10
failed
due to QF1STOPF and QSTOP Flags on FGS 1. Fine lock was briefly
achieved
but, no s-curves were observed. Pre-acquisition OBADs RSS values
were
3437.94 and 6.55 arc-seconds respectively. Post acquisition OBAD
Map RSS
value was 3.71 arc-seconds.
Additionally, received 4 ACS 779 Status Buffer Messages
("Fold Mechanism
Move was Blocked") following the failure of the GSacq. This
resulted in
the TDF to be down when the Fold mechanism move was commanded.
Flight
Software Error Count (JERRCNT) incremented to 86. OPS Note 1645-15
was
executed to change JERRCNT limit to 86.
11264
- GSAcq (2,1,1) failed due to Scan Step Limit Exceeded on FGS 2
REacq (2,1,1) failed 3 times
At Acquisition of Signal (112/18:02:23) GSAcq (2,1,1) scheduled
from
16:54:19-17:01:35 had failed due to Scan Step Limit Exceeded on
FGS 2.
Received QSTEPEXC and QSTOP flags on FGS 2. Pre-acquisition OBADs
RSS
Error value was 3828.70 and 12.54 arc-seconds respectively. Post
acquisition OBAD MAP RSS Error value was 10.15. Awaiting
engineering
data dump to complete further analysis.
REACQ(2,1,1) at 20:04:12 was successful in obtaining fine lock.
REACQ(2,1,1) at 18:28:19 also failed with 486 ESB message
"a0c"
(FGS coarse mode angle check failed).
REACQ(2,1,1) at 21:42:05 failed with 486 ESB message
"a0c" (FGS coarse
mode angle check failed).
REACQ(2,1,1) at 23:28:15 appears to have succeeded, #44 commands
did
update but entire event happened without telemetry
REACQ(2,1,1) at 01:10:00 failed with 486 ESB message
"a0c" (FGS coarse
mode angle check failed).
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSacq
08
06
FGS
REacq
06
03
OBAD
with Maneuver
28
28
SIGNIFICANT
EVENTS: (None)