Status Report

HST Daily Report # 3155 (part 2)

By SpaceRef Editor

May 5, 2003

Filed under Hubble Space Telescope, Space Telescope Science Institute, US

NICMOS 9423

NICMOS Observations of Transient Infrared Jets in the Galactic
Microquasar
GRS1915+105

We propose to use HST/NICMOS to make Target of Opportunity observations
of the
galactic microquasar GRS1915+105. This source possesses transient radio
jets
which exhibit apparent superluminal motions, and resolved infrared
emission
from
these jets has been observed in GRS1915+105 {Sams, Eckart, and Sunyaev,
1996;
Eikenberry and Fazio, 1996}. Because the jet ejection events are
correlated
with
X-ray outbursts, we will use observations of X-ray flares with the Rossi
X-Ray
Timing Explorer to trigger the HST observations. We will then monitor
GRS1915+105 periodically with NICMOS, obtaining relative astrometry,
photometry,
polarimetry, and grism spectroscopy of the jets and the parent object.
These
observations will allow us to greatly increase our understanding of the
jets’
radiative mechanisms and physical conditions, and their evolution with
time. We
require the capabilities of HST and NICMOS due to the small angular
separations
between the jets and the parent object {increasing from ~ 0.1 to ~ 0.8
arcsec
over the span of the TOO observations} and the high reddening towards
GRS1915+105 {A_V ~ 30 mag}.

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.

SNAP 9356

SNAPSHOT survey of the Planetary Nebulae population of the Galactic Bulge

The spectacular structures seen in HST images of planetary nebulae {PNe}
are
generally accepted as originating from hydrodynamical interactions
between
stellar winds: the interacting-stellar wind model {ISW}. Traditionally,
the
shaping is thought to occur after the star becomes hot enough to ionize
the PN.
But recent HST images indicate that the shaping may occur earlier, and
the
newer
GISW model puts the shaping during the pre-planetary nebula evolution.
The
relative importance of both models is not known: GISW shaping will
account for
some fraction of PNe, but estimates range from 15–100 during the PN
phase,
especially for the youngest PNe. We here propose an HST Snapshot survey
of
compact PNe in the Galactic Bulge, to test these predictions. The Bulge
provides
the only PNe population for which progenitor masses are known and nebular
ages
can be measured. In support of these HST measurements we have already
measured
velocity fields and emission line fluxes. The survey will give an
unbiased
sampling of morphologies, and allow evolutionary sequences to be
determined to
test the ISW versus the GISW model. By-products of the survey will be the
determination of nebular masses, diameters and filling factors. We will
also
obtain the White Dwarf mass distribution in the Bulge, and the
initial-final
mass function for low-mass stars.

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.

STIS 9606

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

STIS 9447

Characterizing the Atmosphere of an Extrasolar Planet

HD 209458 b is the first extrasolar planet known to transit the disk of
its
parent star. Precise measurement of both the photometric transit curve
and the
radial velocity orbit has allowed for an accurate estimation of the mass,
radius, average density, and surface gravity. Numerous theoretical
investigations of the planetary atmospheres have been presented in the
literature, but no data capable of addressing these has yet been
published. We
propose to use the method of transmission spectroscopy to constrain
greatly
models of the planetary atmosphere. We will use STIS to disperse the
stellar
flux over a large number of detector pixels. The photometric signal is
produced
by summing the counts over a desired band. For each of twelve bands
spanning the
UV to the near-IR, we will obtain sufficient precision to detect
variations in
the transit depth greater than 5 X 10^-5. We have already made a
detection of
the sodium absorption signature in the planetary atmosphere. With these
new
data, we will be able to detect, if present, absorption due to Rayleigh
scattering, water bands, and/or strong alkali metal lines. These
observations
will allow us to determine the broad characteristics of the planetary
atmosphere. For example, we will be able to distinguish between models
with a
high cloud deck, and those with no clouds but reduced chemical
abundances.

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
S-type
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.

STIS 9708

STIS Pure Parallel Imaging Program: Cycle 11

This is the default archival pure parallel program for STIS during cycle
11.

STIS 9441

Zinc Abundances in Damped Ly-Alpha Systems at z < 0.5: A Missing Link in the Chemical History of Galaxies

The evolution of metallicity in damped Lyman alpha {DLA} quasar
absorption
systems is an important constraint on the global star formation history
of the
universe, but remains a big puzzle at present. The H I column density
weighted
mean metallicity in DLAs is expected to rise to solar values at low
redshifts,
based on cosmic chemical evolution models, because the mass-weighted mean
metallicity of local galaxies is near- solar. However, current DLA
abundance
studies are highly uncertain and cannot distinguish between evolution and
no
evolution in the mean metallicity at redshifts 0.4 < z < 3.5. The existing data are particularly incomplete because no Zn measurements exist for z < 0.4, and only 2 exist for z < 0.5, which spans the past 35-45 % of the age of the universe. To pin down the cosmic age-metallicity relation all the way to the present epoch, we propose to measure Zn abundances in five DLAs at 0.1 < z < 0.5. We propose to use HST STIS because it is the only existing instrument that can measure the necessary UV lines. Our observations will clearly distinguish between no metallicity evolution vs. the predicted evolution. Our data will also provide Cr measurements, which will help to estimate the dust abundance. The proposed observations are crucial for tying together the absorption and emission histories of gas and stars in galaxies and for clarifying the relation of DLAs to present-day galaxies.

STIS/CAL 9628

MAMA Sensitivity and Focus Monitor Cycle 11

Monitor sensitivity of each MAMA grating mode to detect any change due to
contamination or other causes. Also monitor the STIS focus in a
spectroscopic
and imaging mode.

STIS/CCD/MA1 9357

Towards a global understanding of accretion physics –, Clues from an UV
spectroscopic survey of cataclysmic variables

Accretion inflows and outflows are fundamental phenomena in a wide
variety of
astrophysical environments, such as Young Stellar Objects, galactic
binaries,
and AGN. Observationally, cataclysmic variables {CVs} are particularly
well
suited for the study of accretion processes. We propose to carry out a
STIS UV
spectroscopic snapshot survey of CVs that fully exploits the diagnostic
potential of these objects for our understanding of accretion physics.
This
survey will provide an homogenous database of accretion disc and wind
outflow
spectra covering a wide range of mass transfer rates and binary
inclinations. We
will analyze these spectra with state-of-the-art accretion disc model
spectra
{SYNDISK}, testing our current knowledge of the accretion disc structure,
and,
thereby, providing new insight into the so far not well understood
process of
viscous dissipation. We will use our parameterised wind model PYTHON for
the
analysis of the radiation driven accretion disc wind spectra, assessing
the
fundamental question whether the mass loss rate correlates with the disc
luminosity. In addition, our survey data will identify a number of
systems in
which the white dwarf significantly contributes to the UV flux,
permitting an
analysis of the impact of mass accretion on the evolution of these
compact
stars. This survey will at least double, if not triple, the number of
high-quality accretion disc / wind outflow / accreting white dwarf
spectra, and
we waive our proprietary rights to permit a timely use of this database.

STIS/MA1 9466

SBS 1150+599: A Population III Planetary Nebula?

SBS 1150+599 is a puzzling emission-line object. Optical spectra reveal
only
strong Balmer, He II and Ne V lines, along with a hot, featureless
continuum. We
have recently partially resolved the HAlpha emission in a ground-based
image,
and believe the object to be a new halo planetary nebula, one of only
handful
known in the Milky Way. If correct, its lack of significant O III and
other
forbidden emission means that SBS 1150+599 has the lowest metallicity of
any
known planetary nebula. Our estimate of the oxygen abundance places it 40
times
lower than that of K 648 in the globular cluster M15, the previous record
holder, and would make it one of the most metal-poor objects in the
Galaxy. We
propose obtaining ACS images of SBS 1150+599 to confirm that it is a
planetary
nebula and to determine its morphology. Planetary nebulae in old
populations may
occur due to binary-star merging, and the morphology may test this
hypothesis.
We will also study the UV spectrum of SBS 1150+599 using STIS to confirm
the O/H
value and estimate carbon and nitrogen abundances unobtainable in the
optical.

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 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 paralell images of random areas of the
sky,
following the recommendations of the 2002 Parallels Working Group.

WFPC2 9594

WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt2/3

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

WFPC2 9589

WFPC2 Decontaminations and Associated Observations Pt. 1/3

This proposal is for the monthly WFPC2 decons. Also included are
instrument
monitors tied to decons: photometric stability check, focus monitor, pre-
and
post-decon internals {bias, intflats, kspots, & darks}, UV throughput
check,
VISFLAT sweep, and internal UV flat check.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)

HSTAR 9018: Received two ACS 935 Status Buffer messages @ 122/23:06:57Z
and
                       122/23:21:06Z with a parameter of 35; indicating a
Semaphore timeout
                       that is a normal result when the TDF goes down
during a CCD post-flash or
                       Filter Wheel, Fold Mechanism, or Calibration Door
move. This is a routine
                       Status Buffer message that requires an
HSTAR. Received ACS 935 Status Buffer
                       message with parameter 35 @ 124/15:56:33Z. Ops
Note 1102 was revised. Received
                       four more ACS 935 Status Buffer messages @
124/16:41:39Z, 16:43:20Z, 16:45:03Z,
                       and 17:11:45Z. Received ACS 935 Status Buffer
message @ 124/18:22:40Z. Ops
                       Note 1102 was revised. Under investigation.

HSTAR 9019: Batteries 4 and 5 Temperatures (CBAT4TMP, CBAT4TMP) OOL @
124/13:37:23Z.
                       Battery 5 Temperature flagged OOL to 3.19 °C (CCS
upper limit 2.0 °C)
                       @ 124/13:37:23Z. Battery 4 Temperature flagged
OOL
to 2.10 °C (CCS upper
                       limit 2.0 °) @ 124/13:33:23Z. Limit violations
occurred a few minutes following
                       entry to orbit day. Battery 4 and 5 Temperatures
continued to toggle in and out
                       of limits for ~ 12 minutes. Similar violations
occurred the following orbit.
                       While batteries were running slight warmer than in
the past few days, there was
                       no indication a battery thermal run-away was
imminent and no immediate action
                       was necessary. Under investigation.

HSTAR 9020: GS Acquisition (2,3,3) @ 125/02:50:25Z resulted in FL backup
(2,0,2) on FGS 2,
after multiple attempts, due to SSLE (QF3SSLEX) on
FGS 3.Under investigation.

COMPLETED OPS REQs: NONE

OPS NOTES EXECUTED: