Status Report

NASA Hubble Space Telescope Daily Report # 3663

By SpaceRef Editor
July 30, 2004
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science





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/WFC 10210

Groups of Dwarf Galaxies: Pools of Mostly Dark Matter?

Within 5 Mpc, there are 6 groups with well-known luminous galaxies but
there also appears to be a comparable number of groups containing only
dwarfs. If these dwarf entities are truly bound then M/L values are an
order of magnitude higher than values found for groups with luminous
spiral galaxies. There are theoretical reasons to anticipate that low
mass halos may frequently be mostly dark. The dynamical influence of
low mass halos is negligible in familiar groups with luminous members.
By contrast, a study of the dynamics of `groups of dwarfs’ may provide
direct evidence of the existence of dark matter potential wells with
few baryons. The goal of the present study is to gather detailed
information on the 3-D distribution of dwarf galaxies suspected to lie
within 7 groups of dwarfs within 5 Mpc. Distances with 7% relative
accuracy can be measured with the Tip of the Giant Branch method with
ACS and integrations within 1 orbit per target.


Young Massive Clusters in Spiral Galaxies and the Connection with Open

We propose to carry out a census of star clusters in the disks of the
nearby spiral galaxies NGC 45, NGC 1313, NGC 4395, NGC 5236 and NGC
7793. Using ACS, we will identify much fainter and older star clusters
than possible in previous ground-based surveys, or even in HST imaging
of more distant galaxies. For the first time, we will directly explore
the connection between young "massive” {or "super”} star clusters
{YMCs} and lower-mass "open” clusters in different star forming
environments. We will test the universality of the luminosity- and
mass functions of stellar clusters and establish whether the presence
of YMCs is a result of a top-heavy cluster luminosity function, or
follows from generally richer cluster systems. Our target galaxies
span a range of morphological properties, surface brightness and star
formation rate. Some of them are known from ground-based studies to
host large numbers of YMCs while others have more modest cluster
populations. However, previous ground-based data were restricted to
luminous clusters younger than about 500 Myr. Here we will extend the
search to clusters formed throughout the entire lifetime of each
galaxy and reach clusters with properties typical of the Milky Way
open clusters. This will allow us to close the gap between studies of
extragalactic and Galactic disk clusters.

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.

NIC2 9845

NICMOS Confirmation of a Young Planetary-Mass Companion

We have recently discovered a strong candidate for a planetary-mass
{~10 Mjup} companion to a young Sun-like star, based on near-IR
imaging and spectroscopy with the Keck and Subaru adaptive optics {AO}
systems. While the ground-based data strongly suggest that the
candidate has a very low effective temperature, and hence a very low
mass, they are not definitive. We propose to obtain NICMOS
coronagraphy to measure the companion’s 1.9um water-band absorption.
This feature is a distinct signature of very cool objects and is
unobservable from the ground. The combined ground-based and
space-based data set will determine whether the companion has a very
low temperature, and hence if it is the lowest mass companion found to
date by direct imaging.

NIC2 9856

A near-IR imaging survey of submm galaxies with spectroscopic redshifts

Submillimeter {submm} surveys with SCUBA have identified a population
of obscured star-forming and active galaxies at high redshift. Our
recent spectroscopic campaigns with the Keck-10m telescope have
uncovered redshifts for 37 SCUBA galaxies. The wide redshift range of
the radio identified submm population {z=1-4} implies that many
varieties of sources driven by different physical processes may be
selected in a submm survey. We propose to use HST-NICMOS, ACS to
obtain 2-filter images of a sample of 15 SCUBA galaxies with redshifts
spanning z=0.8-3.5. Our goal is to understand what physical process
{major mergers?} drive their strong evolution and great luminosities,
and what the implications are for galaxy evolution models.

STIS/CCD 10018

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

STIS/CCD 10020

CCD Bias Monitor – Part 2

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 columns.

STIS/CCD 10215

STIS follow-up spectroscopy of Seyfert galaxies from Cycle 11 near-UV
imaging survey

We propose a near-UV {3000-5500AA} long-slit spectroscopic study of a
sample of 23 Seyfert galaxies with bright circumnuclear U-band
structures, selected from our Cycle 11 ACS near-UV snapshot survey.
This survey collected HST U-band images for 78 galaxies, which also
have optical and near-IR images available in the archive. We propose
to enrich this image database with STIS spectra in the near-UV. The
novel aspect of the present proposal is the availability of the
near-UV images which will allow us to select the best slit centering
and orientation to probe the circumnuclear structures. Our goal is to
investigate the nature of these structures, characterizing the
circumnuclear continuum and ionizing source of these galaxies at a
spatial resolution of $sim$10 parsecs, where we will probe the black
hole environment. With the proposed observations, we will derive
properties of the circumnuclear stellar populations of the selected
galaxies {ages, masses and metallicities}, evolutionary effects
connecting the growth of the black hole with the growth of the galaxy
bulge, as well as the relation between the black hole mass, accretion
rate {luminosity} and the circumnuclear stellar population properties.
This dataset will also allow us to study the effect of the bulge and
black hole on the evaporation of young star clusters in these

STIS/CCD 10222

The Next Generation Spectral Library

We propose to complete our snapshot program to produce a Next
Generation Spectral Library of 600 stars for use in modeling the
integrated light of galaxies and clusters. This program is using the
low dispersion UV and optical gratings of STIS. The library will be
roughly equally divided among four metallicities, very low {[Fe/H] <
-1.5}, low {-1.5 < [Fe/H] < -0.5}, near-solar {-0.3 < [Fe/H] < 0.1},
and super-solar {[Fe/H] > 0.2}, well-sampling the entire HR-diagram in
each bin. Such a library will surpass all extant compilations and have
lasting archival value, well into the Next Generation Space Telescope
era. Because of the universal utility and community-broad nature of
this venture, we waive the entire proprietary period.


Probing Outflowing Winds from the Galactic Center

We propose to use two extragalactic sightlines to probe our own
Galaxy’s "starburst" wind emanating from the Galactic Center. While
new infrared imaging and spectroscopy have detected massive stars and
very recent {<3×10^6 yrs} star formation in the Galactic Center
region, only indirect evidence {e.g., radio loops and arcs, bi-conical
cavity edges seen in the mid-IR} exists for a wind. However, these
winds are routinely detected from starbursts in other galaxies. Far-UV
STIS echelle spectroscopy {E140M} of two targets on either side of the
Galactic Center at {l, b}={350,-33} and {349, 55} will allow us to map
the kinematics of outflowing gas in high ionization species of N V, Si
IV and C IV. Similar spectra of distant {1.5-5 kpc}, bright B stars in
the same regions of the sky will allow us to remove foreground
contaminating components due to the Sco-Cen OB associations. Lower
resolution STIS first-order and FUSE spectra show highly redshifted
gas in N V and O VI respectively along these sightlines; these new
observations will provide three times better spectral resolution {7-10
km/s in the 1185-1580A region} so that the kinematic signature of the
outflow can definitely be detected. The foreground stars will allow us
to determine whether the outflow is from the Galactic Center or the
Sco-Cen OB associations. Absorption line column densities will be used
to estimate the outflowing mass and energy by assuming a metallicity
and ionizing source for the gas.

WFPC2 10071

WFPC2 CYCLE 12 Supplemental Darks Part 3/3

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


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

HSTAR 9491: GS Acquisition (2,1,1) @ 210/21:30:55Z resulted in FL
backup (2,0,2) due to SSLE on FGS 1. Under investigation.



                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq               10                         10
FGS REacq                07                         07
FHST Update             16                        16


SpaceRef staff editor.