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Daily Rpt #4414



 
 
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Old July 30th 07, 06:03 PM posted to sci.astro.hubble
Bassford, Lynn
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Posts: 44
Default Daily Rpt #4414

Notice: Due to the conversion of some ACS WFC or HRC observations into
WFPC2, or NICMOS observations after the loss of ACS CCD science
capability in January, there may be an occasional discrepancy between
a proposal's listed (and correct) instrument usage and the abstract
that follows it.

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4414

PERIOD COVERED: UT July 27,28,29, 2007 (DOY 208,209,210)

OBSERVATIONS SCHEDULED NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

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 DARKs. 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 11314

Calibration of MARCI UV using WFPC2

Ultraviolet imaging is a major unique component of the MARCI
experiment on MRO. Unfortunately the calibration of the UV, especially
of the 260 nm filter, on MARCI is uncertain due to various unexpected
problems during laboratory calibration. Two orbits of WFPC2
observations are requested to properly calibrate the UV using
simultaneous MRO / HST observations in a favorable geometry where HST
is "looking over the shoulder" of MRO.

WFPC2 11307

Completing the ACS Nearby Galaxy Survey with WFPC2

We are requesting 25 orbits of Director's Discretionary Time to
complete the primary science goals of our highly-ranked ACS Nearby
Galaxy Survey Treasury program {ANGST}. Our program lost ~2/3 of its
orbits due to the ACS failure. Roughly half of these were restored as
a result of an appeal to the Telescope Time Review Board which
re-scoped the program. The Board's response to our appeal was explicit
in terms of which targets were to be observed and how. We were
directed to request Director's discretionary time for the components
of the appeal which were not granted by the Review Board, but which
were vital to the success of the program. The observing strategy for
ANGST is two-fold: to obtain one deep field per galaxy which enables
derivation of an accurate ancient star formation history, and to
obtain radial tilings sufficient for recovering the full star
formation history. The Review Board granted WFPC2 observations for
deep fields in 7 galaxies, but no time for radial tilings. However,
recovering the full star formation history of a galaxy is not possible
without additional radial coverage. We have searched the archives for
observations which may be used in place of the tilings {conceding some
of the Treasury goals, but providing significant constraints on the
full star formation history}, and have identified suitable
observations for all but two of the galaxies. Here we request DD time
for radial tilings for those last two galaxies.

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.

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!

WFPC2/NIC3 11188

First Resolved Imaging of Escaping Lyman Continuum

The emission from star-forming galaxies appears to be responsible for
reionization of the universe at z6. However, the models that attempt
to describe the detailed impact of high- redshift galaxies on the
surrounding inter-galactic medium {IGM} are strongly dependent upon
several uncertain parameters. Perhaps the most uncertain is the
fraction of HI-ionizing photons produced by young stars which escape
into the IGM. Most attempts to measure this "escape fraction" {f_esc}
have produced null results. Recently, a small subset of z~3 Lyman
Break Galaxies {LBGs} has been found exhibiting large escape
fractions. It remains unclear however, what differentiates them from
other LBGs. Several models attempt to explain how such a large
fraction of ionizing continuum can escape through the HI and dust in
the ISM {eg. "chimneys" created by SNe winds, globular cluster
formation, etc.}, each producing unique signatures which can be
observed with resolved imaging of the escaping Lyman continuum. We
propose a deep, high resolution WFPC2 image of the ionizing continuum
{F336W} and the rest-frame 1500 Angstrom continuum {F606W} of five of
the six known LBGs with large escape fractions. These LBGs all fit
within a single WFPC2 pointing, yielding high observing efficiency.
Additionally, they all have z~3.1 or higher, the optimal redshift
range for probing the Lyman Continuum region with available WFPC2
filters. These factors make our proposed sample especially suitable
for follow- up. With these data we will discern the mechanisms
responsible for producing large escape fractions, and therefore gain
insight into the process of reionization.

WFPC2 11176

Location and the Origin of Short Gamma-Ray Bursts

During the past decade extraordinary progress has been made in
determining the origin of long- duration gamma-ray bursts. It has been
conclusively shown that these objects derive from the deaths of
massive stars. Nonetheless, the origin of their observational cousins,
short-duration gamma-ray bursts {SGRBs} remains a mystery. While SGRBs
are widely thought to result from the inspiral of compact binaries,
this is a conjecture. A number of hosts of SGRBs have been identified,
and have been used by some to argue that SGRBs derive primarily from
an ancient population {~ 5 Gyr}; however, it is not known whether this
conclusion more accurately reflects selection biases or astrophysics.
Here we propose to employ a variant of a technique that we pioneered
and used to great effect in elucidating the origins of long-duration
bursts. We will examine the degree to which SGRB locations trace the
red or blue light of their hosts, and thus old or young stellar
populations. This approach will allow us to study the demographics of
the SGRB population in a manner largely free of the distance dependent
selection effects which have so far bedeviled this field, and should
give direct insight into the age of the SGRB progenitor population.

NIC2 11152

Probing the compact dust disk of a nearby Classical T Tauri Star

BP Psc is a high Galactic latitude {b = -57}, bright, IRAS source that
generally has been classified as a T Tauri star but little studied to
date. We have carried out a multiwavelength ground-based study of this
object and find that it is most likely a ~10 Myr classical T Tauri
star surrounded by a gas and dust disk, and less than 100 pc from
Earth, making it one of the oldest and closest such stars known.
Near-IR AO images and IR photometry show it is surrounded by an
compact {0.2"}, almost-edge-on, optically thick disk of dust with a
wide range of temperatures. We propose a multiwavelength polarimetric
study of the compact disk to support quantitative modeling to recover
disk and dust parameters. We also propose coronagraphic imaging to
search for larger- scale dust structures invisible in ground-based
images, and narrowband imaging of an outflow jet and associated
Herbig-Haro objects to study their structure and determine a kinematic
distance of the system. A massive compact disk surrounding an isolated
10 Myr star is a unique environment for planet formation, and its
proximity to Earth allows HST to study it in detail.

WFPC2 11118

Investigating Near-Equinox Atmospheric Change on Uranus

Uranus is approaching its 7 December 2007 equinox, when we will be
able to observe the entire northern hemisphere for the first time with
modern cameras. The large seasonal phase shift expected from its long
radiative time constant implies that it should now exhibit nearly
maximal hemispheric contrast, and should be in the process of
reversing. Many changes already observed, such as the development of
the first visible-wavelength dark spot, discovered in Cycle 15, and
the fading of the south polar cap may be indicative of the expected
reversal. We propose a detailed characterization of Uranus' current
seasonal response with a 7-orbit program consisting of 1 orbit of
NICMOS imaging of cloud bands and 6 orbits of WFPC2 imaging using both
broadband and narrow-band filters capable of tracking dark and bright
discrete cloud features. Filters between 0.467 and 1.87 microns will
provide vertical sensing depths scanning through the pressure range
where the putative methane and deeper H2S clouds might plausibly exist
and provide strong constraints on their contributions and parent gas
mixing ratios. These observations have unique combinations of spectral
range and resolution with needed temporal and spatial resolution not
available from groundbased observations. Only HST is capable of
investigating the Uranus dark spot.

WFPC2 11100

Two new `bullets' for MOND: revealing the properties of dark matter in
massive merging clusters

The principal objective of this proposal is to study the physical
nature of dark matter by using two, massive, newly-identified merging
clusters of galaxies. As shown by the pioneering example of the
``bullet cluster'' {1E0657-56}, such systems are ideal laboratories
for detecting dark matter and distinguishing between cold dark matter
{CDM} and other scenarios {e.g. self- interacting dark matter}. Our
limit on the self-interaction cross-section of dark matter relies on
the assumption of a normal pre-merger mass-to-light ratios, and a
small impact parameter during the collision of the two clusters. In
order to mitigate any possible systematic effects, it is vital to
extend this work to other, similar systems. With detailed observations
of new systems, the systematic uncertainties in the dark matter cross
section calculations can be improved substantially, allowing us to
move from rough order of magnitude estimates to measurements with
quantifiable uncertainties that can be compared usefully with the
predictions from numerical simulations. Our targets are two
extraordinary, high-redshift, merging galaxy clusters recently
discovered by the Massive Cluster Survey {MACS}. This survey is by far
the best matched to this study, since it selects medium redshift
{optimal for gravitational lensing studies} and X-ray luminous {hence
massive} objects. We have selected the best candidates with clear
evidence for considerable offsets between the hot X-ray emitting gas
and optically luminous stellar material. The two most striking
examples are the targets of this proposal. To pin down the position of
the dark matter component we require high resolution, absolutely
calibrated mass maps. The combination of weak and strong lensing
measurements is needed to attain this goal. This can only be achieved
with the excellent resolving power of the HST {in combination with
wide-field, multicolor Subaru data already in hand}. We therefore
request multicolor HST/WFPC2 observations of the two merging clusters.
The combination of constraints from multiply lensed images {identified
via morphology and color information} and high-resolution weak lensing
data will allow us to construct, self-consistently, their mass
distribution from the very centers to the outskirts. Gravitational
lensing thus provides a unique tool transforming these clusters into
dark matter laboratories. They will supply us with answers as to the
nature and properties of dark matter, and how it shapes galaxies and
galaxy clusters and their evolution through cosmic time.

WFPC2 11079

Treasury Imaging of Star Forming Regions in the Local Group:
Complementing the GALEX and NOAO Surveys

We propose to use WFPC2 to image the most interesting star-forming
regions in the Local Group galaxies, to resolve their young stellar
populations. We will use a set of filters including F170W, which is
critical to detect and characterize the most massive stars, to whose
hot temperatures colors at longer wavelengths are not sensitive.
WFPC2's field of view ideally matches the typical size of the
star-forming regions, and its spatial resolution allows us to measure
individual stars, given the proximity of these galaxies. The resulting
H-R diagrams will enable studies of star- formation properties in
these regions, which cover largely differing metallicities {a factor
of 17, compared to the factor of 4 explored so far} and
characteristics. The results will further our understanding of the
star-formation process, of the interplay between massive stars and
environment, the properties of dust, and will provide the key to
interpret integrated measurements of star-formation indicators {UV,
IR, Halpha} available for several hundreds more distant galaxies. Our
recent deep surveys of these galaxies with GALEX {FUV, NUV} and
ground-based imaging {UBVRI, Halpha, [OIII] and [SII]} provided the
identification of the most relevant SF sites. In addition to our
scientific analysis, we will provide catalogs of HST photometry in 6
bands, matched corollary ground-based data, and UV, Halpha and IR
integrated measurements of the associations, for comparison of
integrated star-formation indices to the resolved populations. We
envisage an EPO component.

WFPC2 11033

Full Moon Earth Flats Closeout

Flat field exposures will be obtained by observing the moonlit Earth
with the broadband WFPC2 filters F606W and F814W, which saturate in
the minimum exposure time on the sunlit Earth. These observations will
be used to improve the flats currently in the pipeline and are part of
the WFPC2 closeout operations. Because CTE effects are large for star
flats and small for full field illumination, Earth flats are the
superior technique.

WFPC2 10583

Resolving the LMC Microlensing Puzzle: Where Are the Lensing Objects ?

We are requesting 32 HST orbits to help ascertain the nature of the
population that gives rise to the observed set of microlensing events
towards the LMC. The SuperMACHO project is an ongoing ground-based
survey on the CTIO 4m that has demonstrated the ability to detect LMC
microlensing events in real-time via frame subtraction. The
improvement in angular resolution and photometric accuracy available
from HST will allow us to 1} confirm that the detected flux excursions
arise from LMC source stars rather than extended objects {such as for
background supernovae or AGN}, and 2} obtain reliable baseline flux
measurements for the objects in their unlensed state. The latter
measurement is important to resolve degeneracies between the event
timescale and baseline flux, which will yield a tighter constraint on
the microlensing optical depth.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

#10918 REacq(1,2,1) failed to RGA Control (Gyro Control).

REacq(1,2,1) scheduled at 209/13:56:20 - 14:04:25 failed to RGA Hold
due to (QF1STOPF) stop flag indication on FGS-1. Pre-acq OBADs showed
(RSS) attitude correction values of 888.95 and 17.77 arcseconds. Prior
GSAcq(1,2,1) of 209/12:40:12 was successful. Post-acq OBAD/MAP had
(RSS) value of 10.04 arcseconds.

REacq(1,2,1) at 209/15:33:00 was successful. Upon acquisition of
signal at 209/17:23:59, HST was in Gyro Control with QF1STOPF and STOP
flags set. REacq(1,2,1) at 209/17:08:53 failed to RGA Hold.

#10919 GSAcq(1,3,3) results in fine lock backup (1,0,1).

Upon acquisition of signal at 209/19:08:11, the GSAcq(1,3,3) scheduled
at 209/18:49:46 - 18:57:51 had resulted in fine lock backup (1,0,1)
using FGS-1 due to (QF3STOPF) stop flag indication on the secondary
FGS-3. Pre-acq OBADs (RSS) attitude correction values not available
due to LOS. Post-acq OBAD/MAP showed (RSS) value of 13.60 arcseconds.

Subsequent REacq(1,3,3) scheduled at 209/20:24:07 resulted in fine
lock backup (1,0,1) using FGS-1 due to QF3STOPF stop flag indication
on FGS-3. Pre-acq OBADs were successful.

#10920 GSAcq (1,2,1) failed to RGA Hold (Gyro Control)

AT AOS 209/22:27:15 GSAcq (1,2,1) had failed to RGA Hold (Gyro
Control) with stop flags "QSTOP & QF1STOPF".

OBAD #1 & 2 data unavailable until engineering data dump is
accomplished. OBAD MAP: v1 6.30, V2 -0.41, V3 1.11, RSS 6.41.

At AOS 210/01:04:16 REAcq (1,2,1) scheduled from 209/23:32:20-23:39:50
had failed to RGA Hold (Gyro Control) with stop flags "QSTOP &
QF1STOPF". OBAD data unavailable due to LOS.

REAcq (1,2,1) scheduled from 210/01:08:14-01:15:44 failed to RGA Hold
(Gyro Control) with stop flags "QSTOP & QF1STOPF". FGS 1 reached a PMT
count high of 6393.00244.

OBAD #1: V1 -71.68, V2 -770.33, V3 -15.23, RSS 773.81 OBAD #2: V1
2.32, V2 0.99, V3 -12.84, RSS 13.08 OBAD MAP: not scheduled

Note: The same guide star pair used in HSTAR 10918

COMPLETED OPS REQUEST: (None)

**************************** SCHEDULED SUCCESSFUL
FGS GSacq******************* 22******** 21
FGS REacq******************* 20******** 16
OBAD with Maneuver***** 84******** 84

COMPLETED OPS NOTES: (None)

SIGNIFICANT EVENTS: (None)



 




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