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Daily Report #4471



 
 
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Old October 19th 07, 03:19 PM posted to sci.astro.hubble
Cooper, Joe
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Posts: 568
Default Daily Report #4471

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***** # 4471

PERIOD COVERED: UT October 18, 2007 (DOY 291)

OBSERVATIONS SCHEDULED

FGS 11211

An Astrometric Calibration of Population II Distance Indicators

In 2002 HST produced a highly precise parallax for RR Lyrae. That
measurement resulted in an absolute magnitude, M{V}= 0.61+/-0.11, a
useful result, judged by the over ten refereed citations each year
since. It is, however, unsatisfactory to have the direct,
parallax-based, distance scale of Population II variables based on a
single star. We propose, therefore, to obtain the parallaxes of four
additional RR Lyrae stars and two Population II Cepheids, or W Vir
stars. The Population II Cepheids lie with the RR Lyrae stars on a
common K-band Period-Luminosity relation. Using these parallaxes to
inform that relationship, we anticipate a zero-point error of 0.04
magnitude. This result should greatly strengthen confidence in the
Population II distance scale and increase our understanding of RR
Lyrae star and Pop II Cepheid astrophysics.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

A new procedure proposed to alleviate the CR-persistence problem of
NICMOS. Dark frames will be obtained immediately upon exiting the SAA
contour 23, and every time a NICMOS exposure is scheduled within 50
minutes of coming out of the SAA. The darks will be obtained in
parallel in all three NICMOS Cameras. The POST-SAA darks will be non-
standard reference files available to users with a USEAFTER date/time
mark. The keyword 'USEAFTER=date/time' will also be added to the
header of each POST-SAA DARK frame. The keyword must be populated with
the time, in addition to the date, because HST crosses the SAA ~8
times per day so each POST-SAA DARK will need to have the appropriate
time specified, for users to identify the ones they need. Both the raw
and processed images will be archived as POST-SAA DARKs. Generally we
expect that all NICMOS science/calibration observations started within
50 minutes of leaving an SAA will need such maps to remove the CR
persistence from the science images. Each observation will need its
own CRMAP, as different SAA passages leave different imprints on the
NICMOS detectors.

NIC3 11082

NICMOS Imaging of GOODS: Probing the Evolution of the Earliest Massive
Galaxies, Galaxies Beyond Reionization, and the High Redshift Obscured
Universe

(uses ACS/SBC and WFPC2)

Deep near-infrared imaging provides the only avenue towards
understanding a host of astrophysical problems, including: finding
galaxies and AGN at z 7, the evolution of the most massive galaxies,
the triggering of star formation in dusty galaxies, and revealing
properties of obscured AGN. As such, we propose to observe 60 selected
areas of the GOODS North and South fields with NICMOS Camera 3 in the
F160W band pointed at known massive M 10^11 M_0 galaxies at z 2
discovered through deep Spitzer imaging. The depth we will reach {26.5
AB at 5 sigma} in H_160 allows us to study the internal properties of
these galaxies, including their sizes and morphologies, and to
understand how scaling relations such as the Kormendy relationship
evolved. Although NIC3 is out of focus and undersampled, it is
currently our best opportunity to study these galaxies, while also
sampling enough area to perform a general NIR survey 1/3 the size of
an ACS GOODS field. These data will be a significant resource,
invaluable for many other science goals, including discovering high
redshift galaxies at z 7, the evolution of galaxies onto the Hubble
sequence, as well as examining obscured AGN and dusty star formation
at z 1.5. The GOODS fields are the natural location for HST to
perform a deep NICMOS imaging program, as extensive data from space
and ground based observatories such as Chandra, GALEX, Spitzer, NOAO,
Keck, Subaru, VLT, JCMT, and the VLA are currently available for these
regions. Deep high-resolution near-infrared observations are the one
missing ingredient to this survey, filling in an important gap to
create the deepest, largest, and most uniform data set for studying
the faint and distant universe. The importance of these images will
increase with time as new facilities come on line, most notably WFC3
and ALMA, and for the planning of future JWST observations.

WFPC2 11141

White dwarfs in the open star cluster NGC 188

White dwarf cooling sequences represent the only ways in which we can
determine ages of Galactic components such as the disk and the halo,
and they are an independent check on main sequence ages of globular
star clusters. These age measurements rely heavily on theoretical
cooling models, many of which disagree by as much as a few gigayears
for the coolest white dwarfs. Further, observations of the white dwarf
sequence in the super metal- rich open cluster NGC 6791 have found a
white dwarf age several gigayears younger than the accepted cluster
age determined by main-sequence fitting. The white dwarf sequence of
the solar-metallicity, 7-Gyr old open cluster NGC 188 can provide some
much-needed insight into these uncertainties, but previous HST
observations were too shallow to detect the oldest, faintest white
dwarfs in the cluster. We propose deep imaging of two fields at the
center of the cluster with the following goals: {1} To detect the end
of the white dwarf cooling sequence, providing a much-needed empirical
data point for cool white dwarf evolutionary models, {2} to compare
the white dwarf luminosity function of NGC 188 with that of NGC 6791
to determine if the odd white dwarf sequence in the latter cluster is
due to the cluster's high metallicity or due to a shortcoming in
theoretical models, and {3} to determine via photometry the masses of
white dwarfs formed by solar-mass stars, a quantity not yet
empirically measured.

WFPC2 11202

The Structure of Early-type Galaxies: 0.1-100 Effective Radii

The structure, formation and evolution of early-type galaxies is still
largely an open problem in cosmology: how does the Universe evolve
from large linear scales dominated by dark matter to the highly
non-linear scales of galaxies, where baryons and dark matter both play
important, interacting, roles? To understand the complex physical
processes involved in their formation scenario, and why they have the
tight scaling relations that we observe today {e.g. the Fundamental
Plane}, it is critically important not only to understand their
stellar structure, but also their dark-matter distribution from the
smallest to the largest scales. Over the last three years the SLACS
collaboration has developed a toolbox to tackle these issues in a
unique and encompassing way by combining new non-parametric strong
lensing techniques, stellar dynamics, and most recently weak
gravitational lensing, with high-quality Hubble Space Telescope
imaging and VLT/Keck spectroscopic data of early-type lens systems.
This allows us to break degeneracies that are inherent to each of
these techniques separately and probe the mass structure of early-type
galaxies from 0.1 to 100 effective radii. The large dynamic range to
which lensing is sensitive allows us both to probe the clumpy
substructure of these galaxies, as well as their low-density outer
haloes. These methods have convincingly been demonstrated, by our
team, using smaller pilot-samples of SLACS lens systems with HST data.
In this proposal, we request observing time with WFPC2 and NICMOS to
observe 53 strong lens systems from SLACS, to obtain complete
multi-color imaging for each system. This would bring the total number
of SLACS lens systems to 87 with completed HST imaging and effectively
doubles the known number of galaxy-scale strong lenses. The deep HST
images enable us to fully exploit our new techniques, beat down
low-number statistics, and probe the structure and evolution of
early-type galaxies, not only with a uniform data-set an order of
magnitude larger than what is available now, but also with a fully
coherent and self-consistent methodological approach!

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11029 - ReAcq(2,1,1) failed to RGA Hold (Note, this HSTAR OCCURRED ON
DAY 283)

OTA SE review of PTAS processing showed that ReAcq(2,1,1) at
283/05:07:15 failed due to scan step limit exceeded on FGS2.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

********************** SCHEDULED***** SUCCESSFUL

FGS GSacq************** 06**************** 06
FGS REacq************** 08**************** 08
OBAD with Maneuver **** 24**************** 24

SIGNIFICANT EVENTS: (None)


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