A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Hubble
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Daily Report #5049



 
 
Thread Tools Display Modes
  #1  
Old March 11th 10, 11:35 AM posted to sci.astro.hubble
Cooper, Joe
external usenet poster
 
Posts: 568
Default Daily Report #5049

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5049

PERIOD COVERED: 5am March 9 - 5am March 10, 2010 (DOY 068/10:00z-069/10:00z)

OBSERVATIONS SCHEDULED

ACS/WFC/WFC3/UV 11633

A Precision White Dwarf Cooling Age for NGC 6397

We propose to obtain second epoch imaging of the globular cluster NGC
6397, which has the deepest ACS/WFC dataset (126 orbits in Cycle 13)
ever obtained in a globular cluster. These additional 14 orbits would
enable the construction of a proper motion - cleaned white dwarf
cooling sequence reaching fainter than the observed truncation point
of the white dwarf luminosity function; a byproduct will be absolute
proper motions (relative to the extragalactic reference frame) of the
rich spheroid field population. Our data shows the long sought ``blue
hook'', a feature in the WD cooling sequence predicted in theoretical
white dwarf models; the improved photometry and statistics afforded by
the second epoch observations are needed to confirm the blue hook and
to test other aspects of white dwarf cooling models that contribute to
a 0.5 Gyr or greater uncertainty in the age. The proposed observations
will provide formal constraints on the age and formation timescale of
NGC 6397 that will be smaller than 1 Gyr and place the cluster's
formation epoch relative to the end of reionization. The final proper
motion-purified white dwarf sequence will be a powerful constraint for
white dwarf cooling models and atmospheres, the basis for white
dwarf-based globular cluster age determinations, and also constrain
the fraction of binary white dwarfs.

COS/NUV 11894

NUV Detector Dark Monitor

The purpose of this proposal is to measure the NUV detector dark rate
by taking long science exposures with no light on the detector. The
detector dark rate and spatial distribution of counts will be compared
to pre-launch and SMOV data in order to verify the nominal operation
of the detector. Variations of count rate as a function of orbital
position will be analyzed to find dependence of dark rate on proximity
to the SAA. Dependence of dark rate as function of time will also be
tracked.

NIC3/WFC3/IR 11149

Characterizing the Stellar Populations in Lyman-Alpha Emitters and
Lyman Break Galaxies at 5.7z7 in the Subaru Deep Field

The epoch of reionization marks a major phase transition of the
Universe, during which the intergalactic space became transparent to
UV photons. Determining when this occurred and the physical processes
involved represents the latest frontier in observational cosmology.
Over the last few years, searches have intensified to identify the
population of high-redshift (z6) galaxies that might be responsible
for this process, but the progress is hampered partly by the
difficulty of obtaining physical information (stellar mass, age, star
formation rate/history) for individual sources. This is because the
number of z6 galaxies that have both secure spectroscopic redshifts
and high-quality infrared photometry (especially with Spitzer/IRAC) is
still fairly small. Considering that only several photometric points
are available per source, and that many model SEDs are highly
degenerate, it is crucial to obtain as many observational constraints
as possible for each source to ensure the validity of SED modeling. To
better understand the physical properties of high-redshift galaxies,
we propose here to conduct HST/NICMOS (72 orbits) and Spitzer/IRAC
(102 hours) imaging of spectroscopically confirmed, bright (z26 mag
(AB)) Ly-alpha emitters (LAEs) and Lyman-break galaxies (LBGs) at
5.7z7 selected from the Subaru Deep Field. Spectroscopic redshifts
remove one critical free parameter from SED modeling while bright
source magnitudes ensure high-quality photometric data. By making
accurate determinations of stellar masses, ages, and star-formation
histories, we will specifically address the following major questions:
(1) Do LAEs and LBGs represent physically different galaxy populations
at z6 as suggested recently? (2) Is Ly-alpha emission systematically
suppressed at z6 with respect to continuum emission? (i.e., are we
reaching the epoch of incomplete reionization?), and (3) Do we see any
sign of abnormally young stellar population in any of the z6
galaxies?

STIS/CC 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CC 11847

CCD Bias Monitor-Part 2

Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1,
and 1x1 at gain = 4, to build up high-S/N superbiases and track the
evolution of hot columns.

STIS/CC/MA 11516

COS-GTO: Cold ISM

With the COS, we will be able to observe interstellar spectra in a new
regime, translucent clouds, for atomic, ionic, and molecular lines and
bands, and extinction curves. The COS will allow us to observe stars
with total visual extinctions up to 10 magnitudes, and the grain size
indicator Rv up to 4.5. In translucent clouds we expect to see the
transition from neutral and ionized carbon to mostly C I, and then
from there, we should expect to see carbon increasingly locked up in
molecular form, as CO. Other species are expected to make similar
transitions, so we should find detectable abundances of molecules such
as H2O, OH, CS, CH2, SiO, and others; also, lower ionization fractions
of the metallic elements - and higher depletions of those elements as
well. Given that we expect to find higher depletions, we should see an
altered grain size distribution, which may show up in the extinction
curves, probably as lower far-UV extinction than in diffuse clouds.
Finally, we will search for neutral PAHs in absorption, as diffuse
bands in the UV, paralleling the optical DIBs (which are thought by
some scientists to be formed by singly-ionized PAHs). In translucent
clouds, models show that the PAHs will be neutral, not in cationic
form.

STIS/CCD/MA1/MA2 11860

MAMA Spectroscopic Sensitivity and Focus Monitor

The purpose of this proposal is to monitor the sensitivity of each
MAMA grating mode to detect any change due to contamination or other
causes, and to also monitor the STIS focus in a spectroscopic and an
imaging mode.

WFC3/IR/S/C 11929

IR Dark Current Monitor

Analyses of ground test data showed that dark current signals are more
reliably removed from science data using darks taken with the same
exposure sequences as the science data, than with a single dark
current image scaled by desired exposure time. Therefore, dark current
images must be collected using all sample sequences that will be used
in science observations. These observations will be used to monitor
changes in the dark current of the WFC3-IR channel on a day-to-day
basis, and to build calibration dark current ramps for each of the
sample sequences to be used by Gos in Cycle 17. For each sample
sequence/array size combination, a median ramp will be created and
delivered to the calibration database system (CDBS).

WFC3/UV/IR 11664

The WFC3 Galactic Bulge Treasury Program: Populations, Formation
History, and Planets

Exploiting the full power of the Wide Field Camera 3 (WFC3), we
propose deep panchromatic imaging of four fields in the Galactic
bulge. These data will enable a sensitive dissection of its stellar
populations, using a new set of reddening-free photometric indices we
have constructed from broad-band filters across UV, optical, and
near-IR wavelengths. These indices will provide accurate temperatures
and metallicities for hundreds of thousands of individual bulge stars.
Proper motions of these stars derived from multi-epoch observations
will allow separation of pure bulge samples from foreground disk
contamination. Our catalogs of proper motions and panchromatic
photometry will support a wide range of bulge studies.

Using these photometric and astrometric tools, we will reconstruct the
detailed star-formation history as a function of position within the
bulge, and thus differentiate between rapid- and extended-formation
scenarios. We will also measure the dependence of the stellar mass
function on metallicity, revealing how the characteristic mass of star
formation varies with chemistry. Our sample of bulge stars with
accurate metallicities will include 12 candidate hosts of extrasolar
planets. Planet frequency is correlated with metallicity in the solar
neighborhood; our measurements will extend this knowledge to a remote
environment with a very distinct chemistry.

Our proposal also includes observations of six well-studied globular
and open star clusters; these observations will serve to calibrate our
photometric indices, provide empirical population templates, and
transform the theoretical isochrone libraries into the WFC3 filter
system. Besides enabling our own program, these products will provide
powerful new tools for a host of other stellar-population
investigations with HST/WFC3. We will deliver all of the products from
this Treasury Program to the community in a timely fashion.

WFC3/UVIS 11628

Globular Cluster Candidates for Hosting a Central Black Hole

We are continuing our study of the dynamical properties of globular
clusters and we propose to obtain surface brightness profiles for high
concentration clusters. Our results to date show that the distribution
of central surface brightness slopes do not conform to standard
models. This has important implications for how they form and evolve,
and suggest the possible presence of central intermediate-mass black
holes. From our previous archival proposals (AR-9542 and AR- 10315),
we find that many high concentration globular clusters do not have
flat cores or steep central cusps, instead they show weak cusps.
Numerical simulations suggest that clusters with weak cusps may harbor
intermediate-mass black holes and we have one confirmation of this
connection with omega Centauri. This cluster shows a shallow cusp in
its surface brightness profile, while kinematical measurements suggest
the presence of a black hole in its center. Our goal is to extend
these studies to a sample containing 85% of the Galactic globular
clusters with concentrations higher than 1.7 and look for objects
departing from isothermal behavior. The ACS globular cluster survey
(GO-10775) provides enough objects to have an excellent coverage of a
wide range of galactic clusters, but it contains only a couple of the
ones with high concentration. The proposed sample consists of clusters
whose light profile can only be adequately measured from space-based
imaging. This would take us close to completeness for the high
concentration cases and therefore provide a more complete list of
candidates for containing a central black hole. The dataset will also
be combined with our existing kinematic measurements and enhanced with
future kinematic studies to perform detailed dynamical modeling.

WFC3/UVIS 11905

WFC3 UVIS CCD Daily Monitor

The behavior of the WFC3 UVIS CCD will be monitored daily with a set
of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K
subarray biases are acquired at less frequent intervals throughout the
cycle to support subarray science observations. The internals from
this proposal, along with those from the anneal procedure (Proposal
11909), will be used to generate the necessary superbias and superdark
reference files for the calibration pipeline (CDBS).

WFC3/UVIS 11912

UVIS Internal Flats

This proposal will be used to assess the stability of the flat field
structure for the UVIS detector throughout the 15 months of Cycle 17.
The data will be used to generate on-orbit updates for the delta-flat
field reference files used in the WFC3 calibration pipeline, if
significant changes in the flat structure are seen.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

For DOY 055

12213 - Review of the 053 SMS PTAS lg2 file found that GSAcq(2,1,1) at
055/21:59:00z took two attempts to achieve Coarse Track Data Valid.
The acquisition was eventually successful and finished well within the
time allotted so there was no effect on the science observation.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 7 7
FGS REAcq 7 7
OBAD with Maneuver 6 6

SIGNIFICANT EVENTS: (None)

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Daily Report #4825 Cooper, Joe Hubble 0 April 3rd 09 04:22 PM
Daily Report Cooper, Joe Hubble 0 December 22nd 08 06:17 PM
Daily Report #4437 Cooper, Joe Hubble 0 August 31st 07 10:50 AM
Daily Report [email protected] Hubble 0 October 29th 04 04:59 PM
HST Daily Report 131 George Barbehenn Hubble 0 May 11th 04 02:48 PM


All times are GMT +1. The time now is 10:32 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.