Status Report

HST Daily Report # 3274

By SpaceRef Editor
January 8, 2003
Filed under , ,






NICMOS Post-SAA calibration – CR Persistence Part 1.

A new procedure proposed to alleviate the CR-persistence problem of NICMOS.
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
darks will be non-standard reference files available to users with a USEAFTER
date/time mark.


Closing in on the Hydrogen Reionization Edge of the Universe.

The Space Telescope Imaging Spectrograph (CCD) was used in parallel constrain
the Hydrogen reionization edge in emission that marks the transition from a
neutral to a fully ionized IGM at a predicted redshifts.


Cosmological Parameters from Type Ia Supernovae at High Redshift.

{SNe Ia} that will be of long lasting value as a record of the expansion
of the universe.


SINS: The Supernova Intensive Study– Cycle 10.

The Space Telescope Imaging Spectrograph (CCD) was used to perform closer
observations of supernovae that will create the chemical history of the
Universe, energize the interstellar gas, stiffen the spine of the extragalactic
distance scale and provide the only evidence for an accelerating universe. A
violent encounter is underway between the fast-moving debris and the stationary
inner ring. Monitoring this interaction will help solve the riddles of stellar
evolution posed by the enigmatic three-ring system of SN 1987A. Our UV
observations of Ly- Alpha emission reveal the present location and velocity
of a
remarkable reverse shock that provides a unique laboratory for studying fast
shocks and a powerful tool for dissecting the structure of the vanished star.

FGS 9347

FGS Astrometry of the Extrasolar Planet of Epsilon Eridani

We propose observations with HST/FGS in Position Mode to determine the
astrometric elements {perturbation orbit semimajor axis and inclination} of the
candidate extra-solar planet around the K2 V star Epsilon Eridani that has been
detected by Doppler spectroscopy. These observations will also permit us to
determine the actual mass of the planet by providing the sin{i} factor
which can
not be determined with the radial velocity method. High precision radial
velocity {RV} measurements spanning the years 1980.8–2000.0 for the nearby
{3.22 pc} star Epsilon Eri show convincing variations with a period of ~ 7 yrs.
These data represent a combination of six independent data sets taken with four
different telescopes. A least squares orbital solution using robust estimation
yields orbital parameters of period, P = 6.9 yrs, velocity K- amplitude = 19
m/s, eccentricity e = 0.6, projected companion mass M_B sin{i} = 0.83
An estimate of the inclination yields a perturbation semi-major axis, Alpha =
0arcs0022, easily within the reach of HST/FGS astrometry.

GO 9364

The Parallaxes and Proper Motions of Two Nearby Neutron Stars

We propose to measure the parallax of two nearby neutron stars to the highest
possible level of accuracy, ~.0.5 mas. The primary goal is to determine the
neutron-star radius at infinity with better than 1 km precision, and therewith
obtain a direct constraint on the equation of state of matter at supra-nuclear
density. The required flux and temperature determinations are easiest for the
so-called isolated or radio-quiet neutron stars because of their apparently
completely thermal spectrum. We argue that the importance of the possible
results warrants a study to the best possible level of the best possible
sources, and request 24 orbits for the two brightest isolated neutron stars, RX
J1856.5-3754 and RX J0720.4-3125. We will also determine whether the enigmatic
RX J0720.4-3125 is an old magnetar or an accreting source, based on its
luminosity and proper motion.


The Origin of Gamma-Ray Bursts

The rapid and accurate localization of gamma-ray bursts {GRBs} promised by a
working HETE-2 during the coming year may well revolutionize our ability to
study these enigmatic, highly luminous transients. We propose a program of HST
and Chandra observations to capitalize on this extraordinary opportunity. We
will perform some of the most stringent tests yet of the standard model, in
which GRBs represent collimated relativistic outflows from collapsing massive
stars. NICMOS imaging and STIS CCD spectroscopy will detect broad atomic
features of supernovae underlying GRB optical transients, at luminosities more
than three times fainter than SN 1998bw. UV, optical, and X-ray spectroscopy
will be used to study the local ISM around the GRB. Chandra spectroscopy will
investigate whether the GRB X-ray lines are from metals freshly ripped from the
stellar core by the GRB. HST and CTIO infra-red imaging of the GRBs and their
hosts will be used to determine whether `dark’ bursts are the product of
unusually strong local extinction; imaging studies may for the first time
the hosts of `short’ GRBs. Our early polarimetry and late-time broadband
will further test physical models of the relativistic blast wave that produces
the bright GRB afterglow, and will provide unique insight into the influence of
the GRB environment on the afterglow.


Externally Illuminated Circumstellar Material in the Young Nebulous Cluster NGC

HST imaging of the Orion M42 H II region has revealed circumstellar
emission and
absorption regions {“proplyds”} with sizes comparable to those expected for
protoplanetary disks. Disk morphology is directly observed in a dozen cases;
disk photoevaporation is now the working model to explain the ionized rims seen
at more than 100 Trapezium cluster stars. Are the Trapezium circumstances
unique? Different cluster ages, densities, and UV radiation fields may strongly
affect proplyd characteristics. To address these questions, we have
searched for
proplyds in several other young nebulous clusters, and found that the embedded
infrared cluster associated with the NGC 2024 H II region has a large group of
strong proplyd candidates. Our WFPC2 images of the optically visible edge
of the
cluster have identified an HAlpha proplyd aligned toward a B0 star. Our VLA 3.6
cm maps show compact ionization regions coincident with 20 members of the
infrared cluster – a result similar to the original VLA proplyd discovery
in M42
by Churchwell {1987}. These results strongly indicate that infrared emission
line imaging of selected cluster members should reveal many objects similar to
the those in M42. We propose NIC2 Paschen Alpha and continuum imaging of
fourteen of the NGC 2024 compact VLA sources. Our goal is to resolve and
characterize their circumstellar structures, and compare them with those
seen in

ACS 9480

Cosmic Shear With ACS Pure Parallels

Small distortions in the shapes of background galaxies by foreground mass
provide a powerful method of directly measuring the amount and distribution of
dark matter. Several groups have recently detected this weak lensing by
large-scale structure, also called cosmic shear. The high resolution and
sensitivity of HST/ACS provide a unique opportunity to measure cosmic shear
accurately on small scales. Using 260 parallel orbits in Sloan textiti {F775W}
we will measure for the first time: beginlistosetlength sep0cm
setlength opsep0cm em the cosmic shear variance on scales <0.7 arcmin, em the
skewness of the shear distribution, and em the magnification effect.
endlist Our
measurements will determine the amplitude of the mass power spectrum
sigma_8Omega_m^0.5, with signal-to-noise {s/n} ~ 20, and the mass density
Omega_m with s/n=4. They will be done at small angular scales where non-linear
effects dominate the power spectrum, providing a test of the gravitational
instability paradigm for structure formation. Measurements on these scales are
not possible from the ground, because of the systematic effects induced by PSF
smearing from seeing. Having many independent lines of sight reduces the
uncertainty due to cosmic variance, making parallel observations ideal.

ACS 9482

ACS Pure Parallel Lyman-Alpha Emission Survey {APPLES}

Ly-alpha line emission is an efficient tool for identifying young galaxies at
high redshift, because it is strong in galaxies with young stars and little or
no dust — properties expected in galaxies undergoing their first burst of
star- formation. Slitless spectroscopy with the ACS Wide-Field Camera and G800L
grism allows an unmatched search efficiency for such objects over the
uninterrupted range 4 <~ z <~ 7. We propose the ACS Pure Parallel Ly-alpha
Emission Survey {“APPLES”}, to exploit this unique HST capability and so
obtain the largest and most uniform sample of high redshift Ly-alpha emitters
yet. Parallel observations will allow this survey to be conducted with minimal
impact on HST resources, and we will place reduced images and extracted spectra
in the public domain within three months of observation. We aim to find ~ 1000
Ly-alpha emitters, 5 times the biggest current sample of Ly-alpha emitters.
unprecedented sample will provide robust statistics on the populations and
evolution of Ly-alpha emitters between redshifts 4–7; a robust measurement of
the reionization redshift completely independent of the Gunn-Peterson trough;
spatial clustering information for Ly-alpha emitters which would let us probe
their bias function and hence halo mass as a function of redshift; many
at redshift exceeding 6; and lower redshift serendipitous discoveries.


The NICMOS Parallel Observing Program

We propose to manage the default set of pure parallels with NICMOS. Our
experience with both our GO NICMOS parallel program and the public parallel
NICMOS programs in cycle 7 prepared us to make optimal use of the parallel
opportunities. The NICMOS G141 grism remains the most powerful survey tool for
HAlpha emission-line galaxies at cosmologically interesting redshifts. It is
particularly well suited to addressing two key uncertainties regarding the
global history of star formation: the peak rate of star formation in the
relatively unexplored but critical 1<= z <= 2 epoch, and the amount of star
formation missing from UV continuum-based estimates due to high extinction. Our
proposed deep G141 exposures will increase the sample of known HAlpha emission-
line objects at z ~ 1.3 by roughly an order of magnitude. We will also obtain a
mix of F110W and F160W images along random sight-lines to examine the space
density and morphologies of the reddest galaxies. The nature of the extremely
red galaxies remains unclear and our program of imaging and grism spectroscopy
provides unique information regarding both the incidence of obscured star
and the build up of stellar mass at intermediate redshifts. In addition to
carrying out the parallel program
we will populate a public database with calibrated spectra and images, and
provide limited ground- based optical and near-IR data for the deepest parallel

WFPC2 9592

WFPC2 CYCLE 11 Standard Darks

This dark calibration program obtains dark frames every week in order to
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
will also provide a monitor of radiation damage to the CCDs.

WFPC2 9593


This dark calibration program obtains 3 dark frames every day to provide data
for monitoring and characterizing the evolution of hot pixels.

WFPC2 9598

Earth Flats

This proposal monitors flatfield stability. This proposal obtains sequences of
Earth streak flats to construct high quality flat fields for the WFPC2 filter
set. These flat fields will allow mapping of the OTA illumination pattern and
will be used in conjunction with previous internal and external flats to
generate new pipeline superflats. These Earth flats will complement the Earth
flat data obtained during cycles 4-10.

WFPC2 9599

WFPC2 Cycle 11 UV Earth Flats

Monitor flat field stability. This proposal obtains sequences of earth streak
flats to improve the quality of pipeline flat fields for the WFPC2 UV filter
set. These Earth flats will complement the UV earth flat data obtained during
cycles 8-10.

STIS 9605

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD

STIS 9607

CCD Bias Monitor – Part 1

Monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1
at gain = 4, to build up high-S/N superbiases and track the evolution of hot

STIS 9615

Cycle 11 MAMA Dark Monitor

This test performs the routine monitoring of the MAMA detector dark noise. This
proposal will provide the primary means of checking on health of the MAMA
detectors systems through frequent monitoring of the background count rate. The
purpose is to look for evidence of change in dark indicative of detector

ACS 9647

CCD Daily Monitor Part I

This program consists of basic tests to monitor, the read noise, the
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.

ACS 9669

ACS coronagraph stability and vignetting

This is a two-part activity for the purposes of {1} monitoring the
positions ACS
coronagraph’s occulting spots and the "Fastie Finger, " and {2} determining the
vignetting effects and the ability to flat field images of both point and
extended sources near the edges of the spots and finger.

WFPC2 9676

POMS Test Proposal: WFII parallel archive proposal

This is the generic target version of the WFPC2 Archival Pure Parallel program.
The program will be used to take parallel images of random areas of the sky,
following the recommendations of the 2002 Parallels Working Group.


NICMOS Parallel Thermal Background

NICMOS Camera 2 pure parallel exposures in the F222M and F237M filters to
establish the stability of the HST+NCS+Instrument thermal emission. This data
will be compared against the already available Camera 3 measurements in F222M
which show an increased thermal background.

STIS 9706

STIS Pure Parallel Imaging Program: Cycle 10

This is the default archival pure parallel program for STIS during cycle 10.


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


OPS NOTES EXECUTED: 1051-1 FGS #3-6 Temperature Increase @003/1946z

                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq              7                          7
FGS REacq              8                          8
FHST Update            12                        12


SpaceRef staff editor.