02 May 2003

HUBBLE SPACE TELESCOPE

DAILY REPORT # 3354

PERIOD COVERED: DOY 121

Part 2 of 3

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. 

STIS 9509

Probing the Distance and Structure of the LMC Using Eclipsing
Binaries: STIS The distance to the LMC is crucial to calibrating the
Cosmic Distance Scale but remains controversial and uncertain despite
the efforts of many investigators. We have shown that the analysis of
eclipsing binary {EB} systems has the potential to resolve this
controversy. We have determined accurate distances to three eclipsing
binaries in the LMC. Two EBs in the LMC bar, HV 2274 and EROS 1044,
yield a consistent distance of 46.0+/-1.2 kpc for the bar itself. A
third system, HV 982, is located at a greater distance {50.2+/-1.2
kpc}, which is similar to that of the nearby SN 1987A {51.4+/-1.2
kpc}. These results may suggest a significant depth to the LMC
populations but a larger stellar sample is needed to verify this. The
distances of the program stars were derived from ground-based light
curves, HST or CTIO radial velocity data, and HST UV/optical
spectrophotometry. We propose HST/STIS low-resolution spectra of
seven LMC EBs for which we already have radial velocity and light
curves. This will permit us to complete the analysis and derive
accurate {to ~3%} individual distances. HST/STIS spectroscopy
{covering 115-800nm} is a key dataset because it provides Teff, Fe/H,
and A_lambda. The ensemble of targets, in addition to nailing down
the distance to the LMC, will provide fundamental stellar properties
and a detailed probe of the structure and spatial extent of this
important galaxy, in particular its line-of-sight depth. 

WFPC2 9589

WFPC2 Decontaminations and Associated Observations Pt. 1/3

Photometric stability check, focus monitor, pre- and post-decon
internals {bias, intflats, kspots, & darks}, UV throughput check,
VISFLAT sweep, and internal UV flat check.

WFPC2 9598

Earth Flats

This proposal monitors flatfield stability. This proposal obtains
sequences of Earth streak flats to construct high quality flat fields
for the WFPC2 filter set. These flat fields will allow mapping of the
OTA illumination pattern and will be used in conjunction with
previous internal and external flats to generate new pipeline
superflats. These Earth flats will complement the Earth flat data
obtained during cycles 4-10. 

ACS 9649

ACS internal CTE monitor

The charge transfer efficiency {CTE} of the ACS CCD detectors will
decline as damage due to on-orbit radiation exposure accumulates.
This degradation will be closely monitored at regular intervals,
because it is likely to determine the useful lifetime of the CCDs.
All the data for this program is acquired using internal targets
{lamps} only, so all of the exposures should be taken during Earth
occultation time {but not during SAA passages}. This program emulates
the ACS pre-flight ground calibration and post-launch SMOV testing
{program 8948}, so that results from each epoch can be directly
compared. Extended Pixel Edge Response {EPER} and First Pixel
Response {FPR} data will be obtained over a range of signal levels
for both the Wide Field Channel {WFC}, and the High Resolution
Channel {HRC}. 

ACS 9659

Bias and dark dependence on CCD gains

This program is designed to obtain a set of bias and dark frames at
non-default HRC and WFC CCD gains.

ACS 9674

CCD Daily Monitor

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. 

STIS 9708

STIS Pure Parallel Imaging Program: Cycle 11

This is the default archival pure parallel program for STIS during
cycle 11.

WFPC2 9709

POMS Test Proposal: WFII parallel archive proposal

This is the generic target version of the WFPC2 Archival Pure
Parallel program. The program will be used to take parallel images of
random areas of the sky, following the recommendations of the 2002
Parallels Working Group. 

 - Continued -

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