NASA Hubble Space Telescope Daily Report # 3379 (part 2)
NICMOS 9485
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.
Such
a search has several advantages over field surveys, including greater
sensitivity to VLM objects and the availability of precise parallaxes from
which
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
search
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
will
firmly establish the LF for VLM companions at separations of 1-1000 AU and
the
multiplicity fraction of all stars within 10 pc.
NICMOS 9386
Infrared Photometry of a Statistically Significant Sample of KBOs
While the discovery rate of Kuiper Belt objects is accelerating, the
physical
study of this new region of the solar system has been slowed by a lack of
basic
astrophysical data. Photometric observations of the majority of the more
than
400 known KBOs and Centaurs are rudimentary and incomplete, particularly in
the
infrared. The multicolor optical-infrared photometry that exists for a small
subset of KBOs often shows significant discrepancies between observations by
different observers. Their intrinsic faintness puts them at the practical
limits
of ground-based systems. In July 2001 we began what will be the largest
uniform
sample of optical photometry of KBOs with a WFPC2 SNAPSHOT program that will
perform accurate photometry at V, R, and I on a sample of up to 150 targets.
We
seek to greatly enhance the value of this survey by obtaining J and H
photometry
on the same sample using NICMOS. Combined optical and infrared broad band
photometry is a far more powerful tool for physical studies than is either
alone. Our sample includes objects that will be observed at thermal infrared
wavelengths by SIRTF and will be used with those data to derive the first
accurate diameters, albedos, and surface properties for a large sample of
KBOs.
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.
NICMOS 9360
Paschen-alpha Imaging of a SIRTF-Selected Nearby Galaxy Sample
We propose to carry out a NICMOS snapshot survey in the Paschen-alpha
{PAlpha}
emission line and H-band of the sample of galaxies being observed at 3.5 —
160
microns as part of SIRTF Nearby Galaxies Survey {SINGS} and a related
guaranteed
time survey of starburst galaxies. The PAlpha images, accessible only from
HST,
will be combined with groundbased HAlpha imaging to measure the extinction
in
the star-forming centers of these galaxies, and obtain robust, extinction-
corrected maps of the massive star formation rate {SFR}. The PAlpha data by
themselves will provide reliable `extinction- free’ SFRs, and a
cross-calibration of the {dust–affected} HAlpha– and UV–based SFRs. The
PAlpha–based SFR measurements will extend the SFR-vs.-gas density law
{Schmidt–law} to surface densities at least 30 times higher than what is
accessible using HAlpha–based SFR measurements alone, bridging the gap
between
normal galaxies and IR–luminous starbursts. Furthermore, the combination
of the
HST PAlpha images with the SIRTF images and spectra, as well as ancillary
ground–based UBVRIJHK images and GALEX UV images being obtained as part of
the
SINGS project, will provide a definitive study of the radiative transfer of
starlight and dust heating in star–forming galaxies. The processed NICMOS
images will be incorporated into the public SINGS Legacy Data Archive, to
enable
scores of follow-up studies by the astronomical community at large.
NICMOS 9644
Polarimetric Calibration
One HST standard unpolarized point source is observed to determine the
instrumental polarization for each of the three polarizers on NIC1 {POL0S,
POL120S and POL240S} and NIC2 {POL0L, POL120L, POL240L}. Also, the
polarization
fraction and position angle of polarization are measured for a standard
polarized point source to determine their absolute accuracy in each
polarizer
and each camera. Polarimetric observations of CRL2688 {The Egg Nebula} will
be
performed to evaluate the calibration across the imaging field in both
cameras.
These observations are required after the installation of the NCS.
NICMOS 9375
The Host Galaxies of Time Delay Lenses: , An Independent Route to the Hubble
Constant
Because of its importance in setting the distance scale, the time scale and
in
estimating cosmological parameters from the CMB, astronomy needs an estimate
of
the Hubble constant independent of the local distance scale and its
systematic
problems. This can be achieved using gravitational lenses with time delay
measurements given enough constraints on the gravitational potential of the
lens. We will use deep NICMOS observations of the lensed quasar host
galaxies in
7 gravitational lenses with time delay measurements to obtain the necessary
constraints, determine the dark matter distribution and estimate H_0.
Analysis
of the existing images and the well-developed theory for analyzing Einstein
ring
images of host galaxies suggest the new data will break the familiar
degeneracies between lens mass distributions and the Hubble constant. We
also
request 30 ksec Chandra ACIS images for each of the 2 systems lacking them
{B1608+656 and B1600+434} to measure the mass in nearby or surrounding
groups
and clusters.
NICMOS 9484
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.
SNAP/STIS 9434
A SNAPSHOT Survey of the Hot Interstellar Medium
We propose to obtain SNAPSHOT STIS echelle observations of key tracers of
hot
interstellar gas {CIV, NV and SiIV} for selected FUSE Team OVI survey
targets
with known UV fluxes. By taking advantage of the SNAPSHOT observing mode we
will
efficiently obtain a large number of spectra suitable for the study of the
highly ionized hot component of the interstellar medium {ISM}. Our goals are
to
explore the physical conditions in and distribution of such gas, as well as
to
explore the nature of the interfaces between the hot ISM and the other
interstellar gas phases. Using inter–comparisons of the various ionic
ratios
for CIV, NV, OVI and SiIV, we will be able to discriminate between the
various
models for the production of the highly ionized gas in the Galactic ISM. The
survey will also enable detailed studies of regions already known to
contain hot
gas through X-ray emission measurements {e.g., SNRs and radio loops}. The
proposed SNAPSHOT observations will extend our previous Cycle 9 survey
{which
was compromised by the STIS side 1 failure}, and should roughly double the
number of stars for which high quality STIS observations of the important
hot
gas tracers are available, enabling us to derive a truly global view of the
hot
ISM.
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 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 9331
Variable Interstellar Absorption toward HD 219188 — Probing the Structure
of
an Interstellar
Within the last 10 years, strong, narrow Na I absorption has appeared at
v_SUN ~
-38 km s^-1 toward the halo star HD 219188; that absorption has continued to
strengthen, by a factor 2–3, over the past three years. The line of sight
appears to be moving into/through a relatively cold, quiescent intermediate
velocity {IV} cloud, due to the 13 mas/year proper motion of HD 219188. We
propose to monitor the continuing changes in the IV absorption toward HD
219188
over the next three years with STIS echelle spectra — making use of the
rich
diagnostics provided by the UV lines of various neutral and singly ionized
species to determine abundances/depletions and physical conditions
{temperature,
density, ionization} as functions of depth within the cloud. In addition to
providing a unique view of the detailed structure of an interstellar cloud,
these data will yield constraints on grain scattering parameters {from the
variation of ionization with depth} and on any dependence of depletion on
local
density.
STIS/FUV 9412
The Physical Parameters of the Hottest, Most Luminous Stars as a Function of
Metallicity
We have obtained excellent, new ground-based blue optical and HAlpha spectra
of
a sample of very early-type stars in the Magellanic Clouds in order to
measure
their physical properties, for comparison with the extensive data that
exists
for higher-metallicity Galactic stars. Our aim is to understand how
effective
temperatures depend upon metallicity {necessary in determining IMFs}, and to
explore the astrophysically interesting regime of stars of extreme
temperatures,
masses, and luminosities. In order to do this, we need to measure the
stellar
wind terminal velocities for our stars, necessary to constrain the stellar
models. These can only be measured with STIS/FUV on HST. In addition, we
will
obtain higher spatial resolution data on the HAlpha line for stars for which
nebular contamination is significant in our ground-based data. We also
include
several R136 stars with excellent STIS/CCD data but which lack UV line
measures.
These new HST data will provide important information about the strengths of
stellar winds at extreme luminosities and the calibration of the Wind
Momentum-
Luminosity Relationship at lower metallicities. This proposal was highly
rated
in Cycle 9, but only 4 snapshots were obtained. We have completed the
analysis
of these plus additional data from the archives, but need spectra of the
remaining objects if we are to answer the questions we pose.
STIS/MA2 9474
Intriguing Transient Sources in M87
We have found a remarkable number of transient point sources in M87. Within
the
jet itself we have observed dramatic changes in less than a year. The point
sources are seen well in the bluest regions of the spectrum, where we obtain
high spatial resolution, are free from cosmic ray artifacts and obtain
excellent
discrimination against the underlying old, red galaxy. They display a
variety of
unusual properties: one is brighter than any in the catalogue of novae in
M31;
several are very close to the jet; another hints at rapid variability. We
propose to investigate the population of transient sources in M87 and to
probe
the intrinsic jet variability on short timescales by taking images in the
near
UV. Do the sources show nova-type light curves? Is there a
decline-rate/luminosity relation? If yes, may we use it for distance
estimation,
as in Galactic novae, and hence constrain the still very important Virgo
distance. Are there very rapidly varying sources, flare stars or
gravitational
lenses? Is the variable stellar population related to the excess globular
cluster frequency in M87? Is there a population of flickering objects in and
around the jet, which may be responsive emission arising from their close
proximity to a BL Lac nucleus {viewed down the jet axis}? Can we find
variability in the jet itself indicative of light week length scales?
WFPC2 9710
POMS Test Proposal: WFII backup parallel archive proposal
This is a POMS test proposal designed to simulate scientific plans.
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.
WFPC2 9595
WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt3/3
This dark calibration program obtains 3 dark frames every day to provide
data
for monitoring and characterizing the evolution of hot pixels.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of
potential non-nominal performance that will be investigated.) None
COMPLETED OPS REQs: None
OPS NOTES EXECUTED:
0900-1 COMMAND PROBLEM @ 157/1855z
1118-0 Resubmit: Battery 2 Capacity Test limits @ 157/1646z
0910-2 SI Console response to MCE Resets after FSW 4.8 is activated @
158/0525z
0916-0 Tabulation of Slew Attitude Error (Miss-distance) @160/0444z
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 27 27
FGS REacq 22 22
FHST Update 51 51
LOSS of LOCK
SIGNIFICANT EVENTS: None
