Status Report

NASA Hubble Space Telescope Daily Report # 3400

By SpaceRef Editor
July 9, 2003
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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.


The Galactic Warm Ionized Medium: the First Direct Measures of its
Ionization and Abundances

The warm ionized medium {WIM} is the dominant gaseous component of the
Galactic halo and represents an important sink of the radiative and
kinetic energy output of stars and supernovae, though the source of
its ionization remains unknown. We will use stis spectroscopy of the
post-AGB stars ROB 162 and ZNG 1 in the globular clusters NGC 6397 and
Messier 5 to measure directly the abundances and ionization states of
several key metals in the Galactic WIM. These sight lines are unique:
because the two clusters also contain pulsars with published radio
dispersion measurements, these are the only sight lines for which we
can derive the column densities of both HI, em and ionH2, as well as
the columns of multiple ionization stages of the important metals S,
P, and Fe. We will use the proposed stis observations with existing
use data to derive the total gas-phase abundances of S, P, and Fe for
the material along these sight lines with no ionization uncertainties.
We will directly measure the ionization fractions of S and P in the
WIM. We will also infer the dust content of the WIM. Our study of the
ionization state and dust content of the WIM will provide the best yet
constraints for models of this gas. Our work will also provide the
best constraint for the fundamental “cosmic” reference abundance
{averaged over these sight lines} of the undepleted elements S and P.

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.

WFPC2 9458

Probing the Formation & Evolution of M31’s Outer Disk and Halo

The fossil record of galaxy formation and evolution is imprinted on
the spatial distribution, ages and metallicities of galactic stellar
populations. The observations proposed here build significantly upon
our extensive ground-based and archival WFPC2 programs and aim to
constrain the formation and evolution of our nearest large neighbour,
M31. We propose deep imaging of 8 fields in the outer disk and halo,
several of which have been identified from our panoramic ground-based
CCD survey {covering ~ 26 square degrees} to possess significant
stellar density and/or potential metallicity variations. Deep
colour-magnitude diagrams reaching ~2-3 magnitudes below the
horizontal branch will be constructed, allowing detailed
characterization of the luminous evolved stellar populations via the
red giant metallicity distribution, the luminous asymptotic giant
branch, the horizontal branch morphology and the red clump, as well as
the detection of a main-sequence that may be present from any younger
component. Our primary goals are to: {i} quantify the stellar
population variations associated with M31 halo substructure, including
the newly- discovered giant stellar stream, and {ii} derive stringent
constraints on the age and metallicity of stars in the far outer disk.
These observations will directly address two key predictions of cold
dark matter hierarchical galaxy formation models.

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
< 7. We request ACS parallel observations of duration more than one orbit at high galactic latitude to identify ~ 300 HAlpha emission-line galaxies at 0.5, ~ 720 O IILambda3727 emission-line galaxies at 1.68, and .pg 1000 Ly-alpha emission-line galaxies at 7 with total emission line flux 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 will 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 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. This 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 galaxies 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 bursts 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.

WFPC2 9596


This calibration proposal is the Cycle 11 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A
variety of internal exposures are obtained in order to provide a
monitor of the integrity of the CCD camera electronics in both bays
{gain 7 and gain 15}, a test for quantum efficiency in the CCDs, and a
monitor for possible buildup of contaminants on the CCD windows.

STIS 9606

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

STIS 9608

CCD Bias Monitor – Part 2

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 columns.

ACS 9674

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.

STIS 9708

STIS Pure Parallel Imaging Program: Cycle 11

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

WFPC2 9709

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.

STIS 9786

The Next Generation Spectral Library

We propose to continue the Cycle 10 snapshot program to produce a Next
Generation Spectral Library of 600 stars for use in modeling the
integrated light of galaxies and clusters. This program is using the
low dispersion UV and optical gratings of STIS. The library will be
roughly equally divided among four metallicities, very low {[Fe/H] lt
-1.5}, low {[Fe/H] -1.5 to -0.5}, near-solar {[Fe/H] -0.3 to 0.1}, and
super-solar {[Fe/H] gt 0.2}, well-sampling the entire HR-diagram in
each bin. Such a library will surpass all extant compilations and have
lasting archival value, well into the Next Generation Space Telescope
era. Because of the universal utility and community-broad nature of
this venture, we waive the entire proprietary period.

ACS/HRC 9805

OGLE-TR-56b: The Most Interesting Transiting Planet

Our team has recently succeeded in confirming spectroscopically the
discovery of the first extrasolar giant planet found in a transit
search: OGLE-TR-56b. Its main parameters are: mass = 0.9 Jupiters,
size = 1.3 Jupiters. Thus, OGLE-TR-56b appears to be similar to HD
209458b, the only other known transiting giant planet. Unfortunately,
our planet radius determination is uncertain due to the very limited
precision of the ground-based photometry, and does not allow for a
meaningful comparison with theoretical model predictions. We propose
HST observations with the ACS-HRC of the main transit of OGLE-TR-56b,
which will improve the precision and the accuracy of the planet
parameters by close to a factor of 10. In addition, we propose a
timing experiment for the planet’s extremely close orbit {1.2-day
period, 0.023 AU from the star}, which will allow us to detect the
orbital decay and test convection theories.


A tailored survey of proplyds with the ACS

While our specific understanding of the proto-planetary disks in Orion
is increasing, our general knowledge of what promotes and hinders
their birth and longevity is hampered by having good observations in
only this one region. Observations of proplyds in other regions with
different conditions of ultraviolet irradiation and age can provide
more stringent tests of our present models. We have therefore designed
an ACS/WFC and parallel WFC2 survey of open clusters embedded in H II
regions that, with a small number of orbits, maximizes the probability
of succesfully finding proplyds there. Our observing strategy will
additionally afford a quantitative study of the detected proplyds, as
well as the derivation of a correlation between those characteristics
and the clusters’ stellar population. ACS gives us an unprecedented
opportunity to kick start the mass discovery of proplyds in many
environments, an obvious way in which progress can be made in this
field. This small tailored survey, gives us an excellent chance to
obtain a huge return at low cost.

ACS 9984

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 setlengthemsep0cm 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.


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

16999-0 RMGA Calibration for July 2003 @ 189/1841z

1128-2 Adjust ACS Error Count Limit @ 189/1341z
1115-0 CCC IPCONFIG Connections @ 189/1947z 189/1947z, 190/0147z,
0900-1 COMMAND PROBLEM @ 190/0856z

FGS GSacq 08 08
FGS REacq 08 08
FHST Update 13 13


Successfully completed RMGA Calibration test @ 189/17:00:06Z (OR 16999
with attached RMGA Calibration script and MEGG timeline). Test began
with power-on of RMGA for warm up of gyros. Collection of RMGA data to
determine gyro bias occurred @ 189/18:03:51Z with PSEA configured to
the Test mode. Eighteen iterations of Test mode were run and
subsequently processed by SAC. Test was completed @ 189/18:41Z.

HST SM-4 Aft Flight Deck Internal Command testing scheduled 190/11:00Z
– 21:00Z with GDOC, SOC, HITT, and CCS using CCS “C” String with CCS
Release and PRD S07200. The purpose of this testing is to dry
run Aft Flight Deck commands to validate CCS verifiers, procedure
changes, and scenario files.

SpaceRef staff editor.