Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.stsci.edu/ftp/observing/status_reports/hst_status_06_09_02 Дата изменения: Mon Jun 10 16:19:13 2002 Дата индексирования: Sat Dec 22 19:31:46 2007 Кодировка: Поисковые слова: virgo cluster

HUBBLE SPACE TELESCOPE

DAILY REPORT # 3133

PERIOD COVERED: DOY 158-160: 0000Z (UTC) 06/07/02 - 0000Z (UTC) 06/09/02

OBSERVATIONS SCHEDULED AND ACCOMPLISHED:

9353

Direct imaging of the progenitors of massive, core-collapse supernovae

Modern supernovae searches in the nearby Universe are discovering vast numbers
of SNe which have massive star progenitors {Types II, Ib and Ic}. The extensive
HST {and ground-based} image archives of galaxies within ~20 Mpc enables their
individual bright stellar content to be resolved. As massive, evolved stars are
the most luminous single objects in a galaxy, the progenitors of core-collapse
SNe should be directly detectable on pre-explosion images. Within the last year
we have set direct mass limits on the progenitors of two SNe Type II-P by
analyzing pre-explosion archive images and follow up HST exposures. We have now
identified six other recent, nearby SNe which have WFPC2 archive exposures of
the site taken before explosion. Additionally, our Cycle 10 SNAP program will
double the WFPC2 image archive of nearby galaxies which significantly increases
the chances of having multi-colour photometry of pre-explosion sites for future
SNe. In this Cycle, we request time on two fronts. Firstly we require
imaging of
the six SNe with existing pre-explosion data in order to perform exact
astrometry of the SNe positions to around 0.05''. Secondly, as a follow on from
our two successful Cycle 10 programs, we request ToO status for any nearby
core-collapse SN which explodes during Cycle 11 and which has pre-explosion HST
images. The goal of this proposal is to directly identify the progenitor stars
of core-collapse SNe.

ACS 9027

ACS SBC Geometric Distortion Calibration

This activity will obtain a series of images to evaluate the geometric
distortion over the field of view of the ACS SBC channel, after its image
quality has been optimized with the corrector mechanism. Images will be
obtained
in filter F125LP, with a pattern of POS-TARG offsets in each axis. These data
will be complemented by the images of the same field obtained in proposal 9024,
"ACS SBC Flat Field Strability", which utilizes a similar image offsetting
technique at larger spatial scales. The observations may be scheduled
back-to-back with those from proposal 9024. NGC 6681 {18.7 h, -32 deg} will be
the target, as this star field has been used extensively by the STIS
program for
UV PSF measurement and photometry

ACS 9476

Galaxy Evolution in the Richest Clusters at z=0.8: the EDisCS Cluster Sample

The study of distant cluster galaxies requires two key ingredients: {1} deep
high-resolution imaging, to constrain galaxy structure; and {2} 8m-class
spectroscopy, to measure stellar content, star-formation rates, dynamics, and
cluster membership. We will reach both conditions with the addition of HST/ACS
imaging to our suite of VLT {36 nights} and NTT {20 nights} observations of 10
confirmed clusters at z~0.8, drawn from the ESO Distant Cluster Survey
{EDisCS}.
The proposed HST/ACS data will complement our existing optical/IR imaging and
spectroscopy with quantitative measures of cluster galaxy morphologies {i.e.
sizes and shapes, bulge-disk decompositions, asymmetry parameters}, and with
measurements of cluster masses via weak lensing. Major advantages unique to the
EDisCS project include: {i} uniform selection of clusters; {ii} large enough
sample sizes to characterize the substantial cluster-to-cluster variation in
galaxy populations; {iii} large quantities of high quality data from 8m
telescopes; {iv} uniform measurements of morphologies, spectroscopic and
photometric redshifts, SEDs, star-formation/AGN activities, and internal
kinematics; {v} optical selection of clusters to complement the X-ray selection
of almost all high-z clusters in the ACS GTO programs; {vi} forefront numerical
simulations designed specifically to allow physical interpretation of observed
differences between the high-z and local clusters.

ACS 9395

Is Bulge Formation Still Going-On? An ACS Survey of Pseudo-Bulges

Pseudo-bulges, i.e., bulges with an exponential light profile, have been
unveiled in the centers of many intermediate-type disks. Their structural
similarity with the disks provides support to theoretical scenarios in which
bulges may form due to secular evolution processes within the host disks. If at
play, these processes would likely be active throughout a large fraction of
cosmic history down to our days: `young' bulges should exist. Our previous HST
WFPC2 and NICMOS survey of ~100 spirals has provided V-H colors for 11 Sb-Sc
pseudo-bulges, and these could be interpreted as suggestive of relatively young
stellar ages. Furthermore, dense nuclei have been discovered in these
pseudo-bulges, and their V-H colors may imply stellar masses sufficiently large
to activate the formation of the pseudo- bulge by means of dynamical
dissolution
of progenitor bars. However, the V-H color, on its own, is fully degenerate
towards stellar ages, metallicities and masses, as well as dust content. We
therefore propose to use ACS to observe the 11 pseudo-bulges of our combined
WFPC2 and NICMOS sample in the F330W, F435W, and F814W filters. Extending the
wavelength baseline to the bluer passbands is essential to break the
mass-age-metallicity-dust degeneracy, and will provide far more accurate
estimates for the stellar population properties of the pseudo-bulges and their
nuclei. Proving the existence of `young' bulges in the local Universe would
have
a big impact in our understanding of the formation of the Hubble sequence.

ACS 9024

SBC flat field uniformity

The stability and uniformity of the low-frequency flat fields {L-flat} of all
ACS detectors will be assessed by using multiple pointing observations of the
globular cluster NGC6681 - thus imaging moderately dense stellar fields. By
placing the same star over different portions of the detectors and measuring
relative changes in its brightness it will be possible to determine local
variations in the response of the detectors. Based on previous experience with
STIS, it is deemed that a total of nine different pointings will suffice to
provide adequate characterization of the flat field stability in any given
band.
For each filter to be tested, the baseline consists of 9 pointings with
steps of
~20% of the FOV in a diagonal cross pattern. During SMOV, the complement of
filters to be tested is limited to the following: for the SBC, F125LP and
F150LP. In order to provide complementary data for the geometric distortion
programmes {9027 and 9028}, and also to check that the distortion is not
chromatic, three additional exposures will be taken with F125LP with a very
small {~10 pixel} offset from the centre {see proposals 9027 and 9028}.
Execution of this programme must await completion of programme 9011 {ACS to FGS
alignment} and the ensuing PDB update.

ACS/CAL 9558

ACS weekly Test

This program consists of basic tests to monitor, the read noise, the
development
of hot pixels and test for any source of noise in ACS CCD detectors. This
programme will be executed once a day for the entire lifetime of ACS.

ACS/HRC 9473

Masses and IMF Variations in Super Star Clusters

We are proposing to obtain high spatial resolution images of a set of super
star
clusters for which we have been granted observing time to measure velocity
dispersions via high- resolution ground-based optical echelle and K-band
spectroscopy. The images will allow us to fit the light profiles and
measure the
radii of the clusters, and when combined with the velocity dispersions, will
enable us to estimate the cluster masses. By comparing the mass-to-light ratios
with those predicted from spectral synthesis models, we will investigate
possible variations in the slope and lower mass cut-offs of the initial mass
functions in these clusters. Correlations of the variations of these parameters
with cluster environment may provide insight into the formation mechanisms for
super star clusters. By comparing the light profiles obtained in a blue and red
filter, we will also search for evidence of mass segregation in the clusters.
Since these clusters are too young to have experienced dynamical mass
segregation, differences in the light profiles of the clusters in the two
filters could be due to processes that differentiate between high and low mass
stars during the birth of the clusters and would provide further constraints on
theoretical models of cluster formation. Since these clusters are far too
compact to be resolved by any ground-based observations, the ACS/HRC on board
HST is the only instrument capable of carrying out these observations.

ACS/HRC 9020

Preliminary ACS Sensitivity.

The Advanced Camera for Surveys (HrC) was used to observe a spectrophotometric
standard star through each filter of each camera to assess the sensitivity of
the instrument. The star is placed at the center of the aperture, and two
images
are taken through each filter.

ACS/WFC 9575

Default {Archival} Pure Parallel Program.

The Advanced Camera for Surveys (WFC) was used to test ACS pure parallels in
POMS.

ACS/WFC/HRC 8947

Weekly Test.

The Advanced Camera for Surveys (WFC and HRC) was used to perform basic
tests to
monitor, the read noise, the development of hot pixels and test for any source
of noise in ACS CCD detectors. This program will be executed at least once
a day
for the entire lifetime of ACS.

FGS/1 9034

The Masses and Luminosities of Population II Stars.

Fine Guidance Sensor 11R was used to observe the mass-luminosity relation {MLR}
of Population II stars of which very little is currently known. With the advent
of the Hipparcos Catalogue, improved distances to many spectroscopic binaries
known to be Pop II systems are now available. After surveying the
literature and
making reasonable estimates of the secondary masses, we find 13 systems whose
minimum separation should be larger than the resolution limit of FGS #1.

NICMOS 9269

NICMOS Parallel Thermal Background

NICMOS Camera 3 pure parallel exposures in the F222M filter will be
obtained for
the entire duration of SMOV to establish the stability of the
HST+NCS+Instrument
thermal emission.

NICMOS 8986

NICMOS Photometry Test

This proposal contains the necessary exposures to re-calibrate NICMOS.

NICMOS 8790

NICMOS Post-SAA calibration - CR Persistence Part 1.

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.

STIS 9328

Comprehensive STIS Spectroscopy of the Supernova Remnant 1987A's Formation

The visible consequences of the hard shock of the impact of SN 1987A's ejecta
upon the inner circumstellar ring are apparent and developing rapidly. Over the
past year, this phenomenon has made a transition, from emission originating in
just a few "hot spots" at restricted locations in position angle {PA}
around the
ER, to a collision producing optical emission over a nearly continuous
distribution {with few breaks larger than 45 degrees in PA} and indications of
low-level emission arising from nearly all PAs. We propose a modest but
effective program to trace superbly the development of the entire interaction
region by drawing on capabilities of STIS which are well-matched to the task,
and on the strength of comparison with existing STIS data.

STIS 9619

Echelle Blaze Shift vs. MSM Monthly Offset

In the near future, monthly MSM offsets will probably be disabled for STIS
echelle gratings, alleviating to some extent calibration problems associated
with the monthly offsets. The data from this program will be used to improve
empirical and optical models relating wavelength and blaze function shifts.
These models will in turn be used to improve the calibration of archival
echelle
data obtained while monthly MSM offsets were enabled. The flux standard HZ43
will be observed with the E230H echelle grating at a central wavelength of 2513
Angstroms. Five exposures will be obtained, each with a different monthly
offset
applied to the Mode Select Mechanism {MSM}.

STIS 8643

Ultraviolet Properties of the Metal Rich M87 Globular Cluster System

We propose to use STIS imaging to obtain far-ultraviolet photometry of the
metal
rich globular cluster system of the elliptical galaxy M87. This system
represents a key link between the well understood populations of the clusters
and the hot stars in elliptical galaxies, where our physical insight is
presently limited. Our goal is to establish the relationship between cluster
metal abundance and the production of UV-bright populations of stars on the
``extreme horizontal branch'' at T{eff} > 16000K. These stars are the source of
the surprising ``ultraviolet-upturn'' phenomenon in elliptical galaxies. Our
observations will fill a major gap in the present coverage of cluster metal
abundances. This would be an important step in understanding the dependence of
the upturn on its parent stellar population. A basic motivation is the
expectation that the UV-upturn could be the most sensitive probe of the
ages and
abundances of elliptical galaxy populations. We plan to observe 3 fields in
M87,
which will provide a sample of ~ 30--50 UV-detected objects in the brightest 3
magnitudes of its cluster luminosity function. The program is technically
challenging but appears feasible. Relatively long integrations are needed,
under
conditions of minimum dayglow emission from Earth's atmosphere.

STIS/CCD 8904

Bias Monitor-Part 2.

The Space Telescope Imaging Spectrograph (CCD) was used to monitor the bias in
the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4 in order
to build up high-S/N superbiases and track the evolution of hot columns.

STIS/CCD 8908

CCD Imaging Flats C10.

The Space Telescope Imaging Spectrograph (CCD) was used to investigate
flat-field stability over a monthly period.

STIS/CCD 9066

Closing in on the Hydrogen Reionization Edge of the Universe.

The Space Telescope Imaging Spectrograph (CCD) was used in parallel constrain
the Hydrogen reionization edge in emission that marks the transition from a
neutral to a fully ionized IGM at a predicted redshifts.

STIS/CCD 8902

Dark Monitor-Part 2.

The Space Telescope Imaging Spectrograph (CCD) was used to monitor the darks.

STIS/CCD 9317

Pure Parallel Imaging Program: Cycle 10.

The Space Telescope Imaging Spectrograph (CCD) was used to perform the default
archival pure parallel program for STIS during cycle 10.

STIS/CCD/MA1 9067

UV Detectability of Bright Quasars in the Sloan Fields.

The Space Telescope Imaging Spectrograph (CCD and MA1) was used to take MAMA
spectra of approximately 30 new, bright, high-redshift quasars in each of the
next three cycles.

WF/PC-2 9043

Cepheid Distances to Early-type Galaxies.

The WF/PC-2 was used to continue observations in the HST Key Project on the
Extragalactic Distance Scale and the HST project on the "Calibration of Nearby
Type Ia Supernovae'' that have greatly improved our knowledge of the Hubble
Constant by providing a solid zero point for the Tully- Fisher {TF}
relation and
Type Ia Supernovae {SNIa}. However, severe inconsistencies remain for distance
estimators to early-type galaxies such as surface brightness fluctuations
{SBF},
the planetary nebula luminosity function {PNLF}, the fundamental plane
{FP}, and
the globular cluster luminosity function {GCLF}. As a result, the distance to
the Virgo cluster core remains uncertain by as much as 20 determination is
directly affected by a lingering 0.1 mag {5 uncertainty in the photometric
calibration of the WFPC2. Resolving these issues is essential not only to firm
up the extragalactic distance scale, but also to understand the mass and
velocity structure of the local universe. SBF in particular is emerging as the
method of choice for mapping local velocity fields to 10, 000 kms because it
offers an order of magnitude less Malmquist bias than TF, and SNIa are too rare
to study large scale flows effectively. This project will tighten the
photometric calibration of the WFPC2, and provide a solid Cepheid calibration
for SBF and PNLF.

WF/PC-2 9157

Fundamental Properties Of L-Type Dwarfs In Binaries.

The WF/PC-2 was used to characterize the physical properties of eight L-dwarfs
in four binary systems. The goal is to obtain astrometric, photometric and
spectroscopic measurements of each component that will yield basic information
on atmospheric and dynamical properties.

WF/PC-2 9345

Fundamental Properties of L-type Dwarfs in Binaries.

The WF/PC-2 was used to characterize the physical properties of eight L-dwarfs
in four binary systems. The goal is to obtain astrometric, photometric and
spectroscopic measurements of each component that will yield basic information
on their atmospheric and dynamical properties.

WF/PC-2 9180

Gamma-ray Burst Progenitors: Probing Their Environment.

The WF/PC-2 was used to perform a target of opportunity observation of
gamma ray
burster (GRB), GRB-011121. GRB astronomy is a field maturing at a phenomenal
rate. Three important new observational and theoretical discoveries, formulated
over the last twelve months, allow the proposer to address new, and in many
cases, more sophisticated questions than could have been posed previously.
These
developments: the discovery of X-ray lines in GRB 991216; the observation that
N_H as deduced from X-ray afterglow are one to two orders of magnitude larger
than the dust extinction inferred from optical afterglow; and the growing
realization that the afterglow emission may exhibit features of dust echoes,
appear to offer unexpected and new diagnostics that will directly inform us
about the progenitor, the circum-progenitor material and the immediate
interstellar environs.

WF/PC-2 9050

Outflow Collimation in Bipolar Symbiotic Nebulae.

The WF/PC-2 was used to observe flow collimation in evolved stars that is
neither expected nor understood. Classical theories of stellar evolution do not
predict and cannot explain this bipolarity. More exotic concepts {binary
interactions, spun-up atmospheres, poloidal or toroidal magnetized winds} have
been proposed, but observations are yet to verify or falsify any of their
predictions. This proposal will probe the near-nuclear morphology and
kinematics
of four bright, low-extinction targets whose large-scale structure is highly
bipolar. The goal is to provide a detailed description of the circumnuclear
outflows, to uncover the physical structure and nature of the collimator,
and to
evaluate the speculative collimation mechanisms. The bright nucleus has
hampered
efforts to explore the nebular collimators that lie close to the star, so we'll
use STIS to disperse the nuclear light and, thus, to avoid its glare. A
secondary goal is to obtain second-epoch WFPC2 images of all targets.

WF/PC-2 9319

POMS Test Proposal: WFII Backup Parallel Archive Proposal II.

The WF/PC-2 was used to execute a POMS test proposal, designed to simulate
future scientific plans.

WF/PC-2 9318

POMS Test Proposal: WFII Parallel Archive Proposal Continuation.

The WF/PC-2 was used to perform the generic target version of the WFPC2
Archival
Pure Parallel program. The program was used to take parallel images of random
areas of the sky, following the recommendations of the Parallels Working
Group.

WFPC2 8938

WFPC2 CYCLE 9 SUPPLEMENTAL DARKS pt3/3.

This dark calibration program obtains 3 dark frames every day to provide data
for monitoring and characterizing the evolution of hot pixels. FLIGHT
OPERATIONS
SUMMARY:

HSTARs: (for further details see
http://hst-sers.hst.nasa.gov/SERS/HST/HSTAR.nsf)
8682 GRG2_3GT out of limits @ 158/10:56:27z
8683 GRG2_4GT out of limits @ 158/13:26:00z
8684 C string FOF queue buffer overflow errors @ 158/18:46:00z

8685 Gyro 3 Motor Current OOL 158/22:44:33 GRG2_3MC (RGA 2-3 Motor current)
flagged out of limits yellow high at EV=232.4mA. At 22:44:39 it
flagged out
red high at EV= 330.4mA. At 22:45:51 it flagged out yellow high EV=
252mA and
went back inbounds at 158/22:46:03. The yellow limits L=195 H=220.
The red limits
L=70 H=270. During the time of the OOL we were not guiding, we were
in orbit day and
we were not in a SAA. The following Reacqs using gyro 3 were
successful. Motor
safemode test count reached 1795 which is equivalent to 45 seconds
of a 90 second timer.
PCS SE, MOSES, and NASA on call were contacted. Under investigation.

8686 GSACQ(1,3,3) Fine Lock backup on FGS 3, scan step limit on FGS 1 @
160/05:08:20z
8687 486 status buffer message D08, SYSTEM_MOMENTUM_LIMIT_EXCEEDED @
160/160/23:44:37z
8688 Core Data Server /CCS Process /Ccl Isp alarm @ 160/03:03:00z

COMPLETED OPS REQs:
16786-2 NICMOS EEPROM Dump @ 158/1316z


OPS NOTES EXECUTED:
0900-1 Command Problem
0900-1 Command Problem
1012-0 Change Limits MAMA1Threshold Voltage
1013-0 Gyro 3 and 4 Temperature Adjust
0996-1 Raise Battery Temperature Upper limits to 2 deg
1012-1 Change Limits MAMA1Threshold Voltage
0916-0 Tabulation of Slew Attitude Error (Miss-distance)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 28 28
FGS REacq 26 26
FHST Update 52 52
LOSS of LOCK None

COMMENTS:
1. TTR #'s have been replaced by CDS #'s and DR #'s. Generic problems have
CDS #'s.
Any problem may have a unique DR #. A given occurrence of a generic
problem will
have a CDS #, but may or may not have a DR # assigned by CSC.
2. Loads for SA161M02_F1 are approved and available on CCS-C & CCS-B.
3. ESB code d08 is "System momentum exceeded limit" (Ref: HSTAR # 8687)
4. No new OOL values for gyro 3 current have been observed since HSTAR # 8685.


Continuation of Servicing Mission Orbital Verification and the gradual
resumption of normal science observations and calibrations.