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14 Apr 2003

HUBBLE SPACE TELESCOPE

DAILY REPORT #3340

PERIOD COVERED: DOYS 101-103

Part 1 of 6

OBSERVATIONS SCHEDULED

ACS 9468

ACS Grism Parallel Survey of Emission- line Galaxies at Redshift
z pl 7

We propose an ACS grism parallel survey to search for emission-line
galaxies toward 50 random lines of sight over the redshift interval
0 < zpl 7. We request ACS parallel observations of duration more
than one orbit at high galactic latitude to identify ~ 300 HAlpha
emission-line galaxies at 0.2pl zpl 0.5, ~ 720 O IILambda3727
emission-line galaxies at 0.3pl zpl 1.68, and pg 1000 Ly-alpha
emission-line galaxies at 3pl zpl 7 with total emission line flux fpg
2* 10^-17 ergs s^-1 cm^-2 over 578 arcmin^2. We will obtain direct
images with the F814W and F606W filters and dispersed images with the
WFC/G800L grism at each position. The direct images will serve to
provide a zeroth order model both for wavelength calibration of the
extracted 1D spectra and for determining extraction apertures of the
corresponding dispersed images. The primary scientific objectives are
as follows: {1} We will establish a uniform sample of HAlpha and O II
emission-line galaxies at z<1.7 in order to obtain accurate
measurements of co-moving star formation rate density versus redshift
over this redshift range. {2} We will study the spatial and
statistical distribution of star formation rate intensity in
individual galaxies using the spatially resolved emission-line
morphology in the grism images. And {3} we will study high-redshift
universe using Ly-alpha emitting galaxies identified at z pl 7 in the
survey. The data will be available to the community immediately as
they are obtained.

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 9673

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

ACS 9480

Cosmic Shear With ACS Pure Parallels

Small distortions in the shapes of background galaxies by foreground
mass provide a powerful method of directly measuring the amount and
distribution of dark matter. Several groups have recently detected
this weak lensing by large-scale structure, also called cosmic shear.
The high resolution and sensitivity of HST/ACS provide a unique
opportunity to measure cosmic shear accurately on small scales. Using
260 parallel orbits in Sloan textiti {F775W} we will measure for the
first time: beginlistosetlength sep0cm setlengthemsep0cm setlength
opsep0cm em the cosmic shear variance on scales <0.7 arcmin, em the
skewness of the shear distribution, and em the magnification effect.
endlist Our measurements will determine the amplitude of the mass
power spectrum sigma_8Omega_m^0.5, with signal-to-noise {s/n} ~ 20,
and the mass density Omega_m with s/n=4. They will be done at small
angular scales where non-linear effects dominate the power spectrum,
providing a test of the gravitational instability paradigm for
structure formation. Measurements on these scales are not possible
from the ground, because of the systematic effects induced by PSF
smearing from seeing. Having many independent lines of sight reduces
the uncertainty due to cosmic variance, making parallel observations
ideal. 

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 9293

Massive Black Holes in Early Type Galaxies

Recently, a nearly perfect relation has been recognized between the
masses of the black holes {for 3x10^6 Msun < M_BH < 3x10^9 Msun} at
the centers of galaxies and the velocity dispersions of their bulges.
However, uncertainties over the exact slope of the correlation still
remain, and it is not known if such a relation extends to black holes
of lower and higher masses. The discovery of small {r ~ a few hundred
pc}, well defined, dust and gas disks in the nuclei of some active
elliptical galaxies opened a new avenue for measuring central mass
distributions. When ionized gas is present, a small number of high
spatial resolution {e.g. STIS} spectra are sufficient to characterize
the disk dynamics and the galaxy's central mass {e.g., M87, M81, NGC
4374}. We propose to use STIS spectroscopy to measure black hole
masses, using gas dynamics, in the centers of several brightest
cluster galaxies {BCGs}, 2 nearby galaxies with low velocity
dispersions, and a number of elliptical galaxies known to harbor
small nuclear dust disks. The proposed targets encompass a wide range
of black hole masses, allowing us to fully examine the M_BH -- sigma
relationship. We will also obtain H-alpha and continuum images to
fully characterize the gaseous and dust morphology as well as stellar
surface profile in the central regions. 

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