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Daily Report #4656



 
 
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Old July 21st 08, 04:33 PM posted to sci.astro.hubble
Pataro, Pete
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Posts: 33
Default Daily Report #4656

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT*** #4656

PERIOD COVERED: 5am July 18 - 5am July 21, 2008 (DOY
200/0900z-203/0900z)

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.

NIC2 11547

Characterizing Pre-Main Sequence Populations in Stellar Associations
of the Large Magellanic Cloud

The Large Magellanic Cloud (LMC) offers an extremely rich sample of
resolved low-mass stars (below 1 Solar Mass) in the act of formation
that has not been explored sufficiently yet. These pre-main sequence
(PMS) stars provide a unique snapshot of the star formation process,
as it is being recorded for the last ~20 Myr, and they give important
information on the low-mass Initial Mass Function (IMF) of their host
stellar systems. Studies of young, rich LMC clusters like 30 Doradus
are crowding limited, even at the angular resolution facilitated by
HST in the optical. To learn more about low-mass PMS stars in the LMC,
one has to study less crowded regions like young stellar associations.
We propose to employ WFPC2 to obtain deep photometry (V ~ 25.5 mag) of
four selected LMC stellar associations in order to perform an original
optical analysis of their red PMS and blue bright MS stellar
populations. With these observations we aim at a comprehensive study,
which will add substantial information on the most recent star
formation and the IMF in the LMC. The data reduction and analysis will
be performed with a 2D photometry software package especially
developed by us for WFPC2 imaging of extended stellar associations
with variable background. Our targets have been selected optimizing a
combination of criteria, namely spatial resolution, crowding, low
extinction, nebular contamination, and background confusion in
comparison to other regions in the Local Group. Parallel NICMOS
imaging will provide additional information on near-infrared
properties of the stellar population in the regions surrounding these
systems.

NIC3 11545

A NICMOS Survey of Newly-Discovered Young Massive Clusters

We are on the cusp of a revolution in massive star research triggered
by 2MASS and Spitzer/GLIMPSE, and now is the ideal time to capitalize
on these projects by performing the first survey of massive stars in
young stellar clusters throughout the Galactic plane. A search of the
2MASS and GLIMPSE surveys has produced over 450 newly-identified
massive stellar cluster candidates in the Galactic plane which are
hidden from our view at optical wavelengths due to extinction. Here we
propose a program of 29 orbits to image the most promising candidate
clusters in broad and narrow band filters using HST/NICMOS. We will be
complementing these observations with approved Spitzer and Chandra
programs, numerous approved and planned ground-based spectroscopic
observations, and state-of-the-art modeling. We expect to
substantially increase the numbers of massive stars known in the
Galaxy, including main sequence OB stars and post-main sequence stars
in the Red Supergiant, Luminous Blue Variable and Wolf-Rayet stages.
Ultimately, this programme will address many of the fundamental topics
in astrophysics: the slope to the initial mass function (IMF), an
upper-limit to the masses of stars, the formation and evolution of the
most massive stars, gamma-ray burst (GRB) progenitors, the chemical
enrichment of the interstellar medium, and nature of the first stars
in the Universe.

NIC3 11333

NICMOS Non-linearity tests

This program incorporates a number of tests to analyze the count rate
dependent non-linearity seen in NICMOS spectro-photometric
observations.

We will observe a field with stars of a range in luminosity in NGC3603
with NICMOS in NIC1: F090M, F110W, F140W, F160W NIC2: F110W, F160W,
F187W, F205W, and F222M NIC3: F110W, F150W, F160W, F175W, and F222M.
We will repeat the observations with flatfield lamp on, creating
artificially high count-rates, allowing tests of NICMOS linearity as
function of count rate. We first take exposures with the lamp off,
then exposures with the lamp on, and repeat at the end with lamp off.
Finally, we continue with taking darks during occultation.

We will furthermore observe spectro-photometric standard P041C using
the G096, G141, and G206 grisms in NIC3, and repeat the lamp
off/on/off test to artificially create a high background.

ACS/SBC 11324

UV Contamination Monitor

The observations consist of imaging and spectroscopy with SBC of the
cluster NGC 6681 in order to monitor the temporal evolution of the UV
sensitivity of the SBC.

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.

NIC2 11219

Active Galactic Nuclei in Nearby Galaxies: a New View of the Origin of
the Radio-loud Radio- quiet Dichotomy?

Using archival HST and Chandra observations of 34 nearby early-type
galaxies {drawn from a complete radio selected sample} we have found
evidence that the radio-loud/radio-quiet dichotomy is directly
connected to the structure of the inner regions of their host galaxies
in the following sense: [1] Radio-loud AGN are associated with
galaxies with shallow cores in their light profiles [2] Radio-quiet
AGN are only hosted by galaxies with steep cusps. Since the brightness
profile is determined by the galaxy's evolution, through its merger
history, our results suggest that the same process sets the AGN
flavor. This provides us with a novel tool to explore the co-evolution
of galaxies and supermassive black holes, and it opens a new path to
understand the origin of the radio-loud/radio-quiet AGN dichotomy.
Currently our analysis is statistically incomplete as the brightness
profile is not available for 82 of the 116 targets. Most galaxies were
not observed with HST, while in some cases the study is obstructed by
the presence of dust features. We here propose to perform an infrared
NICMOS snapshot survey of these 82 galaxies. This will enable us to i}
test the reality of the dichotomic behavior in a substantially larger
sample; ii} extend the comparison between radio-loud and radio-quiet
AGN to a larger range of luminosities.

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.

WFPC2 11206

At the Cradle of the Milky Way: Formation of the Most Massive Field
Disk Galaxies at z1

We propose to obtain 2 orbit WFPC2 F814W images of a sample of the 15
most massive galaxies found at $1 z 1.3$. These were culled from
over 20,000 Keck spectra collected as part of DEEP and are unique
among high redshift massive galaxy samples in being kinematically
selected. Through a recent HST NICMOS-2 imaging program {GO-10532}, we
have confirmed that these galaxies have regular stellar disks, and
their emission line kinematics are not due to gradients from merging
components. These potentially very young galaxies are likely
precursors to massive local disks, assuming no further merging. The
proposed WFPC2 and existing NIC-2 data provide colors, stellar masses,
and ages of bulge and disk subcomponents, to assess whether old
stellar bulges and disks are in place at that time or still being
built, and constrain their formation epochs. Finally, this sample will
yield the first statistically significant results on the $z 1$
evolution of the size-velocity-luminosity scaling relations, for
massive galaxies at different wavelengths, and constrain whether this
evolution reflects stellar mass growth, or passive evolution, of
either bulge or disk components.

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!

NIC2 11197

Sweeping Away the Dust: Reliable Dark Energy with an Infrared Hubble
Diagram

We propose building a high-z Hubble Diagram using type Ia supernovae
observed in the infrared rest-frame J-band. The infrared has a number
of exceptional properties. The effect of dust extinction is minimal,
reducing a major systematic that may be biasing dark energy
measurements. Also, recent work indicates that type Ia supernovae are
true standard candles in the infrared meaning that our Hubble diagram
will be resistant to possible evolution in the Phillip's relation over
cosmic time. High signal-to-noise measurements of 16 type Ia events at
z~0.4 will be compared with an independent optical Hubble diagram from
the ESSENCE project to test for a shift in the derived dark energy
equation of state due to a systematic bias. In Cycle 15 we obtained
NICMOS photometry of 8 ESSENCE supernovae and are awaiting template
observations to place them on the IR Hubble diagram. Here we request
another 8 supernovae be studied in the final season of the ESSENCE
search. Because of the bright sky background, H-band photometry of
z~0.4 supernovae is not feasible from the ground. Only the superb
image quality and dark infrared sky seen by HST makes this test
possible. This experiment may also lead to a better, more reliable way
of mapping the expansion history of the universe with the Joint Dark
Energy Mission.

NIC1/NIC2 11172

Defining Classes of Long Period Variable Stars in M31

We propose a thrifty but information-packed investigation {1440
exposures total} with NICMOS F205W, F160W and F110W providing crucial
information about Long Period Variables in M31, at a level of detail
that has recently allowed the discovery of new variable star classes
in the Magellanic Clouds, a very different stellar population. These
observations are buttressed by an extensive map of the same fields
with ACS and WFPC2 exposures in F555W and F814W, and a massive
ground-based imaging patrol producing well-sampled light curves for
more than 400,000 variable stars. Our primary goal is to collect
sufficient NIR data in order to analyze and classify the huge number
of long-period variables in our catalog {see below} through
Period-Luminosity {P/L} diagrams. We will produce accurate P/L
diagrams for both the bulge and a progression of locations throughout
the disk of M31. These diagrams will be similar in quality to those
currently in the Magellanic Clouds, with their lower metallicity,
radically different star formation history, and larger spread in
distance to the variables. M31 offers an excellent chance to study
more typical disk populations, in a manner which might be extended to
more distant galaxies where such variables are still visible, probing
a much more evenly spread progenitor age distribution than cepheids
{and perhaps useful as a distance scale alternative or cross-check}.
Our data will also provide a massive and unique color-magnitude
dataset, and allow us to confirm the microlensing nature of a large
sample of candidate lensed sources in M31. We expect that this study
will produce several important results, among them a better
understanding of P/L and P/L-color relations for pulsating variables
which are essential to the extragalactic distance ladder, will view
these variables at a common distance over a range of metallicities
{eliminating the distance-error vs. metallicity ambiguity between the
LMC and SMC}, allow further insight into possible faint-variable
mass-loss for higher metallicities, and in general produce a sample
more typical of giant disk galaxies predominant in many studies.

WFPC2 11156

Monitoring Active Atmospheres on Uranus and Neptune

We propose Snapshot observations of Uranus and Neptune to monitor
changes in their atmospheres on time scales of weeks and months.
Uranus equinox is only months away, in December 2007. Hubble Space
Telescope observations during the past several years {Hammel et al.
2005, Icarus 175, 284 and references therein} have revealed strongly
wavelength-dependent latitudinal structure, the presence of numerous
visible-wavelength cloud features in the northern hemisphere, at least
one very long-lived discrete cloud in the southern hemisphere, and in
2006 the first dark spot ever seen on Uranus. Long-term ground-based
observations {Lockwood and Jerzekiewicz, 2006, Icarus 180, 442; Hammel
and Lockwood 2007, Icarus 186, 291} reveal 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 HST observations {Sromovsky et al. 2003, Icarus 163, 256 and
references therein} which include previous Snapshot programs {GO 8634,
10170, 10534} show a general increase in activity at south temperate
latitudes until 2004, when Neptune returned to a rather Voyager-like
appearance. 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 features.

WFPC2 11113

Binaries in the Kuiper Belt: Probes of Solar System Formation and
Evolution

The discovery of binaries in the Kuiper Belt and related small body
populations is powering a revolutionary step forward in the study of
this remote region. Three quarters of the known binaries in the Kuiper
Belt have been discovered with HST, most by our snapshot surveys. The
statistics derived from this work are beginning to yield surprising
and unexpected results. We have found a strong concentration of
binaries among low-inclination Classicals, a possible size cutoff to
binaries among the Centaurs, an apparent preference for nearly equal
mass binaries, and a strong increase in the number of binaries at
small separations. We propose to continue this successful program in
Cycle 16; we expect to discover at least 13 new binary systems,
targeted to subgroups where these discoveries can have the greatest
impact.

NIC3 11107

Imaging of Local Lyman Break Galaxy Analogs: New Clues to Galaxy
Formation in the Early Universe

We have used the ultraviolet all-sky imaging survey currently being
conducted by the Galaxy Evolution Explorer {GALEX} to identify for the
first time a rare population of low-redshift starbursts with
properties remarkably similar to high-redshift Lyman Break Galaxies
{LBGs}. These "compact UV luminous galaxies" {UVLGs} resemble LBGs in
terms of size, SFR, surface brightness, mass, metallicity, kinematics,
dust, and color. The UVLG sample offers the unique opportunity of
investigating some very important properties of LBGs that have
remained virtually inaccessible at high redshift: their morphology and
the mechanism that drives their star formation. Therefore, in Cycle 15
we have imaged 7 UVLGs using ACS in order to 1} characterize their
morphology and look for signs of interactions and mergers, and 2}
probe their star formation histories over a variety of timescales. The
images show a striking trend of small-scale mergers turning large
amounts of gas into vigorous starbursts {a process referred to as
dissipational or "wet" merging}. Here, we propose to complete our
sample of 31 LBG analogs using the ACS/SBC F150LP {FUV} and WFPC2
F606W {R} filters in order to create a statistical sample to study the
mechanism that triggers star formation in UVLGs and its implications
for the nature of LBGs. Specifically, we will 1} study the trend
between galaxy merging and SFR in UVLGs, 2} artificially redshift the
FUV images to z=1-4 and compare morphologies with those in similarly
sized samples of LBGs at the same rest- frame wavelengths in e.g.
GOODS, UDF, and COSMOS, 3} determine the presence and morphology of
significant stellar mass in "pre-burst" stars, and 4} study their
immediate environment. Together with our Spitzer {IRAC+MIPS}, GALEX,
SDSS and radio data, the HST observations will form a unique union of
data that may for the first time shed light on how the earliest major
episodes of star formation in high redshift galaxies came about. This
proposal was adapted from an ACS HRC+WFC proposal to meet the new
Cycle 16 observing constraints, and can be carried out using the
ACS/SBC and WFPC2 without compromising our original science goals.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

******************************** SCHEDULED***** SUCCESSFUL

FGS GSacq*********************** 28****************** 28
FGS REacq*********************** 13****************** 13
OBAD with Maneuver********* **** 80****************** 80

SIGNIFICANT EVENTS: (None)


 




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