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Subject: Daily 3359

09 May 2003

HUBBLE SPACE TELESCOPE

DAILY REPORT # 3359

PERIOD COVERED: DOY 128

Part 1 of 3

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/WFC/HRC 9075

Cosmological Parameters from Type Ia Supernovae at High Redshift.

The Advanced Camera for Surveys (WFC and HRC) was used to obtain a
Hubble diagram of Type Ia supernovae {SNe Ia} that will be of long
lasting value as a record of the expansion history of the universe.

STIS/CCD 9186

D/H in Lyman Limit Absorbers with Simple Velocity Structure.

The Space Telescope Imaging Spectrograph (CCD) was used to observe
the deuterium abundance in QSO absorbers that provides a direct
measurement of the baryonic density of the Universe. This proposal
will obtain new high resolution data of two carefully selected,
intermediate redshift absorption systems. 

STIS/MA1 9343

The UV Light Echo of Shock Breakout During SN 1987A

Light echoes {transient reflection nebulae} from SN1987A were
discovered in the optical in 1988 and have been detected in the
vacuum ultraviolet by IUE. The UV data would be the first ``direct''
observation of the hot spectrum emitted by a supernova shock
destroying its progenitor star; unfortunately the large aperture and
pointing instabilities of IUE make these data difficult to calibrate
and interpret in great detail. The breakout signal has also been
modified by the spectral reflectance of the echoing dust. We propose
to confirm the UV detection and to disentangle the incident SN
spectrum from the dust reflectance by observing the UV echo at two
scattering phase angles and combining them with HST and ground-based
data. Sampling two echoes at widely-spaced spectral points and two
scattering angles will provide us with enough independent information
to factor these separately. The resulting early UV spectrum of SN
1987A will allow a direct test of theoretical models of supernova
shock propagation and breakout from a star, as well as provide an
accurate input ionization spectrum for understanding the excitation
and recombination of gas in the observed circumstellar nebulosity
around SN1987A. This study will also strongly constrain the physical
properties of interstellar dust in the Large Magellanic Cloud. 

ACS/HRC 9379

Near Ultraviolet Imaging of Seyfert Galaxies: Understanding the
Starburst-AGN Connection

We propose a near-UV snapshot survey of 101 Seyfert galaxies using
ACS/HRC and the filter F330W, a configuration which is optimal to
detect faint star forming regions around their nuclei. These images
will complement optical and near-IR images available in the HST
archive, thus providing a panchromatic atlas of the inner regions of
active galaxies, which we will use to study the starburst-AGN
connection. The main goals of this proposal are: {1} Determine the
frequency of circumnuclear starbursts in Seyferts, down to levels
which cannot be observed from the ground; {2} characterize the
observational {fluxes, colors, structure, sizes} and intrinsic
{luminosities, masses, ages, global star-formation rate} properties
of these clusters; {3} derive the luminosity functions of young star
clusters around the nucleus of Seyferts and compare these results
with those from normal and starburst galaxies to determine their
survival rate close to the AGN; {4} address questions about the
relation between AGNs and starbursts, like the possible connection
between the masses and luminosities of black holes and starbursts,
and the implications for the evolution of the black holes and their
host galaxy bulges. By adding UV images to the existing optical and
near-IR ones, this project will create an extremely valuable database
for astronomers with a broad range of scientific interests, from the
properties of the AGN to the properties of their host galaxies.

ACS 9462

Systemic and Internal Proper Motions of the Magellanic Clouds from
Astrometry with ACS

We request first epoch observations with ACS of Magellanic Cloud
fields centered on background quasars. Second epoch observations will
be requested ~ 5 years later to allow the measurement of the systemic
and internal proper motions of the Clouds with error <~0.05 mas/year.
These motions are of fundamental importance. The systemic motions of
the LMC and SMC probe the gravitational potential of the dark halo.
The internal proper motion due to rotation can be exploited to yield
a rotational parallax distance to the LMC; the first time that this
will be done for any galaxy. This is particularly important for the
LMC because of its crucial role in the extragalctic distance ladder.
Previous measurements of the proper motion of the LMC yield a
systemic component ranging from 1.4 mas/year to 3.4 mas/year
{differing by several times the quoted errors}, with no useful
determination of the internal motions. The main problem with
measurements of the proper motion of the LMC has been the lack of a
sample of background quasars to use as reference frame. We have
recently been able to identify a sample of 54 quasars behind the
Magellanic Clouds from their variability characteristics in the MACHO
database. With this sample and the advent of ACS an accurate proper
motion measurement has become possible for the very first time.

 - Continued -

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