Daily # 4103 (Corrected Date)

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4103

PERIOD COVERED: UT April 28,29,30, 2006 (DOY 118,119,120)

OBSERVATIONS SCHEDULED

NICMOS 8791

NICMOS Post-SAA calibration - CR Persistence Part 2

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 images. Each observation will need its
own CRMAP, as different SAA passages leave different imprints on the
NICMOS detectors.

ACS/HRC/WFC 10758

ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS. Changes from cycle 13:- The default
gain for WFC is 2 e-/DN. As before bias frames will be collected for
both gain 1 and gain 2. Dark frames are acquired using the default
gain {2}. This program cover the period May, 31 2006- Oct, 1-2006. The
first half of the program has a different proposal number: 10729.

NICS3 10754

Spectrophotometric Standards for Cross-Observatory Calibration

This program will obtain NICMOS spectrophotometry of four main
sequence A stars and four K giants, each selected from the Spitzer
IRAC photometric calibration target and/or candidate calibration
target lists. These observations will supplement existing HST
observations of DA white dwarfs and solar analogs, and will provide a
broad base of stellar types for spectrophotometric cross calibration
of HST, Spitzer, and eventually JWST. The targets are chosen to be
faint enough for unsaturated observations with JWST NIRSPEC, yet still
bright enough for high signal to noise in relatively short
observations with HST+NICMOS and with Spitzer+IRAC.

ACS/WFC 10753

An Astrometric Calibration Field Near the Ecliptic Pole

This program will obtain deep ACS astrometry of a Large Magellanic
Cloud star field lying within the planned continuous viewing zone of
the James Webb Space Telescope, which extends to a 5 degree radius
from the Ecliptic pole. To allow a full astrometric solution to be
calculated, controlling for distortions within ACS that may be time
variable over periods of months to years, we will observe our target
field at two distinct roll angles separated by approximately 90
degrees. To help control for large scale distortions, we will "chop"
the observations in at least one roll angle, using offsets of order
one third the ACS field of view.

NIC3 10728

Flats Stability

This calibration proposal is the Cycle 14 NICMOS flat field monitor
program. A series of camera 1, 2, & 3 flat fields will be obtained to
monitor the health of the cameras.

ACS/WFC 10592

An ACS Survey of a Complete Sample of Luminous Infrared Galaxies in
the Local Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared
selected galaxies exceeds that of optically selected galaxies. These
`luminous infrared galaxies' {LIRGs} are primarily interacting or
merging disk galaxies undergoing enhanced star formation and Active
Galactic Nuclei {AGN} activity, possibly triggered as the objects
transform into massive S0 and elliptical merger remnants. We propose
ACS/WFC imaging of a complete sample of 88 L_IR 10^11.4 L_sun
luminous infrared galaxies in the IRAS Revised Bright Galaxy Sample
{RBGS: i.e., 60 micron flux density 5.24 Jy}. This sample is ideal
not only in its completeness and sample size, but also in the
proximity and brightness of the galaxies. The superb sensitivity,
resolution, and field of view of ACS/WFC on HST enables a unique
opportunity to study the detailed structure of galaxies that sample
all stages of the merger process. Imaging will be done with the F439W
and F814W filters {B and I-band} to examine as a function of both
luminosity and merger state {i} the evidence at optical wavelengths of
star formation and AGN activity and the manner in which instabilities
{bars and bridges} in the galaxies may funnel material to these active
regions, {ii} the relationship between star formation and AGN
activity, and {iii} the structural properties {AGN, bulge, and disk
components} and fundamental parameters {effective radius and surface
brightness} of LIRGs and their similarity with putative evolutionary
byproducts {elliptical, S0 and classical AGN host galaxies}. This HST
survey will also bridge the wavelength gap between a Spitzer imaging
survey {covering seven bands in the 3.6-160 micron range} and a GALEX
UV imaging survey of these galaxies, but will resolve complexes of
star clusters and multiple nuclei at resolutions well beyond the
capabilities of either Spitzer or GALEX. The combined datasets will
result in the most comprehensive multiwavelength study of interacting
and merging galaxies to date.

ACS/WFC 10587

Measuring the Mass Dependence of Early-Type Galaxy Structure

We propose two-color ACS-WFC Snapshot observations of a sample of 118
candidate early- type gravitational lens galaxies. Our lens-candidate
sample is selected to yield {in combination with earlier results} an
approximately uniform final distribution of 40 early-type strong
lenses across a wide range of masses, with velocity dispersions {a
dynamical proxy for mass} ranging from 125 to 300 km/s. The proposed
program will deliver the first significant sample of low-mass
gravitational lenses. All of our candidates have known lens and source
redshifts from Sloan Digital Sky Survey data, and all are bright
enough to permit detailed photometric and stellar- dynamical
observation. We will constrain the luminous and dark-matter mass
profiles of confirmed lenses using lensed-image geometry and
lens-galaxy structural/photometric measurements from HST imaging in
combination with dynamical measurements from spatially resolved
ground-based follow-up spectroscopy. Hence we will determine, in
unprecedented detail, the dependence of early-type galaxy mass
structure and mass-to-light ratio upon galaxy mass. These results will
allow us to directly test theoretical predictions for halo
concentration and star-formation efficiency as a function of mass and
for the existence of a cuspy inner dark- matter component, and will
illuminate the structural explanation behind the fundamental plane of
early-type galaxies. The lens-candidate selection and confirmation
strategy that we propose has been proven successful for high-mass
galaxies by our Cycle 13 Snapshot program {10174}. The program that we
propose here will produce a complementary and unprecedented lens
sample spanning a wide range of lens-galaxy masses.

ACS/WFC 10573

Globular Clusters in the Direction of the Inner Galaxy

The age, chemical and kinematic distributions of stellar populations
provide powerful constraints on models of the formation and evolution
of the Milky Way. The globular clusters constitute an especially
useful case because the stars within individual clusters are coeval
and spatially distinct. But a serious limitation in the study of many
globular clusters -- especially those located near the Galactic Center
-- has been the existence of large absolute and differential
extinction by foreground dust. We propose to use the ACS to map the
differential extinction and remove their effects in a large sample of
globular clusters located in the direction of the inner Galaxy using a
technique refined recently by von Braun and Mateo {2001}. These
observations and their analyses will let us produce high quality
color-magnitude diagrams of these poorly studied clusters that will
allow us to determine these clusters' relative ages, distances and
chemistry and to address important questions about the formation and
the evolution of the inner Galaxy. Our aim for these ACS observations
is to obtain data for the most crowded clusters in the inner Galaxy
where the excellent spatial resolution of the ACS is most necessary.

ACS/SBC 10568

Ultraviolet spectrum of the binary millisecond pulsar J0437-4715

PSR J0437-4715 is the nearest and the brightest millisecond {recycled}
pulsar, and the only one detected at near-optical wavelengths. We
detected it with the HST STIS/FUV-MAMA detector and found that its FUV
spectrum is consistent with being emitted from the neutron star
surface with a temperature of about 0.1 MK, surprisingly high for such
an old object. We also found evidence of an emission line at 1372 A,
tentatively interpreted as a Zeeman component of the hydrogen Ly-alpha
line in a magnetic field of 700 MG. Unfortunately, the spectrum was
imaged in a region of strong detector background, which strongly
hampered the spectral analyses. We propose to re-observe the pulsar
with the ACS/SBC in FUV and ACS/HRC in NUV to obtain the spectrum of
the pulsar in a broad UV range. The spectral analysis will allow us to
measure the temperature of the full neutron star surface and probe the
heating mechanisms operating in old neutron stars. Confirmation of the
spectral line would lead to a first direct measuremnt of the magnetic
field and the radius of a spin-powered neutron star and uniquely
constrain the equation of state of superdense matter. The NUV spectrum
will also probe the magnetospheric emission and the thermal structure
of the cool white dwarf companion.

ACS/SBC 10554

Globular Cluster Systems of Elliptical Galaxies in Low Density
Environments

We propose to use the ACS/WFC to determine colour {metallicity}
distributions and luminosity functions for the globular cluster
populations in a well-defined sample of elliptical galaxies in low-
density environments, and to compare the results with similar samples
taken from a rich cluster environment. Low-luminosity ellipticals are
now recognized to play a pivotal role in testing hierarchical models
of galaxy formation, and their globular cluster populations provide a
unique probe of their star formation and metal enrichment history. The
data will be used to {i} determine whether the bimodal colour
distributions indicative of multiple formation epochs in luminous
ellipticals are also prevalent in low-luminosity field ellipticals;
{ii} place joint constraints on age and metallicity in systems with
more than one population and determine the spread of ages in any one
system; {iii} test whether cluster destruction processes {e.g. tidal
shocking} are more effective in low-luminosity ellipticals, as
predicted from their higher mass densities. ACS observations are
essential to eliminate foreground/background contamination and to
probe deep into the luminosity function to obtain a good statistical
sample of clusters. The TAC has previously awarded HST time to two
large surveys of globular cluster systems in rich cluster
environments, but there is currently no comparable survey in
low-density environments with which to compare these results.

ACS/HRC 10549

SAINTS - Supernova 1987A INTensive Survey

SAINTS is a program to observe SN 1987A, the brightest supernova in
384 years, as it morphs into the youngest supernova remnant at age 18.
HST is the unique and perfect tool for spatially- resolved
observations of the many physical components of SN 1987A. A violent
encounter is underway between the fastest-moving debris and the
circumstellar ring, exciting hotspots seen with HST that are suddenly
lighting up. The optical and X-ray flux from the ring are both rising
rapidly: HST and Chandra observations taken together are needed to
understand the physics of these shocked regions. In Cycle14, the
hotspots may fuse as the shock fully enters the ring. Photons from
these shocks may excite previously hidden gas outside the ring,
revealing the true extent of the mass loss that preceded the
explosion. The inner debris of the explosion itself, still excited by
radioactive isotopes produced in the explosion, is now well resolved
by ACS and seen to be aspherical, providing direct clues to the
mechanism of the explosion. Our search for a compact remnant is
beginning to eliminate some theoretical possibilities and we have the
opportunity in Cycle 14 to place much more stringent limits with
NICMOS. Many questions about SN 1987A remain unanswered. How did the
enigmatic three rings form in the late stages of Sanduleak -69 202?
Precisely what took place in the center during the core collapse and
bounce? Is a black hole or a neutron star left behind in the debris?
SAINTS has been a continuous program since HST was launched-- we
propose to extend this rich and deep data set for present use and
future reference to answer these central questions in the science of
supernovae.

ACS/WFC 10523

The Halo Shape and Metallicity of Massive Spiral Galaxies

We propose to resolve the stellar populations of the halos of seven
nearby, massive disk galaxies using a SNAP survey with WFC/ACS. These
observations will provide star counts and color-magnitude diagrams 2-3
magnitudes below the tip of the Red Giant Branch along the two
principal axes and one intermediate axis of each galaxy. We will
measure the metallicity distribution functions and stellar density
profiles from star counts down to very low average surface
brightnesses, equivalent to ~31 V-mag per square arcsec. This proposal
will create a unique sampling of galaxy halo properties, as our
targets cover a range in galaxy mass, luminosity, inclination, and
morphology. As function of these galaxy properties this survey will
provide:- the first systematic measurement of radial light profiles
and axial ratios of the diffuse stellar halos and outer disks of
spiral galaxies- a comprehensive analysis of halo metallicity
distributions as function of galaxy type and position within the
galaxy- an unprecedented study of the stellar metallicity and age
distribution in the outer disk regions where the disk truncations
occur- the first comparative study of globular clusters and their
field stellar populations We will use these fossil records of the
galaxy assembly process to test halo formation models within the
hierarchical galaxy formation scheme.

ACS/WFC 10505

The Onset of Star Formation in the Universe: Constraints from Nearby
Isolated Dwarf Galaxies.

The details of the early star formation histories of tiny dwarf
galaxies can shed light on the role in galaxy formation of the
reionization which occured at high redshift. Isolated dwarfs are ideal
probes since their evolution is not complicated by environmental
effects owing to the vicinity of the Milky Way and M31. In addition,
dwarf galaxies are the most common type of galaxies, and potentially
the building blocks of larger galaxies. Since we can date the oldest
stars in them, their study represents a complementary approach to the
study of the formation and evolution of galaxies through high-z
observations. We propose to use the ACS to obtain a homogeneus dataset
of high-quality photometry, down to the old {13 Gyr} main-sequence
turnoffs, for a representative sample of 4 isolated Local Group dwarf
galaxies. These data are essential to unambiguously determine their
early star formation histories, through comparison with synthetic
color-magnitude diagrams, and using the constraints provided by their
variable stars. Parallel WFPC2 observations of their halos will allow
us to reveal the actual nature of their stellar population gradients,
providing important aditional constraints on their evolution. The
proposed observations are being complemented with ground-based
spectroscopy, to obtain metallicity and kinematic information. The
observations requested here, which must reach M_I=+3.5 {I=27.5- 28.2}
with S/N=10 in crowded systems, can only be achieved with HST using
ACS, and won't be possible with planned ground- or space-based
facilities such as JWST. Based on deep WFPC2 observations and ACS
image simulations, our team has designed an observational strategy
which carefully considers the optimal filter combination, the
necessary photometry depth and the effects of stellar crowding.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTARS:

10244 - GSAcq(2,1,1) failed to (M2G) due to search radius limit
exceeded on FGS-2 @ 120/06:11:51z

Upon acquisition of signal at 120/06:23:30 the spacecraft was in RGA
control (M2G). The GSAcq(2,1,1) scheduled at 120/05:58:37 -06:06:42
failed to (M2G) due to search radius limit exceeded on FGS-2.
Pre-acquisition OBADs both succeded. OBAD2 at 120/05:51:55 had
attitude correction total (RSS) value of 49.88 arcseconds. Primary FGS
search radius = 57 arcseconds.

10246 - GSAcq(2,1,1) failed to RGA Control @ 120/23:00:16z

The GSAcq(2,1,1) scheduled at 120/23:00:16 - 23:08:21 failed to RGA
control due to stop flag (QF2STOPF) on FGS-2. Pre-acquisition OBADs
both succeded. OBAD2 at 120/22:55:56 had attitude correction total
(RSS) value of 8.48 arcseconds.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 25 23 Hstar #
10244& # 10246
FGS
REacq 17 17
OBAD with Maneuver 72 72

SIGNIFICANT EVENTS: (None)