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Daily Report #4960



 
 
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Old October 28th 09, 02:10 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #4960

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #4960

PERIOD COVERED: 5am October 27 - 5am October 28, 2009 (DOY 300/09:00z-301/09:00z)

OBSERVATIONS SCHEDULED

ACS/WFC 11689

Direct Observations of Dark Matter from a Second Bullet: The
Spectacular Abell 2744

Vigorous cluster mergers provide a unique opportunity to directly
"see" dark matter and to probe its properties through the analysis of
the segregation of the baryonic and non-baryonic components. This is
accomplished through detailed comparison of the mass distributions as
traced by X-ray emitting gas and by gravitational lensing. This
condition is rare and so far only one cluster has met these
requirements, the so-called "bullet" cluster, producing exciting
results and placing constraints to the properties of dark matter.
These constraints have a broad impact on models for formation of
structure and on galaxy evolution. This multi-wavelength analysis has
the potential confront alternative gravity models such as MOND.
Therefore, it is crucial to find new ?bullet clusters? to corroborate
and improve previous measurements. This is the most direct way to
constrain dark matter properties and A2744 is ideal for corroborating
this study since it maximizes all the requirements for this analysis.
Here, we propose to carry out such analysis through combined ACS and
Chandra observations of the cluster merger Abell 2744.

ACS/WFC3 11882

CCD Hot Pixel Annealing

All the data for this program is acquired using internal targets
(lamps) only, so all of the exposures should be taken during Earth
occultation time (but not during SAA passages). This program emulates
the ACS pre-flight ground calibration and post launch SMOV testing
(program 8948), so that results from each epoch can be directly
compared. Extended Pixel Edge Response (EPER) and First Pixel Response
(FPR) data will be obtained over a range of signal levels for the Wide
Field Channel (WFC). The High Resolution Channel (HRC) visits have
been removed since it could not be repaired during SM4.

COS/FUV 11541

COS-GTO: COOL, WARM AND HOT GAS IN THE COSMIC WEB AND IN GALAXY HALOS

COS G130M and G160M 20, 000 resolution observations will be obtained
for 17 QSOs to study cool, warm and hot gas in the cosmic web and in
galaxy halos. 5 QSOs with z from 0.177 to 0.574 and sum z = 1.68 will
be observed with S/N = 40-50 per resolution element. 12 QSOs with z =
0.286 to 0.669 and sum z = 5.57 will be observed with S/N = 30-40. The
observations will allow a wide range of IGM studies including
determining the frequency of occurrence of the different types of
absorption systems detected, along with studies of the physical
conditions and elemental abundances in the different systems. Special
emphasis will be given to a study of the properties of highly ionized
IGM as traced by O VI, O V, O IV, N V, and C IV. The high S/N of the
observations will allow a search for broad Lyman alpha absorption and
weak metal line absorption that can be crucial for the evaluation of
physical conditions and elemental abundances. Supporting ground based
observations will allow studies of the association of the absorbers
with galaxy structures along the 17 lines of sight. The overall goal
of the program will be to obtain the information that will allow an
assessment of the baryonic content of the IGM as revealed by UV and
EUV absorption lines seen in the spectra of QSOs.

COS/FUV 11997

FUV Internal/External Wavelength Scale Monitor

This program monitors the offsets between the wavelength scale set by
the internal wavecal versus that defined by absorption lines in
external targets. This is accomplished by observing two external
targets in the SMC: SK191 with G130M and G160M and Cl* NGC 330 ROB B37
with G140L (SK191 is too bright to be observed with G140L). The
cenwaves observed in this program are a subset of the ones used during
Cycle 17. Observing all cenwaves would require a considerably larger
number of orbits. Constraints on scheduling of each target are placed
so that each target is observed once every ~2-3 months. Observing the
two targets every month would also require a considerably larger
number of orbits.

FGS 11790

HST/FGS Astrometric Search for Young Planets Around Beta Pic and AU
Mic

AU Mic is a nearby Vega-type debris disk star. Its disk system has
been spatially resolved in exquisite detail, predominantly via the ACS
coronagraph and WFPC2 cameras onboard HST. These images exhibit a
wealth of morphological features which provide compelling indirect
evidence that AU Mic likely harbors short-period planetary
body/bodies. We propose to use the superlative astrometric
capabilities of HST/FGS to directly detect these planets, hence
provide the first direct planet detection in a Vega-type system whose
disk has been imaged at high spatial resolution.

NIC2/WFC3/IR 11548

Infrared Imaging of Protostars in the Orion A Cloud: The Role of
Environment in Star Formation

We propose NICMOS and WFC3/IR observations of a sample of 252
protostars identified in the Orion A cloud with the Spitzer Space
Telescope. These observations will image the scattered light escaping
the protostellar envelopes, providing information on the shapes of
outflow cavities, the inclinations of the protostars, and the overall
morphologies of the envelopes. In addition, we ask for Spitzer time to
obtain 55-95 micron spectra of 75 of the protostars. Combining these
new data with existing 3.6 to 70 micron photometry and forthcoming
5-40 micron spectra measured with the Spitzer Space Telescope, we will
determine the physical properties of the protostars such as envelope
density, luminosity, infall rate, and outflow cavity opening angle. By
examining how these properties vary with stellar density (i.e.
clusters vs. groups vs. isolation) and the properties of the
surrounding molecular cloud; we can directly measure how the
surrounding environment influences protostellar evolution, and
consequently, the formation of stars and planetary systems.
Ultimately, this data will guide the development of a theory of
protostellar evolution.

STIS/CCD 11844

CCD Dark Monitor Part 1

The purpose of this proposal is to monitor the darks for the STIS CCD.

STIS/CCD 11846

CCD Bias Monitor-Part 1

The purpose of this proposal is to 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/ACS/UVIS 11360

Star Formation in Nearby Galaxies

Star formation is a fundamental astrophysical process; it controls
phenomena ranging from the evolution of galaxies and nucleosynthesis
to the origins of planetary systems and abodes for life. The WFC3,
optimized at both UV and IR wavelengths and equipped with an extensive
array of narrow-band filters, brings unique capabilities to this area
of study. The WFC3 Scientific Oversight Committee (SOC) proposes an
integrated program on star formation in the nearby universe which will
fully exploit these new abilities. Our targets range from the
well-resolved R136 in 30 Dor in the LMC (the nearest super star
cluster) and M82 (the nearest starbursting galaxy) to about half a
dozen other nearby galaxies that sample a wide range of star-formation
rates and environments. Our program consists of broad band
multiwavelength imaging over the entire range from the UV to the
near-IR, aimed at studying the ages and metallicities of stellar
populations, revealing young stars that are still hidden by dust at
optical wavelengths, and showing the integrated properties of star
clusters. Narrow-band imaging of the same environments will allow us
to measure star-formation rates, gas pressure, chemical abundances,
extinction, and shock morphologies. The primary scientific issues to
be addressed a (1) What triggers star formation? (2) How do the
properties of star-forming regions vary among different types of
galaxies and environments of different gas densities and compositions?
(3) How do these different environments affect the history of star
formation? (4) Is the stellar initial mass function universal or
determined by local conditions?

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 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 11594

A WFC3 Grism Survey for Lyman Limit Absorption at z=2

We propose to conduct a spectroscopic survey of Lyman limit absorbers
at redshifts 1.8 z 2.5, using WFC3 and the G280 grism. This
proposal intends to complete an approved Cycle 15 SNAP program
(10878), which was cut short due to the ACS failure. We have selected
64 quasars at 2.3 z 2.6 from the Sloan Digital Sky Survey
Spectroscopic Quasar Sample, for which no BAL signature is found at
the QSO redshift and no strong metal absorption lines are present at z
2.3 along the lines of sight. The survey has three main

observational goals. First, we will determine the redshift frequency
dn/dz of the LLS over the column density range 16.0 log(NHI) 20.3
cm^-2. Second, we will measure the column density frequency
distribution f(N) for the partial Lyman limit systems (PLLS) over the
column density range 16.0 log(NHI) 17.5 cm^-2. Third, we will
identify those sightlines which could provide a measurement of the
primordial D/H ratio. By carrying out this survey, we can also help
place meaningful constraints on two key quantities of cosmological
relevance. First, we will estimate the amount of metals in the LLS
using the f(N), and ground based observations of metal line
transitions. Second, by determining f(N) of the PLLS, we can constrain
the amplitude of the ionizing UV background at z~2 to a greater
precision. This survey is ideal for a snapshot observing program,
because the on-object integration times are all well below 30 minutes,
and follow-up observations from the ground require minimal telescope
time due to the QSO sample being bright.

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 11908

Cycle 17: UVIS Bowtie Monitor

Ground testing revealed an intermittent hysteresis type effect in the
UVIS detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially found via an unexpected bowtie-shaped feature in flatfield
ratios, subsequent lab tests on similar e2v devices have since shown
that it is also present as simply an overall offset across the entire
CCD, i.e., a QE offset without any discernable pattern. These lab
tests have further revealed that overexposing the detector to count
levels several times full well fills the traps and effectively
neutralizes the bowtie. Each visit in this proposal acquires a set of
three 3x3 binned internal flatfields: the first unsaturated image will
be used to detect any bowtie, the second, highly exposed image will
neutralize the bowtie if it is present, and the final image will allow
for verification that the bowtie is gone.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

12056 - GSAcq (2,1,1) at 300/23:34z and REAcq at 301/01:10:08z,
301/02:39:47z and 301/04:15:42z all failed to RGA Hold due to Scan
Step Limit Exceeded on FGS-1.

Observations affected: COS 15-30 Proposal ID#11541, ACS 61-62 Proposal
ID#11882, STIS 12-16 Proposal ID#11846, WFC3 60-62 Proposal ID#11905.

12057 - GSAcq(2,1,1) at 301/05:51:38z and REAcq(2,1,1) at
301/07:27:30z both failed with Search Radius Limit exceeded on both
FGS 1 and FGS 2.

Observations affected: COS 31-45, proposal ID#11541.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 7 5
FGS REAcq 9 5
OBAD with Maneuver 5 5

SIGNIFICANT EVENTS: (None)

 




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