Notice: Due to the conversion of some ACS
WFC or HRC observations into
WFPC2, or NICMOS observations after the
loss of ACS CCD science
capability in January, there may be an
occasional discrepancy between a
proposal's listed (and correct) instrument
usage and the abstract that
follows it.
HUBBLE SPACE TELESCOPE - Continuing to
collect World Class Science
DAILY REPORT # 4413
PERIOD COVERED: UT July 26, 2007 (DOY
207)
OBSERVATIONS SCHEDULED
WFPC2 10583
Resolving the LMC Microlensing Puzzle:
Where Are the Lensing Objects ?
We are requesting 32 HST orbits to help
ascertain the nature of the
population that gives rise to the
observed set of microlensing events
towards the LMC. The SuperMACHO project
is an ongoing ground-based
survey on the CTIO 4m that has
demonstrated the ability to detect LMC
microlensing events in real-time via
frame subtraction. The improvement
in angular resolution and photometric
accuracy available from HST will
allow us to 1} confirm that the detected
flux excursions arise from LMC
source stars rather than extended objects
{such as for background
supernovae or AGN}, and 2} obtain
reliable baseline flux measurements
for the objects in their unlensed state.
The latter measurement is
important to resolve degeneracies between
the event timescale and
baseline flux, which will yield a tighter
constraint on the microlensing
optical depth.
S/C 4974
TRTTEST
The Transient Response Test is for the
periodic performance monitoring
of the FGS 2R servo A mechanism.
WFPC2 10900
Optical polarimetry of PSR B0540-69 and
its synchrotron nebula.
Polarization measurements of pulsars and
of their synchrotron nebulae
are uniquely able to provide deep
insights into the highly magnetized
relativistic environment of young
rotating neutron stars. Apart from the
radio band, pulsar polarization is best
measured in the optical, for the
rare cases of detectable optical
emission. One of the brightest pulsars
together with Crab {PSR B0531+21} and
Vela {PSR B0833-45}, for which
optical polarization measurements support
the newly developed two-pole
caustic model {TPC}, is PSR B0540-69 in
the Large Magellanic Clouds,
often referred as the Crab Twin for their
overall similarities in both
age and energetics. Together with the
Crab, PSR B0540-69 is also the
only pulsar embedded in a synchrotron
nebula visible at optical
wavelengths. We plan to observe PSR
B0540-69 and its compact nebula {4
arcsec diameter} with the Advanced Camera
for Surveys {ACS} and the Wide
Field Channel {WFC} detector using UV and
visual polarization filters.
Thanks to the superb angular resolution
of ACS, these observations will
allow us to spectacularly resolve the
pulsar from its nebular
background, providing the first firm
measure of the pulsar polarization
which will be crucial to assess, on a
broader sample, the validity of
the TPC model with respect to other
pulsars magnetosphere models. These
observations will also provide the first
detailed polarization map of
the nebula, including the jet and the
torus seen in our previous WFPC2
images.
WFPC2 11079
Treasury Imaging of Star Forming Regions
in the Local Group:
Complementing the GALEX and NOAO Surveys
We propose to use WFPC2 to image the most
interesting star-forming
regions in the Local Group galaxies, to
resolve their young stellar
populations. We will use a set of filters
including F170W, which is
critical to detect and characterize the
most massive stars, to whose hot
temperatures colors at longer wavelengths
are not sensitive. WFPC2's
field of view ideally matches the typical
size of the star-forming
regions, and its spatial resolution
allows us to measure individual
stars, given the proximity of these
galaxies. The resulting H-R diagrams
will enable studies of star- formation properties
in these regions,
which cover largely differing
metallicities {a factor of 17, compared to
the factor of 4 explored so far} and
characteristics. The results will
further our understanding of the
star-formation process, of the
interplay between massive stars and
environment, the properties of dust,
and will provide the key to interpret
integrated measurements of
star-formation indicators {UV, IR,
Halpha} available for several
hundreds more distant galaxies. Our
recent deep surveys of these
galaxies with GALEX {FUV, NUV} and
ground-based imaging {UBVRI, Halpha,
[OIII] and [SII]} provided the
identification of the most relevant SF
sites. In addition to our scientific
analysis, we will provide catalogs
of HST photometry in 6 bands, matched
corollary ground-based data, and
UV, Halpha and IR integrated measurements
of the associations, for
comparison of integrated star-formation
indices to the resolved
populations. We envisage an EPO
component.
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:
#18116-0
TRT Test #15 @ 207/1625z
#18054-0
Preview KF Sun Vector Data via Telemetry Diags (Generic) @ 207/1626z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 9 9
FGS REacq 3 3
OBAD with Maneuver 28
28
SIGNIFICANT EVENTS:
The FGS-2R TRT test #15 was successfully
completed today at 207/16:26z.
Analysis and results will be presented at
the next GSAWG meeting.
-
____________________________________________________________
Lynn F. Bassford
Hubble Space Telescope
CHAMP
Lockheed Martin
NASA GSFC PH#: 301-286-2876
"The Hubble Space Telescope is the
astronomical observatory and key to unlocking the most cosmic mysteries of the
past, present and future." - 7/26/6