Daily # 4176

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4176

PERIOD COVERED: UT August 11,12,13, 2006 (DOY 223,224.225)

OBSERVATIONS SCHEDULED

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

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.

FGS 10989

Astrometric Masses of Extrasolar Planets and Brown Dwarfs

We propose observations with HST/FGS to estimate the astrometric
elements {perturbation orbit semi-major axis and inclination} of
extra-solar planets orbiting six stars. These companions were
originally detected by radial velocity techniques. We have
demonstrated that FGS astrometry of even a short segment of reflex
motion, when combined with extensive radial velocity information, can
yield useful inclination information {McArthur et al. 2004}, allowing
us to determine companion masses. Extrasolar planet masses assist in
two ongoing research frontiers. First, they provide useful boundary
conditions for models of planetary formation and evolution of
planetary systems. Second, knowing that a star in fact has a plantary
mass companion, increases the value of that system to future
extrasolar planet observation missions such as SIM PlanetQuest, TPF,
and GAIA.

ACS/HRC 10891

The Dynamical Mass of the Bright Cepheid Polaris

Cepheid variables are of central importance in Galactic and
extragalactic astronomy. They are the primary standard candles for
measuring extragalactic distances, and they provide critical tests of
stellar-evolution theory. Surprisingly, however, until now there was
not a single Cepheid with a purely dynamical measurement of its mass.
Polaris {alpha UMi} is the nearest and brightest of all Cepheids. It
offers the unique opportunity to measure the dynamical mass of a
Cepheid, because it is in a binary system for which a single-lined
spectroscopic orbit is already available. In Cycle 14, we resolved the
system in the UV using ACS/HRC, thus providing the first direct
detection of the companion, as well as a first approximation to the
dynamical mass. In the present proposal we request one HST orbit per
year for the next 3 Cycles, in order to refine the visual orbit.
Combined with the HST/FGS parallax {see below}, this program will
provide an accurate mass for the Cepheid {the error should be about
0.5 Msun by Cycle 17}, and the only one based purely on dynamical
information. Only HST's combination of high spatial resolution and UV
sensitivity can achieve this result. The parallax is a key ingredient
in the mass determination. In an ongoing multi-year program {GO-9888,
GO-10113, GO-10482}, we are using the FGS to improve significantly
upon the Hipparcos parallax of Polaris. The continued ACS imaging
proposed here will thus provide extremely valuable astrophysical
information from a very modest additional investment of observing
time.

ACS/WFC 10880

The host galaxies of QSO2s: AGN feeding and evolution at high
luminosities

Now that the presence of supermassive black holes in the nuclei of
galaxies is a well established fact, other questions related to the
AGN phenomena still have to be answered. Problems of particular
interest are how the AGN gets fed, how the black hole evolves and how
the evolution of the black hole is related to the evolution of the
galaxy bulge. Here we propose to address some of these issues using
ACS/WFC + F775W snapshot images of 73 QSO2s with redshifts in the
range 0.3z0.4. These observations will be combined with similar
archival data of QSO1s and ground based data of Seyfert and normal
galaxies. First, we will intestigate whether interactions are the most
important feeding mechanism in high luminosity AGNs. This will be done
in a quantitative way, comparing the asymmetry indices of QSO2 hosts
with those of lower luminosity AGNs and normal galaxies. Second, we
will do a detailed study of the morphology of the host galaxies of
both QSO types, to determine if they are similar, or if there is an
evolutionary trend from QSO2s to QSO1s. The results from this project
will represent an important step in the understanding of AGN
evolution, and may also introduce a substantial modification to the
Unified Model.

ACS/WFC 10829

Secular Evolution at the End of the Hubble Sequence

The bulgeless disk galaxies at the end of the Hubble Sequence evolve
at a glacial pace relative to their more violent, earlier-type
cousins. The causes of their internal, or secular evolution are
important because secular evolution represents the future fate of all
galaxies in our accelerating Universe and is a key ingredient to
understanding galaxy evolution in lower-density environments at
present. The rate of secular evolution is largely determined by the
stability of the cold ISM against collapse, star formation, and the
buildup of a central bulge. Key diagnostics of the ISM's stability are
the presence of compact molecular clouds and narrow dust lanes.
Surprisingly, edge-on, pure disk galaxies with circular velocities
below 120 km/s do not appear to contain such dust lanes. We propose to
obtain ACS/WFC F606W images of a well-selected sample of extremely
late-type disk galaxies to measure the characteristic scale size of
the cold ISM and determine if they possess the unstable, cold ISM
necessary to drive secular evolution. Our sample has been carefully
constructed to include disk galaxies above and below the critical
circular velocity of 120 km/s where the dust properties of edge-on
disks change so remarkably. We will then use surface brightness
profiles to search for nuclear star clusters and pseudobulges, which
are early indicators that secular evolution is at work, as well as
measure the pitch angle of the dust lanes as a function of radius to
estimate the central mass concentrations.

ACS/WFC 10816

The Formation History of Andromeda's Extended Metal-Poor Halo

We propose deep ACS imaging in the outer spheroid of the Andromeda
galaxy, in order to measure the star formation history of its true
halo. For the past 20 years, nearly all studies of the Andromeda
"halo" were focused on the spheroid within 30 kpc of the galaxy's
center, a region now known to host significant substructure and
populations with high metallicity and intermediate ages. However, two
groups have recently discovered an extended metal-poor halo beyond 30
kpc; this population is distinct in its surface-brightness profile,
abundance distribution, and kinematics. In earlier cycles, we obtained
deep images of the inner spheroid {11 kpc on the minor axis}, outer
disk {25 kpc on the major axis}, and giant tidal stream, yielding the
complete star formation history in each field. We now propose deep ACS
imaging of 4 fields bracketing this 30 kpc transition point in the
spheroid, so that the inner spheroid and the extended halo populations
can be disentangled, enabling a reconstruction of the star formation
history in the halo. A wide age distribution in the halo, as found in
the inner spheroid, would imply the halo was assembled through ongoing
accretion of satellite galaxies, while a uniformly old population
would be a strong indication that the halo was formed during the early
rapid collapse of the Andromeda proto-galaxy.

NIC2, ACS/WFC 10802

SHOES-Supernovae, HO, for the Equation of State of Dark energy

The present uncertainty in the value of the Hubble constant {resulting
in an uncertainty in Omega_M} and the paucity of Type Ia supernovae at
redshifts exceeding 1 are now the leading obstacles to determining the
nature of dark energy. We propose a single, integrated set of
observations for Cycle 15 that will provide a 40% improvement in
constraints on dark energy. This program will observe known Cepheids
in six reliable hosts of Type Ia supernovae with NICMOS, reducing the
uncertainty in H_0 by a factor of two because of the smaller
dispersion along the instability strip, the diminished extinction, and
the weaker metallicity dependence in the infrared. In parallel with
ACS, at the same time the NICMOS observations are underway, we will
discover and follow a sample of Type Ia supernovae at z 1. Together,
these measurements, along with prior constraints from WMAP, will
provide a great improvement in HST's ability to distinguish between a
static, cosmological constant and dynamical dark energy. The Hubble
Space Telescope is the only instrument in the world that can make
these IR measurements of Cepheids beyond the Local Group, and it is
the only telescope in the world that can be used to find and follow
supernovae at z 1. Our program exploits both of these unique
capabilities of HST to learn more about one of the greatest mysteries
in science.

ACS/WFC 10794

Direct Age Determination of the dE Galaxies NGC 147 and NGC 185

Dwarf elliptical {dE} galaxies form some of the most numerous galaxies
in the universe, yet their origins remain a mystery. The most popular
formation scenarios are that dEs are either ancient, primordial
objects, or the recent remnants of disrupted progenitor galaxies.
These scenarios predict significantly different ratios of old and
intermediate age stars. Stellar population characteristics can
therefore discriminate between these scenarios. Previous spectroscopic
work based on line strengths has had too many uncertainties to
uniquely infer the stellar populations. Resolved color magnitude
diagrams are needed instead. Since dE galaxies generally do not have
stars younger than 1 Gyr, resolving the main sequence turnoff is
required to directly quantify the star formation histories. Only ACS
on HST can reach this depth, and it can only do so for the nearest two
dE galaxies in the Local Group: the M31 dE satellites NGC 147 and NGC
185. Their main sequence turnoffs are expected to be at an apparent
magnitude of V=29; we request F606W/F814W imaging one half magnitude
fainter than this limit {and more than four magnitudes fainter than
the deepest previous dE observations}. This will quantify the ratio of
old to intermediate-age stars and will allow us to discriminate
between the competing models of dE formation. On-going Keck/DEIMOS
spectroscopy of several hundred red giant stars in each of these two
dE galaxies, coupled with dynamical modeling and spectral synthesis,
will complement the ACS measurement by providing information on
chemical abundance patterns, dark matter content and internal
dynamics. The proposed ACS data will be the first to directly quantify
the onset and duration of star formation episodes in any dE galaxy.
This measurement can only be done with HST/ACS, and it can only be
done for these two galaxies in the dE class. This project will
therefore be unique, and will be the most comprehensive study to date
of any dE galaxy.

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.

ACS/HRC 10606

Ultraviolet Snapshots of 3CR Radio Galaxies

Radio galaxies are an important class of extragalactic objects: they
are one of the most energetic astrophysical phenomena and they provide
an exceptional probe of the evolving Universe, lying typically in high
density regions but well-represented across a wide redshift range. In
earlier Cycles we carried out extensive HST observations of the 3CR
sources in order to acquire a complete and quantitative inventory of
the structure, contents and evolution of these important objects.
Amongst the results, we discovered new optical jets, dust lanes,
face-on disks with optical jets, and revealed point-like nuclei whose
properties support FR-I/BL Lac unified schemes. Here, we propose to
obtain ACS NUV images of 3CR sources with z0.3 as a major enhancement
to an already superb dataset. We aim to reveal dust in galaxies,
regions of star and star cluster formation frequently associated with
dust and establish the physical characteristics of the dust itself. We
will measure frequency and spectral energy distributions of point-like
nuclei, seek spectral turnovers in known synchrotron jets and find new
jets. We will strongly test unified AGN schemes and merge these data
with existing X-ray to radio observations for significant numbers of
both FR-I and FR-II sources. The resulting database will be an
incredibly valuable resource to the astronomical community for years
to come.

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 10552

The distance of the Orion Nebula Cluster

The HST Treasury program on the Orion Nebula, currently in execution,
has surprisingly found that background sources are easily detected by
HST at long wavelengths through selected fields within the nebula. We
propose to use these background sources as a reference system to
measure the trigonometric parallax of the Orion Nebula cluster. Using
ACS in the F850LP filter and with a modest investment of HST time, we
will reduce the error on the ~500pc distance of the Orion Nebula to
~15pc, or less, improving by a factor ~6 over current estimates. Our
new value will have a major impact on star formation studies, allowing
to determine with high accuracy the absolute luminosity of the cluster
members and all derived stellar parameters {ages, masses, mass
accretion rates...}. Our current understanding of a great range of
phenomena associated to the star formation activity in Orion will also
benefit from an improved distance estimate.

ACS/HRC 10539

Coronagraphic Imaging of Bright New Spitzer Debris Disks

Fifteen percent of bright main sequence stars possess dusty
circumstellar debris disks revealed by far-infrared photometry. These
disks are signposts of planetary systems: collisions among larger,
unseen parent bodies maintain the observed dust population against
losses to radiation pressure and P-R drag. Images of debris disks at
optical, infrared, and millimeter wavelengths have shown central
holes, rings, radial gaps, warps, and azimuthal asymmetries which
indicate the presence of planetary mass perturbers. Such images
provide unique insights into the structure and dynamics of
exoplanetary systems. Relatively few debris disks have been spatially
resolved. Only nine have ever been resolved at any wavelength, and at
wavelengths 10 microns {where subarcsec resolution is available},
only seven: beta Pictoris, HR 4796, HD 141569, AU Mic, HD 107146, HD
92945, and Fomalhaut. Imaging of many other debris disk targets has
been attempted with various HST cameras/coronagraphs and adaptive
optics, but without success. The key property which renders a debris
disk observable in scattered light is its dust optical depth. The
seven disks imaged so far all have a dust excess luminosity ~ 0.01%
that of the central star; no disks with smaller optical depths have
been detected. Most main sequence stars known to meet this requirement
have already been observed, so future progress in debris disk imaging
depends on discovering additional stars with large infrared excess.
The Spitzer Space Telescope offers the best opportunity in 20 years to
identify new examples of high optical depth debris disk systems. We
propose ACS coronagraphic imaging of nine bright, new debris disks
uncovered during the first year of the Spitzer mission. Our goal is to
obtain the first resolved images of these disks at ~3 AU resolution,
define the disk sizes and orientations, and uncover disk substructures
indicative of planetary perturbations. The results should double the
number of debris disks observed at 0.06" resolution, and open a wider
window into the structure of planetary systems.

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.

NIC1 10517

Imaging Astrometrically-Discovered Brown Dwarfs

We propose to image the astrometrically discovered companions of three
M-dwarfs with NICMOS to more tightly constrain their masses and
determine their stellar or sub-stellar natures. Each of these systems
has been observed with a sensitive ground-based adaptive optics system
and no companions have been detected. NICMOS results will eliminate an
ambiguity in the astrometric mass measurements that arises because a
companion that contributes significantly to the visible light reduces
the motion of the center of light and mimics a small motion of the
center of mass. In addition the astrometric measurements made with
NICMOS will fix the scale of the system, distinguishing among possible
orbits. Finally the color photometry will constrain the spectral types
to within a couple of subtypes. When we measure the masses of
astrophysical objects, we test and assist the development of the
theoretical mass models. Models are based upon parameters such as age
and metallicity. Determining the correct mass thus deepens our
understanding of the fundamental physics of stars and substellar
objects

NIC2 10510

Morphology of massive early-type galaxies at z1.2: constraining
galaxy formation models

We ask for NICMOS-NIC2 H-band imaging of a sample of 10 massive
early-type galaxies spectroscopically identified at 1.2z1.7. Our aim
is to look for possible relics of merging events of their
formation/evolution in their morphology. The requested observations,
sampling their rest- frame at lambda6500A, would map the mass
distribution of the bulk of their stellar content. The targets have
been revealed by our group on the basis of near-IR spectroscopy
obtained in the framework of a spectroscopic survey of a complete
sample of bright EROs {Ks18.5}. Optical and near-IR photometry is
available for all the targets, and low resolution near-IR spectra have
allowed their identification and redshift measurement. Spectroscopic
and photometric data in our hands show that they have already
assembled stellar masses greater than 3 10^11 solar masses, and that
the mean age of their stellar population is estimated older than 2-3
Gyr for 6 of them and about 1 Gyr for the other 4 galaxies. Thus, they
are among the most luminous and massive evolved galaxies detected so
far at z1. Other data are needed to infer how they have assembled
such high stellar masses, i.e. to trace back their evolution. The
requested observations would allow us to reveal signs of past
interaction/merger event. A smooth r^{1/m} profile, coupled with no
other signs of interaction/merger {disturbed morphology}, would place
the possible merger event of formation 1-2 Gyr before their redshift z
pprox 1.5, i.e. at z 2-3. On the other hand, if signs of recent
merger events will be found, the last merger event forming the local
massive spheroids will be constrained at 1.5 z 2. Thus, the
requested HST observations will allow for the first time to see how
massive early-type galaxies at z pprox 1.5 look like, constraining in
any case the redshift of the possible merging event of their
formation.

ACS/WFC/NIC2 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.

ACS/HRC/WFC 10487

A Search for Debris Disks in the Coeval Beta Pictoris Moving Group

Resolved observations of debris disks present us with the opportunity
of studying planetary evolution in other solar systems. We propose to
search for debris disks in the Beta Pictoris moving group {8-20 Myrs,
10-50 pc away} , which provides a coeval sample of multiple spectral
types, and it has already produced two magnificent resolved debris
disks: AU Mic and Beta Pic. Such coeval sample will provide us with a
snapshop of the crucial time in disk evolution in which the disk makes
the transition from optically thick to optically thin, and it will be
useful to study the stellar mass dependence of the disk evolution.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10399 - SA Section 5 Current Anomaly

With the -BB SPA temporarily off-line, the SA Section 5 current should
go to 0 when Battery 5 reaches charge cut-off. Since approximately 222
/ 16:00, the SA section 5 current indicates 1.8A after battery 5
reaches charge cut-off. The anomalous current is not fully seen in the
Structure current (less than 0.2A increase).

10400 - GSacq(2,3,2) failed to RGA control @225/1642z

Only QF2STOPF and QSTOP flags were set. OBADs respective RSS values
were 2863.99 & 7.50. OBAD MAP at 16:53:36 showed an RSS value of 15.17

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 28 27
FGS
REacq 16 16

OBAD with Maneuver 88 88

SIGNIFICANT EVENTS: (None)