Status Report

NASA Hubble Space Telescope Daily Report # 3888

By SpaceRef Editor
June 24, 2005
Filed under , , ,
NASA Hubble Space Telescope Daily Report # 3888

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT        # 3888

PERIOD COVERED: UT June 23, 2005 (DOY 174)


ACS/HRC 10391

Wavelength and Flux Calibration of the ACS prisms

The wavelength calibration of the SBC {PR110L and PR130L} and HRC
{PR200L} prisms will be established by observing a planetary nebula in
the LMC and QSOs at carefully selected redshifts. Flux calibrations
will be derived for each prism by observing white dwarf standards.

ACS/WFC 10152

A Snapshot Survey of a Complete Sample of X-ray Luminous Galaxy
Clusters from Redshift 0.3 to 0.7

We propose a public, uniform imaging survey of a well-studied,
complete, and homogeneous sample of X-ray clusters. The sample of 73
clusters spans the redshift range between 0.3-0.7. The samples spans
almost 2 orders of magnitude of X-ray luminosity, where half of the
sample has X-ray luminosities greater than 10^44 erg/s {0.5- 2.0 keV}.
These snapshots will be used to obtain a fair census of the the
morphology of cluster galaxies in the cores of clusters, to detect
radial and tangential arc candidates, to detect optical jet
candidates, and to provide an approximate estimate of the shear signal
of the clusters themselves, and potentially an assessment of the
contribution of large scale structure to lensing shear.

ACS/WFC 10416

Star Formation Driven Outflows in Actively Star Forming Edge-on Spiral

We will investigate the disk-halo interaction in four actively star
forming edge-on spiral galaxies using the ACS. In recent years
considerable progress has been achieved in testing the disk-halo
interaction scenario which describes the large scale mass exchange of
the ISM between disk and halo including the metal enrichment of the
IGM, which is on galactic scales described by various theoretical
models {e.g., galactic fountains, chimneys, superwinds}. The
investigation of nearby edge-on spirals in this respect offers a
particularly exciting perspective for a quantitative understanding of
this feedback provided by star formation on the ISM. Feedback is the
crucial ingredient in all models of galaxy formation and evolution.
While commonly implemented in simple terms {global energy or metal
injection}, further progress can only be achieved with a better
understanding of the relevant physics. This requires high spatial
resolution studies of nearby galaxies. Whereas groundbased
observations are perfectly suited to study the overall morphology of
the outflowing gas, they are inadequate to describe the structure on
the smallest relevant scales. However, it is the small scale structure
that constrains the microphysics to be applied in theoretical models
of a multiphase medium. Galaxies spanning a wide range of star
formation activity have to be investigated in order to test which
processes for the gas ejection are at work. High spatial resolution
studies, as can be achieved with the ACS onboard HST and yielding a
spatial resolution of 3-7 parsecs for the four proposed target
galaxies, will critically test the existing models for the feedback


Environmental drivers of galaxy evolution: an HST survey of dwarf
galaxy morphologies in the Abell Galaxies in dense environments are
subject to numerous physical processes that leave a lasting impact,
yet studies of galaxy evolution to date have been limited to the most
luminous galaxies — those least sensitive to environmental influence.
We propose to explore the environmental drivers of DWARF galaxy
evolution: with a mosaic of 9×9 ACS pointings in F606W we will
determine morphologies for ~1200 galaxies down to M_V=-14 in the
A901/902 supercluster, spanning 3×3 Mpc at z=0.16. The deep ACS data
will allow us to probe their surface brightness profiles, shapes,
sizes, asymmetry and fine structure such as tidal features. With the
addition of extensive existing multi- wavelength data, we will probe
the dependence of these important parameters on dark matter content
{from weak lensing maps}, the hot intercluster medium {from deep XMM-
Newton imaging}, and local galaxy density {from hyper-accurate
COMBO-17 photometric redshifts with delta z=0.02 to m_R=24}, thus
disentangling the various environmental processes shaping dwarf galaxy
evolution. Furthermore, the 8000+ background galaxies at 0.2

NIC1 10143

Ultracool companions to the nearest L dwarfs

We propose to conduct the most sensitive survey to date for low mass
companions to nearby L dwarfs. We will use NICMOS to image targets
drawn from a volume-complete sample of 70 L dwarfs within 20 parsecs.
The combination of infrared imaging and proximity will allow us to
search for T dwarf companions at separations as small as 1.6 AU. This
is crucial, since no ultracool binaries are currently known with
separations exceeding 15 AU. Only 10 dwarfs in this sample have
previous HST observations primarily at optical wavelengths. With the
increased sensitivity of our survey, we will provide the most
stringent test to date of brown dwarf models which envisage formation
as ejected stellar embryos. In addition, our observations will be
capable of detecting binaries with mass ratios as low as 0.3, and will
therefore also test the apparent preference for equal-mass ultracool
binaries. Finally, our observations offer the best prospect to date of
detecting companions significantly cooler than the coolest t dwarf
currently known.

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 10147

Detecting the elusive low mass companion around epsilon Indi

We propose coronagraphic NICMOS observations of the nearby {d = 3.6
pc} K5V star epsilon Indi {HD 209100} to search for the unknown
companion which causes a low amplitude radial velocity {RV} trend in
our 11 years of precise Doppler measurements. This RV data set places
a lower limit of 4.5 AU for the orbital semimajor axis of this
companion. Moreover, the fact that the RV trend is lacking any sign of
curvature over this long time period clearly points towards a much
larger orbital separation. Epsilon Indi also has a T dwarf {binary}
companion at a separation of 1400 AU. However, these brown dwarf
companions are too distant from the primary to induce the observed RV
variation. It is also unlikely that this nearby star has an unknown
stellar {M dwarf} companion. The RV signal is thus most probably
caused by a yet unknown giant planetary or brown dwarf companion at a
separation of more than 5 AU. Because epsilon Indi is so near to the
Sun, it constitutes an ideal target for high contrast imaging with
NICMOS in its coronagraphic mode. Indeed, NICMOS coronagraphy is
capable of detecting objects down to 15 Jupiter masses at separations
greater than 2.3 arcseconds {S/N=25} – precisely the separation and
mass range indicated by our Doppler spectroscopy. Only 2 orbits of
HST/NICMOS observations could directly image the coolest and lowest
mass companion ever found around a solar-type star.

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.


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

HSTARS: (None)



                       SCHEDULED     SUCCESSFUL    FAILURE TIMES 
 FGS Gsacq           15                       15 
 FGS Reacq            04                       04 
 FHST Update          17                       17 


SpaceRef staff editor.