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Daily Report #5172



 
 
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Old September 1st 10, 04:43 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5172


HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5172

PERIOD COVERED: 5am August 31 - 5am September 1, 2010 (DOY 243/09:00z-244/09:00z)

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

12372 - GSAcq(2,1,1) at 244/06:14:12z and REAcq(2,1,1) at
244/07:45:09z both acquired fine lock backup on FGS 2.

Observations possibly affected WFC3 77-81, Proposal ID#11729.


FOR DOY 228:

12370 - REAcq(1,2,1) at 228/06:33:05z required two attempts to achieve
FL-DV on FGS1. The acquisition was successful.

Observations possibly affected: ACS 12 Proposal ID#11996 and STIS 6
Proposal ID#11668.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 10 10
FGS REAcq 08 08
OBAD with Maneuver 08 08

SIGNIFICANT EVENTS: (None)

OBSERVATIONS SCHEDULED:

ACS/WFC 11996

CCD Daily Monitor (Part 3)

This program comprises basic tests for measuring the read noise and
dark current of the ACS WFC and for tracking the growth of hot pixels.
The recorded frames are used to create bias and dark reference images
for science data reduction and calibration. This program will be
executed four days per week (Mon, Wed, Fri, Sun) for the duration of
Cycle 17. To facilitate scheduling, this program is split into three
proposals. This proposal covers 308 orbits (19.25 weeks) from 21 June
2010 to 1 November 2010.

WFC3/UVIS 11729

Photometric Metallicity Calibration with WFC3 Specialty Filters

The community has chosen to include several filters in the WFC3 filter
complement that have been designed to allow fairly precise estimates
of stellar metallicities, and many science programs are enabled by
this capability. Since these filters do not exactly match those used
for this purpose on the ground, however, the mapping of stellar colors
to stellar metallicities needs to be calibrated. We propose to achieve
this calibration through observations of five stellar clusters with
well known metallicities. We will calibrate several different filter
calibrations which will allow future users to determine what filter
combination best meets their science needs.


STIS/CC/MA 11668

Cosmo-chronometry and Elemental Abundance Distribution of the Ancient
Star HE1523-0901

We propose to obtain near-UV HST/STIS spectroscopy of the extremely
metal-poor, highly r-process-enhanced halo star HE 1523-0901, in order
to produce the most complete abundance distribution of the heaviest
stable elements, including platinum, osmium, and lead. These HST
abundance data will then be used to estimate the initial abundances of
the long-lived radioactive elements thorium and uranium, and by
comparison with their observed abundances, enable an accurate age
determination of this ancient star. The use of radioactive
chronometers in stars provides an independent lower limit on the age
of the Galaxy, which can be compared with alternative limits set by
globular clusters and by analysis from WMAP. Our proposed observations
of HE1523-0901 will also provide significant new information about the
early chemical history of the Galaxy, specifically, the nature of the
first generations of stars and the types of nucleosynthetic processes
that occurred at the onset of Galactic chemical evolution.

ACS/WFC3 11604

The Nuclear Structure of OH Megamaser Galaxies

We propose a snapshot survey of a complete sample of 80 OH megamaser
galaxies. Each galaxy will be imaged with the ACS/WFC through F814W
and a linear ramp filter (FR656N or FR716N or FR782N or FR853N)
allowing us to study both the spheroid and the gas morphology in
Halpha + [N II]. We will use the 9% ramps FR647M (5370-7570 angstroms)
centered at 7000 angstroms and FR914M (7570-10, 719 angstroms) 8000
angstroms for continuum subtraction for the high and low z objects
respectively. OH megamaser galaxies (OHMG) form an important class of
ultraluminous IR-galaxies (ULIRGs) whose maser lines emit QSO-like
luminosities. ULIRGs in general are associated with recent mergers but
it is often unclear whether their power output is dominated by
starbursts or a hidden QSO because of the high absorbing columns which
hide their nuclei even at X-ray wavelengths. In contrast, OHMG exhibit
strong evidence for the presence of an energetically important and
recently triggered active nucleus. In particular it is clear that much
of the gas must have already collapsed to form a nuclear disk which
may be the progenitor of a circum-nuclear torus, a key element of the
unified scheme of AGN. A great advantage of studying OHMG systems over
the general ULIRG population, is that the circum-nuclear disks are
effectively "fixed" at an inner, edge on, orientation, eliminating
varying inclination as a nuisance parameter. We will use the HST
observations in conjunction with existing maser and spectroscopic data
to construct a detailed picture of the circum-nuclear regions of a
hitherto relatively neglected class of galaxy that may hold the key to
understanding the relationship between galaxy mergers, nuclear star-
formation, and the growth of massive black holes and the triggering of
nuclear activity.

COS/NUV 11540

COS-GTO: Search for Hydrocarbons and Nitriles in Pluto's Atmosphere

Methane is highly abundant in Pluto's atmosphere, and methane
photolysis is the starting point for a series of chemical processes
that should result in the production of hydrocarbons and nitriles.
Photochemical modeling of Pluto's atmosphere has suggested that
detectable abundances of various hydrocarbons and nitriles should
occur on Pluto. However, past analysis of 40 orbits of archival
HST/FOS data in the mid-UV has only produced upper limits on
abundances of C4H2, C6H2, HC3N, and C4N2. We will use COS to obtain
spectra from 2060-2460A, including absorption bands of the hydrocarbon
diacetylene (C4H2) and the nitrile cyanoacetylene (HC3N).
Previously-measured 2-sigma upper limits for these compounds are
somewhat below the values computed in the poorly-constrained models;
the measurement uncertainties themselves are of the same order as the
modeled values. By reducing the uncertainties by a factor of a few to
several, we aim to detect the presence of these compounds, or to
provide more restrictive abundance limits. These measurements will
provide valuable new data on the nature and chemistry of the Plutonian
atmosphere.

STIS/CCD 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CCD 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/MA2 11862

MAMA NUV Flats

This program will obtain NUV-MAMA observations of the STIS internal
Deuterium lamp to construct an NUV flat applicable to all NUV modes.

WFC3/ACS/IR 11563

Galaxies at z~7-10 in the Reionization Epoch: Luminosity Functions to
0.2L* from Deep IR Imaging of the HUDF and HUDF05 Fields

The first generations of galaxies were assembled around redshifts
z~7-10+, just 500-800 Myr after recombination, in the heart of the
reionization of the universe. We know very little about galaxies in
this period. Despite great effort with HST and other telescopes, less
than ~15 galaxies have been reliably detected so far at z7,
contrasting with the ~1000 galaxies detected to date at z~6, just
200-400 Myr later, near the end of the reionization epoch. WFC3 IR can
dramatically change this situation, enabling derivation of the galaxy
luminosity function and its shape at z~7-8 to well below L*,
measurement of the UV luminosity density at z~7-8 and z~8-9, and
estimates of the contribution of galaxies to reionization at these
epochs, as well as characterization of their properties (sizes,
structure, colors). A quantitative leap in our understanding of early
galaxies, and the timescales of their buildup, requires a total sample
of ~100 galaxies at z~7-8 to ~29 AB mag. We can achieve this with 192
WFC3 IR orbits on three disjoint fields (minimizing cosmic variance):
the HUDF and the two nearby deep fields of the HUDF05. Our program
uses three WFC3 IR filters, and leverages over 600 orbits of existing
ACS data, to identify, with low contamination, a large sample of over
100 objects at z~7-8, a very useful sample of ~23 at z~8-9, and limits
at z~10. By careful placement of the WFC3 IR and parallel ACS
pointings, we also enhance the optical ACS imaging on the HUDF and a
HUDF05 field. We stress (1) the need to go deep, which is paramount to
define L*, the shape, and the slope alpha of the luminosity function
(LF) at these high redshifts; and (2) the far superior performance of
our strategy, compared with the use of strong lensing clusters, in
detecting significant samples of faint z~7-8 galaxies to derive their
luminosity function and UV ionizing flux. Our recent z~7.4 NICMOS
results show that wide-area IR surveys, even of GOODS-like depth,
simply do not reach faint enough at z~7-9 to meet the LF and UV flux
objectives. In the spirit of the HDF and the HUDF, we will waive any
proprietary period, and will also deliver the reduced data to STScI.
The proposed data will provide a Legacy resource of great value for a
wide range of archival science investigations of galaxies at redshifts
z~2- 9. The data are likely to remain the deepest IR/optical images
until JWST is launched, and will provide sources for spectroscopic
follow up by JWST, ALMA and EVLA.

WFC3/ACS/IR 11647

A Deep Exploration of Classes of Long Period Variable Stars in M31

We propose a thrifty but information-packed investigation with WFC3/IR
F160W and F110W providing crucial information about Long Period
Variables in M31, at a level of detail that has recently allowed the
discovery of new variable star classes in the Magellanic Clouds, a
very different stellar population. These observations are buttressed
by an extensive map of the same fields with ACS and WFC3 exposures in
F555W and F814W, and a massive ground- based imaging patrol producing
well-sampled light curves for more than 400,000 variable stars. Our
primary goal is to collect sufficient NIR data in order to analyze and
classify the huge number of long-period variables in our catalog (see
below) through Period Luminosity (P/L) diagrams. We will produce
accurate P/L diagrams for both the bulge and a progression of
locations throughout the disk of M31. These diagrams will be similar
in quality to those currently in the Magellanic Clouds, with their
lower metallicity, radically different star formation history, and
larger spread in distance to the variables. M31 offers an excellent
chance to study more typical disk populations, in a manner which might
be extended to more distant galaxies where such variables are still
visible, probing a much more evenly spread progenitor age distribution
than cepheids (and perhaps useful as a distance scale alternative or
cross- check). Our data will also provide a massive and unique
color-magnitude dataset; we expect that this study will produce
several important results, among them a better understanding of P/L
and P/L-color relations for pulsating variables which are essential to
the extragalactic distance ladder. We will view these variables at a
common distance over a range of metallicities (eliminating the
distance-error vs. metallicity ambiguity between the LMC and SMC),
allow further insight into possible faint-variable mass-loss for
higher metallicities, and in general produce a sample more typical of
giant disk galaxies predominant in many studies.

WFC3/ACS/IR 11840

Identifying the Host Galaxies for Optically Dark Gamma-Ray Bursts

We propose to use the high spatial resolution of Chandra to obtain
precise positions for a sample of Gamma-Ray Bursts (GRBs) with no
optical afterglows, where the optical light is suppressed relative to
the X-ray flux. These bursts are likely to be highly obscured and may
have different environments from the optically bright GRBs. Our
Chandra observations will (unlike Swift XRT positions) allow for the
unique identification of a host galaxy. To locate these host galaxies
we will follow up our Chandra positions with deep optical and IR
observations with HST. The ultimate aim is to understand any
differences between the host galaxies of optically dark and bright
GRBs, and how these affect the use of GRBs as tracers of starformation
and galaxy evolution at high redshift.

WFC3/ACS/UVIS 11684

The First Proper Motion Measurement for M31: Dynamics and Mass of the
Local Group

We will perform observations to determine the proper motion of the
Andromeda galaxy M31, which has been sought for almost a century
without success. While challenging, this measurement has now become
possible due to the availability of existing deep ACS/WFC images of
several M31 fields. The requested second epoch images will yield the
average shift of the M31 stars with respect to compact galaxies in the
background. Our observing strategy uses six different fields (three
primary and three coordinated parallel) with two different instruments
(ACS and WFC3) to provide a maximum handle on possible systematic
effects. The expected result will be sufficiently accurate to: (a)
discriminate between different histories for the dynamics of the Local
Group; (b) constrain the mass distribution of the Local Group; (c)
determine the details of the expected future merger between M31 and
the Milky Way; (d) infer the past interaction history between M31 and
M33; (e) constrain the internal proper motion kinematics of the M31
spheroid, outer disk, and tidal stream; and (f) obtain a pilot
estimate of the M31 distance through the method of rotational
parallax.

WFC3/IR/ACS/WFC 11663

Formation and Evolution of Massive Galaxies in the Richest
Environments at 1.5 z 2.0

We propose to image seven 1.5z2 clusters and groups from the IRAC
Shallow Cluster Survey with WFC3 and ACS in order to study the
formation and evolution of massive galaxies in the richest
environments in the Universe in this important redshift range. We will
measure the evolution of the sizes and morphologies of massive cluster
galaxies, as a function of redshift, richness, radius and local
density. In combination with allocated Keck spectroscopy, we will
directly measure the dry merger fraction in these clusters, as well as
the evolution of Brightest Cluster Galaxies (BCGs) over this redshift
range where clear model predictions can be confronted. Finally we will
measure both the epoch of formation of the stellar populations and the
assembly history of that stellar mass, the two key parameters in the
modern galaxy formation paradigm.

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/IR/S/C 12089

Persistence - Part 2

The IR detectors on WFC3, like other IR detectors, trap charge when
exposed to sources near or above the full well of the detector diodes.
This charge leaks out, producing detectable afterglow images for
periods which can last for several hours, depending on the amount of
over exposure. These visits, which consist of tungsten lamp exposures
of varying durations followed by darks, are intended to provide a
better calibration of persistence over the full area of the IR
detector of WFC3.

WFC3/UV 12237

Orbits, Masses, Densities, and Colors of Two Transneptunian Binaries

Binaries are the key to learning many crucial bulk properties of
transneptunian objects (TNOs) including their masses. Perhaps the most
interesting mass-dependent property of a TNO is its bulk density,
which provides unique information about its bulk composition and
interior structure. Densities have so far only been measured for a
handful of binary TNO systems. This proposal seeks to determine orbits
and thus masses of two more binary TNOs, both of which are also to be
observed at thermal infrared wavelengths by the Herschel spacecraft.
Combining the masses from Hubble with the sizes from Herschel will
enable us to compute their densities. We will also obtain
multi-wavelength photometric colors of the individual components of
each binary system. It is imperative to link colors to the physical
properties measurable in binary systems in order to use the remnant
planetesimals in today's Kuiper belt to learn more about the early
history of our own solar system, and more generally about how
planetesimals form in nebular disks and subsequently evolve.

WFC3/UVIS 11565

A Search for Astrometric Companions to Very Low-Mass, Population II
Stars

We propose to carry out a Snapshot search for astrometric companions
in a subsample of very low-mass, halo subdwarfs identified within 120
parsecs of the Sun. These ultra-cool M subdwarfs are local
representatives of the lowest-mass H burning objects from the Galactic
Population II. The expected 3-4 astrometric doubles that will be
discovered will be invaluable in that they will be the first systems
from which gravitational masses of metal-poor stars at the bottom of
the main sequence can be directly measured.

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.

 




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