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Daily Report #5058



 
 
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Old March 23rd 10, 03:28 PM posted to sci.astro.hubble
Bassford, Lynn[_2_]
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Default Daily Report #5058

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5058

PERIOD COVERED: 5am March 22 - 5am March 23, 2010 (DOY 081/09:00z-082/09:00z)

OBSERVATIONS SCHEDULED

COS/FUV/STIS/CCD/MA1 11592

Testing the Origin(s) of the Highly Ionized High-Velocity Clouds: A
Survey of Galactic Halo Stars at z3 kpc

Cosmological simulation predicts that highly ionized gas plays an
important role in the formation and evolution of galaxies and their
interplay with the intergalactic medium. The NASA HST and FUSE
missions have revealed high-velocity CIV and OVI absorption along
extragalactic sightlines through the Galactic halo. These highly
ionized high-velocity clouds (HVCs) could cover 85% of the sky and
have a detection rate higher than the HI HVCs. Two competing, equally
exciting, theories may explain the origin of these highly ionized
HVCs: 1) the "Galactic" theory, where the HVCs are the result of
feedback processes and trace the disk-halo mass exchange, perhaps
including the accretion of matter condensing from an extended corona;
2) the "Local Group" theory, where they are part of the local warm-hot
intergalactic medium, representing some of the missing baryonic matter
of the Universe. Only direct distance determinations can discriminate
between these models. Our group has found that some of these highly
ionized HVCs have a Galactic origin, based on STIS observations of one
star at z5.3 kpc. We propose an HST FUV spectral survey to search for
and characterize the high velocity NV, CIV, and SiIV interstellar
absorption toward 24 stars at much larger distances than any previous
searches (4d21 kpc, 3|z|13 kpc). COS will provide atomic to highly
ionized species (e.g.,OI, CII, CIV, SiIV) that can be observed at
sufficient resolution (R~22, 000) to not only detect these highly
ionized HVCs but also to model their properties and understand their
physics and origins. This survey is only possible because of the high
sensitivity of COS in the FUV spectral range.

ACS/SBC 11885

SBC Dark Current Measurement

This takes a series of SBC dark measurements over a continuous period
of about 6 hours (4 orbits). The aim is to collect dark images during
an extended SBC on time. Earlier measurements indicate that the dark
current increases with SBC on time and may also be increasing with
overall SBC use. The 6-hour time matches the longest time used by any
observer. As with all SBC observations this needs continuous SAA free
time.

ACS/WFC 11995

CCD Daily Monitor (Part 2)

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 320 orbits (20 weeks) from 1 February
2010 to 20 June 2010.

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.

FGS 11871

Long Term Stability of FGS1R in Position Mode

This proposal resumes the Long Term Monitoring of FGS1R in Position
Mode using stars in M35 that are a subset of the FGS "OFAD catalog"
using both the "fall" and "spring" seasons (the spring orient was not
available under two gyro mode). The data acquired by this proposal are
used to update the FGS1R "rhoA & kA" parameters that are associated
with the OFAD solution that is applicable at the observation's epoch.
These values are critical to support sub-milli arcsecond astrometry
with FGS1R.

This particular proposal also include a FGS3 visit to M35 for post SM4
verification of its calibration status.

FGS 12098

Post FGS1r AMA Adjustment, OFAD Re-Calibration

The FGS1r AMA was adjusted in January 22, 2009 to restore the
morphology of the FGS S-curves to near ideal. While this significantly
improved FGS1r's angular resolution, it also changed the instrument's
geometric distortion at a level that unacceptably impairs its
astrometric performance. To mitigate this problem, this proposal uses
FGS1r in POS mode to observe OAFD stars in M35 with six HST orbits at
a variety of orientations (75 deg to 113 deg) and translations of the
FGS FOV. The observations will obtain the relative positions of the
selected stars with 1 mas precision. Comparing the observed positions
to the OFAD catalog, which gives the undistorted relative positions of
the same stars to an accuracy of 1 mas, the geometric distortion in
FGS1r will be re-calibrated.

S/C 12046

COS FUV DCE Memory Dump

Whenever the FUV detector high voltage is on, count rate and current
draw information is collected, monitored, and saved to DCE memory.
Every 10 msec the detector samples the currents from the HV power
supplies (HVIA, HVIB) and the AUX power supply (AUXI). The last 1000
samples are saved in memory, along with a histogram of the number of
occurrences of each current value.

In the case of a HV transient (known as a "crackle" on FUSE), where
one of these currents exceeds a preset threshold for a persistence
time, the HV will shut down, and the DCE memory will be dumped and
examined as part of the recovery procedure. However, if the current
exceeds the threshold for less than the persistence time (a
"mini-crackle" in FUSE parlance), there is no way to know without
dumping DCE memory. By dumping and examining the histograms regularly,
we will be able to monitor any changes in the rate of "mini-crackles"
and thus learn something about the state of the detector.

STIS/CC 11626

Searching for the Upper Mass Limit in NGC 3603, the Nearest Giant H II
Region

What is the mass of the highest mass star? 100Mo? 150Mo? 200Mo? Or
higher? Theory gives us little guidance as to what physics sets the
upper mass limit, presuming one exists. Is it due to limitations in
the highest masses that can coalesce? Or is it due to stability issues
in such a behemoth? Observationally, the upper mass limit is poorly
constrained at present, with the strongest evidence coming from the
K-band luminosity function of the Arches cluster near the Galactic
Center. Here we propose to investigate this question by determining
the Initial Mass Function of NGC 3603, the nearest giant H II region.
This cluster is known to contain a wealth of O3 and hydrogen-rich
Wolf-Rayets, the most luminous and massive of stars. By constructing
an accurate H-R diagram for the cluster, we will construct a present
day mass function using newly computed high mass evolutionary tracks,
and convert this to an initial mass function using the inferred ages.
This will allow us to see whether or not there is a true deficit of
high mass stars, evidence of an upper mass cutoff. At the same time we
are likely to establish good masses for the highest mass stars ever
determined. We have laid the groundwork for this project using the
Magellan 6.5-m telescope and the excellent seeing found on Las
Campanas, plus analysis of archival ACS/HRS frames, but we now need to
obtain spectra of the stars unobservable from the ground. This can
only be done with HST and a reburbished STIS.

STIS/CC 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CC 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.

WFC3/UVIS 11588

Galaxy-Scale Strong Lenses from the CFHTLS Survey

We aim to investigate the origin and evolution of early-type galaxies
using gravitational lensing, modeling the mass profiles of objects
over a wide range of redshifts. The low redshift (z = 0.2) sample is
already in place following the successful HST SLACS survey; we now
propose to build up and analyze a sample of comparable size (~50
systems) at high redshift (0.4 z 0.9) using HST WFC3 Snapshot
observations of lens systems identified by the SL2S collaboration in
the CFHT legacy survey.

WFC3/UVIS 11643

A Timeline for Early-Type Galaxy Formation: Mapping the Evolution of
Star Formation, Globular Clusters, Dust, and Black Holes

While considerable effort has been devoted to statistical studies of
the origin of the red sequence of galaxies, there has been relatively
little direct exploration of galaxies transforming from late to early
types. Such galaxies are identified by their post-starburst spectra,
bulge- dominated, tidally-disturbed morphologies, and current lack of
gas. We are constructing the first detailed timeline of their
evolution onto the red sequence, pinpointing when star formation ends,
nuclear activity ceases, globular clusters form, and the bulk of the
merging progenitors' dust disappears. Here we propose to obtain HST
and Chandra imaging of nine galaxies, whose wide range of
post-starburst ages we have precisely dated with a new UV-optical
technique and for which we were awarded Spitzer time. We will address
1) whether the black hole-bulge mass relation arises from nuclear
feedback, 2) whether the bimodality of globular cluster colors is due
to young clusters produced in galaxy mergers, and 3) what happens to
the dust when late types merge to form an early type.

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).

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:

18836-1 - Recover COS FUV to HVLow after CRP shutdown @ 081/2021z

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 10 10
FGS REAcq 1 1
OBAD with Maneuver 8 8

SIGNIFICANT EVENTS:

Flash Reports:

The COS FUV has been successfully recovered to HVLow.

At 81/20:22z the COS FUV HV completed its ramp to HVLow. All voltages
and currents were as expected.

The next FUV observations were scheduled at 82/06:22z (PROP=11592).

 




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