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06 May 2003

HUBBLE SPACE TELESCOPE

DAILY REPORT # 3356

PERIOD COVERED: DOY 125

Part 1 of 4

OBSERVATIONS SCHEDULED

NICMOS 8791

NICMOS Post-SAA calibration - CR Persistence Part 2

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.

ACS 9293

Massive Black Holes in Early Type Galaxies

Recently, a nearly perfect relation has been recognized between the
masses of the black holes {for 3x10^6 Msun < M_BH < 3x10^9 Msun} at
the centers of galaxies and the velocity dispersions of their bulges.
However, uncertainties over the exact slope of the correlation still
remain, and it is not known if such a relation extends to black holes
of lower and higher masses. The discovery of small {r ~ a few hundred
pc}, well defined, dust and gas disks in the nuclei of some active
elliptical galaxies opened a new avenue for measuring central mass
distributions. When ionized gas is present, a small number of high
spatial resolution {e.g. STIS} spectra are sufficient to characterize
the disk dynamics and the galaxy's central mass {e.g., M87, M81, NGC
4374}. We propose to use STIS spectroscopy to measure black hole
masses, using gas dynamics, in the centers of several brightest
cluster galaxies {BCGs}, 2 nearby galaxies with low velocity
dispersions, and a number of elliptical galaxies known to harbor
small nuclear dust disks. The proposed targets encompass a wide range
of black hole masses, allowing us to fully examine the M_BH -- sigma
relationship. We will also obtain H-alpha and continuum images to
fully characterize the gaseous and dust morphology as well as stellar
surface profile in the central regions. 

WF/PC-2 9345

Fundamental Properties of L-type Dwarfs in Binaries.

The WF/PC-2 was used to characterize the physical properties of eight
L-dwarfs in four binary systems. The goal is to obtain astrometric,
photometric and spectroscopic measurements of each component that
will yield basic information on their atmospheric and dynamical
properties. 

NICMOS 9360

Paschen-alpha Imaging of a SIRTF-Selected Nearby Galaxy Sample

We propose to carry out a NICMOS snapshot survey in the Paschen-alpha
{PAlpha} emission line and H-band of the sample of galaxies being
observed at 3.5 -- 160 microns as part of SIRTF Nearby Galaxies
Survey {SINGS} and a related guaranteed time survey of starburst
galaxies. The PAlpha images, accessible only from HST, will be
combined with groundbased HAlpha imaging to measure the extinction in
the star-forming centers of these galaxies, and obtain robust,
extinction-corrected maps of the massive star formation rate {SFR}.
The PAlpha data by themselves will provide reliable
`extinction-free' SFRs, and a cross-calibration of the {dust--
affected} HAlpha-- and UV--based SFRs. The PAlpha--based SFR
measurements will extend the SFR-vs.-gas density law {Schmidt--law}
to surface densities at least 30 times higher than what is accessible
using HAlpha--based SFR measurements alone, bridging the gap between
normal galaxies and IR--luminous starbursts. Furthermore, the
combination of the HST PAlpha images with the SIRTF images and
spectra, as well as ancillary ground--based UBVRIJHK images and GALEX
UV images being obtained as part of the SINGS project, will provide a
definitive study of the radiative transfer of starlight and dust
heating in star--forming galaxies. The processed NICMOS images will
be incorporated into the public SINGS Legacy Data Archive, to enable
scores of follow-up studies by the astronomical community at large.

STIS 9418

The Sight-line toward PHL 1811: A Rare Chance to Probe a Lyman Limit
System at Very Low

The sight-line to an extraordinarily bright quasar, PHL 1811,
penetrates four gas systems at z{abs} < z{em} = 0.192. One of them is
a Lyman limit system {LLS: N{H I} > 10^17.5 cm^-2} at
z{abs} = 0.08088 which is especially well suited for a study of
atomic abundances, local density, and ionization state. We propose to
obtain a STIS E140M spectrum with moderately good S/N so that we can
measure absorption features that will permit the determinations of
overall metallicity of the system, its nucleosynthetic ratios
Alpha/Fe and Alpha/N, the fractions and kinematics of ionized gas,
and the amount of gas-phase element depletions caused by dust. The
LLS should be close enough for us to identify an associated galaxy,
but to be sure we do not miss one very close to the quasar in
projection, we plan to supplement our spectrum with a short- exposure
ACS HRC image of the quasar's immediate surroundings.

ACS 9420

Intensive Coverage of the Eta Carinae Event in 2003

For a variety of reasons, HST can provide a very special and unique
data set when Eta Car experiences its next spectroscopic event in
mid-2003. Explaining the phenomenon is only part of the motivation.
This star and its ejecta have unique characteristics that make them
important for several branches of astrophysics; and when a
spectroscopic event occurs, it's like varying the parameters in an
experiment {or rather, set of experiments}. The 2003 event will be
the last chance in the foreseeable future to obtain such a data set.
Eta Carinae has extreme parameters; it is mysterious in surprisingly
basic ways; and HST/STIS can gather useful data on it at a terrific
rate. As we explain below, the proposed data set will be valuable in
several independent ways: It will help solve a specific set of
current problems, it will constitute a large and unique archival data
base for both stellar and nebular astrophysics, and it will be well-
suited for educational uses. 

 - Continued -

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