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Daily Report #4620



 
 
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Old May 29th 08, 03:28 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #4620

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT*** # 4620

PERIOD COVERED: 5am May 28 - 5am May 29, 2008 (DOY
149/0900z-150/0900z)

OBSERVATIONS SCHEDULED

FGS 11212

Filling the Period Gap for Massive Binaries

The current census of binaries among the massive O-type stars is
seriously incomplete for systems in the period range from years to
millennia because the radial velocity variations are too small and the
angular separations too close for easy detection. Here we propose to
discover binaries in this observational gap through a Faint Guidance
Sensor SNAP survey of relatively bright targets listed in the Galactic
O Star Catalog. Our primary goal is to determine the binary frequency
among those in the cluster/association, field, and runaway groups. The
results will help us assess the role of binaries in massive star
formation and in the processes that lead to the ejection of massive
stars from their natal clusters. The program will also lead to the
identification of new, close binaries that will be targets of long
term spectroscopic and high angular resolution observations to
determine their masses and distances. The results will also be
important for the interpretation of the spectra of suspected and newly
identified binary and multiple systems.

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 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.

NIC3 11120

A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic
Center

The Galactic center (GC) is a unique site for a detailed study of a
multitude of complex astrophysical phenomena, which may be common to
nuclear regions of many galaxies. Observable at resolutions
unapproachable in other galaxies, the GC provides an unparalleled
opportunity to improve our understanding of the interrelationships of
massive stars, young stellar clusters, warm and hot ionized gases,
molecular clouds, large scale magnetic fields, and black holes. We
propose the first large-scale hydrogen Paschen alpha line survey of
the GC using NICMOS on the Hubble Space Telescope. This survey will
lead to a high resolution and high sensitivity map of the Paschen
alpha line emission in addition to a map of foreground extinction,
made by comparing Paschen alpha to radio emission. This survey of the
inner 75 pc of the Galaxy will provide an unprecedented and complete
search for sites of massive star formation. In particular, we will be
able to (1) uncover the distribution of young massive stars in this
region, (2) locate the surfaces of adjacent molecular clouds, (3)
determine important physical parameters of the ionized gas, (4)
identify compact and ultra-compact HII regions throughout the GC. When
combined with existing Chandra and Spitzer surveys as well as a wealth
of other multi-wavelength observations, the results will allow us to
address such questions as where and how massive stars form, how
stellar clusters are disrupted, how massive stars shape and heat the
surrounding medium, and how various phases of this medium are
interspersed.

NIC3 11333

NICMOS non-linearity tests

This program incorporates a number of tests to analyze the count rate
dependent non-linearity seen in NICMOS spectro-photometric
observations.

We will observe a field with stars of a range in luminosity in NGC3603
with NICMOS in NIC1: F090M, F110W, F140W, F160W NIC2: F110W, F160W,
F187W, F205W, and F222M NIC3: F110W, F150W, F160W, F175W, and F222M.
We will repeat the observations with flatfield lamp on, creating
artificially high count-rates, allowing tests of NICMOS linearity as
function of count rate. We first take exposures with the lamp off,
then exposures with the lamp on, and repeat at the end with lamp off.
Finally, we continue with taking darks during occultation.

We will furthermore observe spectro-photometric standard P041C using
the G096, G141, and G206 grisms in NIC3, and repeat the lamp
off/on/off test to artificially create a high background.

WFPC2 11103

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful SNAPshot survey
of a sample of 125 very X-ray luminous clusters in the redshift range
0.3-0.7. As demonstrated by the 25 snapshots obtained so far in
Cycle14 and Cycle15 these systems frequently exhibit strong
gravitational lensing as well as spectacular examples of violent
galaxy interactions. The proposed observations will provide important
constraints on the cluster mass distributions, the physical nature of
galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set
of optically bright, lensed galaxies for further 8-10m spectroscopy.
All of our primary science goals require only the detection and
characterization of high-surface-brightness features and are thus
achievable even at the reduced sensitivity of WFPC2. Because of their
high redshift and thus compact angular scale our target clusters are
less adversely affected by the smaller field of view of WFPC2 than
more nearby systems. Acknowledging the broad community interest in
this sample we waive our data rights for these observations. Due to a
clerical error at STScI our approved Cycle15 SNAP program was barred
from execution for 3 months and only 6 observations have been
performed to date - reinstating this SNAP at Cycle16 priority is of
paramount importance to reach meaningful statistics.

WFPC2 11227

The orbital period for an ultraluminous X-ray source in NGC1313

The ultraluminous X-ray sources {ULXs} are extragalactic point sources
with luminosities that exceed the Eddington luminosity for
conventional stellar-mass black holes by factors of 10 - 100. It has
been hotly debated whether the ULXs are just common stellar-mass black
hole sources with beamed emission or whether they are sub-Eddington
sources that are powered by the long-sought intermediate mass black
holes {IMBH}. To firmly decide this question, one must obtain
dynamical mass measurements through photometric and spectroscopic
monitoring of the secondaries of these system. The crucial first step
is to establish the orbital period of a ULX, and arguably the best way
to achieve this goal is by monitoring its ellipsoidal light curve. The
extreme ULX NGC1313 X-2 provides an outstanding target for an orbital
period determination because its relatively bright optical counterpart
{V = 23.5} showed a 15% variation between two HST observations
separated by three months. This level of variability is consistent
with that expected for a tidally distorted secondary star. Here we
propose a set of 20 imaging observations with HST/WFPC2 to define the
orbital period. This would be the first photometric measurement of the
orbital period of a ULX binary. Subsequently, we will propose to
obtain spectroscopic observations to obtain its radial velocity
amplitude and thereby a dynamical estimate of its mass.

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.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11323 - GSaqc(2,1,2) failed to RGA control

GSacq(2,1,2) scheduled at 149/1913:45 failed to RGA control at
19:17:11. There were no error flags. ESB message "a07" FGS Coarse
Track failed -Timed out waiting for data valid. OBAD1 showed errors of
V1=963.29, V2=1802.49, V3=-2686.73 and RSS=3375.71. ODAB2 showed
errors of V1=-3.07, V2=-1.47, V3=19.89 and RSS=20.18. The Map at
19:21:00 showed errors of V1=-35.89, V2=-29.99, V3=-6.43 and
RSS=47.21.

COMPLETED OPS REQUEST:

18237-0 - Execute ROP NS-11 Reset NICMOS Error Counter @ 149/22:06z

COMPLETED OPS NOTES: (None)

********************** SCHEDULED***** SUCCESSFUL
FGS GSacq************** 11**************** 10
FGS REacq************** 02**************** 02
OBAD with Maneuver **** 26**************** 26

SIGNIFICANT EVENTS: (None)


 




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