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Daily Report #4396



 
 
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Old July 3rd 07, 02:09 PM posted to sci.astro.hubble
Pataro, Pete
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Posts: 33
Default Daily Report #4396

Notice: For the foreseeable future, the daily reports may contain
apparent discrepancies between some proposal descriptions and the
listed instrument usage. This is due to the conversion of previously
approved ACS WFC or HRC observations into WFPC2, or NICMOS
observations subsequent to the loss of ACS CCD science capability in
late January.


HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT*** # 4396

PERIOD COVERED: UT June 02, 2007 (DOY 183)

OBSERVATIONS SCHEDULED

WFPC2 11024

WFPC2 CYCLE 15 INTERNAL MONITOR

This calibration proposal is the Cycle 15 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A
variety of internal exposures are obtained in order to provide a
monitor of the integrity of the CCD camera electronics in both bays
{both gain 7 and gain 15 -- to test stability of gains and bias
levels}, a test for quantum efficiency in the CCDs, and a monitor for
possible buildup of contaminants on the CCD windows. These also
provide raw data for generating annual super-bias reference files for
the calibration pipeline.

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.

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 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 11101

The Relevance of Mergers for Fueling AGNs: Answers from QSO Host
Galaxies

The majority of QSOs are known to reside in centers of galaxies that
look like ellipticals. Numerical simulations have shown that remnants
of galaxy mergers often closely resemble elliptical galaxies. However,
it is still strongly debated whether the majority of QSO host galaxies
are indeed the result of relatively recent mergers or whether they are
completely analogous to inactive ellipticals to which nothing
interesting has happened recently. To address this question, we
recently obtained deep HST ACS images for five QSO host galaxies that
were classified morphologically as ellipticals {GO-10421}. This pilot
study revealed striking signs of tidal interactions such as ripples,
tidal tails, and warped disks that were not detected in previous
studies. Our observations show that at least some "elliptical" QSO
host galaxies are the products of relatively recent merger events
rather than old galaxies formed at high redshift. However, the
question remains whether the host galaxies of classical QSOs are truly
distinct from inactive ellipticals and whether there is a connection
between the merger events we detect and the current nuclear activity.
We must therefore place our results into a larger statistical context.
We are currently conducting an HST archival study of inactive
elliptical galaxies {AR-10941} to form a control sample. We now
propose to obtain deep HST/WFPC2 images of 13 QSOs whose host galaxies
are classified as normal ellipticals. Comparing the results for both
samples will help us determine whether classical QSOs reside in normal
elliptical galaxies or not. Our recent pilot study of five QSOs
indicates that we can expect exciting results and deep insights into
the host galaxy morphology also for this larger sample of QSOs. A
statistically meaningful sample will help us determine the true
fraction of QSO hosts that suffered strong tidal interactions and
thus, whether a merger is indeed a requirement to trigger nuclear
activity in the most luminous AGNs. In addition to our primary science
observations with WFPC2, we will obtain NICMOS3 parallel observations
with the overall goal to select and characterize galaxy populations at
high redshifts. The imaging will be among the deepest NICMOS images:
These NICMOS images are expected to go to a limit a little over 1
magnitude brighter than HUDF-NICMOS data, but over 13 widely separated
fields, with a total area about 1.5 times larger than HUDF-NICMOS.
This separation means that the survey will tend to average out effects
of cosmic variance. The NICMOS3 images will have sufficient resolution
for an initial characterization of galaxy morphologies, which is
currently one of the most active and promising areas in approaching
the problem of the formation of the first massive galaxies. The depth
and area coverage of our proposed NICMOS observations will also allow
a careful study of the mass function of galaxies at these redshifts.
This provides a large and unbiased sample, selected in terms of
stellar mass and unaffected by cosmic variance, to study the on-going
star formation activity as a function of mass {i.e. integrated star
formation} at this very important epoch.

NIC3 11062

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.

WFPC2 11023

WFPC2 CYCLE 15 Standard Darks - part 1

This dark calibration program obtains dark frames every week in order
to provide data for the ongoing calibration of the CCD dark current
rate, and to monitor and characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

WFPC2 11029

WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation Anomaly
Monitor

Intflat observations will be taken to provide a linearity check: the
linearity test consists of a series of intflats in F555W, in each gain
and each shutter. A combination of intflats, visflats, and earthflats
will be used to check the repeatability of filter wheel motions.
{Intflat sequences tied to decons, visits 1-18 in prop 10363, have
been moved to the cycle 15 decon proposal xxxx for easier scheduling.}
Note: long-exposure WFPC2 intflats must be scheduled during ACS
anneals to prevent stray light from the WFPC2 lamps from contaminating
long ACS external exposures.

WFPC2 11175

UV Imaging to Determine the Location of Residual Star Formation in
Galaxies Recently Arrived on the Red Sequence

We have identified a sample of low-redshift {z = 0.04 - 0.10} galaxies
that are candidates for recent arrival on the red sequence. They have
red optical colors indicative of old stellar populations, but blue
UV-optical colors that could indicate the presence of a small quantity
of continuing or very recent star formation. However, their spectra
lack the emission lines that characterize star-forming galaxies. We
propose to use ACS/SBC to obtain high- resolution imaging of the UV
flux in these galaxies, in order to determine the spatial distribution
of the last episode of star formation. WFPC2 imaging will provide B,
V, and I photometry to measure the main stellar light distribution of
the galaxy for comparison with the UV imaging, as well as to measure
color gradients and the distribution of interstellar dust. This
detailed morphological information will allow us to investigate the
hypothesis that these galaxies have recently stopped forming stars and
to compare the observed distribution of the last star formation with
predictions for several different mechanisms that may quench star
formation in galaxies.

WFPC2 11178

Probing Solar System History with Orbits, Masses, and Colors of
Transneptunian Binaries

The recent discovery of numerous transneptunian binaries {TNBs} opens
a window into dynamical conditions in the protoplanetary disk where
they formed as well as the history of subsequent events which sculpted
the outer Solar System and emplaced them onto their present day
heliocentric orbits. To date, at least 47 TNBs have been discovered,
but only about a dozen have had their mutual orbits and separate
colors determined, frustrating their use to investigate numerous
important scientific questions. The current shortage of data
especially cripples scientific investigations requiring statistical
comparisons among the ensemble characteristics. We propose to obtain
sufficient astrometry and photometry of 23 TNBs to compute their
mutual orbits and system masses and to determine separate primary and
secondary colors, roughly tripling the sample for which this
information is known, as well as extending it to include systems of
two near-equal size bodies. To make the most efficient possible use of
HST, we will use a Monte Carlo technique to optimally schedule our
observations.

WFPC2 11201

Systemic and Internal motions of the Magellanic Clouds: Third Epoch
Images

In Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields
in the Magellanic Clouds centered on background quasars. We used these
data to determine the proper motions of the LMC and SMC to better than
5% and 15% respectively. These are by far the best determinations of
the proper motions of these two galaxies. The results have a number of
unexpected implications for the Milky Way-LMC-SMC system. The implied
three-dimensional velocities are larger than previously believed, and
are not much less than the escape velocity in a standard 10^12 solar
mass Milky Way dark halo. Orbit calculations suggest the Clouds may
not be bound to the Milky Way or may just be on their first passage,
both of which would be unexpected in view of traditional
interpretations of the Magellanic Stream. Alternatively, the Milky Way
dark halo may be a factor of two more massive than previously
believed, which would be surprising in view of other observational
constraints. Also, the relative velocity between the LMC and SMC is
larger than expected, leaving open the possibility that the Clouds may
not be bound to each other. To further verify and refine our results
we now request an epoch of WFPC2/PC data for the fields centered on 40
quasars that have at least one epoch of ACS imaging. We request
execution in snapshot mode, as in our previous programs, to ensure the
most efficient use of HST resources. A third epoch of data of these
fields will provide crucial information to verify that there are no
residual systematic effects in our previous measurements. More
importantly, it will increase the time baseline from 2 to 5 yrs and
will increase the number of fields with at least two epochs of data.
This will reduce our uncertainties correspondingly, so that we can
better address whether the Clouds are indeed bound to each other and
to the Milky Way. It will also allow us to constrain the internal
motions of various populations within the Clouds, and will allow us to
determine a distance to the LMC using rotational parallax.

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)

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

FGS GSacq********************** 6*********************** 6
FGS REacq********************** 7*********************** 7
OBAD with Maneuver******* ***** 26********************* 26

COMPLETED OPS NOTES: (None)

SIGNIFICANT EVENTS: (None)

 




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