Daily #3978
- From: Joe Cooper <jcooper@xxxxxxxxxxxx>
- Date: Tue, 8 Nov 2005 15:39:27 +0000 (UTC)
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3978
PERIOD COVERED: UT October 31, 2005 (DOY 304)
OBSERVATIONS SCHEDULED
ACS/HRC 10253
A UV Survey of Quiescent Black Holes and Neutron Stars
Existing STIS observations of quiescent Galactic black hole and neutron
star binaries suggest a striking difference between them. The spectra of
black holes appear to drop off steeply in the near-UV, whereas those of
neutron stars continue to rise, at least down to 1700A. This difference
has been interpreted in terms of advective accretion models, and may
indicate a fundamental signature of the two types of object. The
existing data do not include enough objects to form a representative
sample, however. We will exploit the faint source sensitivity of ACS to
perform a survey of the UV spectral shapes across a larger sample
containing both black holes and neutron stars. This survey will test the
assertion that their UV spectra are strikingly different; allow
modelling of the broad band spectral energy distribution; test for
variability in the UV flux; and identify suitable targets for subsequent
spectroscopic follow-up..
ACS/HRC 10547
A SNAP Program to Obtain Complete Wavelength Coverage of Interstellar
Extinction
We propose a SNAP program to obtain ACS/HRC spectra in the near-UV
{PR200L} and near-IR {G800L} for a set of main sequence B stars with
available IUE UV spectrophotometry, optical photometry, and 2MASS IR
photometry. Together with these existing data, the new observations will
provide complete photometric and spectrophotometric coverage from 1150
to 11000 A and enable us to produce complete extinction curves from the
far-UV to the near-IR, with well- determined values of R{V}. The
proposed set of 50 program sight lines includes the full range of
interstellar extinction curve types and a wide range of color excesses.
The new data will allow us to examine variability in the near-UV through
near-IR spectral regions, including the UV-optical "knee" and the "Very
Broad Structure." We will examine the response of these features to
different interstellar environments and their relationship to other
curve features. These are largely unexplored aspects of extinction
curves which will provide additional constraints on the properties of
interstellar grains. The curves will be derived using stellar atmosphere
models to represent the intrinsic spectral energy distributions of the
program stars, eliminating the need to observe unreddened "standard
stars." This approach virtually eliminates "mismatch error", allowing us
to derive extinction curves with much higher precision than previously
possible. In addition, the new spectra will provide higher S/N data for
the peak of the 2175 A bump than previously available.
ACS/HRC/WFC 10729
ACS CCDs daily monitor
This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise in
ACS CCD detectors. The files, biases and dark will be used to create
reference files for science calibration. This programme will be for the
entire lifetime of ACS. Changes from cycle 13:- The default gain for WFC
is 2 e-/DN. As before bias frames will be collected for both gain 1 and
gain 2. Dark frames are acquired using the default gain {2}. This
program cover the period Oct, 2 2005- May, 29-2006. The second half of
the program has a different proposal number: 10758.
ACS/WFC 10523
The Halo Shape and Metallicity of Massive Spiral Galaxies
We propose to resolve the stellar populations of the halos of seven
nearby, massive disk galaxies using a SNAP survey with WFC/ACS. These
observations will provide star counts and color-magnitude diagrams 2-3
magnitudes below the tip of the Red Giant Branch along the two principal
axes and one intermediate axis of each galaxy. We will measure the
metallicity distribution functions and stellar density profiles from
star counts down to very low average surface brightnesses, equivalent to
~31 V-mag per square arcsec. This proposal will create a unique sampling
of galaxy halo properties, as our targets cover a range in galaxy mass,
luminosity, inclination, and morphology. As function of these galaxy
properties this survey will provide:- the first systematic measurement
of radial light profiles and axial ratios of the diffuse stellar halos
and outer disks of spiral galaxies- a comprehensive analysis of halo
metallicity distributions as function of galaxy type and position within
the galaxy- an unprecedented study of the stellar metallicity and age
distribution in the outer disk regions where the disk truncations occur-
the first comparative study of globular clusters and their field stellar
populations We will use these fossil records of the galaxy assembly
process to test halo formation models within the hierarchical galaxy
formation scheme.
ACS/WFC 10592
An ACS Survey of a Complete Sample of Luminous Infrared Galaxies in the
Local Universe
At luminosities above 10^11.4 L_sun, the space density of far-infrared
selected galaxies exceeds that of optically selected galaxies. These
`luminous infrared galaxies' {LIRGs} are primarily interacting or
merging disk galaxies undergoing enhanced star formation and Active
Galactic Nuclei {AGN} activity, possibly triggered as the objects
transform into massive S0 and elliptical merger remnants. We propose
ACS/WFC imaging of a complete sample of 88 L_IR > 10^11.4 L_sun luminous
infrared galaxies in the IRAS Revised Bright Galaxy Sample {RBGS: i.e.,
60 micron flux density > 5.24 Jy}. This sample is ideal not only in its
completeness and sample size, but also in the proximity and brightness
of the galaxies. The superb sensitivity, resolution, and field of view
of ACS/WFC on HST enables a unique opportunity to study the detailed
structure of galaxies that sample all stages of the merger process.
Imaging will be done with the F439W and F814W filters {B and I-band} to
examine as a function of both luminosity and merger state {i} the
evidence at optical wavelengths of star formation and AGN activity and
the manner in which instabilities {bars and bridges} in the galaxies may
funnel material to these active regions, {ii} the relationship between
star formation and AGN activity, and {iii} the structural properties
{AGN, bulge, and disk components} and fundamental parameters {effective
radius and surface brightness} of LIRGs and their similarity with
putative evolutionary byproducts {elliptical, S0 and classical AGN host
galaxies}. This HST survey will also bridge the wavelength gap between a
Spitzer imaging survey {covering seven bands in the 3.6-160 micron
range} and a GALEX UV imaging survey of these galaxies, but will resolve
complexes of star clusters and multiple nuclei at resolutions well
beyond the capabilities of either Spitzer or GALEX. The combined
datasets will result in the most comprehensive multiwavelength study of
interacting and merging galaxies to date.
ACS/WFC 10635
Galaxy Transformation as probed by Morphology and Velocity Fields of
Distant Cluster Galaxies
We seek to obtain ACS imaging of four distant {0.3<z<0.6} clusters of
galaxies within a 6'x6' field covered by a 2x2 mosaic to determine
morphological and structural parameters of late-type galaxies. We
specifically concentrate on peculiarities indicative of past or ongoing
interaction processes. The ~90 target galaxies have been {Period74} or
will be {P75} observed with 3D- spectroscopy at ESO-VLT yielding
2D-velocity fields with unprecedented spatial coverage and sampling. The
good spatial resolution of the ground-based data will be further
enhanced by a deconvolution method based on the proposed ACS images. The
velocity field and the morphology in restframe-UV light will reveal
possible transformation mechanisms affecting not only the stellar
populations but also the mass distribution of the galaxies.
Additionally, it will be possible to pin down the nature of the
interaction {e.g. tidally or ram-pressure induced}. This assessment gets
supported by our N-body/SPH simulations {including star formation} of
different interaction processes that allow the direct comparison of
structural and kinematical characteristics at each time step with the
observations on an individual basis taking into account all
observational constraints for a given galaxy. All together, we will be
able to explore the relative efficiency of the various proposed
transformation phenomena. In the case of non-disturbed spirals, a
rotation curve can be extracted from the full 2D velocity field with
unprecedented quality, from which the maximum rotation speed can be
derived with high confidence. In combination with accurate size and
luminosity determinations from the ACS images, we will be able to
establish the Tully-Fisher and Fundamental Plane relations of cluster
spiral members at cosmological epochs. At these distances cluster
assembly is predicted to peak and we can probe the galaxies' luminosity,
size and mass evolution with robust methods. Together with our already
existing sample of ~200 distant {z<=1} spiral galaxies in the field, we
will put strong constraints on current theories of galaxy formation and
evolution in different environments.
ACS/WFC 10713
Hubble Heritage Observations of NGC 281
The Hubble Heritage team will use a single pointing of ACS WFC to obtain
F435W, F555W, F658N, and F814W images of NGC 281 as part of a public
release image.
ACS/WFC/HRC 10536
What Are Stalled Preplanetary Nebulae? An ACS SNAPshot Survey
Essentially all planetary nebulae {PNs} are aspherical, whereas the
mass-loss envelopes of AGB stars are strikingly spherical. Our previous
SNAPshot surveys of a morphologically unbiased sample of pre-planetary
nebulae {PPNs} -- objects in transition between the AGB and PN
evolutionary phases -- show that roughly half our observed targets are
resolved, with bipolar or multipolar morphologies. Spectroscopic
observations of our sample confirm that these objects have not yet
evolved into planetary nebulae. Thus, the transformation from spherical
to aspherical geometries has already fully developed by the time these
dying stars have become PPNs. Although our current studies have yielded
exciting results, they are limited in two important ways -- {1} the
number of well-resolved objects is still small {18}, and the variety of
morphologies observed relatively multitudinous, hence no clear trends
can yet be established between morphology and other source properties
{e.g., near-IR, far-IR colors, stellar spectral type, envelope mass},
and {2} the current samples are strongly biased towards small PPNs, as
inferred from their low 60-to-25 micron flux ratios [R{60/25}<1].
However, the prototype of objects with R{60/25}>1, the Frosty Leo
Nebula, has a puzzlingly large post-AGB age {almost 10^4 yr} and a
fairly cool central star, very different from the expectations of
single-star stellar evolutionary models. A proposed, but still
speculative, hypothesis for such objects is that the slow evolution of
the central star is due to backflow of material onto the mass-losing
star, retarding its evolution towards the PN phase. This hypothesis has
significant consequences for both stellar and nebular evolution. We
therefore propose a survey of PPNs with R{60/25}>1 which is heavily
weighted towards the discovery of such "stalled PPNs". Supporting
kinematic observations using long-slit optical spectroscopy {with the
Keck}, millimeter and radio interferometric observations {with OVRO, VLA
& VLBA} are being undertaken. The results from this survey {together
with our previous work} will allow us to draw general conclusions about
the complex mass-outflow processes affecting late stellar evolution, and
will provide crucial input for theories of post-AGB stellar evolution.
Our survey will produce an archival legacy of long-standing value for
future studies of dying stars.
ACS/WFC/NIC2 10189
PANS-Probing Acceleration Now with Supernovae
Type Ia supernovae {SNe Ia} provide the most direct evidence for an
accelerating Universe, a result widely attributed to dark energy. Using
HST in Cycle 11 we extended the Hubble diagram with 6 of the 7
highest-redshift SNe Ia known, all at z>1.25, providing conclusive
evidence of an earlier epoch of cosmic deceleration. The full sample of
16 new SNe Ia match the cosmic concordance model and are inconsistent
with a simple model of evolution or dust as alternatives to dark energy.
Understanding dark energy may be the biggest current challenge to
cosmology and particle physics. To understand the nature of dark energy,
we seek to measure its two most fundamental properties: its evolution
{i.e., dw/dz}, and its recent equation of state {i.e., w{z=0}}. SNe Ia
at z>1, beyond the reach of the ground but squarely within the reach of
HST with ACS, are crucial to break the degeneracy in the measurements of
these two basic aspects of dark energy. The SNe Ia we have discovered
and measured with HST in Cycle 11, now double the precision of our
knowledge of both properties. Here we propose to quadruple the sample of
SNe Ia at z>1 in the next two cycles, complementing on-going surveys
from the ground at z<1, and again doubling the precision of dark energy
constraints. Should the current best fit model prove to be the correct
one, the precision expected from the current proposal will suffice to
rule out a cosmological constant at the 99% confidence level. Whatever
the result, these objects will provide the basis with which to extend
our empirical knowledge of this newly discovered and dominant component
of the Universe, and will remain one of the most significant legacies of
HST. In addition, our survey and follow-up data will greatly enhance the
value of the archival data within the target Treasury fields for galaxy
studies.
NIC1 10517
Imaging Astrometrically-Discovered Brown Dwarfs
We propose to image the astrometrically discovered companions of three
M-dwarfs with NICMOS to more tightly constrain their masses and
determine their stellar or sub-stellar natures. Each of these systems
has been observed with a sensitive ground-based adaptive optics system
and no companions have been detected. NICMOS results will eliminate an
ambiguity in the astrometric mass measurements that arises because a
companion that contributes significantly to the visible light reduces
the motion of the center of light and mimics a small motion of the
center of mass. In addition the astrometric measurements made with
NICMOS will fix the scale of the system, distinguishing among possible
orbits. Finally the color photometry will constrain the spectral types
to within a couple of subtypes. When we measure the masses of
astrophysical objects, we test and assist the development of the
theoretical mass models. Models are based upon parameters such as age
and metallicity. Determining the correct mass thus deepens our
understanding of the fundamental physics of stars and substellar objects
NIC1/NIC2/NIC3 8793
NICMOS Post-SAA calibration - CR Persistence Part 4
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.
WFPC2 10359
WFPC2 CYCLE 13 Standard Darks
This dark calibration program obtains dark frames every week in order to
provide 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 data will also provide a monitor of radiation
damage to the CCDs.
WFPC2 10748
WFPC2 CYCLE 14 Standard Darks
This dark calibration program obtains dark frames every week in order to
provide 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 data will also provide a monitor of radiation
damage to the CCDs.
WFPC2 10751
WFPC2 CYCLE 14 Intflat Linearity Check and Filter Rotation Anomaly
Monitor
Intflat observations will be taken to provide a linearity check: the
linearity test consists of a series of intflats in F555W, in each gain
and each shutter. A combination of intflats, visflats, and earthflats
will be used to check the repeatability of filter wheel motions.
{Intflat sequences tied to decons, visits 1-18 in prop 10363, have been
moved to the cycle 14 decon proposal 10744 for easier scheduling.} Note:
long-exposure WFPC2 intflats must be scheduled during ACS anneals to
prevent stray light from the WFPC2 lamps from contaminating long ACS
external exposures.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports
of potential non-nominal performance that will be investigated.)
HSTARS:
9996 - GSAcq (1,2,1) resulted in finelock back-up (2,0,2) @ 305/0454z
GSAcq (1,2,1) scheduled at 305/04:50:21 resulted in finelock backup
(2,0,2) due to scan step limit exceeded on FGS 1.
OBAD #1 = V1 -1155.79, V2 5116.89, V3 97.16, RSS 5246.70
OBAD #2 = V1 -3.21, V2 -14.91, V3 5.93, RSS 16.36
OBAD MAP = V1 -2.13, V2 -8.14, V3 1.54, RSS 8.55
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 10 10
FGS REacq 4 4
OBAD with Maneuver 28 28
SIGNIFICANT EVENTS: (None)
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