Status Report

HST Daily Report # 3271

By SpaceRef Editor
January 2, 2003
Filed under , ,



PERIOD COVERED: DOYs 2002/365-2003/01



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.


Understanding High-Redshift and Starburst Galaxies: A UV Spectroscopic
Survey of
B- Stars in the SMC.

The Space Telescope Imaging Spectrograph (CCD and MA2) was used to construct a
high quality spectral library at low metallicity in order to synthesize the UV
spectra of high redshift star-forming galaxies and nearby starbursts.


NGC 2610: A Benchmark for Photoionization Physics.

observe lines of H I, He II, C III, C IV, N IV, N V, O III, O IV, Ne III,
Ne IV,
and Ne V from 1240Angstrom to 6563Angstrom. He II Lambda1640/Lambda4686 will
determine the {small} reddening accurately. These observations will provide a
benchmark against which it can test the understanding of high T_e nebulae,
are ubiquitous in low abundance environments, but which have proved
difficult to


A Survey for Missing Baryons in Highly Ionized Intergalactic Gas at Low

The Space Telescope Imaging Spectrograph (CCD and MA1) was used to observe six
additional low-z QSOs with the STIS FUV E140M echelle mode {7 km s^-1
resolution}. Combined with archival data, this will increase the sample
path by a factor of ~7 compared to the published data. With the echelle
data, we
will {1} measure the number of O VI absorbers per unit redshift {dN/dz} and
their minimum cosmological mass density with a limiting equivalent width of
W_Lambda ~50 mAngstrom , {2} examine whether the O VI absorption arises in
photoionized, collisionally ionized, or multiphase gas, and {3} study the
dependence of the O VI system properties on environment. In addition to testing
this prediction regarding the location of the missing baryons, the data will
have applications to many other topics such as low-z LyAlpha absorbers and the
physical properties and abundances of gas in the Milky Way halo.

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.

ACS 9352

The Deceleration Test from Treasury Type Ia Supernovae at Redshifts 1.2 to 1.6

Type Ia supernovae {SNe Ia} provide the only direct evidence for an
universe, an extraordinary result that needs a rigorous test. The case for
cosmic acceleration rests on the observation that SNe Ia at z ~ 0.5 are ~ 0.25
mag fainter than they would be in a universe without acceleration. A powerful
and straightforward way to assess the reliability of the SN Ia measurement and
the conceptual framework of its interpretation is to look for cosmic
deceleration at z >= 1. This would be a clear signature of a mixed dark-matter
and dark-energy universe. Systematic errors in the SN Ia result attributed to
grey dust or cosmic evolution of the SN Ia peak luminosity would not show this
change of sign. We have demonstrated proof of this concept with a single SN Ia,
SN 1997ff at z = 1.7, found and followed by HST. The results suggest an early
epoch of deceleration, but this is too important a conclusion to rest on just
one object. Here we propose to use HST for observations of six SNe Ia in the
range 1.2 <= z <= 1.6, that will be discovered as a byproduct from proposed
Treasury programs for high-latitude ACS surveys. Six objects will provide a
firmer foundation for a conclusion that touches on important questions of
fundamental physics.

ACS/WFC 9353

Direct imaging of the progenitors of massive, core-collapse supernovae

Modern supernovae searches in the nearby Universe are discovering vast numbers
of SNe which have massive star progenitors {Types II, Ib and Ic}. The extensive
HST {and ground-based} image archives of galaxies within ~20 Mpc enables their
individual bright stellar content to be resolved. As massive, evolved stars are
the most luminous single objects in a galaxy, the progenitors of core-collapse
SNe should be directly detectable on pre-explosion images. Within the last year
we have set direct mass limits on the progenitors of two SNe Type II-P by
analyzing pre-explosion archive images and follow up HST exposures. We have now
identified six other recent, nearby SNe which have WFPC2 archive exposures of
the site taken before explosion. Additionally, our Cycle 10 SNAP program will
double the WFPC2 image archive of nearby galaxies which significantly increases
the chances of having multi-color photometry of pre-explosion sites for future
SNe. In this Cycle, we request time on two fronts. Firstly we require
imaging of
the six SNe with existing pre-explosion data in order to perform exact
astrometry of the SNe positions to around 0.05”. Secondly, as a follow on from
our two successful Cycle 10 programs, we request ToO status for any nearby
core-collapse SN which explodes during Cycle 11 and which has pre-explosion HST
images. The goal of this proposal is to directly identify the progenitor stars
of core-collapse SNe.

ACS/HRC 9379

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

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.

HST 9382

A Large Targeted Survey for z < 1.6 Damped Lyman Alpha Lines in SDSS QSO
MgII-FeII Systems.

We have searched the first public release of SDSS QSO spectra for low-z
metal absorption lines and found over 200 large rest equivalent width MgII-FeII
systems. Previously, we empirically showed that such systems are good
tracers of
large neutral gas columns, with ~50% being classical damped Lyman alpha {DLA}
systems {N_HI>=2*10^20 cm^-2}. Here we propose to follow up a well-defined
subset of 79 of them to search for DLAs with 0.47<z<1.60. Only QSOs brighter
than g’=19 were selected. The QSO emission and DLA absorption redshifts were
constrained to virtually eliminate data loss due to intervening Lyman limit
absorption. Consequently, we expect to discover ~40 new DLAs, which is a
three-fold increase in this redshift interval. This will significantly improve
our earlier low-z DLA statistical results on their incidence, cosmological mass
density, and N_HI distribution. The results will also allow us to better
quantify the empirical DLA — metal-line correlation. With this improved
understanding, the need for follow-up UV spectroscopy will lessen and, with the
release of the final database of SDSS QSO spectra {an ~25-fold increase}, the
number of low-z DLAs could be increased arbitrarily. Thus, the power of the
large and statistically-sound SDSS database in combination with a proven
technique for finding low-z DLAs will, over the next few years, essentially
solve the problem of making an accurate determination of the cosmic
evolution of
the neutral gas component down to z~0.4.

GO 9428

SINS: The Supernova Intensive Study– Cycle 11

Supernovae create the chemical history of the Universe, energize the
interstellar gas, form the spine of the extragalactic distance scale, and
provide the only direct evidence for an accelerating universe. SINS is a
to study supernovae, near and far. HST is the perfect match in field and scale
for spatially-resolved observations of SN 1987A. There, a violent encounter
between the fast-moving debris and the stationary inner ring is well underway.
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 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. For more distant events, we propose
Target-of-Opportunity observations. In addition to one bright new supernova in
Cycle 11 discovered by any search at any time, we propose to discover two
supernovae for study in the ultraviolet at times specified in advance,
using the
Lick Observatory Supernova Search. SINS will study the historic SN 1987A,
explore UV emission from supernovae, and press late-time observations of
supernovae into uncharted territory of infrared catastrophes, light echoes, and
stellar remnants.

ACS 9453

The Age of the Andromeda Halo

With the advent of the ACS, we can cross a critical threshold in the study of
galaxy formation: For the first time, we can resolve the old main sequence
in the Andromeda halo, and thus directly determine the ages of the halo
stars in
a giant galaxy other than our own. As the nearest giant galaxy, Andromeda
the best testing ground for understanding galaxy formation and evolution.
Resolution of its halo will tell us about its spread in age and metallicity,
thus providing a formation history. Via extensive simulations, we demonstrate
that we can unambiguously characterize the halo population via a deep
F606W/F814W color-magnitude diagram reaching below the main sequence turnoff.
The data will distinguish whether the halo formed quickly or through protracted
infall and merging episodes, and would detect even a few percent trace of
intermediate age stars. Our field was carefully chosen to meet two criteria: an
optimal stellar density ensuring adequate statistics while avoiding
overcrowding, and the inclusion of an Andromeda globular cluster matched to the
peak halo metallicity. We also propose very brief observations in the same two
bands of five Galactic globular clusters spanning a wide metallicity range,
establishing population templates in the ACS photometric system that will be
used to calibrate and interpret the Andromeda data.

ACS 9468

ACS Grism Parallel Survey of Emission- line Galaxies at Redshift z pl 7

We propose an ACS grism parallel survey to search for emission-line galaxies
toward 50 random lines of sight over the redshift interval 0 < z pl 7. We
request ACS parallel observations of duration more than one orbit at high
galactic latitude to identify ~ 300 HAlpha emission-line galaxies at 0.2 pl
z pl
0.5, ~ 720 O IILambda3727 emission-line galaxies at 0.3 pl z pl 1.68, and pg
1000 Ly-alpha emission-line galaxies at 3 pl z pl 7 with total emission line
flux f pg 2* 10^-17 ergs s^-1 cm^-2 over 578 arcmin^2. We will obtain direct
images with the F814W and F606W filters and dispersed images with the WFC/G800L
grism at each position. The direct images will serve to provide a zeroth order
model both for wavelength calibration of the extracted 1D spectra and for
determining extraction apertures of the corresponding dispersed images. The
primary scientific objectives are as follows: {1} We will establish a uniform
sample of HAlpha and O II emission-line galaxies at z<1.7 in order to obtain
accurate measurements of co-moving star formation rate density versus redshift
over this redshift range. {2} We will study the spatial and statistical
distribution of star formation rate intensity in individual galaxies using the
spatially resolved emission-line morphology in the grism images. And {3} we
study high-redshift universe using Ly-alpha emitting galaxies identified at z
pl 7 in the survey. The data will be available to the community immediately as
they are obtained.

ACS/WFC 9471

The Hunt for the Optical Counterpart of the Fastest Pulsar

PSR J0537-6910 is a fast, young {~ 5, 000 yrs} X-ray pulsar –still undetected
in radio– at the center of the SNR N157B in the LMC. PSR J0537-6910 is a
champion pulsar — with a period of 16 ms it is the fastest rotator among
“ordinary” pulsars, with the sharpest X-ray pulse among young pulsars. It is
the most energetic one {together with the Crab}, with a rotational energy loss
dot E ~ 5 10^38 erg s^-1, and its space velocity {>1, 000 km/s}, inferred from
the shape of its X-ray bow-shock nebula, is probably the highest in the pulsar
family. Soon after its discovery, we performed multicolor observations with the
ESO NTT to search for the optical counterpart. However, none of the several
potential candidates detected within, or close to, the original ROSAT/HRI error
circle {~eq 3 "} could be associated with the pulsar, which remained undetected
down to V ~ 23.4. The results could not be improved by using the more accurate
Chandra position {~eq 1 "}. Since the crowding of the area, with a relatively
bright star close to the pulsar position, makes the search for the PSR
J0537-6910 optical counterpart virtually hopeless from the ground, we
propose to
obtain deep high-resolution multicolor imaging with ACS/WFC. The same data will
allow us to study, for the first time, in the optical the compact nebula
detected around the pulsar by Chandra. Since the target is in a CVZ, the whole
program can be completed in two orbits.

ACS 9472

A Snapshot Survey for Gravitational Lenses among z >= 4.0 Quasars

Over the last few years, the Sloan Digital Sky Survey has revolutionized the
study of high-redshift quasars by discovering over 200 objects with redshift
greater than 4.0, more than doubling the number known in this redshift
The sample includes eight of the ten highest redshift quasars known. We propose
a snapshot imaging survey of a well-defined sample of 250 z > 4.0 quasars in
order to find objects which are gravitationally lensed. Lensing models
magnification bias predict that at least 4% of quasars in a flux-limited sample
at z > 4 will be multiply lensed. Therefore this survey should find of order 10
lensed quasars at high redshift; only one gravitationally lensed quasar is
currently known at z > 4. This survey will provide by far the best sample to
date of high-redshift gravitational lenses. The observed fraction of lenses can
put strong constraints on cosmological models, in particular on the
constant Lambda. In addition, magnification bias can significantly bias
estimates of the luminosity function of quasars and the evolution thereof; this
work will constrain how important an effect this is, and thereby give us a
better understanding of the evolution of quasars and black holes at early
epochs, as well as constrain models for black hole formation.

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/WFPC2 9481

Pure Parallel Near-UV Observations with WFPC2 within High-Latitude ACS Survey

In anticipation of the allocation of ACS high-latitude imaging survey{s}, we
request a modification of the default pure parallel program for those WFPC2
parallels that fall within the ACS survey field. Rather than duplicate the red
bands which will be done much better with ACS, we propose to observe in the
near-ultraviolet F300W filter. These data will enable study of the rest-frame
ultraviolet morphology of galaxies at 0<z<1. We will determine the
k-correction, and the location of star formation within galaxies, using a
that is likely to be nearly complete with multi-wavelength photometry and
spectroscopic redshifts. The results can be used to interpret observations of
higher redshift galaxies by ACS.


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 fields.


Completing A Near-Infrared Search for Very Low Mass Companions to Stars within
10 pc of the Sun

Most stars are fainter and less massive than the Sun. Nevertheless, our
knowledge of very low mass {VLM} red dwarfs and their brown dwarf cousins is
quite limited. Unknown are the true luminosity function {LF}, multiplicity
fraction, mass function, and mass-luminosity relation for red and brown dwarfs,
though they dominate the Galaxy in both numbers and total mass. The best way to
constrain these relations is a search for faint companions to nearby stars.
a search has several advantages over field surveys, including greater
sensitivity to VLM objects and the availability of precise parallaxes from
luminosities and masses can be derived. We propose to complete our four-filter
NICMOS snapshot search for companions to stars within 10 pc. With a 10 sigma
detection limit of M_J ~ 20 at 10 pc, we can detect companions between 10 and
100 AU that are at least 9 mag fainter than the empirical end of the main
sequence and at least 6.5 mag fainter than the brown dwarf Gl 229B. When
completed, our search will be the largest, most sensitive, volume-limited
for VLM companions ever undertaken. Our four-filter search will permit
unambiguous identification of VLM-companion candidates for follow-up
observation. Together with IR speckle and deep imaging surveys, our program
firmly establish the LF for VLM companions at separations of 1-1000 AU and the
multiplicity fraction of all stars within 10 pc.

WFPC2 9593


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.

FGS 9603

Monitoring FGS1r’s Interferometric Response as a Function of Spectral Color

This proposal obtains reference point source Transfer Functions {S-Curves} for
FGS1r through the F583W filter and the F5ND attenuator at the center
position of
the FGS1r FOV for a variety of stars with different stellar spectral
colors. The
data will be added to the library of point source interferograms that was
assembled from the Cycles 8 and 9 calibration programs. These Transfer
are needed to support the analysis of GO science data for the study of
close and
wide binary star systems and for determining the angular size and shape of
extended sources. This proposal observes stars that have been observed in
previous cycles to check for long term temporal stability of the FGS1r
This proposal monitors the cycle 10 calibration the FGS1r Lateral Color
{using stars Latcol-A and Latcol-B}, as well as calibrates the "Pos/Trans" bias
of a star’s position as determined from Transfer mode and Position mode
observations, and finally the shift of a star’s centroid when observed with
relative to that when observed with F583W {the cross filter shift} is
for the fainter stars in this proposal {stars brighter than V=8 can not be
observed with F583W.}

STIS 9605

CCD Dark Monitor-Part 1

STIS 9607

CCD Bias Monitor – Part 1

high-S/N superbiases and track the evolution of hot columns.

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

STIS 9633

STIS parallel archive proposal – Nearby Galaxies – Imaging and Spectroscopy

Using parallel opportunities with STIS which were not allocated by the TAC, we
propose to obtain deep STIS imagery with both the Clear {50CCD} and Long-Pass
{F28X50LP} filters in order to make color-magnitude diagrams and luminosity
functions for nearby galaxies. For local group galaxies, we also include G750L
slitless spectroscopy to search for e.g., Carbon stars, late M giants and
stars. This survey will be useful to study the star formation histories,
chemical evolution, and distances to these galaxies. These data will be placed
immediately into the Hubble Data Archive.

WFPC2 9634

POMS Test Proposal: WFII targeted parallel archive proposal

The parallel opportunities available with WFPC2 in the neighborhood of bright
galaxies are treated in a slightly different way from the normal pure
Local Group galaxies offer the opportunity for a closer look at young stellar
populations. Narrow-band images in F656N can be used both to identify young
stars via their emission lines, and to map the gas distribution in star-forming
regions. Thus, the filter F656N is added to the four standard filters. Near
distant galaxies, up to about 10 Mpc, we can map the population of globular
clusters; for this purpose, F300W is less useful, and only F450W, F606W, and
F814W will be used.

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 9650

CCD Hot Pixel Annealing

Hot pixel annealing will be performed once every 4 weeks. The CCD TECs will be
turned off and heaters will be activated to bring the WFC detector temperature
to about +10C. The HRC temperature will reach about 30C.This state will be held
for approximately 24 hours, after which the heaters are turned off, the TECs
turned on, and the CCDs returned to normal operating condition. To assess the
effectiveness of this procedure, a bias and two dark images will be taken
and after the annealing procedure for both WFC and HRC.

ACS 9657

ACS Internal Flat Field Stability

The flat field stability and characterisation obtained during the ground
calibration and SMOV phases will be tested and verified through a sub-sample of
the filter set. Only internal exposures with the calibration lamps will be


SDSS Primary Standards

The ACS HRC and WFC cameras have Sloan Digital Sky Survey standard filters, the
first use of these on HST. Calibration of the u, g, r, i, z filters in ACS will
be obtained in order to assure that observers can place HST and SDSS
observations on a common system. The SDSS has adopted the 10th magnitude star,
BD+17D4708 as their fundamental reference. STIS calibration spectra of this
be obtained over the full 0.2-1.0+ micron range covered by G230LB, G430L and
G750L in order to generate a reference spectrum of this star in the HST system
in order for SYNPHOT to generate robust synthetic magnitudes {the STIS
observations are through the STIS program, 9631, Bohlin PI}. ACS observations
will be obtained through the SDSS filters in order to reference u, g, r, i, z
photometry to the same fundamental standard used by SDSS. In addition, since
this will become a useful additional standard star, we will also obtain
observations through the full suite of ACS UV-optical filters in order to
photometric transformations between different systems

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.

WFPC2 9699

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans.

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



                           SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq               17                       17
FGS REacq               14                       14
FHST Update             36                       36


SpaceRef staff editor.