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#38144
Thu 12 Jun 2008 10:58:AM
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Joined: Feb 2001
Posts: 381,903
Launch Director
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OP
Launch Director
Joined: Feb 2001
Posts: 381,903 |
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 4629
PERIOD COVERED: 5am June 10 - 5am June 11, 2008 (DOY 162/0900z-163/0900z)
OBSERVATIONS SCHEDULED
NIC1/NIC2 11155
Dust Grain Evolution in Herbig Ae Stars: NICMOS Coronagraphic Imaging
and Polarimetry
We propose to take advantage of the sensitive coronagraphic capabilities
of NICMOS to obtain multiwavelength coronagraphic imaging and
polarimetry of primordial dust disks around young intermediate-mass
stars {Herbig Ae stars}, in order to advance our understanding of how
dust grains are assembled into larger bodies. Because the polarization
of scattered light is strongly dependent on scattering particle size and
composition, coronagraphic imaging polarimetry with NICMOS provides a
uniquely powerful tool for measuring grain properties in spatially
resolved circumstellar disks. It is widely believed that planets form
via the gradual accretion of planetesimals in gas-rich, dusty
circumstellar disks, but the connection between this suspected process
and the circumstellar disks that we can now observe around other stars
remains very uncertain. Our proposed observations, together with
powerful 3-D radiative transfer codes, will enable us to quantitatively
determine dust grain properties as a function of location within disks,
and thus to test whether dust grains around young stars are in fact
growing in size during the putative planet-formation epoch. HST imaging
polarimetry of Herbig Ae stars will complement and extend existing
polarimetric studies of disks around lower-mass T Tauri stars and debris
disks around older main-sequence stars. When combined with these
previous studies, the proposed research will help us establish the
influence of stellar mass on the growth of dust grains into larger
planetesimals, and ultimately to planets. Our results will also let us
calibrate models of the thermal emission from these disks, a critical
need for validating the properties of more distant disks inferred on the
basis of spectral information alone.
NIC1/NIC2/NIC3 11318
NICMOS Cycle 16 Multiaccum Darks
The purpose of this proposal is to monitor the dark current, read noise,
and shading profile for all three NICMOS detectors throughout the
duration of Cycle 16. This proposal is a slightly modified version of
proposal 10380 of cycle 13 and 9993 of cycle12 and is the same as Cycle
15. Covers the period from April 08 to November 08 (inclusive)
NIC1/NIC2/NIC3 8795
NICMOS Post-SAA Calibration - CR Persistence Part 6
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 i
mages. Each observation will need its own CRMAP, as different SAA
passages leave different imprints on the NICMOS detectors.
NIC2/WFPC2 11142
Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3<z<2.7
Using HST and Spitzer
We aim to determine physical properties of IR luminous galaxies at
0.3<z<2.7 by requesting coordinated HST/NIC2 and MIPS 70um observations
of a unique, 24um flux-limited sample with complete Spitzer mid-IR
spectroscopy. The 150 sources investigated in this program have S{24um}
> 0.8mJy and their mid-IR spectra have already provided the majority
targets with spectroscopic redshifts {0.3<z<2.7}. The proposed
150~orbits of NIC2 and 66~hours of MIPS 70um will provide the physical
measurements of the light distribution at the rest-frame ~8000A and
better estimates of the bolometric luminosity. Combining these
parameters together with the rich suite of spectral diagnostics from the
mid-IR spectra, we will {1} measure how common mergers are among LIRGs
and ULIRGs at 0.3<z<2.7, and establish if major mergers are the drivers
of z>1 ULIRGs, as in the local Universe. {2} study the co-evolution of
star formation and blackhole accretion by investigating the relations
between the fraction of starburst/AGN measured from mid-IR spectra vs.
HST morphologies, L{bol} and z. {3} obtain the current best estimates of
the far-IR emission, thus L{bol} for this sample, and establish if the
relative contribution of mid-to-far IR dust emission is correlated with
morphology {resolved vs. unresolved}.
WFPC2 11129
The Star Formation History of the Fornax Dwarf Spheroidal Galaxy
The Fornax dwarf spheroidal galaxy is one of the most luminous dwarf
satellites of the Milky Way. It is unusual in many ways: it hosts 5
globular clusters, shows some relatively young stars, and has faint
sub-structures which have been interpreted as signs of recent
interactions. It is thus of great interest to learn the complete star
formation history {SFH} of Fornax to establish a link between its
evolutionary path and the predictions from numerical simulations, as a
test of our understanding of dwarf galaxy evolution. Yet many questions
remain open. Is the old stellar population made up of stars formed in a
very early burst, perhaps before the epoch of re-ionization, or the
result of a more continuous star formation between 13 and 9 Gyr ago ?
How quickly did Fornax increase its metallicity during its initial
assembly and during subsequent episodes of star formation ? Are
accretion episodes required to explain the age-metallicity history of
Fornax ? However, there has never been a comprehensive study of the
global SFH of the Fornax field based on data of sufficient depth to
unambiguously measure the age mixture of the stellar populations and
their spatial variation. We propose to use the WFPC2 to obtain very deep
images in several fields across the central region of Fornax in order to
reach the oldest main-sequence turnoffs. The number of fields is
determined by the need to measure the SFH over different regions with
distinct kinematics and metallicity. The resolution achievable with HST
is crucial to answer these questions because, to derive the age
distribution of the oldest stars, we are interested in I magnitude
differences of the order 0.2 mag in crowded fields at V=24.5. We will
directly measure the time variation in star-formation rate over the
entire galaxy history, from first stars coeval with the Milky Way halo
to the youngest populations 200 Myr ago. The combination of detailed CMD
analysis with WFPC2 with our existing metallicity and kinematic
information will allow us to trace out the early phases of its
evolution.
WFPC2 11235
HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies
in the Local Universe
At luminosities above 10^11.4 L_sun, the space density of far-infrared
selected galaxies exceeds that of optically selected galaxies. These
`luminous infrared galaxies' {LIRGs} are primarily interacting or
merging disk galaxies undergoing enhanced star formation and Active
Galactic Nuclei {AGN} activity, possibly triggered as the objects
transform into massive S0 and elliptical merger remnants. We propose
NICMOS NIC2 imaging of the nuclear regions of a complete sample of 88
L_IR > 10^11.4 L_sun luminous infrared galaxies in the IRAS Revised
Bright Galaxy Sample {RBGS: i.e., 60 micron flux density > 5.24 Jy}.
This sample is ideal not only in its completeness and sample size, but
also in the proximity and brightness of the galaxies. The superb
sensitivity and resolution of NICMOS NIC2 on HST enables a unique
opportunity to study the detailed structure of the nuclear regions,
where dust obscuration may mask star clusters, AGN and additional nuclei
from optical view, with a resolution significantly higher than possible
with Spitzer IRAC. This survey thus provides a crucial component to our
study of the dynamics and evolution of IR galaxies presently underway
with Wide-Field, HST ACS/WFC and Spitzer IRAC observations of these 88
galaxies. Imaging will be done with the F160W filter {H-band} to examine
as a function of both luminosity and merger stage {i} the luminosity and
distribution of embedded star clusters, {ii} the presence of optically
obscured AGN and nuclei, {iii} the correlation between the distribution
of 1.6 micron emission and the mid- IR emission as detected by Spitzer
IRAC, {iv} the evidence of bars or bridges that may funnel fuel into the
nuclear region, and {v} the ages of star clusters for which photometry
is available via ACS/WFC observations. The NICMOS data, combined with
the HST ACS, Spitzer, and GALEX observations of this sample, will result
in the most comprehensive study of merging and interacting galaxies to
date.
WFPC2 11340
X-ray Observations of 11 Millisecond Pulsars in M28
We propose a deep X-ray survey of the globular cluster M28 which will
yield a wealth of important and unique science, ranging from the first
direct measurement of the magnetic field of a millisecond pulsar and
constraints on the neutron star equation of state to likely
X-ray/optical (HST) detection of a re-exchanged binary MSP. The proposed
joint HST WFPC2 observation will tie the X-ray, optical, and radio data
to a common astrometric frame allowing an unambiguous identification of
numerous cataclysmic variables and active binaries in M28 as well as
making possible the first direct optical detection of a millisecond
pulsar.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports
of potential non-nominal performance that will be investigated.)
HSTARS:
11334 - REAcq(2,1,2) failed to RGA Hold (Gyro Control)
Upon acquisition of signal at 162/12:34:30, REAcq(2,1,2) scheduled at
162/12:30:52 - 12:38:57 was observed to have failed to RGA Hold due to
stop flag (QF2STOPF) on FGS-2. Pre-acq OBAD1 attitude correction (RSS)
value was not available due to LOS. OBAD2 had (RSS) value of 5.48
arcseconds. Post-acq OBAD/MAP had (RSS) value of 13.10 arcseconds. Prior
GSAcq(2,1,2) at 162/10:55:26 was successful.
Possible Observations Affected: WFPCII 87 thru 91, Proposal # 11340.
NICMOS 19, 20, Proposal # 11318
At AOS 162/14:17:45, subsequent REAcq(2,1,2) at 162/14:06:46 also failed
to RGA Hold due to stop flag on FGS-2.
Observations Affected: WFPC 92 thru 96 Proposal # 11340. NICMOS 24, 25
Proposal # 11318
11335 - NICMOS Status Buffer Message
Parameter=1, Time= 4274; NIC in Operate mode; next obs at
163/05:28:10z.#668 indicates MECH_UNSTABLE_INDUCTOSYN Description:
"While verifying the mechanical position following a mechanism movement,
consecutive position calculations give inconsistent values. This
indicates the inductosyn coarse and fine positions are changing. "FSW
Action: Status Buffer Message ERROR Parameter indicates: Mechanism no.
(FW1=0, FW2=1, FW3=2, FOMX=3, FOMY=4). Ground Action: None.
Obs might be affected: NIC #26-28 of Proposal #11155.
Ops Request 18241-0, to reset the NICMOS error counter, was
successfully executed at 162/19:35:45.
COMPLETED OPS REQUEST:
18241-0 - Execute ROP NS-11 Reset NICMOS Error Counter @ 162/1935z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 06 06
FGS REacq 08 06
OBAD with Maneuver 28 27
SIGNIFICANT EVENTS: (None)
David Cottle
UBB Owner & Administrator
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