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Daily #4058



 
 
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Old February 27th 06, 02:28 PM posted to sci.astro.hubble
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Default Daily #4058

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4058

PERIOD COVERED: UT February 24,25,26, 2006 (DOY 055,056,057)

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 10779

WFPC2 WF4 Temperature Reduction Test #2

A serious 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. The severity and
frequency of the problem is rapidly increasing, and it is possible
that WF4 will soon become unusable if no work-around is found. The
other three CCDs {PC1, WF2, and WF3} appear to be unaffected and
continue to operate properly. This is a second test to further reduce
temperatures. Orbits: internal 26, external 1

NIC3 10761

The X-ray Spectral and Optical/IR Flux Variability in Magnetars

In the last decade it has become clear that there exists a small
subset of pulsars that are powered neither by rotation nor accretion
but by the decay of their enormous magnetic fields -- magnetars. The
origin of the X-ray emission from magnetar-candidate AXPs {Anomalous
X-ray Pulsars} is fairly well understood within the framework of the
magnetar model. However, where and how the optical/IR emission is
produced is unclear. If, as recent models suggest, the optical/IR
emission is magnetospheric, then any variation in the optical/IR flux
should be accompanied by variation in the X-ray spectra. We therefore
propose for joint Chandra-Hubble observations of two magnetar
candidates in order to test the optical/IR emission models for
magnetars.

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.

FGS 10610

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 10599

Multi-color imaging of two 1 Gyr old debris disks within 20 pc of the
Sun: Astrophysical mirrors of our Kuiper

We report the first scattered light detections of two debris disk
around an F star and a K star using optical coronagraphy and the
Hubble Space Telescope. With ages ~1 Gyr, these are the oldest debris
disks thus far seen in the optical. We propose deep, multi-roll angle
coronagraphic imaging with HST ACS and NICMOS to confirm and
characterize the disks in terms of structure and composition. The
disks appear to have belt-like morphology that is consistent with the
existence of planetary companions or other perturbing bodies. Since
these disks are close to our Kuiper Belt in an evolutionary context,
detailed understanding of their mass, structure and composition will
provide a fresh perspective for inferring the history and properties
of our own trans-Neptunian region.

ACS/WFC 10597

Resolving the Connection Between Globular Clusters and Low-Mass X-ray
Binaries

Because of their high central densities, globular clusters {GCs} are
efficient producers of low- mass X-ray binaries {LMXBs}. To shed light
on the detailed formation mechanism of LXMBs in GCs, we propose to
measure accurate structural parameters for hundreds of GCs in NGC
5128: the only giant elliptical galaxy within 5 Mpc of the Milky Way.
We will carry out the first complete survey of GCs in the inner region
of NGC 5128, measure GC structural parameters of unprecedented
acccuracy, and derive GC luminosity profiles in the cluster cores.
These measurement will allow us to determine precisely which GC
structural properties control the presence of an X-ray source and thus
probe the details of the LXMB formation process in GCs. We will
additionally use the measured structural parameters to perform the
most comprehensive study of the fundamental plane of GCs in early-type
galaxies, a fundamental set of correlations which holds key
information on GC formation and evolution.

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 10582

Probing The Galaxy-wide Globular Cluster - Low Mass X-ray Binary
Connection in Early-type Galaxies

The combination of high-resolution imaging from Hubble {HST} and
Chandra {CXO} has completely revolutionized our understanding of
extragalactic low-mass X-ray binaries {LMXBs} and globular clusters
{GCs}; however, studies have been limited by short X-ray exposures and
relatively small fields. NGC 4697 amd NGC 4365 are relatively simple
elliptical galaxies in the X- ray that will have deep CXO
observations. We propose ACS observations in six flanking fields per
galaxy to provide a study of the GC-LMXB connection in normal
early-type galaxies with unprecedented depth, spatial resolution and
areal coverage. Combined with existing central field observations, we
will detect ~900 and ~2700 GCs GCs in most of NGC 4697 and all of NGC
4365. These two galaxies will have the greatest number of detected
GC-LMXBs to date {~70 & 120}. We will measure the fraction of LMXBs
found in GCs, and the fraction of GCs which contain LMXBs, as a
function of X-ray luminosity, galactocentric distance, color, GC
half-light radius, and local GC specific frequency. We will test
existing models of GC formation/evolution and LMXB
formation/evolution. Using the radial profile of optical light, GCs,
and LMXBS, we will determine the percentage of field LMXBs which may
have originated in GCs.

ACS/WFC 10579

ULX counterparts: the key to finding intermediate-mass black holes

The origin and formation mechanism for supermassive black holes
{SMBHs} found in the centres of most, if not all, galaxies remains one
of the outstanding questions in astrophysics. Most scenarios involve
the presence of massive black holes in the early universe, formed by
the collapse of primordial Population III stars. It is predicted that
a relic of this population could still be present in galactic halos in
the current epoch, possessing masses from a few hundred times solar
mass upwards. However, to date no CONCLUSIVE evidence for such a class
of "intermediate-mass" black holes has been found. The most likely
current candidates are the ultraluminous X-ray sources {ULXs}, which
show tantalising evidence for IMBHs {e.g. the extreme X-ray
luminosities and low disk temperatures expected from accreting IMBHs}.
We propose to address this issue by identifying optical counterparts
for six of the nearest ULXs. We will use this programme as a
pathfinder for future radial velocity measurements, which will allow
the orbital parameters and hence the first undisputed mass constraints
for these systems to be determined.

ACS/HRC 10557

Probing Asteroid Families for Evidence of Ultraviolet Space Weathering
Effects

We propose six HST orbits to obtain UV reflectance spectra covering
200-460 nm of two Vesta asteroid family members, asteroid 832 Karin,
and two Karin family members. These observations extend work done
under a Cycle 13 AR grant, where we analyzed all of the existing IUE
and HST S-class asteroids in the MAST database to investigate the
effects of space weathering at UV wavelengths. Our hypothesis is that
the manifestation of space weathering at UV wavelengths is a spectral
bluing, in contrast with a spectral reddening at visible-NIR
wavelengths, and that UV wavelengths can be more sensitive to
relatively small amounts of weathering than longer wavelengths. The
proposed observations will address two objectives: {1} Measure the
UV-visible spectra of 832 Karin and two members of the young Karin
family {absolute age of 5.8 My}, in order to determine whether
intermediate space weathering is observable in objects likely pristine
when they originated from the interior of Karin's pa rent body. {2}
Measure the UV-visible spectra of two members of the Vesta family to
compare with our analysis of IUE Vesta spectra. These observations
will probe Vesta's interior, and test our hypothesis by contrasting
the apparent amount of alteration on the surfaces of Vestoids with
excavated material on Vesta.

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 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/WFC 10486

A Cosmic String Lens Candidate

We propose two-band imaging observations with ACS of a cosmic string
lens candidate, CSL-1, to look for a feature predicted by the cosmic
string model: a low-surface brightness discontinuity in between the
two galaxy images.

NIC1 10415

A Proper Motion Study of the Ionized Gas in the Vicinity of the
Galactic Center Black Hole

The Galactic Center's distance of only 8 kpc provides a unique
opportunity to study the interaction of a supermassive black hole with
its environment at a level of detail not possible for other galaxies.
We propose to observe the inner parsec of the Galaxy in the Paschen
alpha line with Camera 1 of NICMOS in order to study the kinematics of
ionized gas in the vicinity of the supermassive black hole coincident
with Sgr A*. Our previous GO program 7842 yielded detailed Pa alpha
images revealing complex, filamentary structure at 0.16 arcsec {0.006
pc} resolution. However, proper motions could not be robustly derived
from that data set due to the fact that the two epochs were spaced
only 7 months apart. In order to follow up on preliminary results
showing evidence for high proper motions within 2'' of Sgr A* and to
characterize the rest of the central parsec, we propose to obtain two
additional epochs within Cycle 13 so that the dataset will comprise
independent measurements of the proper motions ranging from intervals
of 5 months to 7 years, with the 7 year interval giving a 1 sigma
accuracy of 45 km/s. These will be combined with existing radial
velocity measurements to provide the first complete characterization
of the kinematics of the ionized gas in the central parsec. This is
crucial to interpreting the relative importance of gravitational
forces, stellar winds, and possible accretion onto or outflow from the
black hole. These observations may possibly lead to the first direct
observation of gas in the process of accretion {or ejection via a jet}
associated with the Galactic Center black hole. The kinematics of the
gas may also imply that accretion may be inhibited, and this could
explain the low luminosity of Sgr A*.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10146 - REacq (2,1,1) results in finelock backup (1,0,1) due to scan
step limit exceeded FGS-2 @055/1237z

The Target REacq(2,1,1) scheduled at 055/12:37:39 - 12:45:44 Z
resulted in finelock backup (1,0,1)using FGS-1, due to scan step limit
exceeded on FGS-2. Prior OBAD2 at 055/12:33:09 had total attitude
correction (RSS) value of 7.05 arcseconds.

10147 - Gsacq(1,2,2) stop guiding @056/0628z

GSacq(1,2,2) scheduled at 056/06:15:40 stop guiding at 06:27:57 and
transition from F2G to T2G. There was a Genslew offset request at
06:25:36.

10148 - GSAcq (2,1,2) failed to RGA control @057/2026z

GSAcq (2,1,2) scheduled at 057.20:22:12 failed to RGA control. No
flags were evident other than already indicated. No ESB messages were
received prior to or during Acq. OBAD #1: V1 195.65, V2 -2814.86, V3
-69.91, RSS 2822.51 OBAD #2: V1 -7.04, V2 -12.21, V3 -8.34, RSS 16.37

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS
GSacq 29 28 @057/2026z
(HSTAR 10148)
FGS REacq 13 13
OBAD with Maneuver 78 78
LOSS of
LOCK @056/0628z
(HSTAR 10147)

SIGNIFICANT EVENTS: (None)

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