HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5179
PERIOD
COVERED: 5am September 13 - 5am September 14, 2010 (DOY 256/09:00z-257/09:00z)
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
12402
- COS 1021 STB Message received at 257/01:22z, following successful
GSAcq (2,1,1) at
257/01:15:46z, indicating take data flag was down when a target
acquisition macro was about to
make a slew request.
Observations possibly
affected: WFC3 20-21 Proposal ID#11905.
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSAcq
7
7
FGS
REAcq
9
9
OBAD
with Maneuver 3
3
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.
ACS/WFC
12210
SLACS
for the Masses: Extending Strong Lensing to Lower Masses and
Smaller
Radii
Strong
gravitational lensing provides the most accurate possible
measurement
of mass in the central regions of early-type galaxies
(ETGs).
We propose to continue the highly productive Sloan Lens ACS
(SLACS)
Survey for strong gravitational lens galaxies by observing a
substantial
fraction of 135 new ETG gravitational-lens candidates with
HST-ACS
WFC F814W Snapshot imaging. The proposed target sample has been
selected
from the seventh and final data release of the Sloan Digital
Sky
Survey, and is designed to complement the distribution of previously
confirmed
SLACS lenses in lens-galaxy mass and in the ratio of Einstein
radius
to optical half-light radius. The observations we propose will
lead
to a combined SLACS sample covering nearly two decades in mass,
with
dense mapping of enclosed mass as a function of radius out to the
half-light
radius and beyond. With this longer mass baseline, we will
extend
our lensing and dynamical analysis of the mass structure and
scaling
relations of ETGs to galaxies of significantly lower mass, and
directly
test for a transition in structural and dark-matter content
trends
at intermediate galaxy mass. The broader mass coverage will also
enable
us to make a direct connection to the structure of well-studied
nearby
ETGs as deduced from dynamical modeling of their line-of-sight
velocity
distribution fields. Finally, the combined sample will allow a
more
conclusive test of the current SLACS result that the intrinsic
scatter
in ETG mass-density structure is not significantly correlated
with
any other galaxy observables. The final SLACS sample at the
conclusion
of this program will comprise approximately 130 lenses with
known
foreground and background redshifts, and is likely to be the
largest
confirmed sample of strong-lens galaxies for many years to come.
ACS/WFC
12292
SWELLS:
Doubling the Number of Disk-dominated Edge-on Spiral Lens
Galaxies
The
formation of realistic disk galaxies within the LCDM cosmology is
still
largely an unsolved problem. Theory is now beginning to make
predictions
for how dark matter halos respond to galaxy formation, and
for
the properties of disk galaxies. Measuring the density profiles of
dark
matter halos on galaxy scales is therefore a strong test for the
standard
paradigm of galaxy formation, offering great potential for
discovery.
However, the degeneracy between the stellar and dark matter
contributions
to galaxy rotation curves remains a major obstacle. Strong
gravitational
lensing, when combined with spatially resolved kinematics
and
stellar population models, can solve this long-standing problem.
Unfortunately,
this joint methodology could not be exploited until
recently
due to the paucity of known edge-on spiral lenses. We have
developed
and demonstrated an efficient technique to find exactly these
systems.
During supplemental cycle-16 we discovered five new spiral lens
galaxies,
suitable for rotation curve measurements. We propose
multi-color
HST imaging of 16 candidates and 2 partially-imaged
confirmed
systems, to measure a sample of eight new edge-on spiral
lenses.
This program will at least double the number of known
disk-dominated
systems. This is crucial for constraining the relative
contribution
of the disk, bulge and dark halo to the total density
profile.
ACS/WFC3
11734
The
Hosts of High Redshift Gamma-Ray Bursts
Gamma-ray
bursts are the most luminous explosive events known, acting as
beacons
to the high redshift universe. Long duration GRBs have their
origin
in the collapse of massive stars and thus select star forming
galaxies
across a wide range of redshift. Due to their bright afterglows
we
can study the details of GRB host galaxies via absorption
spectroscopy,
providing redshifts, column densities and metallicities
for
galaxies far too faint to be accessible directly with current
technology.
We have already obtained deep ground based observations for
many
hosts and here propose ACS/WFC3 and WFC3 observations of the fields
of
bursts at z>3 which are undetected in deep ground based images. These
observations
will study the hosts in emission, providing luminosities
and
morphologies and will enable the construction of a sample of high-z
galaxies
with more detailed physical properties than has ever been
possible
before.
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/CCD/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.
STIS/CCD/MA1
11737
The
Distance Dependence of the Interstellar N/O Abundance Ratio: A Gould
Belt
Influence?
The
degree of elemental abundance homogeneity in the interstellar medium
is
a function of the enrichment and mixing processes that govern
galactic
chemical evolution. Observations of young stars and the
interstellar
gas within ~500 pc of the Sun have revealed a local ISM
that
is so well-mixed it is having an impact on ideas regarding the
formation
of extrasolar planets. However, the situation just beyond the
local
ISM is not so clear. Sensitive UV absorption line measurements
have
recently revealed a pattern of inhomogeneities in the interstellar
O,
N, and Kr gas-phase abundances at distances of ~500 pc and beyond
that
appear nucleosynthetic in origin rather than due to dust depletion.
In
particular, based on a sample of 13 sightlines, Knauth et al. (2006)
have
found that the nearby stars (d < 500 pc) exhibit a mean
interstellar
N/O abundance ratio that is significantly higher (0.18 dex)
than
that toward the more distant stars. Interestingly, all of their
sightlines
lie in the sky vicinity of the Gould Belt of OB associations,
molecular
clouds, and diffuse gas encircling the Sun at a distance of
~400
pc. Is it possible that mixing processes have not yet smoothed out
the
recent ISM enrichment by massive stars in the young Belt region? By
measuring
the interstellar N/O ratios in a strategic new sample of
sightlines
with STIS, we propose to test the apparent N/O homogeneity
inside
the Gould Belt and determine if the apparent decline in the N/O
ratio
with distance is robust and associated with the Belt region.
STIS/MA1/MA2
11857
STIS
Cycle 17 MAMA Dark Monitor
This
proposal monitors the behavior of the dark current in each of the
MAMA
detectors.
The
basic monitor takes two 1380s ACCUM darks each week with each
detector.
However, starting Oct 5, pairs are only included for weeks
that
the LRP has external MAMA observations planned. The weekly pairs of
exposures
for each detector are linked so that they are taken at
opposite
ends of the same SAA free interval. This pairing of exposures
will
make it easier to separate long and short term temporal variability
from
temperature dependent changes.
For
both detectors, additional blocks of exposures are taken once every
six
months. These are groups of five 1314s FUV-MAMA Time-Tag darks or
five
3x315s NUV ACCUM darks distributed over a single SAA-free interval.
This
will give more information on the brightness of the FUV MAMA dark
current
as a function of the amount of time that the HV has been on, and
for
the NUV MAMA will give a better measure of the short term
temperature
dependence.
WFC3/IR
12265
Determining
the Physical Nature of a Unique Giant Lya Emitter at z=6.595
We
propose deep WFC3/IR imaging for a giant Lya emitter (LAE) with a
Keck
spectroscopic redshift of z=6.595 discovered by extensive
narrow-band
imaging with Subaru in the SXDS-UKIDSS/UDS field. This
remarkable
object is unique in many respects including its large stellar
mass
and luminous nebula which extends over 17 kpc; no equivalent source
has
been found in other surveys. The nature of this rare object is
unclear.
Fundamental to progress is determining the origin of star
formation
in such an early massive object; if the age of the stellar
population
is short we are likely witnessing a special moment in the
formation
history of a massive galaxy. The heating source for the nebula
is
also unclear; options include intense star formation, the infall of
cold
gas onto a dark halo or shock heating from a merger. We will take
deep
broad-band (F125W and F160W) images and an intermediate-band
(F098M)
image which will be analyzed in conjunction with ultra-deep IRAC
3.6
and 4.5 micron data being taken by the Spitzer/SEDS project. These
data
will enable us to constrain the star formation rate and stellar
age.
Moreover, the UV continuum morphology and Lya-line distribution
will
be investigated for evidence of a major merger, cold accretion, or
hot
bubbles associated with outflows. We will address the physical
origin
of the remarkable object observed at an epoch where massive
galaxies
are thought to begin their assembly.
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/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
11914
UVIS
Earth Flats
This
program is an experimental path finder for Cycle 18 calibration.
Visible-wavelength
flat fields will be obtained by observing the dark
side
of the Earth during periods of full moon illumination. The
observations
will consist of full-frame streaked WFC3 UVIS imagery: per
22-
min total exposure time in a single "dark-sky" orbit, we anticipate
collecting
7000 e/pix in F606W or 4500 e/pix in F814W. To achieve
Poisson
S/N > 100 per pixel, we require at least 2 orbits of F606W and 3
orbits
of F814W.
For
UVIS narrowband filters, exposures of 1 sec typically do not
saturate
on the sunlit Earth, so we will take sunlit Earth flats for
three
of the more-commonly used narrowband filters in Cycle 17 plus the
also-popular
long-wavelength quad filters, for which we get four filters
at
once.
Why
not use the Sunlit Earth for the wideband visible-light filters? It
is
too bright in the visible for WFC3 UVIS minimum exposure time of 0.5
sec.
Similarly, for NICMOS the sunlit-Earth is too bright which
saturates
the detector too quickly and/or induces abnormal behaviors
such
as super-shading (Gilmore 1998, NIC 098-011). In the narrowband
visible
and broadband near- UV is not too bright (predictions in Cox et
al.
1987 "Standard Astronomical Sources for HST: 6. Spatially Flat
Fields."
and observations in ACS Program 10050).
Other
possibilities? Cox et al.'s Section II.D addresses many other
possible
sources for flat fields, rejecting them for a variety of
reasons.
A remaining possibility would be the totally eclipsed moon.
Such
eclipses provide approximately 2 hours (1 HST orbit) of opportunity
per
year, so they are too rare to be generically useful. An advantage of
the
moon over the Earth is that the moon subtends less than 0.25 square
degree,
whereas the Earth subtends a steradian or more, so scattered
light
and light potentially leaking around the shutter presents
additional
problems for the Earth. Also, we're unsure if HST can point
180
deg from the Sun.
WFC3/UVIS/IR
11909
UVIS
Hot Pixel Anneal
The
on-orbit radiation environment of WFC3 will continually generate new
hot
pixels. This proposal performs the procedure required for repairing
those
hot pixels in the UVIS CCDs. During an anneal, the two-stage
thermo-electric
cooler (TEC) is turned off and the four-stage TEC is
used
as a heater to bring the UVIS CCDs up to ~20 deg. C. As a result of
the
CCD warmup, a majority of the hot pixels will be fixed; previous
instruments
such as WFPC2 and ACS have seen repair rates of about 80%.
Internal
UVIS exposures are taken before and after each anneal, to allow
an
assessment of the procedure's effectiveness in WFC3, provide a check
of
bias, global dark current, and hot pixel levels, as well as support
hysteresis
(bowtie) monitoring and CDBS reference file generation. One
IR
dark is taken after each anneal, to provide a check of the IR
detector.
-Lynn HST
AOD Mission Success: "There is only DO...no try. "*
Lynn F.
Bassford office#: 301-286-2876 Work Cell#: 301-741-9095
Hubble Space Telescope
CHAMP Mission Operations Manager
CHAMP Flight Operations Team Manager
Lockheed Martin Mission Services (LMMS)
Text/Pager: 3017419095@vtext.com
* Ref: "Do, or do not. There is no
'try.' "by Jedi Master Yoda, SW:
Episode V, 1980.