Status Report

NASA Hubble Space Telescope Daily Report # 3601

By SpaceRef Editor
April 29, 2004
Filed under , ,
NASA Hubble Space Telescope Daily Report # 3601

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 9744

HST Imaging of Gravitational Lenses

Gravitational lenses offer unique opportunities to study cosmology,
dark matter, galactic structure, galaxy evolution and quasar host
galaxies. They are also the only sample of galaxies selected based on
their mass rather than their luminosity or surface brightness. We will
obtain ACS/WFC V and I images and NICMOS H images of 21 new lenses
never observed by HST and NICMOS H images of 16 lenses never observed
by HST in the IR. As in previous cycles, we request that the data be
made public immediately.

ACS/WFC 9788

A Narrow-band Snapshot Survey of Nearby Galaxies

We propose to use ACS/WFC to conduct the first comprehensive HST
narrow-band {H-alpha + [N II]} imaging survey of the central regions
of nearby bulge-dominated disk {S0 to Sbc} galaxies. This survey will
cover, at high angular resolution extending over a large field, an
unprecedented number of galaxies representing many different
environments. It will have important applications for many
astrophysical problems of current interest, and it will be an
invaluable addition to the HST legacy. The observations will be
conducted in snapshot mode, drawing targets from a complete sample of
145 galaxies selected from the Palomar spectroscopic survey of nearby
galaxies. Our group will use the data for two primary applications.
First, we will search for nuclear emission-line disks suitable for
future kinematic measurements with STIS, in order to better constrain
the recently discovered relations between black hole mass and bulge
properties. Preliminary imaging of the type proposed here must be
done, sooner or later, if we are to make progress in this exciting new
field. Second, we will investigate a number of issues related to
extragalactic star formation. Specifically, we will systematically
characterize the properties of H II regions and super star clusters on
all galactic scales, from circumnuclear regions to the large-scale

ACS/WFC 9842

A Snapshot Search for Halo Very-Low-Mass Binaries

We propose a snapshot search for binary M subdwarf stars. These nearby
stars have high velocities and low metallicies that identify them as
members of the old Galactic halo {Population II}. ACS imaging is
requested to search for secondary companions. This supplements a
previous snapshot program that only obtained 10 observations. The
observed binary fraction will be compared to the disk M dwarf fraction
to look for differences in star formation. It is likely that a system
suitable for orbital mass determinations will be found. In this case,
future HST observations could determine the first masses for
very-low-mass, low-metallicity stars.

GO 9367

Unique Opportunities to Search for the Optical Counterparts to High-Z
Damped LyAlpha Systems

The galaxies responsible for damped LyAlpha absorption in QSO spectra
are difficult to observe against the strong background QSO emission.
We propose to detect even low luminosity galaxies associated with QSO
absorption line systems out to redshifts as high as z = 1.8 by
observing them in the shadow cast by an even higher redshift damped
LyAlpha absorber. As a result the galaxy will be observed free of
contamination by the background AGN and of the uncertainties which
arise when image processing techniques are required to remove the AGN
emission. We propose two approaches. In the first we will attempt to
detect a z = 1.8634 system seen in the optical spectrum of a high-z BL
Lac object in the shadow of two higher-redshift systems seen in the
same optical spectrum. In the second only the higher redshift
shadowing LyAlpha system is seen in the optical spectrum and the
presence of the lower- redshift systems at z = 0.713 and z = 1.0466
are inferred from the presence of strong MgII, SiII and FeII
absorption lines.

NIC1/NIC2/NIC3 8792

NICMOS Post-SAA calibration – CR Persistence Part 3

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 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 9786

The Next Generation Spectral Library

We propose to continue the Cycle 10 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] lt
-1.5}, low {[Fe/H] -1.5 to -0.5}, near-solar {[Fe/H] -0.3 to 0.1}, and
super-solar {[Fe/H] gt 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.

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.


Volatile Abundances and the D/H Ratio in Long-Period Comets

Comet NEAT {C/2001 Q4} is predicted to reach naked-eye visibility in
the spring of 2004, under excellent conditions for observations with
HST. Although predicting cometary magnitudes more than 1 year in
advance is notoriously risky, C/NEAT seems likely to be exceptionally
active, allowing us for the first time to perform sensitive
measurements of the D/H and OD/OH ratios. Accurate measurements of the
deuterium abundance in comets, which can vary in different species,
are crucial for determining if comets retain a signature of their
possible interstellar origin and if they supplied a significant
fraction of the water on Earth. HST observations of C/NEAT will
additionally provide accurate abundances for highly volatile ices in
the nucleus, such as CO, CO2 {via Cameron band emission}, and S2,
which also provide important insights on the comet’s origin and
evolution. This opportunity in cycle 12 is unique in the history of
HST and is unlikely to be repeated during its remaining lifetime.


Confirmation of New Candidates for the Study of Intergalactic Helium

The reionization of intergalactic helium is believed to take place
between redshift 3 and 4. The study of HeII Lyman-alpha absorption in
four quasars at 2.7<z<3.3 demonstrates the great potential of such an
intergalactic-medium {IGM} probe and suggests that the reionization
epoch is at higher redshifts. Clean quasar sightlines may be found
only from massive pre-selection processes in the optical and UV,
because of random, severe absorption by intervening Lyman-limit
systems. The SDSS has discovered approximately 36000 quasars, and we
propose to verify the UV detectability in 70 top candidates for helium
studies extending to even higher redshift. Our proposed approach has
already proven successful, and additional positive confirmations will
allow follow-up observations, with STIS or COS, to pinpoint the epoch
of reionization of the IGM, and the evolution of its properties near
that period.


Where is the Local Hot Gas?

We wish to sample the absorption characteristics of 3 lines-of-sight
in the local interstellar medium to establish the physical location of
the production sites of the highly ionized absorption lines of CIV,
SiIV and NV. Such lines are formed at gas temperatures of ~ 100, 000K
and all have been widely observed throughout the Galaxy. However,
evidence for the formation of any of these high ions within the hot
gas of the Local Bubble {LB} remains inconclusive, supporting the
similar lack of detections of the OVI ion {T ~ 300, 000K} within 100pc
recently reported by the FUSE satellite. Using our recently gained
information on the contours of the neutral boundary to the LB, we have
selected 3 pairs of stars located just within, and just beyond the LB
boundary. We shall test whether high ionization ions are formed either
{a} beyond the LB boundary in more distant interstellar bubbles of hot
gas, {b} at the conductive interface of the LB neutral boundary, or
{c} at possible conductive interfaces between hot gas within the LB
and the diffuse clouds embedded within it. Hopefully, these
observations will enable theorists to better model the {anomalous}
ionization state, pressure and chemical abundance of the local
interstellar gas and will assist in the interpretation of data soon to
be gained from the NASA CHIPS mission.

WFPC2 10070

WFPC2 CYCLE 12 Supplemental Darks Part 2/3

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
investigated.) None


Adjust Recharge Ratio Limits for High Sun DOY 2004/110-119 @ 119/10:00z

                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq              13                           13
FGS REacq               05                           05
FHST Update            17                          17


Successfully completed Battery Capacity Test Steps 32 – 35, Battery
ROC Safemode test disabled, patched FULROC value back to 21.3 Amperes,
enabled Battery ROC Safemode test, and enabled OCA @ 119/12:48:40Z
(OR17146-4 with attached script).

SpaceRef staff editor.