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Daily Report #5122



 
 
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Old June 22nd 10, 03:55 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5122

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5122

PERIOD COVERED: 5am June 21 - 5am June 22, 2010 (DOY 172/09:00z-173/09:00z)

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 8 8
FGS REAcq 7 7
OBAD with Maneuver 2 2

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 11604

The Nuclear Structure of OH Megamaser Galaxies

We propose a snapshot survey of a complete sample of 80 OH megamaser
galaxies. Each galaxy will be imaged with the ACS/WFC through F814W
and a linear ramp filter (FR656N or FR716N or FR782N or FR853N)
allowing us to study both the spheroid and the gas morphology in
Halpha + [N II]. We will use the 9% ramps FR647M (5370-7570 angstroms)
centered at 7000 angstroms and FR914M (7570-10, 719 angstroms) 8000
angstroms for continuum subtraction for the high and low z objects
respectively. OH megamaser galaxies (OHMG) form an important class of
ultraluminous IR-galaxies (ULIRGs) whose maser lines emit QSO-like
luminosities. ULIRGs in general are associated with recent mergers but
it is often unclear whether their power output is dominated by
starbursts or a hidden QSO because of the high absorbing columns which
hide their nuclei even at X-ray wavelengths. In contrast, OHMG exhibit
strong evidence for the presence of an energetically important and
recently triggered active nucleus. In particular it is clear that much
of the gas must have already collapsed to form a nuclear disk which
may be the progenitor of a circum-nuclear torus, a key element of the
unified scheme of AGN. A great advantage of studying OHMG systems over
the general ULIRG population, is that the circum-nuclear disks are
effectively "fixed" at an inner, edge on, orientation, eliminating
varying inclination as a nuisance parameter. We will use the HST
observations in conjunction with existing maser and spectroscopic data
to construct a detailed picture of the circum-nuclear regions of a
hitherto relatively neglected class of galaxy that may hold the key to
understanding the relationship between galaxy mergers, nuclear
star-formation, and the growth of massive black holes and the
triggering of nuclear activity.

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/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/CC 11693

Follow-up Observations of Debris Disks around Two Solar-Type Stars

Circumstellar debris disks offer direct views into the structure of
extrasolar planetary systems. Their constituent dust, seen in
scattered light and thermal emission, is created by the collisions of
asteroidal and cometary parent bodies. The distribution of this dust
provides information on the location of the parent bodies, and can be
strongly affected by planetary perturbations. Dynamical signatures of
planets can include asymmetries, warps, central clearings, and radial
gaps in a disk, and thus are key features to search for in resolved
images. Following up recent Spitzer measurements, we have now detected
two new, nearby debris disks in scattered light. Our initial ACS F606W
coronagraphic images show faint ringlike structures around the
solar-type stars HD 10647 (F9V) and HD 207129 (G0V); both are also
spatially resolved in Spitzer/MIPS 70 micron images. The HD 10647
disk, seen close to edge-on, represents the first disk ever imaged in
scattered light around a star known to have a radial velocity planet.
The inclined ring around HD 207129 is the faintest disk ever imaged in
scattered light, and seems in the MIPS image to be asymmetric like the
eccentric ring around Fomalhaut. We propose to obtain deep ACS
coronagraphic images of these two disks. Our goals are to get
definitive measurements of the dust spatial distributions (including
disk asymmetries and sharpness of the ring edges), and measure the
overall F606W-F814W color of each disk in order to constrain the dust
properties. The results will be a definitive exploration of the Kuiper
belts of two nearby, Sun-like stars. NOTE: HD 207129 was deleted from
this program.

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.

STIS/CCD/MA2 11568

A SNAPSHOT Survey of the Local Interstellar Medium: New NUV
Observations of Stars with Archived FUV Observations

We propose to obtain high-resolution STIS E230H SNAP observations of
MgII and FeII interstellar absorption lines toward stars within 100
parsecs that already have moderate or high-resolution far-UV (FUV),
900-1700 A, observations available in the MAST Archive. Fundamental
properties, such as temperature, turbulence, ionization, abundances,
and depletions of gas in the local interstellar medium (LISM) can be
measured by coupling such observations. Due to the wide spectral range
of STIS, observations to study nearby stars also contain important
data about the LISM embedded within their spectra. However, unlocking
this information from the intrinsically broad and often saturated FUV
absorption lines of low-mass ions, (DI, CII, NI, OI), requires first
understanding the kinematic structure of the gas along the line of
sight. This can be achieved with high resolution spectra of high-mass
ions, (FeII, MgII), which have narrow absorption lines, and can
resolve each individual velocity component (interstellar cloud). By
obtaining short (~10 minute) E230H observations of FeII and MgII, for
stars that already have moderate or high- resolution FUV spectra, we
can increase the sample of LISM measurements, and thereby expand our
knowledge of the physical properties of the gas in our galactic
neighborhood. STIS is the only instrument capable of obtaining the
required high resolution data now or in the foreseeable future.

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 11712

Calibration of Surface Brightness Fluctuations for WFC3/IR

We aim to characterize galaxy surface brightness fluctuations (SBF),
and calibrate the SBF distance method, in the F110W and F160W filters
of the Wide Field Camera 3 IR channel. Because of the very high
throughput of F110W and the good match of F160W to the standard H
band, we anticipate that both of these filters will be popular choices
for galaxy observations with WFC3/IR. The SBF signal is typically an
order of magnitude brighter in the near-IR than in the optical, and
the characteristics (sensitivity, FOV, cosmetics) of the WFC3/IR
channel will be enormously more efficient for SBF measurements than
previously available near-IR cameras. As a result, our proposed SBF
calibration will allow accurate distance derivation whenever an
early-type or bulge-dominated galaxy is observed out to a distance of
150 Mpc or more (i.e., out to the Hubble flow) in the calibrated
passbands. For individual galaxy observations, an accurate distance is
useful for establishing absolute luminosities, black hole masses,
linear sizes, etc. Eventually, once a large number of galaxies have
been observed across the sky with WFC3/IR, this SBF calibration will
enable accurate mapping of the total mass density distribution in the
local universe using the data available in the HST archive. The
proposed observations will have additional important scientific value;
in particular, we highlight their usefulness for understanding the
nature of multimodal globular cluster color distributions in giant
elliptical galaxies.

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/COS/FUV 11536

COS-GTO: Sleuthing the Source of Distant Cometary Activity

Distant comets and Centaurs often show cometary activity and outbursts
well beyond 3 AU, the boundary of the sublimation zone of water.
Super-volatiles (most likely CO, but possibly CH4, N2, or S2) are
suspected to be responsible, but have never been detected in distant
comets in the UV. We will obtain FUV spectra of active bodies to cover
important CO emission bands. We plan two sets of observations: comet
29P/Schwassmann-Wachmann at 6 AU, whose outbursts are too short to
capture as a Target of Opportunity, but which also shows persistent
cometary activity in quiescence; and Target of Opportunity
observations of the Centaur 2060 Chiron (at ~15.5 AU) in outburst.

WFC3/UVIS 11697

Proper Motion Survey of Classical and SDSS Local Group Dwarf Galaxies

Using the superior resolution of HST, we propose to continue our
proper motion survey of Galactic dwarf galaxies. The target galaxies
include one classical dwarf, Leo II, and six that were recently
identified in the Sloan Digital Sky Survey data: Bootes I, Canes
Venatici I, Canes Venatici II, Coma Berenices, Leo IV, and Ursa Major
II. We will observe a total of 16 fields, each centered on a
spectroscopically-confirmed QSO. Using QSOs as standards of rest in
measuring absolute proper motions has proven to be the most accurate
and most efficient method. HST is our only option to quickly determine
the space motions of the SDSS dwarfs because suitable ground-based
imaging is only a few years old and such data need several decades to
produce a proper motion. The two most distant galaxies in our sample
will require time baselines of four years to achieve our goal of a
30-50 km/s uncertainty in the tangential velocity; given this and the
finite lifetime of HST, it is imperative that first-epoch observations
be taken in this cycle. The SDSS dwarfs have dramatically lower
surface brightnesses and luminosities than the classical dwarfs.
Proper motions are crucial for determining orbits of the galaxies and
knowing the orbits will allow us to test theories for the formation
and evolution of these galaxies and, more generally, for the formation
of the Local Group.

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 11730

Continued Proper Motions of the Magellanic Clouds: Orbits, Internal
Kinematics, and Distance

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. The results had a number of unexpected
implications for the Milky Way-LMC-SMC system and received
considerable attention in the literature and in the press. The implied
three-dimensional velocities are larger than previously believed and
close to the escape velocity in a standard 10^12 solar mass Milky Way
dark halo. Our orbit calculations suggest the Clouds may not be bound
to the Milky Way or may just be on their first passage, both of which
are unexpected in view of traditional interpretations of the
Magellanic Stream. Alternatively, the Milky Way dark halo may be a
factor 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 was 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 requested an
additional epoch data in Cycle 16 which is being executed with
WFPC2/PC due to the failure of ACS. A detailed analysis of one LMC
field shows that the field proper motion using all three epochs of
data is consistent within 1-sigma with the two- epoch data, thus
verifying that there are no major systematic effects in our previous
measurements. The random errors, however, are only smaller by a factor
of 1.4 because of the relatively large errors in the WFPC2 data. A
prediction for a fourth epoch with measurement errors similar to
epochs 1 and 2 shows that the uncertainties will improve by a factor
of 3. This will allow us to 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 to determine a distance to the LMC using rotational
parallax. Continuation of this highly successful program is therefore
likely to provide important additional insights. Execution in SNAPshot
mode guarantees maximally efficient use of HST resources.

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).

WFC3/UVIS/IR 11662

Improving the Radius-Luminosity Relationship for Broad-Lined AGNs with
a New Reverberation Sample

The radius-luminosity (R-L) relationship is currently the fundamental
basis for all techniques used to estimate black hole masses in AGNs,
in both the nearby and distant universe. However, the current R-L
relationship is based on 34 objects that cover a limited range in
black hole mass and luminosity. To improve our understanding of black
hole growth and evolution, the R-L relationship must be extended to
cover a broader range of black hole masses using the technique known
as reverberation mapping. To this end, we have been awarded an
unprecedented 64 nights on the Lick Observatory 3-m telescope between
March 24 and May 31, 2008, to spectroscopically monitor 12 AGNs in
order to measure their black hole masses. To properly determine the
luminosities of these 12 AGNs, we must correct them for their
host-galaxy starlight contributions using high-resolution images.
Previous work by Bentz et al. (2006) has shown that the starlight
correction to AGN luminosity measurements is an essential component to
interpreting the R-L relationship. The correction will be substantial
for each of the 12 sources we will monitor, as the AGNs are relatively
faint and embedded in nearby, bright galaxies. Starlight corrections
are not possible with ground-based images, as the PSF and bulge
contributions become indistinguishable under typical seeing
conditions, and adaptive optics are not yet operational in the
spectral range where the corrections are needed. In addition, spectral
decompositions are very model-dependent and are limited by the degree
of accuracy to which we understand emission processes and stellar
populations in galaxies. Without correcting for starlight, we will be
unable to apply the results of our Spring 2008 campaign to the body of
knowledge from previous reverberation mapping work. Therefore, we
propose to obtain high resolution, high dynamic range images of the
host galaxies of the 12 AGNs in our ground-based monitoring sample, as
well as one white dwarf which will be used as a PSF model.

WFC3/UVIS/IR 11909

UVIS Hot Pixel Anneal

The on-orbit radiation environment of WFC3 will continually generate
new hot pixels. This proposal performs the procedure required for
repairing those hot pixels in the UVIS CCDs. During an anneal, the
two-stage thermo-electric cooler (TEC) is turned off and the
four-stage TEC is used as a heater to bring the UVIS CCDs up to ~20
deg. C. As a result of the CCD warmup, a majority of the hot pixels
will be fixed; previous instruments such as WFPC2 and ACS have seen
repair rates of about 80%. Internal UVIS exposures are taken before
and after each anneal, to allow an assessment of the procedure's
effectiveness in WFC3, provide a check of bias, global dark current,
and hot pixel levels, as well as support hysteresis (bowtie)
monitoring and CDBS reference file generation. One IR dark is taken
after each anneal, to provide a check of the IR detector.

 




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