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Daily Report #5166



 
 
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Old August 24th 10, 03:29 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5166

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5166

PERIOD COVERED: 5am August 23 - 5am August 24, 2010 (DOY 234/09:00z-235/09:00z)

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

12358 - Uncorrectable EDACS during SSR-3 Playback @ 235/11:02z.

Observations possibly affected: COS 9 Proposal ID#11897

12360 - The REAcq(1,2,1) scheduled at 235/14:22:02z required three
attempts to achieve FL-DV on FGS1. The REAcq was successful.

Observations possibly affected: WFC3 8, Proposal ID#11638; ACS 7-8,
Proposal ID#11996; STIS 9-10, Proposal ID#11857; COS 13-14, Proposal
ID#11895.


COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 04 04
FGS REAcq 12 12
OBAD with Maneuver 03 03

SIGNIFICANT EVENTS: (None)


OBSERVATIONS SCHEDULED:

ACS/WFC 11996

CCD Daily Monitor (Part 3)

This program comprises basic tests for measuring the read noise and
dark current of the ACS WFC and for tracking the growth of hot pixels.
The recorded frames are used to create bias and dark reference images
for science data reduction and calibration. This program will be
executed four days per week (Mon, Wed, Fri, Sun) for the duration of
Cycle 17. To facilitate scheduling, this program is split into three
proposals. This proposal covers 308 orbits (19.25 weeks) from 21 June
2010 to 1 November 2010.

ACS/WFC3 11670

The Host Environments of Type Ia Supernovae in the SDSS Survey

The Sloan Digital Sky Survey Supernova Survey has discovered nearly
500 type Ia supernovae and created a large, unique, and uniform sample
of these cosmological tools. As part of a comprehensive study of the
supernova hosts, we propose to obtain Hubble ACS images of a large
fraction of these galaxies. Integrated colors and spectra will be
measured from the ground, but we require high-resolution HST imaging
to provide accurate morphologies and color information at the site of
the explosion. This information is essential in determining the
systematic effects of population age on type Ia supernova luminosities
and improving their reliability in measuring dark energy. Recent
studies suggest two populations of type Ia supernovae: a class that
explodes promptly after star-formation and one that is delayed by
billions of years. Measuring the star-formation rate at the site of
the supernova from colors in the HST images may be the best way to
differentiate between these classes.

COS/FUV 11895

FUV Detector Dark Monitor

Monitor the FUV detector dark rate by taking long science exposures
without illuminating the detector. The detector dark rate and spatial
distribution of counts will be compared to pre-launch and SMOV data in
order to verify the nominal operation of the detector. Variations of
count rate as a function of orbital position will be analyzed to find
dependence of dark rate on proximity to the SAA. Dependence of dark
rate as function of time will also be tracked.

COS/FUV 11897

FUV Spectroscopic Sensitivity Monitoring

The purpose of this proposal is to monitor sensitivity in each FUV
grating mode to detect any changes due to contamination or other
causes.

COS/NUV 11894

NUV Detector Dark Monitor

The purpose of this proposal is to measure the NUV detector dark rate
by taking long science exposures with no light on the detector. The
detector dark rate and spatial distribution of counts will be compared
to pre-launch and SMOV data in order to verify the nominal operation
of the detector. Variations of count rate as a function of orbital
position will be analyzed to find dependence of dark rate on proximity
to the SAA. Dependence of dark rate as function of time will also be
tracked.

STIS/CCD 11721

Verifying the Utility of Type Ia Supernovae as Cosmological Probes:
Evolution and Dispersion in the Ultraviolet Spectra

The study of distant type Ia supernova (SNe Ia) offers the most
practical and immediate discriminator between popular models of dark
energy. Yet fundamental questions remain over possible
redshift-dependent trends in their observed and intrinsic properties.
High-quality Keck spectroscopy of a representative sample of 36
intermediate redshift SNe Ia has revealed a surprising, and
unexplained, diversity in their rest-frame UV fluxes. One possible
explanation is hitherto undiscovered variations in the progenitor
metallicity. Unfortunately, this result cannot be compared to local UV
data as only two representative SNe Ia have been studied near maximum
light. Taking advantage of two new `rolling searches' and the
restoration of STIS, we propose a non-disruptive TOO campaign to
create an equivalent comparison local sample. This will allow us to
address possible evolution in the mean UV spectrum and its diversity,
an essential precursor to the study of SNe beyond z~1.

STIS/CCD 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CCD 11847

CCD Bias Monitor-Part 2

Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1,
and 1x1 at gain = 4, to build up high-S/N superbiases and track the
evolution of hot columns.

STIS/CCD 11852

STIS CCD Spectroscopic Flats C17

The purpose of this proposal is to obtain pixel-to-pixel lamp flat
fields for the STIS CCD in spectroscopic mode.

STIS/CCD/MA 12179

The Stellar Winds of Evolved, Braked O-Type Magnetic Oblique Rotators

Magnetic fields have recently been discovered on several massive
stars, but their origin and influence on the evolution of these stars
are poorly understood. Two of these objects, HD 191612 and HD 108, are
of particular interest. Very recent spectropolarimetric observations
have shown that they are most likely magnetic oblique rotators, like
the young O star Theta1 Ori C, whose 15d periodically variable field
was found somewhat earlier. However, the two new objects are much
slower rotators, unusually so for O stars, with periods of 538d and
50-60yrs, respectively, and there are other indications that they are
older. They provide an opportunity to study the efficiency of wind
braking of magnetic O stars through angular momentum loss. We shall
perform STIS high-resolution UV spectroscopy of HD 191612 and HD 108
(phase resolved for the former) to derive more complete estimates of
fundamental quantities than available from optical data alone. We
shall measure the mass-loss rates from the UV wind profiles, which
will constrain the extreme wind confinement of these stars and
establish whether the large H-alpha emission variations are
wind-related or geometrical. We shall also derive more accurate ages
and stellar surface properties. In turn, these results will support a
more definitive discussion of the angular momentum evolution versus
the ages of HD 191612 and HD 108, and of the comparison with the
younger and faster Theta1 Ori C.

STIS/MA1/MA2 11857

STIS Cycle 17 MAMA Dark Monitor

This proposal monitors the behavior of the dark current in each of the
MAMA detectors.

The basic monitor takes two 1380s ACCUM darks each week with each
detector. However, starting Oct 5, pairs are only included for weeks
that the LRP has external MAMA observations planned. The weekly pairs
of exposures for each detector are linked so that they are taken at
opposite ends of the same SAA free interval. This pairing of exposures
will make it easier to separate long and short term temporal
variability from temperature dependent changes.

For both detectors, additional blocks of exposures are taken once
every six months. These are groups of five 1314s FUV-MAMA Time-Tag
darks or five 3x315s NUV ACCUM darks distributed over a single
SAA-free interval. This will give more information on the brightness
of the FUV MAMA dark current as a function of the amount of time that
the HV has been on, and for the NUV MAMA will give a better measure of
the short term temperature dependence.

WFC3/IR/S/C 11929

IR Dark Current Monitor

Analyses of ground test data showed that dark current signals are more
reliably removed from science data using darks taken with the same
exposure sequences as the science data, than with a single dark
current image scaled by desired exposure time. Therefore, dark current
images must be collected using all sample sequences that will be used
in science observations. These observations will be used to monitor
changes in the dark current of the WFC3-IR channel on a day-to-day
basis, and to build calibration dark current ramps for each of the
sample sequences to be used by Gos in Cycle 17. For each sample
sequence/array size combination, a median ramp will be created and
delivered to the calibration database system (CDBS).

WFC3/UV 11638

Illuminating the HI Structure of a Proto-cluster Region at z=2.84

We propose very deep intermediate-band Lyman alpha imaging in the
field of a newly-discovered proto-cluster region surrounding the
extremely luminous QSO HS1549+19 at z=2.844. The large structure,
initially discovered in a spectroscopic survey of galaxies in fields
surrounding the brightest QSOs at z=2.5-2.8, represents an ideal
laboratory for studying the response of the intergalactic medium to a
source of ionizing photons that exceeds the UV background by factors
1000. Within a single pointing of WFC3-UVIS there are already more

than 45 known Lyman alpha emitters, most of which are already
spectroscopically confirmed, and at least 3 of which are giant ``Lyman
alpha blobs''. Many of the objects have properties similar to those
expected from the process of fluorescence, in which Lyman alpha
emission is induced by the UV radiation field of the QSO in any HI gas
that dense enough to remain partially self-shielded. Fortuitously, the
F467M filter (Stromgren "b") in WFC3-UVIS is a perfect match to Lyman
alpha at z=2.844. In combination with an equally deep broad-band
continuum image, the observations will allow the construction of a
Lyman alpha map tracing dense gas throughout the inner parts of a
proto-cluster region at sub-kpc resolution. The ability to measure the
spatial sub-structure and surface brightness distribution of Lya
emission, relative to known protocluster galaxies and AGN, will
illuminate the ?cosmic web'' in a dense region caught in a violent
stage of formation.

WFC3/UVIS 11707

Detecting Isolated Black Holes through Astrometric Microlensing

This proposal aims to make the first detection of isolated
stellar-mass black holes (BHs) in the Milky Way, and to determine
their masses. Until now, the only directly measured BH masses have
come from radial-velocity measurements of X-ray binaries. Our proposed
method uses the astrometric shifts that occur when a galactic-bulge
microlensing event is caused by a BH lens. Out of the hundreds of
bulge microlensing events found annually by the OGLE and MOA surveys,
a few are found to have very long durations (200 days). It is
generally believed that the majority of these long-duration events are
caused by lenses that are isolated BHs.

To test this hypothesis, we will carry out high-precision astrometry
of 5 long-duration events, using the ACS/HRC camera. The expected
astrometric signal from a BH lens is 1.4 mas, at least 7 times the
demonstrated astrometric precision attainable with the HRC.

This proposal will thus potentially lead to the first unambiguous
detection of isolated stellar- mass BHs, and the first direct mass
measurement for isolated stellar-mass BHs through any technique.
Detection of several BHs will provide information on the frequency of
BHs in the galaxy, with implications for the slope of the IMF at high
masses, the minimum mass of progenitors that produce BHs, and
constraints on theoretical models of BH formation.

WFC3/UVIS 11905

WFC3 UVIS CCD Daily Monitor

The behavior of the WFC3 UVIS CCD will be monitored daily with a set
of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K
subarray biases are acquired at less frequent intervals throughout the
cycle to support subarray science observations. The internals from
this proposal, along with those from the anneal procedure (Proposal
11909), will be used to generate the necessary superbias and superdark
reference files for the calibration pipeline (CDBS).

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