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Daily Report #3987



 
 
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Old November 14th 05, 04:14 PM
Joe Cooper
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Default Daily Report #3987

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3987

PERIOD COVERED: UT November 11, 12, 13, 2005 (DOY 315, 316, 317)

OBSERVATIONS SCHEDULED

NICMOS 8790

NICMOS Post-SAA calibration - CR Persistence Part 1.

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.

ACS/WFC 10740

Absolute Photometric & Spectrophometric Calibration

This program has several goals: 1.}Verify repeatability of the ACS
instrumentation on a single bright star to +/-0.2%. 2.}Determine any
shift in the filter bandpasses since the preflight lab measurements.
3.}Determine the relative magnitude of the 3 primary WD calibrators to
0.1%. 4.}Refine the sensitivity calibration of the CCD prism and
grisms at field center and determine the repeatability accuracy of
this calibration. 5.}Determine the level of variability of the three
HST red standard stars: VB-8 {M7}, 2M0038+18 {L3.5} and 2M0559-14
{T5}, and also measure their short wavelength {7000A} fluxes.
6.}Cross calibrate with a faint STIS and NICMOS standard WD and solar
analog star.

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.

NIC1/NIC3 10726

NICMOS non-linearity tests

This program incorporates a number of tests to analyse the count rate
dependent non-linearity seen in NICMOS spectro-photometric
observations. In visit 1 we will observe a few fields with stars of a
range in luminosity in NGC1850 with NICMOS in NIC1 in F090M, F110W and
F160W and NIC2 F110W, F160W, and F180W. We will repeat the
observations with flatfield lamp on, creating artificially high
count-rates, allowing tests of NICMOS linearity as function of count
rate. To access the effect of charge trapping and persistence, we
first take darks {so there is not too much charge already trapped},
than take exposures with the lamp off, exposures with the lamp on, and
repeat at the end with lamp off. Finally, we continue with taking
darks during occultation. In visit 2 we will observe
spectro-photometric standard P041C using the G096 and G141 grisms in
NIC3, and repeat the lamp off/on/off test to artificially create a
high background. In visits 3&4 we repeat photometry measurements of
faint standard stars SNAP-2 and WD1657+343, on which the NICMOS
non-linearity was originally discovered using grism observations.
These measurements are repeated, because previous photometry was
obtained with too short exposure times, hence substantially affected
by charge trapping non-linearity. Measurements will be made with NIC1:
Visit 5 forms the persistence test of the program. The bright star
GL-390 {used in a previous persistence test} will iluminate the 3
NICMOS detectors in turn for a fixed time, saturating the center many
times, after which a series of darks will be taken to measure the
persistence {i.e. trapped electrons and the decay time of the traps}.
To determine the wavelength dependence of the trap chance, exposures
of the bright star in different filters will be taken, as well as one
in the G096 grism with NIC3. Most exposures will be 128s long, but two
exposures in the 3rd orbit will be 3x longer, to seperate the effects
of count rate versus total counts of the trap probability {in one
exposure, we get the full PSF worth of count rates, but we need a
longer exposure to separate the effect of rate versus total couts}.
Filters used: NIC1 F090M, F110W, F170M and F160W; NIC2 F110W, F160W,
F205W, F187W; NIC3 G096, F110W, F160W; 3x longer exposures: NIC1 and
NIC2 F110W.

NIC2 10717

Quasar Bolometri Luminosity and Spectral Energy Distributions from
Radio to X-ray

We propose to build the best SED data set spanning from radio to X-ray
wavelengths for 35 quasars. We will use new and archival mid-to-far IR
data from Spitzer as well as other existing multi-wavelength data. We
have unique quasi-simultaneous FUV/UV-optical spectra for our sample,
greatly reducing the uncertainty due to quasar intrinsic time
variability in the UV bump. We will derive accurate bolometric
luminosities for the sample and seek to establish a more reliable and
accurate way to obtain the bolometric luminosity of quasars from their
partial SEDs and/or spectral properties. We will also apply
multivariate analysis to the SEDs, study the quasar multi-wavelength
spectral properties and their dependence on the overall SEDs, and thus
better understand the physical processes quasars employ emitting
across the entire electromagnetic spectrum. HST NICMOS observations
will be used to remove host galaxy contamination from the quasar SEDs.
This is a joint Spitzer-HST project.

FGS 10610

Astrometric Masses of Extrasolar Planets and Brown Dwarfs

We propose observations with HST/FGS to estimate the astrometric
elements {perturbation orbit semi-major axis and inclination} of
extra-solar planets orbiting six stars. These companions were
originally detected by radial velocity techniques. We have
demonstrated that FGS astrometry of even a short segment of reflex
motion, when combined with extensive radial velocity information, can
yield useful inclination information {McArthur et al. 2004}, allowing
us to determine companion masses. Extrasolar planet masses assist in
two ongoing research frontiers. First, they provide useful boundary
conditions for models of planetary formation and evolution of
planetary systems. Second, knowing that a star in fact has a plantary
mass companion, increases the value of that system to future
extrasolar planet observation missions such as SIM PlanetQuest, TPF,
and GAIA.

ACS/WFC 10586

The Rosetta Stone without a Distance: Hunting for Cepheids in the
Primordial Galaxy I Zw 18

The Blue Compact Dwarf galaxy I Zw 18 is one of the most intriguing
objects in the Local Universe. It has the lowest nebular metallicity
of all known galaxies {Z=1/32 solar}. It has long been regarded as a
possible example of a galaxy undergoing its first burst of star
formation. However, its real evolutionary state continues to be
controversial. The WFPC2 and NICMOS detection of AGB stars by our
group and others suggested the presence of an underlying older
population. However, deeper ACS observations by Izotov & Thuan {2004}
recently failed to detect the signature of RGB stars. This was
interpreted as confirmation that I Zw 18 is in fact a galaxy "in
formation", a local analog of primordial galaxies in the distant
Universe. This result was widely reported in the international news
media. However, an alternative possibility is that I Zw 18 is somewhat
further away than previously believed, so that Red Giant Branch stars
were too faint to detect. Quoted distances in the literature have
ranged from 10 to 20 Mpc. We intend to resolve this controversy by
direct determination of the distance to 1 Mpc accuracy using Cepheids.
For this we request 12 visits of two orbits each, to execute at
carefully planned intervals. We will obtain V and I band ACS/WFC
photometry in each visit. The new data will be combined with archival
data, but we show that the archival data by themselves are
insufficient to achieve our science goals. The distance will allow us
to place I Zw 18 into its proper place in the evolutionary sequence of
galaxy formation.

ACS/WFC/WFPC2 10585

NGC 4449: a Testbed for Starbursts in the Low- and High-Redshift
Universe

We will obtain deep ACS/WFC broad-band imaging in F435W, F555W, and
F814W of the Magellanic irregular galaxy NGC 4449 in order to infer
the properties of the resolved {young and old} stellar population,
compare the current strong star-formation activity to that at earlier
epochs, trace the major episodes of star formation over cosmic time,
and relate them to the past history of interaction/merging of this
galaxy. NGC 4449 is one of the closest { 5 Mpc} global starbursts
with a widespread star-formation activity that could have been
triggered by interaction or accretion. It is, therefore, the perfect
laboratory where to address issues related to star formation in
extreme environments and investigate processes connected to the
formation and evolution of galaxies in the early universe. At a
distance of 4.2 Mpc, the stellar content in NGC 4449 can easily be
resolved with HST. Yet, up to date no comprehensive dataset has been
collected that is suited to infer a global star-formation history of
the galaxy and to better understand its evolution. ACS/WFC provides
the angular resolution and sensitivity to easily reach magnitude
limits necessary for the detection of individual stars at the tip of
the red giant branch {i.e., with ages from 1 Gyr up to 12 Gyr} with
the required accuracy. A mosaic of 2 pointings along the major axis
will give a good coverage of the galaxy and will allow us to infer a
star- formation history unbiased by local properties of peculiar
regions. Narrow-band imaging in F658N {Halpha} will provide a map of
the ionized gas. Finally, WFPC2 parallel observations in F555W and
F814W will allow to search deep in the HI halo of NGC 4449 for
evidence of stars belonging to tidal streams. Our investigation of NGC
4449 will benefit from the wealth of observations already available
over almost the whole electromagnetic spectrum and will be crucial in
better understanding how starbursts can be influenced by merging
phenonema in both the low- and high-redshift universe.

ACS/WFC 10576

An ACS Imaging Survey of the Galaxies Hosting Strong Mg II Absorption

Strong MgII absorbers {with rest-frame absorption equivalent width
W_MgII 0.3 A} at redshift z 1 are known to arise in extended
gaseous halos around luminous galaxies. Detailed absorption line
studies based on high-solution spectra of background quasars yield
tight constraints on the metallicity, ionization state, and kinematics
of the gaseous clouds. But whether they originate in gas accreted from
surrounding satellite galaxies or outflows associated with active
starburst in the host galaxies remains unclear. We have recently
completed a search of the Sloan Digital Sky Survey data archive for
strong MgII absorbers and identified over 1000 new systems that are
previously unknown. A subset of these MgII absorbers with W_MgII 1.8
A exhibit extreme kinematics with velocity widths {exceeding 200 km/s}
in our follow-up echelle spectra. Their dynamics are consistent with
various scenarios that include gas accretion {with speeds exceeding
the virial velocity} and starburst outflows {possibly driven by recent
merger events}. Independent of their exact nature, it is clear that
strong MgII systems serve as signposts to galactic halos with extreme
gas dynamics. Here we propose to conduct a snapshot survey of galaxies
in the fields toward high-redshift quasars with known, strong MgII
absorbers at 0.5 z 2. We plan to obtain high spatial-resolution
ACS/WFC images of 60 fields to uncover galaxies fainter than L* at the
redshifts of these absorbers and study their morphology. We will
complement the HST observations with follow-up spectroscopic
observations and IR images acquired at the Keck and Magellan
Observatories to for redshift identifications and for measuring
broad-band colors. We will investigate the correlation between
absorption line kinematics and galaxy morphology. In particular, we
will address whether on-going mergers is responsible for the extreme
dynamics observed in MgII absorption based on their rest-frame
ultraviolet morphology.

ACS/HRC/WFC 10575

Lyman alpha morphology of local starburst galaxies

Our pilot imaging study of 6 local galaxies using ACS/SBC in the
cosmologically important Lyman- alpha line has begun to reveal
intriguing results. Here we propse ACS/HRC imaging of this sample, the
approval of the which will allow for a significant increase in the
impact of the original study and extend the limits of current
understanding of Lyman-alpha escape. With this data we can accurately
calibrate our Lyman-alpha line-only images and explore for the first
time Lyman- alpha fluxes and equivalent widths in spatially resolved
systems. These data would also allow us to test the current models of
Lyman-alpha escape mechanisms and investigate possible correlations
between Lyman-alpha emission and other local parameters such as age
and internal reddening. The addition of high-resolution H-alpha data
allows us to quantitatively study the decoupling of Lyman-alpha from
non-resonant radiation and spatially explore the destruction and
attenuation of Lyman-alpha. The study will go a long way towards
resolving the outstanding issues complicating the interpretation of
high redshift studies and the use of Lyman-alpha to quantitatively
study the distant universe.

ACS/HRC 10556

Neutral Gas at Redshift z=0.5

Damped Lyman-alpha systems {DLAs} are used to track the bulk of the
neutral hydrogen gas in the Universe. Prior to HST UV spectroscopy,
they could only be studied from the ground at redshifts z1.65.
However, HST has now permitted us to discover 41 DLAs at z1.65 in our
previous surveys. Followup studies of these systems are providing a
wealth of information about the evolution of the neutral gas phase
component of the Universe. But one problem is that these 41
low-redshift systems are spread over a wide range of redshifts
spanning nearly 70% of the age of the Universe. Consequently, past
surveys for low-redshift DLAs have not been able to offer very good
precision in any small redshift regime. Here we propose an ACS-HRC-
PR200L spectroscopic survey in the redshift interval z=[0.37, 0.7]
which we estimate will permit us to discover another 41 DLAs. This
will not only allow us to double the number of low-redshift DLAs, but
it will also provide a relatively high-precision regime in the
low-redshift Universe that can be used to anchor evolutionary studies.
Fortunately DLAs have high absorption equivalent width, so
ACS-HRC-PR200L has high-enough resoultion to perform this proposed
MgII-selected DLA survey.

ACS/WFC 10550

The Nature of LSB galaxies revealed by their Globular Clusters

Low Surface Brightness {LSB} galaxies encompass many of the extremes
in galaxy properties. Their understanding is essential to complete our
picture of galaxy formation and evolution. Due to their historical
under-representation on galaxy surveys, their importance to many areas
of astronomy has only recently began to be realized. Globular clusters
are superb tracers of the formation histories of galaxies and have
been extensively used as such in high surface brightness galaxies. We
propose to investigate the nature of massive LSB galaxies by studying
their globular cluster systems. No globular cluster study has been
reported for LSB galaxies to date. Yet, both the presence or absence
of globular clusters set very strong constraints on the conditions
prevailing during LSB galaxy formation and evolution. Both in dwarf
and giant high surface brightness {HSB} galaxies, globular clusters
are known to form as a constant fraction of baryonic mass. Their
presence/absence immediately indicates similarities or discrepancies
in the formation and evolution conditions of LSB and HSB galaxies. In
particular, the presence/absence of metal-poor halo globular clusters
infers similarities/differences in the halo formation and assembly
processes of LSB vs. HSB galaxies, while the presence/absence of
metal-rich globular clusters can be used to derive the occurrence and
frequency of violent events {such as mergers} in the LSB galaxy
assembly history. Two band imaging with ACS will allow us to identify
the globular clusters {just resolved at the selected distance} and to
determine their metallicity {potentially their rough age}. The
composition of the systems will be compared to the extensive census
built up on HSB galaxies. Our representative sample of six LSB
galaxies {cz 2700 km/s} are selected such, that a large system of
globular clusters is expected. Globular clusters will constrain phases
of LSB galaxy formation and evolution that can currently not be probed
by other means. HST/ACS imaging is the only facility capable of
studying the globular cluster systems of LSB galaxies given their
distance and relative scarcity.

ACS/HRC 10545

Icy planetoids of the outer solar system

Early HST studies of satellites of Kuiper belt object focussed on the
50-200 km objects that were the largest known at the time. In the past
3 years we have discovered a population of much more rare and much
larger {500-2000+ km} icy planetoids in the Kuiper belt. These objects
are the largest and brightest known in the Kuiper belt and, in the era
when we now know of more than 1000 Kuiper belt objects, these few
planetoids are likely to be the focus of much of the research on
physical properties of the outer solar system for years to come. We
are currently engaged in an intensive program involving Spitzer, Keck,
and other telescopes to study the physical and dynamical properties of
this new population. HST is uniquely capable of addressing one
parameter fundamental to completing the physical picture of these
planetoids: the existence and size of any satellites. The detection
and characterization of satellites to these large planetoids would
allow us to address unique issues critical to the formation and
evolution of the outer solar system, including the measurement of
densities, internal properties, sizes and shapes of these objects, the
study of binary formation as a function of primary size, and the
context of the Pluto-Charon binary. For these bright objects, a
satellite search takes less than a full orbit, allowing the
opportunity for a new project on UV spectroscopy of the planetoids to
piggyback at no added time cost. This poorly explored spectral range
has the potential to show unique signatures of trapped gasses,
cosmochemically important ices, and complex organic materials.

NIC2 10519

Testing the Stellar Coalescence and Accretion Disk Theories of Massive
Star Formation with NICMOS

The importance of massive stars cannot be underestimated - they
produce most of the heavy elements in the universe and dominate the
evolution of the interstellar medium in their vicinity. In spite of
their significance, our understanding of their formation is meager.
Both accretion through disks, analogous to the process of low-mass
star formation, and coalescence of low-mass stars through collisions
in the dense cores of stellar clusters have been suggested. Possibly
both mechanisms occur. High spatial resolution polarization
measurements of the closest massive young stellar objects {YSOs} will
enable us to search for evidence of disk accretion or coalescence in
the form of patterns indicative of light scattered off a coherent disk
or off a disk disrupted by an infalling star, respectively. Here we
propose to use 2 micron polarimetry with NICMOS to identify the
presence of accretion disks around massive YSOs or to characterize
their environments as possibly disrupted from a close stellar
encounter. There are only a few sources that meet the stringent
selection criteria for this investigation {even with HST}, which we
will examine here. High spatial resolution is required, but even more
important, the point spread function {PSF} must be stable with time.
Furthermore, the PSF must put minimal flux into large spatial scales,
something that cannot be achieved with adaptive optics. This
combination of high Strehl ratio and stable PSF can only be achieved
from space.

ACS/HRC/WFC 10514

Kuiper Belt Binaries: Probes of Early Solar System Evolution

Binaries in the Kuiper Belt are a scientific windfall: in them we have
relatively fragile test particles which can be used as tracers of the
early dynamical evolution of the outer Solar System. We propose a
Snapshot program using the ACS/HRC that has a potential discovery
efficiency an order of magnitude higher than the HST observations that
have already discovered the majority of known transneptunian binaries.
By more than doubling the number of observed objects in dynamically
hot and cold subpopulations we will be able to answer, with
statistical significance, the question of whether these groups differ
in the abundance of binaries as a result of their particular dynamical
paths into the Kuiper Belt. Today's Kuiper Belt bears the imprints of
the final stages of giant-planet building and migration; binaries may
offer some of the best preserved evidence of that long-ago era.

WFPC2 10501

Extending the Heritage: Clusters, Dust, and Star Formation in M51

Strongly interacting systems in the Local Universe offer the
opportunity to investigate the modality of star formation under
dynamical conditions more typical of the intermediate redshift
Universe {z~0.5-1}, at an exquisite resolution unmatched by distant
galaxies. M51 is one such system. Most recently, the Hubble Heritage
program dedicated 24 HST orbits to obtain a 3X2 ACS mosaic of M51 in
BVI, and Halpha. While this is designed to produce a lovely
multi-color image of this photogenic target, its scientific return
will be limited for star formation studies. Hence we propose to
augment these observations by obtaining WFPC2 U band and NICMOS H band
primary imaging {with NICMOS Paschen alpha in parallel} of selected
pointings of this interacting galaxy system. At the modest cost of 14
additional orbits, we will: {1} accurately determine the ages of the
young star cluster population; {2} secure the identification of 60-70
old globular clusters; {3} search for heavily dust enshrouded stellar
clusters; {4} investigate the distribution of the cluster populations
as a function of location {galactocentric, arms, interarms, etc.}; and
{5} both remove the effects of dust and determine its properties. In
addition to our specific science goals, these observations lend
themselves, on their own or in synergy with data from GALEX and
Spitzer, to a host of other investigations, including those on evolved
diffuse stellar populations, galactic structure, and dust radiative
transfer. We will thus release these data early to the community, by
relinquishing part of the proprietary period.

ACS/WFC 10497

Cepheid Calibrations of the Luminosity of Two Reliable Type Ia
Supernovae and a Re- determination of the Hubble Constant

We propose to determine the luminosity of two type Ia supernovae {SNe
Ia}, 1995al in NGC 3021 and SN 2002fk in NGC 1309, by observing
Cepheids in their spiral hosts. Modern CCD photometry yields an
extremely tight Hubble diagram for SNe Ia with a precisely determined
intercept {i.e., Delta H_0/H_0}. Yet, the measurement of the true
Hubble constant via SNe Ia is limited by the calibration derived from
problematic and unreliable SN data. Most of the SNe Ia calibrated by
HST to date are significantly compromised by the systematics of
photographic photometry, high reddening and SN peculiarity, and by the
photometric anomolies associated with WFPC2. The extended reach of ACS
now provides opportunities to more reliably calibrate SNe Ia and H_0.
Our Cepheid calibration of a reliable SN Ia dataset, SN 1994ae, using
ACS in Cycle 11 resulted in a 15% increase in H_0 from the value
derived by the HST SN Ia Calibration Program. Yet, there remains a
terribly small sample of reliable SN Ia data sets on which to base
such a crucial cosmological result. SN 1995al and SN 2002fk are two of
the best observed SNe Ia both with little reddening. They provide two
opportunities to use ACS for placing the calibration of H_0 via SN Ia
on firmer footing and potentially improve its precision.

ACS/WFC 10494

Imaging the mass structure of distant lens galaxies

The surface brightness distribution of extended gravitationally lensed
arcs and Einstein rings contains super-resolved information about the
lensed object, and, more excitingly, about the smooth and clumpy mass
distribution of the lens galaxies. The source and lens information can
non-parametrically be separated, resulting in a direct
"gravitational-mass image" of the inner mass-distribution of
cosmologically-distant galaxies {Koopmans 2005}. With this goal in
mind, we propose deep HST ACS-F555W/F814W and NICMOS-F160W imaging of
15 gravitational-lens systems with spatially resolved lensed sources,
selected from the 17 new lens systems discovered by the Sloan Lens ACS
Survey {Bolton et al. 2004}. Each system has been selected from the
SDSS and confirmed in a time-efficient HST-ACS snapshot program
{cycle-13}; they show highly-magnified arcs or Einstein rings, lensed
by a massive early-type lens galaxy. High- fidelity multi-color HST
images are required {not delivered by the 420-sec snapshot images} to
isolate these lensed images {properly cleaned, dithered and
extinction-corrected} from the lens galaxy surface brightness
distribution, and apply our "gravitational-mass imaging" technique.
The sample of galaxy mass distributions - determined through this
method from the arcs and Einstein ring HST images - will be studied
to: {i} measure the smooth mass distribution of the lens galaxies
{Dark and luminous mass are separated using the HST images and the
stellar M/L values derived from a joint stellar-dynamical analysis of
each system}; {ii} quantify statistically and individually the
incidence of mass-substructure {with or without obvious luminous
counter- parts such as dwarf galaxies}. Since dark-matter substructure
should be considerably more prevalent at higher redshift, both results
provide a direct test of this prediction of the CDM hierarchical
structure-formation model.

ACS/WFC 10491

A Snapshot Survey of the most massive clusters of galaxies

We propose a snapshot survey of a sample of 124 high X-ray luminosity
clusters in the redshift range 0.3-0.7. Similarly luminous clusters at
these redshifts frequently exhibit strong gravitational lensing. The
proposed observations will provide important constraints on the nature
of the cluster mass distributions and a set of optically bright,
lensed galaxies for further 8-10m spectroscopy. We acknowledge the
broad community interest in this sample and waive our data rights for
these observations.

ACS/WFC 10483

HH110: Collision between a Jet and a Cloud

We propose to study the shortlived event when a high-velocity
protostellar outflow collides with a dense molecular cloud core. It
has recently been realized that Herbig-Haro flows can attain gigantic
proportions, with flow lobes stretching over many parsecs. This
greatly increases the probability that an outflow rams into an
obstacle such as a molecular cloud core as it plows through the
interstellar medium. The HH 110 flow represents the rare case of an
outflow that has suffered a grazing collision with a cloud core.
Fortunately, the resulting shock is so bright that only a few orbits
are required for analysis. ACS imaging in Halpha in Cycles 12 and 14
will permit the study of detailed structure and kinematics of the flow
as it passes through the region of impact. This study has consequences
for our general understanding of the energy cycle and chemical
processing of the interstellar medium, turbulence in molecular clouds,
and the role of sequential star formation among low mass stars.

ACS/WFC/WFPC2 10402

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 a {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.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10014 - Loss of Lock while guiding under two FGSs @ 315/10:29:01z At
315/10:29:01, while guiding under two FGSs, a loss of lock occured,
and HST transitioned from F2GFnLSc to T2GAttHd. Subsequent
REACQ(2,1,2) at 315/11:07:15 was successful.

10015 - GSACQ(2,1,2) failed, search radius limit exceeded @
315/18:43:51z OBAD at 18:43:51 had attitude correction of -42158 arc
seconds on V3 and resulted in 486 ESB flag 1902, indicating "OBAD
failed ID". GSACQ(2,1,2) occurred while HST was LOS, at AOS the
vehicle was in M2G control with search radius limit flag on FGS 2. Map
at 18:56:25 showed error of 102.80 arcseconds in V2, outside of search
radius.

10016 - GSAcq(2,1,2) results in finelock backup (2,0,2) using FGS2 @
318/07:45:52z The GSAcq(2,1,2) scheduled at 318/07:45:52 - 07:53:56
resulted to finelock backup (2,0,2) using FGS2 after multiple attempts
during acquisition walkdown. Prior OBAD at 318/07:41:22, correction
was successful (RSS) value ~9.00 arcsec. Followed by 486 ESB 1806 (T2G
Open Loop Timer Expired) at 318/07:43:26.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 37 36 Hstar
# 10015
FGS REacq 22 22
OBAD with Maneuver 110 110


 




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NASA PDF Mercury, Gemini, Apollo reports free online Rusty Barton History 81 October 3rd 04 05:33 PM
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