Daily # 4205

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4205

PERIOD COVERED: UT September 22,23,24, 2006 (DOY 265,266,267)

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.

ACS/WFC 10997

The Environmental Effects of Large Scale Structures Around the Galaxy
Cluster RXJ0152.7- 1357 at z=0.84

Large scale {~10 Mpc} filaments of galaxies associated with X-ray
luminous clusters at z~1 have recently been discovered in ground based
wide-field observations. This make it possible to investigate the
fundamental properties of galaxies {mass, structure and stellar
content} in a variety of environments {field, groups, clusters} and
compare the environmental effects on galaxy properties at z~1 to those
a z~0. We propose to observe filamentary structures around the galaxy
cluster RX J0152.7-1357 at z=0.84 in two filters with the Wide Field
Camera {WFC} on the ACS to track down morphological and stellar
population differences in the cluster environment and in the less
massive substructures in the filaments, providing key elements to
understand how the correlations we observe between galaxy properties
and galaxy location within a cluster are established and evolve with
redshift.

WFPC2 10915

ACS Nearby Galaxy Survey

Existing HST observations of nearby galaxies comprise a sparse and
highly non-uniform archive, making comprehensive comparative studies
among galaxies essentially impossible. We propose to secure HST's
lasting impact on the study of nearby galaxies by undertaking a
systematic, complete, and carefully crafted imaging survey of ALL
galaxies in the Local Universe outside the Local Group. The resulting
images will allow unprecedented measurements of: {1} the star
formation history {SFH} of a 100 Mpc^3 volume of the Universe with a
time resolution of Delta[log{t}]=0.25; {2} correlations between
spatially resolved SFHs and environment; {3} the structure and
properties of thick disks and stellar halos; and {4} the color
distributions, sizes, and specific frequencies of globular and disk
clusters as a function of galaxy mass and environment. To reach these
goals, we will use a combination of wide-field tiling and pointed deep
imaging to obtain uniform data on all 72 galaxies within a
volume-limited sample extending to ~3.5 Mpc, with an extension to the
M81 group. For each galaxy, the wide-field imaging will cover out to
~1.5 times the optical radius and will reach photometric depths of at
least 2 magnitudes below the tip of the red giant branch throughout
the limits of the survey volume. One additional deep pointing per
galaxy will reach SNR~10 for red clump stars, sufficient to recover
the ancient SFH from the color-magnitude diagram. This proposal will
produce photometric information for ~100 million stars {comparable to
the number in the SDSS survey} and uniform multi-color images of half
a square degree of sky. The resulting archive will establish the
fundamental optical database for nearby galaxies, in preparation for
the shift of high-resolution imaging to the near-infrared.

ACS/HRC 10878

An ACS Prism Snapshot Survey for z~2 Lyman Limit Systems

We propose to conduct a spectroscopic survey of Lyman limit absorbers
at redshifts 1.7 z 2.2, using ACS/HRC and the PR200L prism. We
have selected 100 quasars at 2.3 z 2.6 from the Sloan Digital Sky
Survey Spectroscopic Quasar sample, for which no BAL signature is
found at the QSO redshift and no strong metal absorption lines are
present at z 2.3 along the lines of sight. The survey has three main
observational goals. First, we will determine the redshift frequency
dN/dz of the LLS over the column density range 16.3 log N_HI 20.3
cm^-2. Second, we will measure the column density frequency
distribution f{N} for the partial Lyman limit systems {PLLS} over the
column density range 16.3 log N_HI 17.5 cm^-2. Third, we will
identify new sightlines for measurements of the primordial D/H ratio.
With this survey, we will also constrain two key quantities of
cosmological relevance: First, the measurements of dN/dz for optically
thick LLS and f{N} for the PLLS are critical to estimating the
attenuation of extragalactic ionizing sources {e.g. QSOs}. Currently,
uncertainties in dN/dz and f{N} are the greatest sources of
uncertainty for inferring the shape and intensity of the UV background
radiation field. Second, we will estimate the amount of metals in the
LLS using the f{N} and ground based observations of metal line
transitions. It is possible that a significant fraction of the
"missing metals" at z~2 are associated with these highly ionized
absorbers. Third, analysis of the LLS lends to investigations of the
interface between galaxies {i.e. the damped Lyman alpha systems} and
the intergalactic medium {i.e. the Lyman alpha forest}. This survey is
ideal for a snapshot observing program, because the on-object
integration times are less than 10 minutes, and the targets cover the
majority of the northern sky.

NIC2 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.

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.

NIC3 10632

Searching for galaxies at z6.5 in the Hubble Ultra Deep Field

We propose to obtain deep ACS {F606W, F775W, F850LP} imaging in the
area of the original Hubble Ultra Deep Field NICMOS parallel fields
and - through simultaneous parallel observations - deep NICMOS {F110W,
F160W} imaging of the ACS UDF area. Matching the extreme imaging depth
in the optical and near-IR bands will result in seven fields with
sufficiently sensitive multiband data to detect the expected typical
galaxies at z=7 and 8. Presently no such a field exist. Our combined
optical and near-IR ultradeep fields will be in three areas separated
by about 20 comoving Mpc at z=7. This will allow us to give a first
assessment of the degree of cosmic variance. If reionization is a
process extending over a large redshift interval and the luminosity
function doesn't evolve strongly beyond z=6, these data will allow us
to identify of the order of a dozen galaxies at 6.5z8.5 - using the
Lyman break technique - and to place a first constrain on the
luminosity function at z6.5. Conversely, finding fewer objects would
be an indication that the bulk of reionization is done by galaxies at
z=6. By spending 204 orbits of prime HST time we will capitalize on
the investment of 544 prime orbits already made on the Hubble Ultra
Deep Field {UDF}. We have verified that the program as proposed is
schedulable and that it will remain so even if forced to execute in
the 2-gyro mode. The data will be non-proprietary and the reduced
images will be made public within 2 months from the completion of the
observations.

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

FGS 10482

Trigonometric Calibration of the Period- Luminosity Relations for
Fundamental and First-Overtone Galactic

Cepheids are the primary distance indicators for the extragalactic
distance scale and the Hubble constant. The Hubble Constant Key
Project set the zero-point for their Cepheid distance scale by
adopting a distance to the LMC, averaged over a variety of techniques.
However, different methods give an LMC distance modulus ranging from
18.1 to 18.8, and the uncertainty in the Cepheid zero-point is now the
largest contributor to the error budget for H_0. Moreover, the low
metallicity of the LMC raises additional concerns, since the PL
relation probably depends on metallicity. The zero-point can be
determined from Hipparcos parallaxes of Galactic Cepheids out to
several hundred parsecs, but with a typical parallax error of 0.5-1
mas, the Hipparcos error bars are uncomfortably large for this
demanding application. By contrast, HST's FGS1R interferometer can
achieve astrometric accuracy of 0.2 mas. We propose to use FGS1R to
determine trigonometric parallaxes for a sample of 9 nearby Cepheids,
including both fundamental {F} and first-overtone {FO} pulsators. We
show that the improvement in the PL relations for F and FO Cepheids
will be dramatic. We will determine the PL slopes from our nearby
solar- metallicity sample alone, without recourse to nearby galaxies
and the issue of [Fe/H] dependence. The zero-point will be determined
robustly to about 0.05 mag, based on accurate, purely geometrical
measurements. All of this can be achieved in the next few years with
HST, without having to wait for the SIM and GAIA missions well into
the next decade.

FGS 10432

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.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10435 - REacq (2,1,2) failed due to search radius limit exceeded

REacq(2,1,2) scheduled at 266/09:23:24 failed at 09:28:12 due to
search radius limit exceeded on FGS 2. OBAD1 showed errors of
V1=-62.14, V2=561.17, V3=-12.68, RSS=564.75. OBAD2 showed errors of
V1=-5.14, V2=-11.57, V3=-10.76, and RSS=16.62.

10436 - ACS Suspend STB Messages 707 & 715 received

Upon acquisition of signal at 266/16:04:00 observed ACS Suspended at
266/15:21:25. Received ACS STB messages 707 parameter 4003
(octal)(Limit_Check_Failue) and STB 715 parametr 150(octal)
(Limits_Suspend_Request). ACS was in operate, spacecraft was in Gyro
Hold when anomaly occurred.

10437 - GSacq (2,1,2) failed due to search radius limit exceeded for
FGS 2

At AOS 266/22:56:00 GSacq (2,1,2) scheduled from 266/17:33:39 -
17:41:43 failed due to search radius limit exceeded on FGS 2. Also at
AOS one a05 (Exceeded SRL) message. OBADs scheduled at
266/17:21:24-17:29:19 and 266/17:29:19-17:33:34 were LOS. At AOS, MAP
scheduled at 266/17:41:43-17:44:28 showed the following: V1 - 0.11, v2
- -2.28, v3 - 0.57 and RSS 2.35. OBADs scheduled previous to REacq
were LOS. At AOS, MAP scheduled at 266/19:16:57 completed with V1
-0.76, V2 7.63, V3 0.17, RSS 7.67.

10440 - Status Buffer Message (402) during ACS Memory Dump

At 266/18:06:00 status buffer message 402 parameter=16317 (octal) was
received during a ACS Memory Dump after Suspend (Ref HSTAR 10436). The
memory dump was performed (OPS REQ 17932-0) following ACS Suspend.
Procedure JMDMPRAW was used to dump. As procedure JMDMPRAW completed
execution, it cleaned up after dump by sending a science data output
cease command, the EXEC 402 status buffer resulted.

10441 - GSACQ(2,1,1) failed

GSACQ(2,1,1) at 267/00:13:33 failed to RGA control with QF2STOPF and
QSTOP flags set at 00:16:44. No other flags were seen. REACQ(2,1,1) at
01:51:10 also failed (no engineering data is vailable but #44 commands
did not change when signal was acquired at 02:20:00).

10444 - REacq(1,2,1) failed to RGA Control

Upon acquisition of signal at 267/17:01:05, the Target REacq(1,2,1)
scheduled at 267/15:51:22 - 15:59:26 was observed to have failed to
RGA Hold due to search radius limit exceeded on FGS-1. Per ESB Dump at
267/17:09:00, one 486 ESB "a05" (FGS Coarse Track failed - Search
Radius Limit Exceeded) was received at 267/15:56:44. Two ESB 1805
(T2G_MOVING_TARGET_DETECTED) was received at 267/15:48::59, and
267/15:49:04 respectively. Prior OBADs attitude corrections values not
available due to LOS. Prior GSacq using same star id was successful.
Observations affected none.

COMPLETED OPS REQUEST:
17926-0 - Eclipse Management
17923-1 - Update BM SOC , SOC-1 and SOC-2 following DOY 265 Eclipse Event
17932-0 - Memory dump after ACS Suspend


COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 23 21
FGS REacq 15 11
OBAD with Maneuver 76 76

SIGNIFICANT EVENTS:

Flash Report - One eclipse event over the period of GMT 265/10:02
through 265/10:33 occurred near start of orbit day and having a peak
darkness of ~88 percent darkness. ROP PS-02 was performed to minimize
the impacts from this eclipse on the spacecraft. Increasing the
duration of the CSS failure timer was completed prior to the first
eclipse event at GMT 265/06:47. Additional steps were also taken to
lower the SOC 1 and SOC 2 safemode limits by 10 A-hrs to 202 A-hr and
142 A-hr, respectively. This recommendation was performed as a
proactive measure. Following the eclipse, CSS timer was reset to its
nominal value at 265/11:54. Update of the SOC 1, SOC 2, Battery
Pressure safemode limits and SOC benchmark was also performed to
reflect the proper system capacity value as determined from the 2006
battery capacity testing. Preliminary results of the eclipse event
showed that at the start of that orbit day the pressure-based SOC was
237 A-hr. Telemetry wasn't available throughout this eclipse. The SOC
level reached a maximum value of about 251 A-hr prior to the peak
darkness and reduced to about 24 8 A-hr around the time of the peak
darkness. It was also determined that the Benchmark Reset Threshold
was achieved prior to EON by observing the trickle charge elapse timer
in the subsequent orbit after the eclipse.

Flash Report The ACS suspended at 266/15:21:25 GMT. An Ops Briefing
was held at 6 pm on September 23, 2006. At 266/15:21:25, ACS 715 and
ACS 707 status buffer (STB) messages were received indicating the ACS
HRC CEB ASPC2 +35 volt power supply voltage was out of limits low that
resulted in the ACS suspend. The event occurred during the transition
from SBC to HRC operations. At the time of the anomaly, the vehicle
was in an LOS, but outside of the SAA. The data was subsequently
dumped with the ACS memory dump indicating the single out of limit
violation of the HRC CEB ASPC2 35 volt power supply. ACS commanding
has been removed from next week's SMS and replaced with other science.
A detailed analysis of the event is underway with a tiger team meeting
at 1pm Sunday. A follow-up status meeting is planned with HSTP for 9am
Monday in. Actions from the tiger team meeting: -Investigate whether
ASPC-2 relay status are analog, if analog assess the raw data for
shifts that indicate whether or not all the relays switched. -Provide
bus voltage at time of anomaly to tiger team. Presentation is posted
at the following web site:
http://edocs.hst.nasa.gov/hstsysman/...ation/ACS_707-
715_Suspend_DOY266.ppt

Loads for SA268Q03_F1 (with minimal ACS commanding included) generated
in response to ACS HSTAR # 10436 were reviewed by the FOT on grave
shift. (The STScI worked as late as 2 AM Sunday morning, to complete
the SMS delivery.) Following SI SE approval, the loads were then
authorized at 267/14:06:50z. First load-after time was 267/17:01:05z
(Sunday 1:01 PM Local).

Flash Report - ACS Suspend Status Update Mtg - Monday 9am 3/S107A (by
D. Haskins, Sun, 24 Sep 16:29:40) - A status meeting on the ACS
suspend event will be held at 9am on Monday, September 25 in 3/S107A.