Status Report

NASA Hubble Space Telescope Daily Report # 3669

By SpaceRef Editor
August 6, 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.


What drives the outflows in powerful radio galaxies?

There is increasing speculation that activity-induced outflows are an
important feedback mechanism in evolution of galaxy bulges, yet
uncertainties remain about the nature, dominant driving mechanism and
powers of the outflows. In order to address these issues, we propose
to make deep ACS and STIS observations of two compact radio sources
in which we recently found unequivocal evidence for powerful emission
line outflows, and in which all the potential drivers for the
outflows — quasar nuclei, relativistic jets and starbursts — are
known to be present. Using the unique capabilities of HST/ACS we will
map the outflow regions in these sources at high spatial resolution
and thereby determine the dominant outflow driving mechanism. In
addition, by combining the morphological information from the ACS
data with information on the kinematics and physical conditions
derived from STIS and ground-based spectra, we will determine the
mass outflow rates and powers in the outflows. This will be the first
comprehensive study of the near-nuclear outflows in radio galaxies.
Such studies are crucial for determining whether the activity
associated with powerful extragalactic radio sources has a major
impact on the evolution of the host early-type galaxies.

ACS/WFC 10146

Solving the problem of the White Dwarf Cooling Sequence End in M4: an
efficent approach

The end of the white dwarf {WD} cooling sequence {WDCS} has never
been observed, despite the importance that it has in providing an age
estimate of old stellar systems, independent from the standard method
of the main sequence turn off. The best targets for this
investigation are the closest stellar clusters, and, among them,
globular clusters are the most interesting ones. Being the oldest
stellar aggregates, they allow to probe the advanced WD cooling
phases, and the independent age estimate coming from the end of their
WDCS has an important cosmological impact. M4 is the best target for
this investigation. Despite huge observational efforts, we still miss
the end of its WDCS. The ACS camera offers a unique opportunity to
identify it. Coupled with already existing observations, we here
prove that we can finally reach it with only 10 HST orbits.The data
we are requesting here, will also be used to complete other two
programs of great astrophysical impact: the observational detection
of the main sequence hydrogen burning limit, and the measurement of
the geometrical distance of M4.

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. While
gravitational lenses can be discovered with ground-based optical and
radio observations, converting them into astrophysical tools requires
HST. 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.

NIC/NIC3 10226

The NICMOS Grism Parallel Survey

We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency
of our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at
0.7<z<1.9, which provides an excellent measure of current star
formation rate. We will also detect star-forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial–but poorly observed–redshift range where
galaxies appear to have assembled most of their stellar mass. This
key process of galaxy evolution needs to be studied with IR data; we
found that observations at shorter wavelengths appear to have missed
a large fraction of the star-formation in galaxies, due to dust
reddening. We will also obtain deep F110W and F160W images, to
examine the space densities and morphologies of faint red galaxies.
In addition to carrying out the public parallels, we will make the
fully reduced and calibrated images and spectra available on-line,
with some ground-based data for the deepest parallel fields included.

NIC1/NIC2 9844

Brown dwarf atmospheric variability observations

We propose to use NIC1 and NIC2 to study brown dwarfs for atmospheric
variability. We will observe a sequence of early Ts, a detected
variable T2, a T3 and a T4.5. Atmospheric variability, that is
expected by some models for these objects, would constrain the
physical parameters of cloud vertical distribution, horizontal
homogeneity and the dynamics of the very cool atmospheres. The
existence and amplitude of the variations would reveal the size and
distribution of the cloud cover over the surface of the brown dwarf
and test a model explaining the rapidity of the L to T type
transition. The relative color changes would constrain the vertical
extent of dynamical process and the depth in the atmosphere at which
they take place. If a periodicity is measured, the rotational period
of the dwarf could be estimated.

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.


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

                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq               7                           7
FGS REacq               8                           8
FHST Update            13                        13


SpaceRef staff editor.