Status Report

HST Daily Report # 3280

By SpaceRef Editor
January 16, 2003
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NICMOS Post-SAA calibration – CR Persistence Part 1.

A new procedure proposed to alleviate the CR-persistence problem of NICMOS.
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
darks will be non-standard reference files available to users with a USEAFTER
date/time mark.


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.

ACS 9293

Massive Black Holes in Early Type Galaxies

3×10^6 Msun < M_BH < 3×10^9 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
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
H-alpha and continuum images to fully characterize the gaseous and dust
morphology as well as stellar surface profile in the central regions.

STIS 9417

New Clues to the Origin of the Extreme Helium Stars

The extreme helium stars {EHes} are H-poor supergiants whose origins are
not yet
understood despite thorough analyses of optical spectra. This proposal seeks
STIS echelle spectra for 7 stars from which novel data on their chemical
compositions will be obtained to pin down key abundances. First, even the EHe’s
initial metallicity is uncertain; certain abundance ratios – e.g., Ca/S, Ti/S,
and Fe/S – imply alterations of surface abundances among elements from Na to Ni
resulting from fractionation or diffusive separation, possibly the result of
winnowing of dust grains from gas. The zinc abundance measurable only from UV
spectra will be a powerful clue to the true metallicity because it is known not
to be removed by such winnowing. Second, elements affected by the
s-process, the
last of the major nucleosynthetic processes for which surface abundances are
unknown for EHes, will be studied. The new abundances will be used to probe the
evolutionary origins of these peculiar stars by comparisons with theoretical
scenarios involving a merger of white dwarfs or a final He-shell flash in a low
mass white dwarf, and with observed abundances for R Coronae Borealis stars
would seem to be close relatives of the EHes. Spectrophotometric
observations of
EHes obtained with GO 8603 will give accurate estimates of effective
and surface gravity that will be used in our abundance determinations.

ACS 9478

The Duty Cycle of Star Formation : Far-UV imaging of the Hubble Deep Field

We propose deep far-UV imaging of the Hubble Deep Field {HDF} with the
Previously, we surveyed 1/5 of the HDF in the UV and now propose to
complete the
area. Near- and far-UV number counts suggest that there is a large
population of
UV- bright starbursts at moderate redshifts {z<0.6}, and our proposed
observations will investigate their nature. We will measure the star formation
properties of these galaxies and their morphologies in the UV, optical, and
near-IR. This catalog of starbursts will also be important to the astronomical
community after Cycle 11 in interpreting planned SIRTF observations of the
field. We will also set strict limits on the flux escaping in intermediate
redshift {1<z<2} galaxies at wavelengths below the rest-frame 912 Angstrom
limit, and thus infer the contribution of star forming galaxies at z~ 5 to the
metagalactic ionizing radiation. Finally, we will measure the diffuse far-UV
background at 1600 Angstrom. The HDF is the best field in the sky for the
background measurements, given the legacy of ultra-deep observations at other
wavelengths. In the spirit of the Hubble Deep Fields, we waive proprietary
rights to these data.

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
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/WFPC2 9481

Pure Parallel Near-UV Observations with WFPC2 within High-Latitude ACS Survey

the default pure parallel program for those WFPC2 parallels that fall
within the
ACS survey field. Rather than duplicate the red bands which will be done much
better with ACS, we propose to observe in the near-ultraviolet F300W filter.
These data will enable study of the rest-frame ultraviolet morphology of
galaxies at 0<z<1. We will determine the morphological k-correction, and the
location of star formation within galaxies, using a sample that is likely to be
nearly complete with multi-wavelength photometry and spectroscopic redshifts.
The results can be used to interpret observations of higher redshift
galaxies by


The NICMOS Parallel Observing Program

We propose to manage the default set of pure parallels with NICMOS. Our
experience with both our GO NICMOS parallel program and the public parallel
NICMOS programs in cycle 7 prepared us to make optimal use of the parallel
opportunities. The NICMOS G141 grism remains the most powerful survey tool for
HAlpha emission-line galaxies at cosmologically interesting redshifts. It is
particularly well suited to addressing two key uncertainties regarding the
global history of star formation: the peak rate of star formation in the
relatively unexplored but critical 1<= z <= 2 epoch, and the amount of star
formation missing from UV continuum-based estimates due to high extinction. Our
proposed deep G141 exposures will increase the sample of known HAlpha emission-
line objects at z ~ 1.3 by roughly an order of magnitude. We will also obtain a
mix of F110W and F160W images along random sight-lines to examine the space
density and morphologies of the reddest galaxies. The nature of the extremely
red galaxies remains unclear and our program of imaging and grism spectroscopy
provides unique information regarding both the incidence of obscured star
bursts and the build up of stellar
mass at intermediate redshifts. In addition to carrying out the parallel
we will populate a public database with calibrated spectra and images, and
provide limited ground- based optical and near-IR data for the deepest parallel

ACS/WFC 9492

Extragalactic Distances: the Need for Accurate Photometry of Blue Supergiants
and Cepheids

The investigation of the Wind Momentum-Luminosity Relationship {WLR} of blue
supergiant stars as an independent extragalactic distance indicator has reached
a critical phase. Following our recent discovery and spectroscopic follow-up of
several tens of stars outside of the Local Group in NGC 300 and NGC 3621,
we can
now calibrate the WLR in terms of spectral subtype and metallicity with a
accuracy than hithertho possible with the statistically limited samples
available in the nearby galaxies studied so far. This, however, requires
high-resolution imaging to obtain accurate BVI photometry of a significant
fraction of those stars for which we have spectroscopic information. This
can be
effectively accomplished with eight ACS/WFC fields in these two galaxies. As a
further step, we can use the calibrated WLR to measure the first independent
extragalactic distance. We then propose additional imaging of six ACS/WFC
in M101 to select blue supergiant candidates for spectroscopic follow-up.
recently discovered more than a hundred new Cepheids in NGC 300, the
high-resolution imaging proposed for the photometry of blue supergiants can
be used, with no additional observing effort, to verify the effects of blending
on the Cepheid distance to this galaxy, an important calibrator of secondary
distance indicators.

GO 9508

A binary system in the Kuiper Belt: 1998_WW31

1998_WW31 is the first Kuiper Belt Object, outside the pair Pluto/Charon, to be
discovered as a binary object. Though only preliminary results are available
from two orbits of HST DDT observation when this proposal is submitted, the
exhibits a very high eccentricity {larger than 0.5} and a period of 570 days.
The purpose of this proposal is to complete the monitoring of the pair on a
orbit, up to February 2003. Monitoring will then have to cease {Sun too close}.
The binarity of an asteroid allows the determination of the total mass of the
system and provides important information on the past Kuiper Belt environment
{formation/collisions/capture processes}. If size can be obtained from albedo
determination, the mass will give the density, a key parameter for any study of
the origin and evolution of the Kuiper Belt. Hubble’s unparalleled resolution
provides the unique way to acquire observations of the pair good enough to
access the physical characteristics of this system with a high degree of
confidence, as the high eccentricity of the orbit keeps the two components less
than 1 arc-second apart for most of the orbit. The observations would be made
public immediately to allow the continuation of the education program offering
to follow the pair on a regular basis to illustrate the prediction/verification
iterative process of science and the direct use of simple laws for the
determination of key parameters.

WFPC2 9594


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

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.

WFPC2 9599

WFPC2 Cycle 11 UV Earth Flats

Monitor flat field stability. This proposal obtains sequences of earth streak
flats to improve the quality of pipeline flat fields for the WFPC2 UV filter
set. These Earth flats will complement the UV earth flat data obtained during
cycles 8-10.

STIS 9605

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD

STIS 9607

CCD Bias Monitor – Part 1

Monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1
at gain = 4, to build up high-S/N superbiases and track the evolution of hot

STIS 9624

STIS FUV-MAMA Cycle 11 Flats

This program will obtain FUV-MAMA observations of the STIS internal Krypton
to construct an FUV flat applicable to all FUV modes

STIS 9633

STIS parallel archive proposal – Nearby Galaxies – Imaging and Spectroscopy

Using parallel opportunities with STIS which were not allocated by the TAC, we
propose to obtain deep STIS imagery with both the Clear {50CCD} and Long-Pass
{F28X50LP} filters in order to make color-magnitude diagrams and luminosity
functions for nearby galaxies. For local group galaxies, we also include G750L
slitless spectroscopy to search for e.g., Carbon stars, late M giants and
stars. This survey will be useful to study the star formation histories,
chemical evolution, and distances to these galaxies. These data will be placed
immediately into the Hubble Data Archive.

WFPC2 9634

POMS Test Proposal: WFII targeted parallel archive proposal

The parallel opportunities available with WFPC2 in the neighborhood of bright
galaxies are treated in a slightly different way from the normal pure
Local Group galaxies offer the opportunity for a closer look at young stellar
populations. Narrow-band images in F656N can be used both to identify young
stars via their emission lines, and to map the gas distribution in star-forming
regions. Thus, the filter F656N is added to the four standard filters. Near
distant galaxies, up to about 10 Mpc, we can map the population of globular
clusters; for this purpose, F300W is less useful, and only F450W, F606W, and
F814W will be used.


Photometric Stability

This NICMOS calibration proposal carries out photometric monitoring
during cycle 11.

ACS 9673

CCD Daily Monitor

This program consists of basic tests to monitor, the read noise, the
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

WFPC2 9676

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.

WFPC2 9699

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans.

STIS 9706

STIS Pure Parallel Imaging Program: Cycle 10

This is the default archival pure parallel program for STIS during cycle 10.


Significant Spacecraft Anomalies: (The following are preliminary reports of
potential non-nominal performance that will be investigated.) None



                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq              8                          8
FGS REacq              4                          4
FHST Update            13                        13


SpaceRef staff editor.