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Daily Report # 4349



 
 
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Old April 26th 07, 02:06 PM posted to sci.astro.hubble
Cooper, Joe
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Posts: 568
Default Daily Report # 4349

Notice: For the foreseeable future, the daily reports may contain apparent
discrepancies between some proposal descriptions and the listed instrument
usage. This is due to the conversion of previously approved ACS WFC or HRC
observations into WFPC2, or NICMOS observations subsequent to the loss of
ACS CCD science capability in late January.


HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4349

PERIOD COVERED: UT April 25, 2007 (DOY 115)

OBSERVATIONS SCHEDULED

WFPC2 10798

Dark Halos and Substructure from Arcs & Einstein Rings

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 image" of the inner
mass-distribution of cosmologically-distant galaxies {Koopmans 2005;
Koopmans et al. 2006 [astro-ph/0601628]}. With this goal in mind, we propose
deep HST ACS-F555W/F814W and NICMOS-F160W WFC imaging of 20 new
gravitational-lens systems with spatially resolved lensed sources, of the 35
new lens systems discovered by the Sloan Lens ACS Survey {Bolton et al.
2005} so far, 15 of which are being imaged in Cycle-14. Each system has been
selected from the SDSS and confirmed in two time- efficient HST-ACS snapshot
programs {cycle 13&14}. High-fidelity multi-color HST images are required
{not delivered by the 420s snapshots} to isolate these lensed images
{properly cleaned, dithered and extinction-corrected} from the lens galaxy
surface brightness distribution, and apply our "gravitational maging"
technique. Our sample of 35 early-type lens galaxies to date is by far the
largest, still growing, and most uniformly selected. This minimizes
selection biases and small-number statistics, compared to smaller, often
serendipitously discovered, samples. Moreover, using the WFC provides
information on the field around the lens, higher S/N and a better understood
PSF, compared with the HRC, and one retains high spatial resolution through
drizzling. 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 could be more prevalent at higher redshift, both
results provide a direct test of this prediction of the CDM hierarchical
structure-formation model.

WFPC2 10809

The nature of "dry" mergers in the nearby Universe

Recent studies have shown that "dry" mergers of red, bulge-dominated
galaxies at low redshift play an important role in shaping today's most
massive ellipticals. These mergers have been identified in extremely deep
ground-based images of red sequence galaxies at z ~ 0.1. The ground-based
images reach surface brightness limits of AB ~ 29, but lack the resolution
to study the morphologies of the galaxies inside the effective radius. Here
we propose to obtain ACS images of a representative sample of 40 of these
red sequence galaxies: 15 ongoing dry mergers, 15 remnants, and 10
undisturbed objects. We will measure the isophote shapes and ellipticities
of the galaxies, their dust content, morphological fine structure {shells
and ripples}, AGN content, and their location on the Fundamental Plane. By
comparing galaxies in different stages of the merging process we can
constrain the amount of gas associated with these red mergers, the effect of
active nuclei, and track structural changes. As two galaxies can be observed
in a single orbit 20 orbits are requested to observe the 40 galaxies.

NIC1 11061

NICMOS Imaging of Grism Spectrophotometric Standards

In this program we will take imaging observations with all 3 cameras with a
range of filters of a significant number of stars that are part of the
spectroscopic standard star project. These stars will form the fainter
reference star backbone for programs as JWST, Sophia, and SNAP. With this
program we will: 1. Accurately calibrate relative brightness of standard
stars, which can be done more accurately with photometry than with
spectroscopy. This has been proven to be vary valuable to straighten out the
problems in the spectroscopic data reduction and calibrations so far. 2.
Increase the number of stars over a large magnitude range to provide a more
accurate cross check of our count rate dependent non-linearity correction 3.
Include stars with radically different {very red} spectra to investigate
whether the filter curves as measured before flight are still valid by
comparing the throughput estimates from these stars to those used for the
standard calibration. 4. Repeat a few standard star observations from cycle
7 and post-NCS installation SMOV, to increase the accuracy in the change in
sensitivity measurement with just a few observations thanks to the long
baseline.

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 DARKSs. 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 10792

Quasars at Redshift z=6 and Early Star Formation History

We propose to observe four high-redshift quasars {z=6} in the NIR in order
to estimate relative Fe/Mg abundances and the central black hole mass. The
results of this study will critically constrain models of joint quasar and
galaxy formation, early star formation, and the growth of supermassive black
holes. Different time scales and yields for alpha-elements {like O or Mg}
and for iron result into an iron enrichment delay of ~0.3 to 0.6 Gyr. Hence,
despite the well-known complexity of the FeII emission line spectrum, the
ratio iron/alpha - element is a potentially useful cosmological clock. The
central black hole mass will be estimated based on a recently revised back
hole mass - luminosity relationship. The time delay of the iron enrichment
and the time required to form a supermassive black hole {logM8 Msol, tau
~0.5Gyr} as evidenced by quasar activity will be used to date the beginning
of the first intense star formation, marking the formation of the first
massive galaxies that host luminous quasars, and to constrain the epoch when
supermassive black holes start to grow by accretion.

S/C 4974

TRTTEST

The Transcient Response Test is for the periodic performance monitoring of
the FGS 2R servo A mechanism.

WFPC2 11083

The Structure, Formation and Evolution of Galactic Cores and Nuclei

A surprising result has emerged from the ACS Virgo Cluster Survey {ACSVCS},
a program to obtain ACS/WFC gz imaging for a large, unbiased sample of 100
early-type galaxies in the Virgo Cluster. On subarcsecond scales {i.e.,
0.1"-1"}, the HST brightness profiles vary systematically from the
brightest giants {which have nearly constant surface brightness cores} to
the faintest dwarfs {which have compact stellar nuclei}. Remarkably, the
fraction of galaxy mass contributed by the nuclei in the faint galaxies is
identical to that contributed by supermassive black holes in the bright
galaxies {0.2%}. These findings strongly suggest that a single mechanism is
responsible for both types of Central Massive Object: most likely internally
or externally modulated gas inflows that feed central black holes or lead to
the formation of "nuclear star clusters". Understanding the history of gas
accretion, star formation and chemical enrichment on subarcsecond scales has
thus emerged as the single most pressing question in the study of nearby
galactic nuclei, either active or quiescent. We propose an ambitious HST
program {199 orbits} that constitutes the next, obvious step forward:
high-resolution, ultraviolet {WFPC2/F255W} and infrared {NIC1/F160W} imaging
for the complete ACSVCS sample. By capitalizing on HST's unique ability to
provide high-resolution images with a sharp and stable PSF at UV and IR
wavelengths, we will leverage the existing optical HST data to obtain the
most complete picture currently possible for the history of star formation
and chemical enrichment on these small scales. Equally important, this
program will lead to a significant improvement in the measured structural
parameters and density distributions for the stellar nuclei and the
underlying galaxies, and provide a sensitive measure of "frosting" by young
stars in the galaxy cores. By virtue of its superb image quality and stable
PSF, NICMOS is the sole instrument capable of the IR observations proposed
here. In the case of the WFPC2 observations, high-resolution UV imaging {
0.1"} is a capability unique to HST, yet one that could be lost at any any
time.

WFPC2 11020

Cycle 15 Focus Monitor

The focus of HST is measured primarily with ACS/HRC over full CVZ orbits to
obtain accurate mean focus values via a well sampled breathing curve. Coma
and astigmatism are also determined from the same data in order to further
understand orbital effects on image quality and optical alignments. To
monitor the stability of ACS to WFPC2 relative focii, we've carried over
from previous focus monitor programs parallel observations taken with the
two cameras at suitable orientations of previously observed targets, and
interspersed them with the HRC CVZ visits.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10788 - GSAcq (1,3,1) failed to RGA Hold (Gyro Control)

At AOS (116/01:09:46) GSAcq (1,3,1) scheduled from 116/00:55:12-01:02:31 had
failed to RGA Hold (Gyro Control) due to QF1STOPF and QSTOP flag on FGS 1.

OBAD #1 data is unavailable until the next scheduled engineering data dump.
OBAD #2: RSS 13.95
OBAD MAP: RSS 4135.71

COMPLETED OPS REQUEST:

18043-0 - TRT Test#14
18046-0 - MSS/CSS Gyro1 KF Initialization Convergence Testing for SMS
113 Test 15
18046-0 - MSS/CSS Gyro1 KF Initialization Convergence Testing for SMS
113 Test 14
18052-0 - PCS KF OOT Support

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL

FGS GSacq 08 07
FGS REacq 05 05
OBAD with Maneuver 30 30

SIGNIFICANT EVENTS:

Evaluation of Universal Kalman Filter performance continued. Multiple text
segments were executed. Details follow.

The Kalman Filter (KF) was halted at 115/14:47 (OR 18046-0) during orbit day
and during an M2G guiding interval. The filter was restarted at 115/14:59
during orbit day, during a vehicle maneuver and during a fast changing
B-field. The filter was activated with the MSS, CSS and Gyro1 sensor inputs
enabled. All UKF parameters showed nominal operation. The test was an
MSS/CSS/Gyro1 Initialization Test Case with the vehicle in maneuver and
during a fast changing B-field (MC_G1_IVF, Test #15). The MSS/CSS default KF
configuration was restored at 115/16:45.

The Kalman Filter (KF) was halted at 115/23:50 (OR 18046-0) during orbit day
and during an T2G guiding interval. The filter was restarted at 115/23:33
during orbit night with no vehicle maneuver and during a slow changing
B-field. The filter was activated with the MSS, CSS and Gyro1 sensor inputs
enabled, however since the vehicle was in orbit night no CSS inputs were
available. All UKF parameters showed nominal operation. The test was an
MSS/Gyro1 Initialization Test Case with the vehicle inertially fixed and
during a slow changing B-field (M_G1_INS, Test #14). The MSS/CSS default KF
configuration was restored at 115/23:51.

The test above completes KF convergence testing for the week of the 113 SMS.

Flash Report: TRTT

The FGS-2R TRTT was successfully completed this morning at 115/14:40z using
Ops Request 18043. Both iterations of the test completed nominally. OTA SEs
will analyze the resulting data to continue trending FGS-2R.
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