Daily Report #4053

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4053

PERIOD COVERED: UT February 17,18,19, 2006 (DOY 048,049,050)

OBSERVATIONS SCHEDULED

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration - CR Persistence Part 4

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.

WFPC2 10772

WF4 Anomaly Characterization

A anomaly has been found in images from the WF4 CCD in WFPC2. The WF4
CCD bias level appears to have become unstable, resulting in sporadic
images with either low or zero bias level. Calibration images will be
obtained to further characterize the anomaly.

ACS/HRC/WFC 10729

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 Oct, 2 2005- May, 29-2006. The
second half of the program has a different proposal number: 10758.

ACS/WFC 10621

ACS Zero Point Verification

The uncertainties in the photometric zero points create a fundamental
limit to the accuracy of photometry. The current state of the ACS
calibration is with zero point uncertainties of 0.03 magnitudes. The
reason for this is that the ACS calibrations are based primarily on
semi-emprical synthetic zero points and observations of fields too
crowded for accurate ground-based photometry. I propose to obtain ACS
images of the omega Cen standard field with all nine broadband ACS/WFC
filters. This will permit the direct determination of the ACS zero
points by comparison with excellent ground-based photometry, and
should reduce their uncertainties to less than 0.01 magnitudes. A
second benefit is that it will facilitate the comparison of the WFPC2
and ACS photometric systems, which will be important as WFPC2 is
phased out and ACS becomes HST's primary imager. Finally, three of the
filters will be repeated from my Cycle 12 observations, allowing for a
measurement of any change in sensitivity.

FGS 10611

Precise Distances to Nearby Planetary Nebulae

We propose to carry out astrometry with the FGS to obtain accurate and
precise distances to four nearby planetary nebulae. In 1992, Cahn et
al. noted that ``The distances to Galactic planetary nebulae remain a
serious, if not THE most serious, problem in the field, despite
decades of study.'' Twelve years later, the same statement still
applies. Because the distances to planetary nebulae are so uncertain,
our understanding of their masses, luminosities, scale height, birth
rate, and evolutionary state is severely limited. To help remedy this
problem, HST astrometry can guarantee parallaxes with half the error
of any other available approach. These data, when combined with
parallax measurements from the USNO, will improve distance
measurements by more than a factor of two, producing more accurate
distances with uncertainties that are of the order of ~6%. Lastly,
most planetary nebula distance scales in the literature are
statistical. They require several anchor points of known distance in
order to calibrate their zero point. Our program will provide "gold
standard" anchor points by the end of 2006, a decade before any
anticipated results from future space astrometry missions.

ACS/HRC 10607

Probing Circumstellar and Interstellar Dust with Scattered-Light
Echoes

Scattered-light echoes are one of the most powerful and efficient
probes of the structure and composition of dust in circumstellar and
interstellar {ISM} environments. Observations of light echoes provide
exact three-dimensional positions of dust while constraining its
density, grain- size and chemical make-up. Furthermore, echoes can be
used as distance indicators via polarization measurements. We propose
to take deep, high-resolution ACS/HRC images of five supernovae {SNe}.
Two of these, SNe 1991T and 1998bu, have known circumstellar echoes
that have only recently become fully resolvable with HST, and
therefore require new observations. Only four echo-producing SNe are
currently known, and in an attempt to increase this sample, we will
also observe SNe 1999bw, 2002hh, and 2004dj. All three SNe are strong
candidates for producing echoes from circumstellar and ISM dust, but
only at angular sizes that HST can resolve. With these observations,
we will use light echoes to their full advantage, to study {1} the
mass-loss histories of Type II and Ia SN progenitors, {2} the
contributions of these SNe and their progenitors to the dust content
of their galaxies, {3} the structure of gas and stars in the ISM of
external galaxies, and {4} we will independently measure the distance
to the host galaxies, including a member of the Virgo cluster, and
M96, a Type Ia cosmological distance- scale calibrator.

ACS/WFC 10596

AGNs with Intermediate-mass Black Holes: A Test of the Black
Hole-Bulge Paradigm

The recent progress in the study of central black holes in galactic
nuclei has led to a general consensus that supermassive {10^6-10^9
solar mass} black holes are closely connected with the formation and
evolutionary history of large galaxies, especially their bulge
component. Two outstanding issues, however, remain unresolved. Can
central black holes form in the absence of a bulge? And does the mass
function of central black holes extend below 10^6 solar masses?
Intermediate-mass black holes {10^4-10^6 solar masses}, if they exist,
may offer important clues to the nature of the seeds of supermassive
black holes. In a first systematic search using the Sloan Digital Sky
Survey, we have recently discovered 19 Type 1 AGNs with candidate
intermediate-mass black holes that reside in low-luminosity,
presumably late-type host galaxies. Follow-up observations with Keck
indicate that these objects obey the low-mass extension of the
well-known correlation between black hole mass and bulge stellar
velocity dispersion. However, very little is known about the host
galaxies themselves, including the crucial question of whether they
have bulges or not. We propose to obtain ACS/WFC images of this unique
sample of AGNs in order to investigate the detailed structural
properties of the host galaxies. We are particularly keen to determine
whether the hosts contain bulges, and if so, where they lie on the
fundamental plane of spheroids compared to the bulges of supermassive
black holes. We will also be able to measure an accurate optical
luminosity for the AGN, which is an essential ingredient to improve
the current mass estimates.

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 10577

Resolving the non-radiative shock in SN1006

An ACS image of the H alpha filament in the supernova remnant SN1006
will resolve the thickness of the H alpha emission zone. This will
permit us to derive an accurate pre-shock density, which in turn can
be used to model the time-dependent X-ray spectrum of the bright X-
ray ridge with no free parameters, thus benchmarking these widely used
models. We will also search for evidence of a shock precursor, and we
will use the scale of ripples in the shock to estimate the level of
density inhomogeneity in the pre-shock gas.

ACS/HRC 10556

Neutral Gas at Redshift z=0.5

Damped Lyman-alpha systems {DLAs} are used to track the bulk of the
neutral hydrogen gas in the Universe. Prior to HST UV spectroscopy,
they could only be studied from the ground at redshifts z1.65.
However, HST has now permitted us to discover 41 DLAs at z1.65 in our
previous surveys. Followup studies of these systems are providing a
wealth of information about the evolution of the neutral gas phase
component of the Universe. But one problem is that these 41
low-redshift systems are spread over a wide range of redshifts
spanning nearly 70% of the age of the Universe. Consequently, past
surveys for low-redshift DLAs have not been able to offer very good
precision in any small redshift regime. Here we propose an ACS-HRC-
PR200L spectroscopic survey in the redshift interval z=[0.37, 0.7]
which we estimate will permit us to discover another 41 DLAs. This
will not only allow us to double the number of low-redshift DLAs, but
it will also provide a relatively high-precision regime in the
low-redshift Universe that can be used to anchor evolutionary studies.
Fortunately DLAs have high absorption equivalent width, so
ACS-HRC-PR200L has high-enough resoultion to perform this proposed
MgII-selected DLA survey.

ACS/WFC 10543

Microlensing in M87 and the Virgo Cluster

Resolving the nature of dark matter is an urgent problem. The results
of the MACHO survey of the Milky Way dark halo toward the LMC indicate
that a significant fraction of the halo consists of stellar mass
objects. The VATT/Columbia survey of M31 finds a similar lens fraction
in the M31 dark halo. We propose a series of observations with ACS
that will provide the most thorough search for microlensing toward
M87, the central elliptical galaxy of the Virgo cluster. This program
is optimized for lenses in the mass range from 0.01 to 1.0 solar
masses. By comparing with archival data, we can detect lenses as
massive as 100 solar masses, such as the remnants of the first stars.
These observations will have at least 15 times more sensitivity to
microlensing than any previous survey, e.g. using WFPC2. This is due
to the factor of 2 larger area, factor of more than 4 more sensitivity
in the I-band, superior pixel scale and longer baseline of
observations. Based on the halo microlensing results in the Milky Way
and M31, we might expect that galaxy collisions and stripping would
populate the overall cluster halo with a large number of stellar mass
objects. This program would determine definitively if such objects
compose the cluster dark matter at the level seen in the Milky Way. A
negative result would indicate that such objects do not populate the
intracluster medium, and may indicate that galaxy harassment is not as
vigorous as expected. We can measure the level of events due to the
M87 halo: this would be the best exploration to date of such a lens
population in an elliptical galaxy. Star-star lensing should also be
detectable. About 20 erupting classical novae will be seen, allowing
to determine the definitive nova rate for this giant elliptical
galaxy. We will determine if our recent HST detection of an M87
globular cluster nova was a fluke, or indicative of a 100x higher rate
of incidence of cataclysmic variables and nova eruptions in globulars
than previously believed. We will examine the populations of variable
stars, and will be able to cleanly separate them from microlensing.

ACS/WFC/NIC3/WFPC2 10530

Probing Evolution And Reionization Spectroscopically {PEARS}

While imaging with HST has gone deep enough to probe the highest
redshifts, e.g. the GOODS survey and the Ultra Deep Field,
spectroscopic identifications have not kept up. We propose an ACS
grism survey to get slitless spectra of all sources in a wide survey
region {8 ACS fields} up to z =27.0 magnitude, and an ultradeep field
in the HUDF reaching sources up to z =28 magnitude. The PEARS survey
will: {1} Find and spectrocopically confirm all galaxies between
z=4-7. {2} Probe the reionization epoch by robustly determining the
luminosity function of galaxies and low luminosity AGNs at z = 4 - 6.
With known redshifts, we can get a local measure of star formation and
ionization rate in case reionization is inhomogeneous. {3} Study
galaxy formation and evolution by finding galaxies in a contiguous
redshift range between 4 z 7, and black hole evolution through a
census of low-luminosity AGNs. {4} Get a robust census of galaxies
with old stellar populations at 1 z 2.5, invaluable for checking
consistency with heirarchical models of galaxy formation. Fitting
these galaxies' spectra will yield age and metallicity estimates. {5}
Study star-formation and galaxy assembly at its peak at 1 z 2 by
identifying emission lines in star-forming galaxies, old populations
showing the 4000A break, and any combination of the two. {6} Constrain
faint white dwarfs in the Galactic halo and thus measure their
contribution to the dark matter halo. {7} Derive spectro-photometric
redshifts by using the grism spectra along with broadband data. This
will be the deepest unbiased spectroscopy yet, and will enhance the
value of the multiwavelength data in UDF and the GOODS fields to the
astronomical community. To this end we will deliver reduced spectra to
the HST archives.

NIC2 10527

Imaging Scattered Light from Debris Disks Discovered by the Spitzer
Space Telescope Around 20 Sun-like Stars

We propose to use the high contrast capability of the NICMOS
coronagraph to image a sample of newly discovered circumstellar disks
associated with sun-like stars. These systems were identified by their
strong thermal infrared emission with the Spitzer Space Telescope as
part of the Spitzer Legacy Science program titled, "The Formation and
Evolution of Planetary Systems {FEPS}." Modelling of the thermal
excess emission in the form of spectral energy distributions alone
cannot distinguish between narrowly confined high opacity disks and
broadly distributed, low opacity disks. However, our proposed NICMOS
observations can, by imaging the light scattered from this material.
Even non- detections will place severe constraints on the disk
geometry, ruling out models with high optical depth. Unlike previous
disk imaging programs, our program contains a well defined sample of
solar mass stars covering a range of ages from ~10Myrs to a few Gyrs,
allowing us to study the evolution of disks from primordial to debris
for the first time. These results will greatly improve our
understanding of debris disks around Sun- like stars at stellar ages
nearly 10x older than any previous investigation. Thus we will have
fit a crucial piece into the puzzle concerning the formation and
evolution of our own solar system.

ACS/WFC 10520

Resolving the Complex Star Formation History of the Leo I Dwarf
Spheroidal Galaxy

Determining the star formation histories {SFHs} and chemical evolution
of nearby galaxies gives us powerful constrains on the physical
processes that regulate galaxy evolution. The SFHs can be measured
most accurately by comparing the observed densities of stars in
color-magnitude diagrams {CMDs} to predictions from stellar
evolutionary models. WFPC2 imaging of the Leo I dSph shows it is
unique because its stellar population is relatively young.
Approximately 68% of its stars formed between 1 and 7 Gyr ago and only
12% of its stars formed ~ 10 Gyr ago. We propose to vastly improve
the derived SFH of Leo I by exploiting ACS/WFC's higher quantum
efficiency at bluer wavelengths, higher spatial resolution, and larger
field-of-view. The figure of merit for our proposed observations,
defined as the age resolution times the number of stars detected, will
be a factor of 12 higher than existing WFPC2 observations. To surmount
the degeneracy of age and metallicity in the CMD, we have
independently measured the metallicity distribution of its stars using
spectroscopy. Simultaneously modeling the metallicity distribution and
CMD, we will firmly constrain the evolution of the Leo I dSph, a
unique example of an isolated dwarf galaxy that has not been
influenced by interactions with the Milky Way or M31.

ACS/HRC 10508

Orbits, Masses, and Densities of Three Transneptunian Binaries

The subset of transneptunian objects {TNOs} having natural satellites
offers unique opportunities for physical studies of these distant
relics from the outer parts of the protoplanetary nebula. HST/ACS is
ideally suited to determining orbits of TNO satellites, resulting in
the system masses. In conjunction with thermal emission observations
by Spitzer, which provides sizes, we can determine the densities of
TNOs. Densities offer a powerful window into their bulk compositions
and interior structures.

ACS/WFC 10496

Decelerating and Dustfree: Efficient Dark Energy Studies with
Supernovae and Clusters

We propose a novel HST approach to obtain a dramatically more useful
"dust free" Type Ia supernovae {SNe Ia} dataset than available with
the previous GOODS searches. Moreover, this approach provides a
strikingly more efficient search-and-follow-up that is primarily pre-
scheduled. The resulting dark energy measurements do not share the
major systematic uncertainty at these redshifts, that of the
extinction correction with a prior. By targeting massive galaxy
clusters at z 1 we obtain a five-times higher efficiency in
detection of Type Ia supernovae in ellipticals, providing a
well-understood host galaxy environment. These same deep cluster
images then also yield fundamental calibrations required for future
weak lensing and Sunyaev-Zel'dovich measurements of dark energy, as
well as an entire program of cluster studies. The data will make
possible a factor of two improvement on supernova constraints on dark
energy time variation, and much larger improvement in systematic
uncertainty. They will provide both a cluster dataset and a SN Ia
dataset that will be a longstanding scientific resource.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

#10138: OM1EBOXT & OOBBH6T Temperture Limits @ 050/0245z
At 050/00:37:43 OM1EBOXT (MAMA 1 Electrical Box Temp) and OOBBH6T
(Optical Bench Bulkhead 6 Temp) started displaying the following OOL
values: OM1EBOXT: Red Low EU= -0.15 (LL = 0). OOBBH6T: Red Low EU=
9.75667 (LL = 10). Mnemonics continued to flag OOL till LOS @
050/01:26:15. Contacted SI/SE who advised due to HST being in a "cold
angle", to change the temp limits of the effected mnemonics for 24 hours
(see Ops Note 1452-1).

#10139: GSACQ(1,3,1) failed, Search Radius Limit Exceeded on FGS 1 @ 050/1912z
GSACQ(1,3,1) at 050/19:08:08 failed due to Search Radius Limit Exceeded
on FGS 1 at 19:12:47. One 486 status buffer message A05 (Search Radius
Limit Exceeded on FGS1). OBAD at 19:02:35 prior to GSACQ had total RSS
attitude error correction of 23.68 arcseconds OBAD at 19:15:09 after
failed GSACQ had total RSS error of 195.48 arcseconds. REACQ(1,3,1) at
20:48:27 failed with 486 ESB message A05. REACQ(1,3,1) at 22:19:49
failed with 486 ESB message A0E.

#10140: Roll (V1) attitude error vector limit violation (QDVEFGS1) at AOS @
051/0057z
Upon AOS @ 051/00:57:16 mnemonic (QDVEFGS1) V1 attitude error vector
flagged out of limits showing Red Low -307.106 arcseconds. At the time a
T2 slew (00:41:04 - 00:54:05) had just finished. No 486 ESB messages
were noted. Last prior GSAcq (050/19:08:06) failed as well as the next
two REAcq (050/20:48:27 & 050/22:47:45), see HSTAR 10139. At 051/01:19:34
QDVEFGS1 flagged out of limits for a second time showing Red Low
-307.106 arcseconds.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES:
#1452-1: OM1EBOXT & OOBBH6T Temperature Limits @050/0237z, (closed
@051/0300z)

SCHEDULED SUCCESSFUL
FGS GSacq 24 23
FGS REacq 20 18
OBAD with Maneuver 88 88

SIGNIFICANT EVENTS: (None)