Status Report

NASA Hubble Space Telescope Daily Report # 3880

By SpaceRef Editor
June 14, 2005
Filed under , ,
NASA Hubble Space Telescope Daily Report # 3880

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science

DAILY REPORT      # 3880

PERIOD COVERED: UT June 12-13, 2005 (DOY 163-164)


WFPC2 9740

CIII] Imagery of Planetary Nebulae and HII Regions — A Snap Program

We propose to undertake a SNAP program of WFPC2 imagery of several
planetary nebulae and extragalactic HII regions with the F185W filter
to study the spatial variation of the CIII] 1909 Angstrom emission
lines across the nebulae. Much of our current knowledge of carbon
abundances in planetary nebulae and HII regions are based on UV
spectroscopic observations of this line yet there have not been any
studies of its spatial variations in nebulae compared to several of
the prominent optical lines {e.g. [OIII] 5007 Angstroms}. Such
observations, coupled with photoionization modeling of the nebulae,
will enable us to assess the utility of using the CIII] line in
abundance calculations of C/O and C/H in nebulae and possibly permit
improved empirical emission-line diagnostic techniques for ionization
corrections to get the elemental carbon abundances from C++/O++
observations based on CIII]/[OIII] 1909/5007. We also plan to study
the spatial variation of the CIII] 1909 Angstrom collisionally excited
lines against the CII 4267 Angstrom permitted line in many of the
nebulae using previous and planned ground-based longslit echelle
spectroscopy coupled with the HST WFPC2 F185W imagery.

NIC1/NIC2/NIC3 8792

NICMOS Post-SAA calibration – CR Persistence Part 3

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.

NIC3 10709

Linearity Test for Long Grism Integrations

In cycle 12, 24 orbits were used to measure the NICMOS grism mode
sensitivities and to establish a set of IR flux standards with a goal
of 1% accuracy. However, the short wavelength response shows a
5.6%/dex apparent non-linearity in the overlap region {Bohlin,
Lindler, & Riess NICMOS ISR 2005-02}. Studies of the _ima files for
both the grism data and for stellar photometry suggest that the NICMOS
count rates are a monotonically rising function of integration time.
The typical integration time of the grism observations are typically
1-2min with a maximum of 3min, while the most interesting science
observations are typically 5-10x longer. At a declination of +72deg, a
previous observation of WD1057+719 obtained 04Apr2 reached at an
exposure time of ~3min for each of 15 dither positions. By reducing
the dithers to 2, exposure times of 20-25min will be obtained. This
program addresses the NICMOS count rate growth from 0.8-1.9microns as
a function of integration times that are relevant for faint source
science. Results will include count rate growth curves for several
wavelength bins covering the range of maximum non-linearity around
1micron to where the previously measured non-linearity disappears
around 1.7microns. The count rates for the existing short integrations
can be attached seamlessly to those for the new long integrations,
because NICMOS sensitivities are constant with time to <1%. A definitive answer is expected to the question of whether the count rates rise enough with exposure time to explain the full apparent grism non-linearity for short exposure times and whether the rise is enough to explain the apparent lack of any non-linearity in the prime science from photometry of faint point sources. II. NICMOS Non-Linearity Measurement as a Function of Wavelength WD1057+719 is one of two faint stars used by {Bohlin, Lindler, & Riess NICMOS ISR 2005-02} to establish the wavelength dependence of the non-linearity. However, the uncertainty in the linearity correction vs. wavelength is as big as 3%/dex at 1.8microns. These new data should reduce that uncertainty by sqrt{2} and answer the crucial question of whether the non-linearity changes slope from positive to negative longward of 1.7microns.

S/C 10706

SMS spanning anneal for Flight Software Update {ACS}

This is an anneal that will take the place of the regularly scheduled
anneal, and will span a calendar boundary. 1. Visit 1 must be
scheduled to start within 6 hours of an SMS boundary.

ACS/WFC 10493

A Survey for Supernovae in Massive High-Redshift Clusters

We propose to measure, to an unprecedented 30% accuracy, the SN-Ia
rate in a sample of massive z=0.5-0.9 galaxy clusters. The SN-Ia rate
is a poorly known observable, especially at high z, and in cluster
environments. The SN rate and its redshift dependence can serve as
powerful discrimiminants for a number of key issues in astrophysics
and cosmology. Our observations will: 1. Put clear constraints on the
characteristic SN-Ia “delay time, ” the typical time between the
formation of a stellar population and the explosion of some of its
members as SNe-Ia. Such constraints can exclude entire categories of
SN-Ia progenitor models, since different models predict different
delays. 2. Help resolve the question of the dominant source of the
high metallicity in the intracluster medium {ICM} – SNe-Ia, or
core-collapse SNe from an early stellar population with a top-heavy
IMF, perhaps those population III stars responsible for the early
re-ionization of the Universe. Since clusters are excellent
laboratories for studying enrichment {they generally have a simple
star-formation history, and matter cannot leave their deep
potentials}, the results will be relevant for understanding metal
enrichment in general, and the possible role of first generation stars
in early Universal enrichment. 3. Reveal, via nuclear variability, the
AGN fraction in clusters at this redshift, to be compared with the
field AGN fraction. This will be valuable input for understanding
black-hole demographics, AGN evolution, and ICM energetics. 4.
Potentially discover intergalactic cluster SNe, which can trace the
stripped stellar population at high z.

NIC2 10428

The colours of QSO host galaxies at z=2 and the evolution of their
stellar masses

We propose to use NICMOS imaging to measure the rest-frame optical/UV
colours of a complete sample of 10 QSO host galaxies at redshifts
between z=1.5 and z=2. From our cycle 11 HST observations {the GEMS
project} we know that QSO host galaxies at redshifts of z~1 show blue
colors despite having early-type morphologies. This is in excellent
agreement with recent SDSS results on low-z AGN hosts, suggesting that
QSO-type activity in galaxies correlates strongly with the presence of
a young stellar population. Our proposed NICMOS observations will
allow us to test the validity of this hypothesis out to z~2, by
relating the observed QSO host colours to those of normal galaxies at
similar redshifts taken from GOODS. We have already established within
GEMS that the QSO hosts in our sample possess substantial UV
luminosities, most likely originating from young stars. Knowing
rest-frame colors, we can estimate stellar ages and stellar masses.
For the first time will it be possible to determine the evolution of
stellar masses in QSO host galaxies from z=2, the epoch of maximum QSO
activity, to the present. Our results will shed light on the relation
between nuclear activity and the star formation history of galaxies,
and how these processes may jointly drive the cosmic evolution of QSOs
and galaxies.

ACS/WFC 10412

The host galaxies of dust-reddened quasars

We have used the 2MASS near-infrared and FIRST radio surveys, together
with the Palomar Observatory Sky Survey plates to select a sample of
dust-reddened, radio-intermediate quasars. We wish to use ACS to study
the host galaxies of these quasars. The dust reddening of the quasars
makes it possible to study the hosts at rest-frame optical-UV
wavelengths much more easily than the hosts of normal quasars of
similar bolometric luminosity. Our study will compare the hosts of our
dust-reddened quasars to those of normal quasars from the HST archive
to test the hypothesis that dust-reddened quasars are young objects,
whose hosts still show morphological evidence of recent merger events
which triggered the quasar.


The Formation and Evolution of Spirals: An ACS and WFPC2 Imaging
Survey of Nearby Galaxies

Over 50% of galaxies in the local universe are spirals. Yet the star
formation histories and evolution of this crucial population remain
poorly understood. We propose to combine archival data with new
ACS/WFC and WFPC2 observations of 11 galaxies, to tackle a
comprehensive investigation of nearby spirals covering the entire
spiral sequence. The new observations will fill a serious deficiency
in HST’s legacy, and maximize the scientific return of existing HST
data. The filter combination of UBVI, and Halpha is ideal for studying
stellar populations, dust properties, and the ISM. Our immediate
scientific objectives are: {i} to use the resolved cluster
populations, both young massive clusters and ancient globular clusters
as a chronometer, to understand how spirals assembled as a function of
time; {ii} study the rapid disruption properties of young clusters;
and {iii} understand dust distributions in spirals from pc to kpc
scales. Each of these goals provides an important step towards
charting the evolution of galaxies, and an essential baseline for
interpreting the galaxy populations being surveyed in both the early
and present universe. The resolution of our survey, which exploits the
excellent imaging capabilities of HST’s two optical cameras, will
enable us to understand the record of star cluster, and galaxy
formation in a level of detail which is not possible for more distant
systems. Finally, the proposed observations will provide a key to
interpret an extensive, multiwavelength archive of space- and ground-
based data at lower spatial resolution {SPITZER, CHANDRA, GALEX,
NICMOS P alpha and H band imaging} for local spirals.


Accurate and Robust Calibration of the Extragalactic Distance Scale
with the Maser Galaxy NGC4258 II

The extragalactic distance scale {EDS} is defined by a comparison of
Cepheid Period-Luminosity {PL} relations for nearby galaxies and the
LMC, whose uncertain distance is thereby the SOLE anchor. Studies of
masers orbiting the central black hole in NGC4258 have provided the
most accurate extragalactic distance ever {7.2+/-0.5 Mpc}, and new
radio data and analysis techniques will reduce the uncertainty to < 3.5% {0.07 mag} by 2005. Since this distance is well determined and based on geometric arguments, NGC4258 can provide a much needed new anchor for the EDS. Ultimately, the combination of an independent measurement of H0 and measurements of CMB fluctuations {e.g., WMAP} can be used to directly constrain cosmological parameters including the equation of state of dark energy. In our Cycle 12 proposal, we defined a program spanning two cycles. The Cycle 12 portion was accepted. We have acquired WFC images and are constructing well sampled PL relations in 3 colors {BVI}. The purpose of the Cycle 13 observations is to address systematic sources of error and is crucial for the success of the entire program. To disentangle the effects of reddening and metallicity, and to characterize the effects of blending, we require 50 orbits to obtain H-band photometry {NICMOS/NIC2} and high resolution images {ACS/HRC}.


ACS CCDs daily monitor – Cycle 13 – Part 2

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 program will be
for the entire lifetime of ACS.

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.

ACS/HRC 10262

The 3D Morphology of the Extreme Red Supergiant VY Cma

The extreme RSG and powerful OH/IR source VY CMa is surrounded by an
asymmetric reflection nebula dominated by a prominent nebulous arc,
bright filamentary arcs, and several clumps of dusty knots that are
evidence for multiple and asymmetric mass loss events. Our groundbased
velocities show that these structures are kinematically distinct from
the gneral flow of the diffuse gas and may be directional. We have
speculated that these arcs and knots may be caused by localized
activity on the star involving convection and possibly magnetic fields
analogous to lower mass stars. If correct this would have important
implications for the causes of high mass loss events in evolved
massive stars. Fortunately, VY CMa provides us with an opportunity to
learn more about its possible mass loss mechanisms and history from
the morphology of its ejecta. We propose to use polarimetry and second
epoch images combined with our radial velocities to map the morphology
of the nebula and the discrete structures embedded in it.

ACS/HRC 10198

Probing the Dynamics of the Galactic Bar through the Kinematics of
Microlensed Stars

The observed optical depths to microlensing of stars in the Galactic
bulge are difficult to reconcile with our present understanding of
Galactic dynamics. The main source of uncertainty in those comparisons
is now shifting from microlensing measurements to the dynamical models
of the Galactic bar. We propose to constrain the Galactic bar models
with proper motion observations of Bulge stars that underwent
microlensing by determining both the kinematic identity of the
microlensed sources and the importance of streaming motions. The
lensed stars are typically farther than randomly selected stars.
Therefore, our proper motion determinations for 36 targeted MACHO
events will provide valuable constraints on the dynamics of bulge
stars as a function of distance. The first epoch data for our proposed
events is already available in the HST archive so the project can be
completed within a single HST cycle. The exceptional spatial
resolution of HST is essential for completion of the project.
Constraints on the total mass in the bulge will ultimately lead to the
determination of the amount of dark matter in inner Galaxy.

FGS 10197

The Astrophysical Parameters of Very Metal-Poor Halo Binaries

Little is currently known concerning the mass-luminosity relation
{MLR} of Population II stars. In Cycle 10, we began an initial study
with FGS1 to resolve a sample of known spectroscopic binaries
preselected as high-velocity and/or low metallicity objects. This has
resulted in significant new information about the astrophysical
parameters of metal-poor stars, but was limited mainly to intermediate
metallicities, not to true Population II stars. A new sample of metal-
poor spectroscopic binaries identified by Latham and his collaborators
{e.g. Latham et al 2002} contains three new very metal-poor objects
resolvable with FGS. We propose to observe these binaries and obtain
additional observations of two very important resolved targets from
our initial sample. As with that program, we will couple the
already-known spectroscopic orbits with astrometric information which
only FGS can deliver at present. To ensure that the most will be
gained from these data, we also request observations of three
metal-poor single stars to be used as calibration objects. In
combination with results from our previous program, these observations
can be expected to resolve the question of the location of the
Population II main sequence and give valuable insight into the
accuracy of isochrone fitting for determination of globular clusters
ages. Due to the combination of target magnitudes and expected
separations, no object in this sample can be resolved without the
unique capabilities of FGS.

NIC2 10173

Infrared Snapshots of 3CR Radio Galaxies

Radio galaxies are an important class of extragalactic objects: they
are one of the most energetic astrophysical phenomena and they provide
an exceptional probe of the evolving Universe, lying typically in high
density regions but well-represented across a wide redshift range. In
earlier Cycles we carried out extensive HST observations of the 3CR
sources in order to acquire a complete and quantitative inventory of
the structure, contents and evolution of these important objects.
Amongst the results, we discovered new optical jets, dust lanes,
face-on disks with optical jets, and revealed point-like nuclei whose
properties support FR-I/BL Lac unified schemes. Here, we propose to
obtain NICMOS infrared images of 3CR sources with z<0.3 as a major enhancement to an already superb dataset. We aim to deshroud dusty galaxies, study the underlying host galaxy free from the distorting effects of dust, locate hidden regions of star formation and establish the physical characteristics of the dust itself. We will measure frequency and spectral energy distributions of point-like nuclei, expected to be stronger and more prevalent in the IR, seek spectral turnovers in known synchrotron jets and find new jets. We will strongly test unified AGN schemes and merge these data with existing X-ray to radio observations. The resulting database will be an incredibly valuable resource to the astronomical community for years to come.

WFPC2 10170

Atmospheric Variability on Uranus and Neptune

We propose Snapshot observations of Uranus and Neptune to monitor
changes in their atmospheres on time scales of weeks, months, and
years. Uranus is rapidly approaching equinox in 2007, with another 4
degrees of latitude becoming visible every year. Recent HST
observations during this epoch {including 6818: Hammel, Lockwood, and
Rages; 7885: Hammel, Karkoschka, and Marley; 8680: Hammel, Rages,
Lockwood, and Marley; and 8634: Rages, Hammel, Lockwood, Marley, and
McKay} have revealed strongly wavelength-dependent latitudinal
structure and the presence of numerous visible-wavelength cloud
features in the northern hemisphere. Long-term ground-based
observations {Lockwood and Thompson 1999} show seasonal brightness
changes whose origins are not well understood. Recent near-IR images
of Neptune obtained using adaptive optics on the Keck Telescope
together with images from our Cycle 9 Snapshot program {8634} show a
general increase in activity at south temperate latitudes as well as
the possible development of another Great Dark Spot. Further Snapshot
observations of these two dynamic planets will elucidate the nature of
long-term changes in their zonal atmospheric bands and clarify the
processes of formation, evolution, and dissipation of discrete albedo

ACS/WFC 10152

A Snapshot Survey of a Complete Sample of X-ray Luminous Galaxy
Clusters from Redshift 0.3 to 0.7

We propose a public, uniform imaging survey of a well-studied,
complete, and homogeneous sample of X-ray clusters. The sample of 73
clusters spans the redshift range between 0.3-0.7. The samples spans
almost 2 orders of magnitude of X-ray luminosity, where half of the
sample has X-ray luminosities greater than 10^44 erg/s {0.5-2.0 keV}.
These snapshots will be used to obtain a fair census of the the
morphology of cluster galaxies in the cores of clusters, to detect
radial and tangential arc candidates, to detect optical jet
candidates, and to provide an approximate estimate of the shear signal
of the clusters themselves, and potentially an assessment of the
contribution of large scale structure to lensing shear.

ACS/HRC 10144

The Gas Environment of Comet 9P/Tempel 1 During the Deep Impact

We propose a series of observations of the periodic comet 9P/Tempel 1
in conjunction with NASA’s Deep Impact mission. This mission is a
spacecraft that will release a 360 kg impactor into the nucleus of the
comet on July 4, 2005. Our primary objective is to study the
generation and evolution of the gaseous coma resulting from this
impact. To this end we plan to obtain ultraviolet spectra during, and
following the impact. As a secondary objective we will obtain
wide-band images of the visual outburst resulting from the impact. We
also plan to use the high resolution capability of the ACS/HRC, in
conjunction with the camera on board the spacecraft, two weeks prior
to impact, to determine the spatial orientation of active jets
emanating from the comet’s nucleus and to assess the potential hazards
of these jets to the spacecraft.

ACS/WFC 10135

Unveiling the Progenitors and Physics of Cosmic Explosions

GRBs and XRFs are clearly highly asymmetric explosions and require a
long-lived power source {central engine}. In contrast, nearby
core-collapse events are essentially spherical explosions. However,
the failure of spherical neutrino driven collapses has led to the idea
that asymmetric energy release is essential for the explosion. The
recent finding of a Type Ic SN in GRB 030329, the association of the
low energy event GRB 980425 with SN 1998bw, the theoretical
development discussed above and the rise of collapsar models make it
timely to consider whether all these explosions contain engines. Given
the uncertainties in theoretical modeling it is clear that
observations are needed to guide models. A priori there is little
reason to expect connection between the ultra-relativistic jet that
powers the GRB and the explosive nucleosynthesis of the ~0.5 solar
masses of Nickel-56 that powers the accompanying supernova. We propose
a comprehensive program of ACS photometric searches {and measurements}
for SNe associated with GRBs and XRFs. In concert, we will undertake
ground- based spectroscopy to determine velocity widths, and measure
engine parameters from pan- chromatic afterglow observations. Our goal
is to produce a comprehensive database of engine and SN physical
parameters against which theoretical modeling will be guided.


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


9846 – GSACQ(2,1,1) results in finelock backup (2,0,2) @ 164/1502z



                           SCHEDULED     SUCCESSFUL    FAILURE TIMES 
 FGS Gsacq                 8                         8 
 FGS Reacq                 8                          8 
 FHST Update             16                        16 


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