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Daily #4034



 
 
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Old January 24th 06, 04:14 PM posted to sci.astro.hubble
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Default Daily #4034

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4034

PERIOD COVERED: UT January 23, 2006 (DOY 023)

OBSERVATIONS SCHEDULED

ACS/HRC/WFC 10570

Hosts of Quasars with Opaque Partial Covering

A few quasars are known to exhibit associated absorption lines with
opaque partial covering. These are the lines which are clearly
saturated but not completely dark, so that these absorbing clouds are
opaquely and partially covering the quasar light. In some cases,
ionization parameter and density arguments indicate that the absorbers
are on kpc scale. This implies that at least in some cases, the
residual, unabsorbed optical {rest-UV} continuum component originates
from ~kpc scales, rather than microscopic scales {such as ~100
Schwarzschild radii}. This could be a superluminous host galaxy or
starbursting core, and could be resolved by HST. We address the nature
of these opaquely and partially covered quasars with a simple and
robust ACS imaging.

ACS/HRC/WFC 10729

ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS. Changes from cycle 13:- The default
gain for WFC is 2 e-/DN. As before bias frames will be collected for
both gain 1 and gain 2. Dark frames are acquired using the default
gain {2}. This program cover the period Oct, 2 2005- May, 29-2006. The
second half of the program has a different proposal number: 10758.

ACS/WFC 10494

Imaging the mass structure of distant lens galaxies

The surface brightness distribution of extended gravitationally lensed
arcs and Einstein rings contains super-resolved information about the
lensed object, and, more excitingly, about the smooth and clumpy mass
distribution of the lens galaxies. The source and lens information can
non-parametrically be separated, resulting in a direct
"gravitational-mass image" of the inner mass-distribution of
cosmologically-distant galaxies {Koopmans 2005}. With this goal in
mind, we propose deep HST ACS-F555W/F814W and NICMOS-F160W imaging of
15 gravitational-lens systems with spatially resolved lensed sources,
selected from the 17 new lens systems discovered by the Sloan Lens ACS
Survey {Bolton et al. 2004}. Each system has been selected from the
SDSS and confirmed in a time-efficient HST-ACS snapshot program
{cycle-13}; they show highly-magnified arcs or Einstein rings, lensed
by a massive early-type lens galaxy. High- fidelity multi-color HST
images are required {not delivered by the 420-sec snapshot images} to
isolate these lensed images {properly cleaned, dithered and
extinction-corrected} from the lens galaxy surface brightness
distribution, and apply our "gravitational-mass imaging" technique.
The sample of galaxy mass distributions - determined through this
method from the arcs and Einstein ring HST images - will be studied
to: {i} measure the smooth mass distribution of the lens galaxies
{Dark and luminous mass are separated using the HST images and the
stellar M/L values derived from a joint stellar-dynamical analysis of
each system}; {ii} quantify statistically and individually the
incidence of mass-substructure {with or without obvious luminous
counter- parts such as dwarf galaxies}. Since dark-matter substructure
should be considerably more prevalent at higher redshift, both results
provide a direct test of this prediction of the CDM hierarchical
structure-formation model.

ACS/WFC 10496

Decelerating and Dustfree: Efficient Dark Energy Studies with
Supernovae and Clusters

We propose a novel HST approach to obtain a dramatically more useful
"dust free" Type Ia supernovae {SNe Ia} dataset than available with
the previous GOODS searches. Moreover, this approach provides a
strikingly more efficient search-and-follow-up that is primarily pre-
scheduled. The resulting dark energy measurements do not share the
major systematic uncertainty at these redshifts, that of the
extinction correction with a prior. By targeting massive galaxy
clusters at z 1 we obtain a five-times higher efficiency in
detection of Type Ia supernovae in ellipticals, providing a
well-understood host galaxy environment. These same deep cluster
images then also yield fundamental calibrations required for future
weak lensing and Sunyaev-Zel'dovich measurements of dark energy, as
well as an entire program of cluster studies. The data will make
possible a factor of two improvement on supernova constraints on dark
energy time variation, and much larger improvement in systematic
uncertainty. They will provide both a cluster dataset and a SN Ia
dataset that will be a longstanding scientific resource.

ACS/WFC 10515

The Unique Star Cluster System of M85

Even with its long history as one of the pillars of modern astronomy,
the study of star clusters has continued to reveal new and surprising
things. Over the past decade, numerous programs with HST have shown
that extragalactic star clusters powerfully probe the processes of
galactic formation, evolution, and destruction. The diversity of star
cluster systems is a testament to the rich variation in galaxy
properties. During the course of the ACS Virgo Cluster Survey, we have
discovered that the early-type galaxy M85 has a system of star
clusters unlike any other galaxy studied to date. Hundreds of star
clusters in M85 are fainter and more extended than typical globular
clusters, and have no local analog. We propose deep optical- infrared
imaging with ACS and NICMOS to obtain ages, metallicities,
luminosities, and sizes of unprecedented precision to characterize
these new star clusters and unravel the evolutionary state of M85 that
gave rise to them.

ACS/WFC 10543

Microlensing in M87 and the Virgo Cluster

Resolving the nature of dark matter is an urgent problem. The results
of the MACHO survey of the Milky Way dark halo toward the LMC indicate
that a significant fraction of the halo consists of stellar mass
objects. The VATT/Columbia survey of M31 finds a similar lens fraction
in the M31 dark halo. We propose a series of observations with ACS
that will provide the most thorough search for microlensing toward
M87, the central elliptical galaxy of the Virgo cluster. This program
is optimized for lenses in the mass range from 0.01 to 1.0 solar
masses. By comparing with archival data, we can detect lenses as
massive as 100 solar masses, such as the remnants of the first stars.
These observations will have at least 15 times more sensitivity to
microlensing than any previous survey, e.g. using WFPC2. This is due
to the factor of 2 larger area, factor of more than 4 more sensitivity
in the I-band, superior pixel scale and longer baseline of
observations. Based on the halo microlensing results in the Milky Way
and M31, we might expect that galaxy collisions and stripping would
populate the overall cluster halo with a large number of stellar mass
objects. This program would determine definitively if such objects
compose the cluster dark matter at the level seen in the Milky Way. A
negative result would indicate that such objects do not populate the
intracluster medium, and may indicate that galaxy harassment is not as
vigorous as expected. We can measure the level of events due to the
M87 halo: this would be the best exploration to date of such a lens
population in an elliptical galaxy. Star-star lensing should also be
detectable. About 20 erupting classical novae will be seen, allowing
to determine the definitive nova rate for this giant elliptical
galaxy. We will determine if our recent HST detection of an M87
globular cluster nova was a fluke, or indicative of a 100x higher rate
of incidence of cataclysmic variables and nova eruptions in globulars
than previously believed. We will examine the populations of variable
stars, and will be able to cleanly separate them from microlensing.

ACS/WFC 10740

Absolute Photometric & Spectrophometric Calibration

This program has several goals: 1.}Verify repeatability of the ACS
instrumentation on a single bright star to +/-0.2%. 2.}Determine any
shift in the filter bandpasses since the preflight lab measurements.
3.}Determine the relative magnitude of the 3 primary WD calibrators to
0.1%. 4.}Refine the sensitivity calibration of the CCD prism and
grisms at field center and determine the repeatability accuracy of
this calibration. 5.}Determine the level of variability of the three
HST red standard stars: VB-8 {M7}, 2M0038+18 {L3.5} and 2M0559-14
{T5}, and also measure their short wavelength {7000A} fluxes.
6.}Cross calibrate with a faint STIS and NICMOS standard WD and solar
analog star.

NICMOS 8790

NICMOS Post-SAA calibration - CR Persistence Part 1.

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.

WFPC2 10748

WFPC2 CYCLE 14 Standard Darks

This dark calibration program obtains dark frames every week in order
to provide data for the ongoing calibration of the CCD dark current
rate, and to monitor and characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

WFPC2 10778

WFPC2 WF4 Supplemental Darks

These darks are to supplement those in program 10748 to ensure
sufficient dark frames for routine calibration.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10100 - REAcq (2,1,2) failed due to search radius limit exceeded on
FGS 2 @ 024/0301z

At AOS (024/03:11:30) REAcq (2,1,2) scheduled @ 024/03:01:23 indicated
failed due to search radius limit exceeded. ESB "a05", Exceeded SRL
was received. No OBADs prior to REAcq. Prior OBAD MAP showed the
following errors: V1 6.83, V2 0.46, V3 -1.60, RSS 7.03. Following OBAD
MAP showed the following errors: V1 -741.22, V2 530.18, V3 -355.15,
RSS 978.07

COMPLETED OPS REQUEST:
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 08 08
FGS
REacq 05 04 024/0301z
(HSTAR 10100)
OBAD with Maneuver 24 24


COMPLETED OPS NOTES: (None)

SIGNIFICANT EVENTS:

FLASH REPORT: VTFE Curve Adjustment K1L4 Equivalent

On DOY 2006/023 at 14:52 GMT, the VTFE curves were increased from
K1L4-100mv to K1L4 in an effort to take advantage of the low battery
temperatures. The system was monitored for one orbit and nominal
performance was observed with the benchmark reset threshold satisfied
and the maximum system SOC increased from 246 Ah to 253 Ah. Peak
battery temperatures are still below -1 degC.



 




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