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Daily Report #4568



 
 
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Old March 17th 08, 02:44 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #4568

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4568

PERIOD COVERED: UT March 14,15,16, 2008 (DOY 074,075,076)

OBSERVATIONS SCHEDULED

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA calibration - CR Persistence Part 6

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 11308

Planetary Nebulae, Globular Clusters, and Binary Mergers

Four planetary nebulae (PNe) have been found within 130 of the 150 globular
clusters (GCs) of our Galaxy. This might not seem like many, but stellar
evolution predicts that the old populations of these clusters should contain
no PN at all Our request to use DD time for this proposal was encouraged by
the Telescope Time Review Board after they denied an instrument change
request for our cancelled ACS/WFC program. The denial resulted from a
substantial change in observing strategy which was deemed too complex not to
be reviewed by a TAC.

WFPC2 11235

HST NICMOS Survey of the Nuclear Regions 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 NICMOS NIC2 imaging of the
nuclear regions 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 and resolution of NICMOS NIC2 on HST
enables a unique opportunity to study the detailed structure of the nuclear
regions, where dust obscuration may mask star clusters, AGN and additional
nuclei from optical view, with a resolution significantly higher than
possible with Spitzer IRAC. This survey thus provides a crucial component to
our study of the dynamics and evolution of IR galaxies presently underway
with Wide-Field, HST ACS/WFC and Spitzer IRAC observations of these 88
galaxies. Imaging will be done with the F160W filter {H-band} to examine as
a function of both luminosity and merger stage {i} the luminosity and
distribution of embedded star clusters, {ii} the presence of optically
obscured AGN and nuclei, {iii} the correlation between the distribution of
1.6 micron emission and the mid- IR emission as detected by Spitzer IRAC,
{iv} the evidence of bars or bridges that may funnel fuel into the nuclear
region, and {v} the ages of star clusters for which photometry is available
via ACS/WFC observations. The NICMOS data, combined with the HST ACS,
Spitzer, and GALEX observations of this sample, will result in the most
comprehensive study of merging and interacting galaxies to date.

ACS/SBC 11225

The Wavelength Dependence of Accretion Disk Structure

We can now routinely measure the size of quasar accretion disks using
gravitational microlensing of lensed quasars. The next step to testing
accretion disk models is to measure the size of accretion disks as a
function of wavelength, particularly at the UV and X-ray wavelengths that
should probe the inner, strong gravity regime. Here we focus on two
four-image quasar lenses that already have optical {R band} and X-ray size
measurements using microlensing. We will combine the HST observations with
ground-based monitoring to measure the disk size as a function of wavelength
from the near-IR to the UV. We require HST to measure the image flux ratios
in the ultraviolet continuum near the Lyman limit of the quasars. The
selected targets have estimated black hole masses that differ by an order of
magnitude, and we should find wavelength scalings for the two systems that
are very different because the Blue/UV wavelengths should correspond to
parts of the disk near the inner edge for the high mass system but not in
the low mass system. The results will be modeled using a combination of
simple thin disk models and complete relativistic disk models. While
requiring only 18 orbits, success for one system requires observations in
both Cycles 16 and 17.

FGS 11212

Filling the Period Gap for Massive Binaries

The current census of binaries among the massive O-type stars is seriously
incomplete for systems in the period range from years to millennia because
the radial velocity variations are too small and the angular separations too
close for easy detection. Here we propose to discover binaries in this
observational gap through a Faint Guidance Sensor SNAP survey of relatively
bright targets listed in the Galactic O Star Catalog. Our primary goal is to
determine the binary frequency among those in the cluster/association,
field, and runaway groups. The results will help us assess the role of
binaries in massive star formation and in the processes that lead to the
ejection of massive stars from their natal clusters. The program will also
lead to the identification of new, close binaries that will be targets of
long term spectroscopic and high angular resolution observations to
determine their masses and distances. The results will also be important for
the interpretation of the spectra of suspected and newly identified binary
and multiple systems.

FGS 11211

An Astrometric Calibration of Population II Distance Indicators

In 2002 HST produced a highly precise parallax for RR Lyrae. That
measurement resulted in an absolute magnitude, M{V}= 0.61+/-0.11, a useful
result, judged by the over ten refereed citations each year since. It is,
however, unsatisfactory to have the direct, parallax-based, distance scale
of Population II variables based on a single star. We propose, therefore, to
obtain the parallaxes of four additional RR Lyrae stars and two Population
II Cepheids, or W Vir stars. The Population II Cepheids lie with the RR
Lyrae stars on a common K-band Period-Luminosity relation. Using these
parallaxes to inform that relationship, we anticipate a zero-point error of
0.04 magnitude. This result should greatly strengthen confidence in the
Population II distance scale and increase our understanding of RR Lyrae star
and Pop II Cepheid astrophysics.

FGS 11210

The Architecture of Exoplanetary Systems

Are all planetary systems coplanar? Concordance cosmogony makes that
prediction. It is, however, a prediction of extrasolar planetary system
architecture as yet untested by direct observation for main sequence stars
other than the Sun. To provide such a test, we propose to carry out FGS
astrometric studies on four stars hosting seven companions. Our
understanding of the planet formation process will grow as we match not only
system architecture, but formed planet mass and true distance from the
primary with host star characteristics for a wide variety of host stars and
exoplanet masses. We propose that a series of FGS astrometric observations
with demonstrated 1 millisecond of arc per-observation precision can
establish the degree of coplanarity and component true masses for four
extrasolar systems: HD 202206 {brown dwarf+planet}; HD 128311
{planet+planet}, HD 160691 = mu Arae {planet+planet}, and HD 222404AB =
gamma Cephei {planet+star}. In each case the companion is identified as such
by assuming that the minimum mass is the actual mass. For the last target, a
known stellar binary system, the companion orbit is stable only if coplanar
with the AB binary orbit.

WFPC2 11207

Star Formation in the Perseus Cluster Cooling Flow

We propose to obtain high resolution, UV/optical imaging of the "accretion
populations" in the massive cooling flow of the Perseus cluster of galaxies.
New GALEX observations show that the dominant galaxy in this nearby cluster,
NGC 1275, has an extended network of UV-bright populations apparently formed
recently from the intracluster gas. Cluster cooling flows are the most
prominent of the environments where we can readily observe the cycle of gas
accretion, star formation, and feedback from active nuclei that is thought
to play a central role in the formation and evolution of galaxies. Because
they can be readily age-dated, the accretion populations help to trace the
sequence of exchange of material between galaxies and the intracluster
medium. The ACS/SBC and WFPC2/PC cameras offer the highest spatial
resolution and best panchromatic performance available to map the spatial
and age distribution of the accretion populations and their relationship to
radio-emitting plasma and the hot intracluster gas.

WFPC2 11202

The Structure of Early-type Galaxies: 0.1-100 Effective Radii

The structure, formation and evolution of early-type galaxies is still
largely an open problem in cosmology: how does the Universe evolve from
large linear scales dominated by dark matter to the highly non-linear scales
of galaxies, where baryons and dark matter both play important interacting,
roles? To understand the complex physical processes involved in their
formation scenario, and why they have the tight scaling relations that we
observe today {e.g. the Fundamental Plane}, it is critically important not
only to understand their stellar structure, but also their dark-matter
distribution from the smallest to the largest scales. Over the last three
years the SLACS collaboration has developed a toolbox to tackle these issues
in a unique and encompassing way by combining new non-parametric strong
lensing techniques, stellar dynamics, and most recently weak gravitational
lensing, with high-quality Hubble Space Telescope imaging and VLT/Keck
spectroscopic data of early-type lens systems. This allows us to break
degeneracies that are inherent to each of these techniques separately and
probe the mass structure of early-type galaxies from 0.1 to 100 effective
radii. The large dynamic range to which lensing is sensitive allows us both
to probe the clumpy substructure of these galaxies, as well as their
low-density outer haloes. These methods have convincingly been demonstrated,
by our team, using smaller pilot-samples of SLACS lens systems with HST
data. In this proposal, we request observing time with WFPC2 and NICMOS to
observe 53 strong lens systems from SLACS, to obtain complete multi-color
imaging for each system. This would bring the total number of SLACS lens
systems to 87 with completed HST imaging and effectively doubles the known
number of galaxy-scale strong lenses. The deep HST images enable us to fully
exploit our new techniques, beat down low-number statistics, and probe the
structure and evolution of early-type galaxies, not only with a uniform
data-set an order of magnitude larger than what is available now, but also
with a fully coherent and self-consistent methodological approach!

NIC3 11195

Morphologies of the Most Extreme High-Redshift Mid-IR-luminous Galaxies II:
The `Bump' Sources

The formative phase of some of the most massive galaxies may be extremely
luminous, characterized by intense star- and AGN-formation. Till now, few
such galaxies have been unambiguously identified at high redshift, and thus
far we have been restricted to studying the low-redshift ultraluminous
infrared galaxies as possible analogs. We have recently discovered a sample
of objects which may indeed represent this early phase in galaxy formation,
and are undertaking an extensive multiwavelength study of this population.
These objects are optically extremely faint {R26} but nevertheless bright
at mid-infrared wavelengths {F[24um] 0.5 mJy}. Mid-infrared spectroscopy
with Spitzer/IRS reveals that they have redshifts z~2, implying luminosities
~1E13 Lsun. Their mid-IR SEDs fall into two broad, perhaps overlapping,
categories. Sources with brighter F[24um] exhibit power-law SEDs and SiO
absorption features in their mid-IR spectra characteristic of AGN, whereas
those with fainter F[24um] show a "bump" characteristic of the redshifted
1.6um peak from a stellar population, and PAH emission characteristic of
starformation. We have begun obtaining HST images of the brighter sources in
Cycle 15 to obtain identifications and determine kpc-scale morphologies for
these galaxies. Here, we aim to target the second class {the "bump" sources}
with the goal of determining if these constitute morphologically different
objects, or simply a "low-AGN" state of the brighter class. The proposed
observations will help us determine whether these objects are merging
systems, massive obscured starbursts {with obscuration on kpc scales!} or
very reddened {locally obscured} AGN hosted by intrinsically low-luminosity
galaxies.

WFPC2 11184

Imaging the Shock Precursor in Tycho's SNR

Cosmic ray acceleration in supernova remnant shocks requires shock
precursors where particles are trapped by plasma turbulence. The precursors
also heat and compress the upstream gas, producing H alpha emission and
affecting line profiles. We propose to image the brightest non-radiative
shock in Tycho's SNR to measure the brightness and width of the precursor.
These measurements will constrain 2 key parameters in cosmic ray
acceleration models, and they will improve the accuracy of shock speed and
electron-ion equilibration derived from H alpha profiles.

WFPC2 11169

Collisions in the Kuiper belt

For most of the 15 year history of observations of Kuiper belt objects, it
has been speculated that impacts must have played a major role in shaping
the physical and chemical characteristics of these objects, yet little
direct evidence of the effects of such impacts has been seen. The past 18
months, however, have seen an explosion of major new discoveries giving some
of the first insights into the influence of this critical process. From a
diversity of observations we have been led to the hypotheses that: {1}
satellite-forming impacts must have been common in the Kuiper belt; {2} such
impacts led to significant chemical modification; and {3} the outcomes of
these impacts are sufficiently predictable that we can now find and study
these impact-derived systems by the chemical and physical attributes of both
the satellites and the primaries. If our picture is correct, we now have in
hand for the first time a set of incredibly powerful tools to study the
frequency and outcome of collisions in the outer solar system. Here we
propose three linked projects that would answer questions critical to the
multiple prongs of our hypothesis. In these projects we will study the
chemical effects of collisions through spectrophotometric observations of
collisionally formed satellites and through the search for additional
satellites around primaries with potential impact signatures, and we will
study the physical effects of impacts through the examination of tidal
evolution in proposed impact systems. The intensive HST program that we
propose here will allow us to fully test our new hypotheses and will provide
the ability to obtain the first extensive insights into outer solar system
impact processes.

NIC3 11149

Characterizing the Stellar Populations in Lyman-Alpha Emitters and Lyman
Break Galaxies at 5.7z7 in the Subaru Deep Field

The epoch of reionization marks a major phase transition of the Universe,
during which the intergalactic space became transparent to UV photons.
Determining when this occurred and the physical processes involved
represents the latest frontier in observational cosmology. Over the last few
years, searches have intensified to identify the population of high-redshift
(z6) galaxies that might be responsible for this process, but the progress
is hampered partly by the difficulty of obtaining physical information
(stellar mass, age, star formation rate/history) for individual sources.
This is because the number of z6 galaxies that have both secure
spectroscopic redshifts and high-quality infrared photometry (especially
with Spitzer/IRAC) is still fairly small. Considering that only several
photometric points are available per source, and that many model SEDs are
highly degenerate, it is crucial to obtain as many observational constraints
as possible for each source to ensure the validity of SED modeling. To
better understand the physical properties of high-redshift galaxies, we
propose here to conduct HST/NICMOS (72 orbits) and Spitzer/IRAC (102 hours)
imaging of spectroscopically confirmed, bright (z26 mag (AB)) Ly-alpha
emitters (LAEs) and Lyman-break galaxies (LBGs) at 5.7z7 selected from the
Subaru Deep Field. Spectroscopic redshifts remove one critical free
parameter from SED modeling while bright source magnitudes ensure
high-quality photometric data. By making accurate determinations of stellar
masses, ages, and star-formation histories, we will specifically address the
following major questions: (1) Do LAEs and LBGs represent physically
different galaxy populations at z6 as suggested recently? (2) Is Ly-alpha
emission systematically suppressed at z6 with respect to continuum
emission? (i.e., are we reaching the epoch of incomplete reionization?), and
(3) Do we see any sign of abnormally young stellar population in any of the
z6 galaxies?

WFPC2/NIC3 11144

Building on the Significant NICMOS Investment in GOODS: A Bright, Wide-Area
Search for z=7 Galaxies

One of the most exciting frontiers in observational cosmology has been to
trace the buildup and evolution of galaxies from very early times. While
hierarchical theory teaches us that the star formation rate in galaxies
likely starts out small and builds up gradually, only recently has it been
possible to see evidence for this observationally through the evolution of
the LF from z~6 to z~3. Establishing that this build up occurs from even
earlier times {z~7-8} has been difficult, however, due to the small size of
current high-redshift z~7-8 samples -- now numbering in the range of ~4-10
sources. Expanding the size of these samples is absolutely essential, if we
are to push current studies of galaxy buildup back to even earlier times.
Fortunately, we should soon be able to do so, thanks to ~50 arcmin**2 of
deep {26.9 AB mag at 5 sigma} NICMOS 1.6 micron data that will be available
over the two ACS GOODS fields as a result of one recent 180- orbit ACS
backup program and a smaller program. These data will nearly triple the deep
near-IR imaging currently available and represent a significant resource for
finding and characterizing the brightest high-redshift sources -- since
high-redshift candidates can be easily identified in these data from their
red z-H colours. Unfortunately, the red z-H colours of these candidates are
not sufficient to determine that these sources are at z=7, and it is
important also to have deep photometry at 1.1 microns. To obtain this
crucial information, we propose to follow up each of these z-H dropouts with
NICMOS at 1.1 microns to determine which are at high redshift and thus
significantly expand our sample of luminous, z=7 galaxies. Since
preliminary studies indicate that these candidates occur in only 30% of the
NIC3 fields, our follow-up strategy is ~3 times as efficient as without this
preselection and 9 times as efficient as a search in a field with no
pre-existing data. In total, we expect to identify ~8 luminous z-dropouts
and possibly ~2 z~10 J-dropouts as a result of this program, more than
tripling the number currently known. The increased sample sizes are
important if we are to solidify current conclusions about galaxy buildup and
the evolution of the LF from z~8. In addition to the high redshift science,
these deep 1.1 micron data would have significant value for many diverse
endeavors, including {1} improving our constraints on the stellar mass
density at z~7-10 and {2} doubling the number of galaxies at z~6 for which
we can estimate dust obscuration.

WFPC2 11138

The Physics of the Jets of Powerful Radio Galaxies and Quasars

We propose to obtain HST polarimetry of the jets of the quasars 1150+497 and
PKS 1136-135. Our goal is to solve the riddle of their high-energy emission
mechanism, and tackle issues such as particle acceleration and jet dynamics.
Our targets are the optically brightest quasar jets, and they span the range
of luminosities and beaming parameters seen in these objects. Recent
observations with Spitzer, HST and Chandra have shed new light on the
spectral morphology of quasar jets, throwing wide open the question of the
nature of their optical and X-ray emission. Three mechanisms are possible,
including synchrotron emission as well as two Comptonization processes.
Polarimetry can uniquely determine which of these mechanisms operates in the
optical. We will compare the optical polarimetry to in- hand radio
polarimetry as well as in-hand and new Spitzer, HST and Chandra imaging to
gain new insights on the structure of these jets, as well as particle
acceleration mechanisms and jet dynamics.

WFPC2 11083

The Structure, Formation and Evolution of Galactic Cores and Nuclei

A surprising result has emerged from the ACS Virgo Cluster Survey {ACSVCS},
a program to obtain ACS/WFC gz imaging for a large, unbiased sample of 100
early-type galaxies in the Virgo Cluster. On subarcsecond scales {i.e.,
0.1"-1"}, the HST brightness profiles vary systematically from the
brightest giants {which have nearly constant surface brightness cores} to
the faintest dwarfs {which have compact stellar nuclei}. Remarkably, the
fraction of galaxy mass contributed by the nuclei in the faint galaxies is
identical to that contributed by supermassive black holes in the bright
galaxies {0.2%}. These findings strongly suggest that a single mechanism is
responsible for both types of Central Massive Object: most likely internally
or externally modulated gas inflows that feed central black holes or lead to
the formation of "nuclear star clusters". Understanding the history of gas
accretion, star formation and chemical enrichment on subarcsecond scales has
thus emerged as the single most pressing question in the study of nearby
galactic nuclei, either active or quiescent. We propose an ambitious HST
program {199 orbits} that constitutes the next, obvious step forward:
high-resolution, ultraviolet {WFPC2/F255W} and infrared {NIC1/F160W} imaging
for the complete ACSVCS sample. By capitalizing on HST's unique ability to
provide high-resolution images with a sharp and stable PSF at UV and IR
wavelengths, we will leverage the existing optical HST data to obtain the
most complete picture currently possible for the history of star formation
and chemical enrichment on these small scales. Equally important, this
program will lead to a significant improvement in the measured structural
parameters and density distributions for the stellar nuclei and the
underlying galaxies, and provide a sensitive measure of "frosting" by young
stars in the galaxy cores. By virtue of its superb image quality and stable
PSF, NICMOS is the sole instrument capable of the IR observations proposed
here. In the case of the WFPC2 observations, high-resolution UV imaging {
0.1"} is a capability unique to HST, yet one that could be lost at any time.

WFPC2 11022

WFPC2 Cycle 15 Decontaminations and Associated Observations

This proposal is for the 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.

WFPC2 11020

Cycle 15 Focus Monitor

The focus of HST is measured primarily with ACS/HRC over full CVZ orbits to
obtain accurate mean focus values via a well sampled breathing curve. Coma
and astigmatism are also determined from the same data in order to further
understand orbital effects on image quality and optical alignments. To
monitor the stability of ACS to WFPC2 relative focii, we've carried over
from previous focus monitor programs parallel observations taken with the
two cameras at suitable orientations of previously observed targets, and
interspersed them with the HRC CVZ visits.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11224 - GSACQ(1,2,2) failed

GSACQ(1,2,2) at 077/05:26:12 failed to RGA control with QF1STOPF and QSTOP
flags set. No other flags were seen. Vehicle was LOS at time of failure.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL

FGS GSacq 28 27
FGS REacq 14 14
OBAD with Maneuver 84 84

SIGNIFICANT EVENTS: (None)
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