Daily #4051

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4051

PERIOD COVERED: UT February 15, 2006 (DOY 046)

OBSERVATIONS SCHEDULED

ACS/HRC 10774

Confirming the Discovery of Two New Satellites of Pluto

We detected two new objects ~2 arcsec from Pluto during our recent
deep search for companions using the ACS / WFC mode {HST GO program
10427}. Either these objects are newly discovered satellites of Pluto,
or they are previously undiscovered Plutino KBOs that happened to be
located along the line-of-sight to Pluto. The ramifications are
enormous for our understanding of the origin and evolution of the
Pluto-Charon system, and for our understanding of KBO satellite
formation in general, if these new objects are satellites of Pluto.
Thus, we request two orbits of HST observing time as soon as possible,
to confirm that these newly discovered objects are truly satellites of
Pluto.

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 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 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/WFC 10615

Timing Studies of the X-ray Binary Populations in Globular Clusters

Close binaries are fundamental to the dynamical stability and
evolution of globular clusters, but large populations have been
extremely difficult to identify. Chandra X-ray images provide a
revolutionary resource, revealing a few to dozens of low-luminosity
X-ray sources in every cluster deeply examined; our own Chandra
programs uniformly study these ubiquitous X-ray sources {close
binaries and their progeny} in a dozen clusters. We have obtained
multicolor, single-epoch, ACS images, from which to obtain initial
optical counterparts, especially CVs {the dominant population in most
clusters}, BY Dra's, and qLMXBs. As HST capability for follow-on,
confirming, spectra of our multicolor-selected counterparts is now
severely curtailed, we propose an ACS time-series imaging program that
will yield equivalent follow-on information for 5 of our clusters. The
proposed ACS time-series data with 6 min resolution and 8 hr
time-span, will: provide variability information to secure our
suggested multicolor identifications; allow secure classifications of
the various X-ray subpopulations {e.g., CVs vs. BY Dra's}; yield
quality lightcurves, whose shape will help test the notion that
magnetic CVs are more common in globular clusters than the field; and,
provide interesting contraints on the period distributions of cluster
X-ray binaries.

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.

FGS 10614

Internal Structure and Figures of Binary Asteroids

The goal of this proposal is to obtain very important information on
the internal structure of a number of asteroids, and insight on the
gravitational reaccumulation-process after a catastrophic disruptive
collision. High resolutions observations with the HST/FGS
interferometer are proposed to obtain high precision data for the
topographic shape and size of a number of selected asteroids. Here we
focus on objects with satellites, hence with known masses, so that the
bulk density and porosity will be derived in the most accurate manner.
This will yield plausible estimates on the internal properties of the
objects, test wether they are close or not to figures of equilibrium
{in terms of shape and adimensional rotational frequency}, and provide
estimates of their relative density. The HST/FGS in interferometric
mode is an ideal facility to carry out this program.

NIC1/NIC2/NIC3 8792

NICMOS Post-SAA calibration - CR Persistence Part 3

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.

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.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10133 - GSacq(1,2,2) failed due to search radius limit exceeded on FGS
1 @ 046/1756z

During LOS the GSacq(1,2,2) scheduled at 046/17:56:03 failed due to
search radius limit exceeded on FGS 1. ESB a07 FGS Coarse Track failed
- Timed out waiting for data valid was received. The OBAD before the
GSacq showed errors of V1=-8.30, V2=-8.41, V3=-13.00, RSS= 17.57.

10134 - REacq(1,2,2) failed @ 046/1908z

Reacq(1,2,2) scheduled at 046/19:02:17 failed. ESB a0e (FGS Sequential
Attitude update failed because error was too large to correct) was
received. The OBAD before the Reacg showed errors of V1=5.27,
V2=-2.44, V3=6.27, RSS= 8.55. The Map at 19:09:20 showed errors of
V1=1.86, V2= -3.67, V3=8.09, RSS= 9.07.

10135 - Roll (V1) attitude error vector limit violation (QDVEFGS1) @
046/2051z

During GSacq(1,2,2) of 046/20:51:37, the mnemonic (QDVEFGS1) V1
attitude error vector flagged out of limits high 299.361 arcseconds.
Per ref (HSTARs 10133,10134) when the acquisition fails, we do not
compute a V1 Bias, but we still save the guide star quaternion at the
occultation. Correct value for the V1 Bias was restored during #44 CMD
(FGS Sequential attitude update). The acquisition was successful

COMPLETED OPS REQUEST:
17645-0 - ESTR-2R Monthly Recondition @ 047/0604z

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 11 10 046/1756z
(HSTAR 10133)
FGS REacq 04 03 046/1908z
(HSTAR 10134)
OBAD with Maneuver 30 30

SIGNIFICANT EVENTS: (None)