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 # 4450
PERIOD
COVERED: UT September 18, 2007 (DOY 261)
OBSERVATIONS
SCHEDULED
ACS/SBC
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.
ACS/WFC
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.
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
11081
RR
Lyrae stars in M31 Globular Clusters: How did the M31 Spiral Galaxy
Form?
The
pulsation properties of the RR Lyrae stars in the globular clusters
of
the Andromeda galaxy {M31} have the potential to provide essential
insight
on the first epoch of the galaxy formation and to trace the
merging
episodes that led to the assembly of M31. Their mean periods
along
with the cluster metallicities can provide an independent estimate
of
the M31 cluster ages and, in turn, of the time scale of the M31 halo
formation,
by comparison with their Milky Way counterparts. We will
observe
RR Lyrae stars in 6 appropriately selected globular clusters of
M31
using WFPC2 to derive periods, light curves, and physical parameters
of
these eyewitnesses of the first epochs of the M31 formation.
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 Monte Carlo
technique to
optimally
schedule our observations.
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
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
04
04
FGS
REacq
11
11
OBAD
with Maneuver
30
30
SIGNIFICANT
EVENTS: (None)