Status Report

NASA Hubble Space Telescope Daily Report # 3694

By SpaceRef Editor
September 15, 2004
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




ACS/HRC 10050

ACS Earth Flats

High signal sky flats will be obtained by observing the bright Earth
with the HRC and WFC. These observations will be used to verify the
accuracy of the flats currently used by the pipeline and will provide
a comparison with flats derived via other techniques: L-flats from
stellar observations, sky flats from stacked GO observations, and
internal flats using the calibration lamps. Weekly coronagraphic
monitoring is required to assess the changing position of the spots.

ACS/HRC 10238

The nature of quasar host galaxies: combining ACS imaging and VLT
Integral Field Spectroscopy.

We propose to perform ACS/F606W imaging of a complete sample of 29
quasar host galaxies {0.08<z<0.34}. The spatial resolving power of the
ACS HRC, in combination with the acquisition of empirical PSFs and
advanced deconvolution techniques, will allow to study in detail
structures on scales of a few tens of parsecs, and to access the inner
regions of the host galaxies, even in the presence of bright nuclei.
We demonstrate that combining deep spectroscopy with high resolution
imaging in stable PSF conditions definitely constitutes the solution
to characterize the complex physical properties of quasar host
galaxies, from their outer regions to the inner 0.1 kpc, where most of
the information on the interplay between quasars and their hosts is
hidden. We propose to combine new ACS images with existing Integral
Field VLT Spectra. We will map the stellar and gas velocity fields in
2D, constrain the mass models, derive the radial host M/L ratios, map
and characterize the stellar populations and the ionization state of
the gas.


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}.


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.


Galaxy Evolution in Action : The Detailed Morphology of Post-Starburst

If galaxies evolve morphologically, then some should be in transition
between late and early types. One proposed evolutionary mechanism is a
galaxy-galaxy merger, but evolved merger products are difficult to
find. Fortunately, spectroscopic surveys have now uncovered large
numbers of E+A galaxies, a class of objects whose post-starburst
spectra, current lack of HI gas, and pressure-supported kinematics
suggest that they are the missing panel that connects the "Toomre
sequence" of merging spirals with normal ellipticals and S0s. Our
first HST observations of five of these galaxies are intriguing. We
find a considerable range of tidally disturbed morphologies, an "E+A"
fundamental plane, significant differences among the color gradients
within 1 kpc {~0.8”}, and populations of bright, blue globular
clusters. These initial results are difficult to interpret, however,
because they are drawn from a small sample of galaxies whose very blue
overall colors may have selected a particular evolutionary path of
E+As. Here we propose for ACS imaging of the remaining 15 E+As from
the Las Campanas Redshift Survey to probe the full range of E+A
properties. The proposed observations will allow us to 1} determine
what fraction of the interactions that lead to E+As destroy all
disk-like structures {and therefore necessarily lead to elliptical
formation}, 2} measure the inner color gradients and constrain the
spatial distribution of stars produced as gas sinks to the center
during a merger, and 3} determine whether these interactions produce
globular clusters in the required numbers to account for the increased
specific frequency of clusters in early-type galaxies.

ACS/WFC 10043

External CTE Monitor

Monitor CTE changes during cycle 11. Determine CTE.

ACS/WFC 10126

The 3-D Shape of the SMC: Is It Tidally Distorted?

We propose to exploit the exceptional spatial resolution of HST to
definitively show whether the SMC is tidally elongated along the
line-of-sight, and therefore the status of the Milky Way’s
interaction/destruction of the Magellanic Clouds. We use BVI ACS
images of several crowded SMC fields in the region predicted by models
of the orbit and tidal evolution of the Magellanic Clouds {and by
observations of Cepheids} to have a large depth. We exploit the red
clump feature {and the rarer true horizontal branch} to derive the
depth. Specifically, we will observe six fields along the predicted
region of maximum distance gradient of the SMC, along with two ACS
fields and several WFPC2 fields in the archives, to map out the depth
of the SMC in this region. We are searching for substructure, such as
a tidal tail, that may be present. Crowding in this region of the SMC
is so severe that this project cannot be done from the ground.

ACS/WFC 10135

Unveiling the Progenitors and Physics of Cosmic Explosions

GRBs and XRFs are clearly highly asymmetric explosions and require a
long-lived power source {central engine}. In contrast, nearby
core-collapse events are essentially spherical explosions. However,
the failure of spherical neutrino driven collapses has led to the idea
that asymmetric energy release is essential for the explosion. The
recent finding of a Type Ic SN in GRB 030329, the association of the
low energy event GRB 980425 with SN 1998bw, the theoretical
development discussed above and the rise of collapsar models make it
timely to consider whether all these explosions contain engines. Given
the uncertainties in theoretical modeling it is clear that
observations are needed to guide models. A priori there is little
reason to expect connection between the ultra-relativistic jet that
powers the GRB and the explosive nucleosynthesis of the ~0.5 solar
masses of Nickel-56 that powers the accompanying supernova. We propose
a comprehensive program of ACS photometric searches {and measurements}
for SNe associated with GRBs and XRFs. In concert, we will undertake
ground-based spectroscopy to determine velocity widths, and measure
engine parameters from pan-chromatic afterglow observations. Our goal
is to produce a comprehensive database of engine and SN physical
parameters against which theoretical modeling will be guided.

ACS/WFC 10257

Astrometric and Photometric Study of NGC 6397 for Internal Motions,
Dark Binaries, and X-Ray Sources

We propose to observe the central regions of the globular cluster NGC
6397 with ACS/WFC once per month for the 10 months of its visibility
in Cycle 13. The project has three main goals: {1} Measure internal
motions for roughly 3000 stars within 150 arcseconds of the cluster
center, using archival WFPC2 as a first epoch. The motion of the
typical star will be measured to 10-20%. We will detect any central
black hole {BH} with a mass greater than 1000 solar masses, and will
also measure core-collapse signatures such as anisotropy. {2} Conduct
the first-ever search for heavy binaries by looking for the
astrometric "wobble" of the luminous secondary. We should find all
heavy binaries in the field with separations between 1 and 5 AU and
periods between 3 months and 5 years. {3} Search for optical
counterparts to X-ray sources found by Chandra.

NIC1 10208

NICMOS Differential Imaging Search for Planetary Mass Companions to
Nearby Young Brown Dwarfs

We propose to use the differential spectral imaging capability of
HST/NICMOS {NIC1} to search for planetary mass companions. We target
the twelve most nearby {within 30 pc}, isolated {no known close
companion}, and young {< 1Gyr} brown dwarfs. All of them have spectral
type L and show signs of Lithium absorption, which clearly proves
their substellar nature and youth. Planetary mass companions with
masses down to 6 Jupiter masses, and at separations larger than 3 A.U.
are bright enough for a direct detection with HST/NICMOS using the
spectral differential imaging technique in two narrow-band filters
placed on and off molecular bands. The proposed project has the
potential to lead to the first direct detection of a planetary mass
object in orbit around a nearby brown dwarf.

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.

NIC1/NIC2/NIC3 9993

Cycle 12 NICMOS dark current, shading profile, and read noise
monitoring program

The purpose of this proposal is to monitor the dark current, read
noise, and shading profile for all three NICMOS detectors throughout
the duration of Cycle 12. This proposal is an essentially unchanged
continuation of PID 9636 which cover the duration of Cycle 11.

NIC2 10176

Coronagraphic Survey for Giant Planets Around Nearby Young Stars

A systematic imaging search for extra-solar Jovian planets is now
possible thanks to recent progress in identifying "young stars near
Earth". For most of the proposed young {<~ 30 Myrs} and nearby {<~ 60
pc} targets, we can detect a few Jupiter-mass planets as close as a
few tens of AUs from the primary stars. This represents the first time
that potential analogs of our solar system – that is planetary systems
with giant planets having semi-major axes comparable to those of the
four giant planets of the Solar System – come within the grasp of
existing instrumentation. Our proposed targets have not been observed
for planets with the Hubble Space Telescope previously. Considering
the very successful earlier NICMOS observations of low mass brown
dwarfs and planetary disks among members of the TW Hydrae Association,
a fair fraction of our targets should also turn out to posses low mass
brown dwarfs, giant planets, or dusty planetary disks because our
targets are similar to {or even better than} the TW Hydrae stars in
terms of youth and proximity to Earth. Should HST time be awarded and
planetary mass candidates be found, proper motion follow-up of
candidate planets will be done with ground-based AOs.

WFPC2 10068

WFPC2 CYCLE 12 Standard Darks

This dark calibration program obtains dark frames every week in order
to provide data for the ongoing calibration of the CCD dark current
rate, and to monitor and characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

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

WFPC2 10072


This calibration proposal is the Cycle 12 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A
variety of internal exposures are obtained in order to provide a
monitor of the integrity of the CCD camera electronics in both bays
{gain 7 and gain 15}, a test for quantum efficiency in the CCDs, and a
monitor for possible buildup of contaminants on the CCD windows.


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



                             SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS Gsacq                  12                       12
FGS Reacq                   04                       04
FHST Update                17                       17


SpaceRef staff editor.