HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5155
PERIOD
COVERED: 5am August 6 - 5am August 9, 2010 (DOY 218/09:00z-221/09:00z)
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
12351
- GSAcq (1,2,1) scheduled at 218/10:49:29z and REAcqs(1,2,1)
scheduled at 218/11:51:11z, at
218/13:27:02z, and at 218/15:09:02z all
results in fine lock backup
(1,0,1) using FGS-1, scan step limit
exceeded on FGS-2.
Observations possibly
affected: WFC3 113-118 Proposal ID#11694; COS 132
Proposal ID#11579; ACS 124-125
Proposal ID#11996; STIS 22-23 Proposal
ID#11845; STIS 24, 25, 26
Proposal ID#11847
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSAcq
15
15
FGS
REAcq
24
24
OBAD
with Maneuver
11
11
SIGNIFICANT
EVENTS: (None)
OBSERVATIONS
SCHEDULED:
ACS/WFC/WFC3/IR/UV
12056
A
Panchromatic Hubble Andromeda Treasury - I
We
propose to image the north east quadrant of M31 to deep limits in the
UV,
optical, and near-IR. HST imaging should resolve the galaxy into
more
than 100 million stars, all with common distances and foreground
extinctions.
UV through NIR stellar photometry (F275W, F336W with
WFC3/UVIS,
F475W and F814W with ACS/WFC, and F110W and F160W with
WFC3/NIR)
will provide effective temperatures for a wide range of
spectral
types, while simultaneously mapping M31's extinction. Our
central
science drivers are to: understand high-mass variations in the
stellar
IMF as a function of SFR intensity and metallicity; capture the
spatially-resolved
star formation history of M31; study a vast sample of
stellar
clusters with a range of ages and metallicities. These are
central
to understanding stellar evolution and clustered star formation;
constraining
ISM energetics; and understanding the counterparts and
environments
of transient objects (novae, SNe, variable stars, x-ray
sources,
etc.). As its legacy, this survey adds M31 to the Milky Way and
Magellanic
Clouds as a fundamental calibrator of stellar evolution and
star-formation
processes for understanding the stellar populations of
distant
galaxies. Effective exposure times are 977s in F275W, 1368s in
F336W,
4040s in F475W, 4042s in F814W, 699s in F110W, and 1796s in
F160W,
including short exposures to avoid saturation of bright sources.
These
depths will produce photon-limited images in the UV. Images will
be
crowding-limited in the optical and NIR, but will reach below the red
clump
at all radii. The images will reach the Nyquist sampling limit in
F160W,
F475W, and F814W.
S/C
12046
COS
FUV DCE Memory Dump
Whenever
the FUV detector high voltage is on, count rate and current
draw
information is collected, monitored, and saved to DCE memory. Every
10
msec the detector samples the currents from the HV power supplies
(HVIA,
HVIB) and the AUX power supply (AUXI). The last 1000 samples are
saved
in memory, along with a histogram of the number of occurrences of
each
current value.
In
the case of a HV transient (known as a "crackle" on FUSE), where one
of
these currents exceeds a preset threshold for a persistence time, the
HV
will shut down, and the DCE memory will be dumped and examined as
part
of the recovery procedure. However, if the current exceeds the
threshold
for less than the persistence time (a "mini-crackle" in FUSE
parlance),
there is no way to know without dumping DCE memory. By
dumping
and examining the histograms regularly, we will be able to
monitor
any changes in the rate of "mini-crackles" and thus learn
something
about the state of the detector.
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/IR/S/CCD
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
11920
WFC3
IR Image Quality
The
IR imaging performance over the detector will be assessed
periodically
(every 4 months) in two passbands to check for image
stability.
The field around star 58 in the open cluster NGC188 is the
chosen
target because it is sufficiently dense to provide good sampling
over
the FOV while providing enough isolated stars to permit accurate
PSF
(point spread function) measurement. It is available year-round and
used
previously for ACS image quality assessment. The field is
astrometric,
and astrometric guide stars will be used, so that the plate
scale
and image orientation may also be determined if necessary (as in
SMOV
proposals 11437 and 11443). Full frame images will be obtained at
each
of 4 POSTARG offset positions designed to improve sampling over the
detector
in F098M, F105W, and F160W. The PSFs will be sampled at 4
positions
with subpixel shifts in filters F164N and F127M.
This
proposal is a periodic repeat (once every 4 months) of the visits
in
SMOV proposal 11437 (activity ID WFC3-24). The data will be analyzed
using
the code and techniques described in ISR WFC3 2008-41 (Hartig).
Profiles
of encircled energy will be monitored and presented in an ISR.
If
an update to the SIAF is needed, (V2, V3) locations of stars will be
obtained
from the Flight Ops. Sensors and Calibrations group at GSFC,
the
(V2, V3) of the reference pixel and the orientation of the detector
will
be determined by the WFC3 group, and the Telescopes group will
update
and deliver the SIAF to the PRDB branch.
The
specific PSF metrics to be examined are encircled energy for
aperture
diameter 0.25, 0.37, and 0.60 arcsec, FWHM, and sharpness. (See
ISR
WFC3 2008-41 tables 2 and 3 and preceding text.) ~20 stars
distributed
over the detector will be measured in each exposure for each
filter.
The mean, rms, and rms of the mean will be determined for each
metric.
The values determined from each of the 4 exposures per filter
within
a visit will be compared to each other to see to what extent they
are
affected by "breathing". Values will be compared from visit to
visit,
starting with the values obtained during SMOV after the fine
alignment
has been performed, to see if the measures of the compactness
of
the PSF indicate degradation over time. The analysis will be repeated
for
stars on the inner part of the detector and stars on the outer part
of
the detector to check for differential degradation of the PSF.
As
an example of the analysis, one can examine the sharpness of the
F160W
PSF exposures made during thermal vacuum testing (ISR WFC3
2008-41).
To compare two samples, one can define the PSFs on each half
of
the detector (lower and upper) as a sample (with 7 and 8 PSFs,
respectively).
The mean, rms, and rms of the mean sharpness are 0.0826,
0.0067,
and 0.0027 for one half, and 0.0773, 0.0049, and 0.0019 for the
other.
The difference of the means is 0.0053 and the statistical error
in
that difference is 0.0033, so the difference is not significant.
WFC3/UVIS
11908
Cycle
17: UVIS Bowtie Monitor
Ground
testing revealed an intermittent hysteresis type effect in the
UVIS
detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially
found via an unexpected bowtie-shaped feature in flatfield
ratios,
subsequent lab tests on similar e2v devices have since shown
that
it is also present as simply an overall offset across the entire
CCD,
i.e., a QE offset without any discernable pattern. These lab tests
have
further revealed that overexposing the detector to count levels
several
times full well fills the traps and effectively neutralizes the
bowtie.
Each visit in this proposal acquires a set of three 3x3 binned
internal
flatfields: the first unsaturated image will be used to detect
any
bowtie, the second, highly exposed image will neutralize the bowtie
if
it is present, and the final image will allow for verification that
the
bowtie is gone.
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/UV
11904
UVIS
Droplets
To
characterize the effects of the contamination (i.e., droplets) on the
UVIS
window, we will observe a star cluster in three wide band filters
(F225W,
F555W, and F814W) as well as a narrow band filter (F502N) and
step
the stars in the cluster across randomly located droplets. The step
size
is 20 pixels, and we execute a five point line dither for each
filter.
This should provide for observations both on and off the
droplets,
for the same star. Internal flat fields are also obtained,
but,
due to the high f/# of the internal calibration system, the flats
will
be of limited utility, but will serve to map and crudely track any
changes
in the droplets. The cluster needs to contain both hot and cool
stars,
and therefore we select NGC 6752, a nearby globular with a hot
horizontal
branch. Note, although the total population of HB stars may
be
larger in systems such as NGC 2419, NGC 6715, and NGC 2808, those
clusters
are much further away and will not provide a high density of
stars
over the global image (the droplets are located over the entire
frame).
There will be three visits (initial, 7 days later, and 30 days
later),
with each visit requiring 4 orbits. The total program thus
requires
12 orbits total.
COS/NUV
11900
NUV
Internal/External Wavelength Scale Monitor
This
program monitors the offsets between the wavelength scale set by
the
internal wavecal versus that defined by absorption lines in external
targets.
This is accomplished by observing two external radial velocity
standard
targets: HD187691 with G225M and G285M and HD6655 with G285M
and
G230L. The two standard targets have little flux in the wavelength
range
covered by G185M and so Feige 48 (sdO) is observed with this
grating.
Both Feige 48 and HD6655 are also observed in SMOV. The
cenwaves
observed in this program are a subset of the ones used during
Cycle
17. Observing all cenwaves would require a considerably larger
number
of orbits. Constraints on scheduling of each target are placed so
that
each target is observed once every ~2-3 months. Observing the three
targets
every month would also require a considerably larger number of
orbits.
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
11845
CCD
Dark Monitor Part 2
Monitor
the darks for the STIS CCD.
COS/NUV/FUV
11741
Probing
Warm-Hot Intergalactic Gas at 0.5 < z < 1.3 with a Blind Survey
for
O VI, Ne VIII, Mg X, and Si XII Absorption Systems
Currently
we can only account for half of the baryons (or less) expected
to
be found in the nearby universe based on D/H and CMB observations.
This
"missing baryons problem" is one of the highest-priority challenges
in
observational extragalatic astronomy. Cosmological simulations
suggest
that the baryons are hidden in low-density, shock-heated
intergalactic
gas in the log T = 5 - 7 range, but intensive UV and X-ray
surveys
using O VI, O VII, and O VIII absorption lines have not yet
confirmed
this prediction. We propose to use COS to carry out a
sensitive
survey for Ne VIII and Mg X absorption in the spectra of nine
QSOs
at z(QSO) > 0.89. For the three highest-redshift QSOs, we will also
search
for Si XII. This survey will provide more robust constraints on
the
quantity of baryons in warm-hot intergalactic gas at 0.5 < z < 1.3,
and
the data will provide rich constraints on the metal enrichment,
physical
conditions, and nature of a wide variety of QSO absorbers in
addition
to the warm-hot systems. By comparing the results to other
surveys
at lower redshifts (with STIS, FUSE, and from the COS GTO
programs),
the project will also enable the first study of how these
absorbers
evolve with redshift at z < 1. By combining the program with
follow-up
galaxy redshift surveys, we will also push the study of
galaxy-absorber
relationships to higher redshifts, with an emphasis on
the
distribution of the WHIM with respect to the large-scale matter
distribution
of the universe.
WFC3/IR
11696
Infrared
Survey of Star Formation Across Cosmic Time
We
propose to use the unique power of WFC3 slitless spectroscopy to
measure
the evolution of cosmic star formation from the end of the
reionization
epoch at z>6 to the close of the galaxy- building era at
z~0.3.Pure
parallel observations with the grisms have proven to be
efficient
for identifying line emission from galaxies across a broad
range
of redshifts. The G102 grism on WFC3 was designed to extend this
capability
to search for Ly-alpha emission from the first galaxies.
Using
up to 250 orbits of pure parallel WFC3 spectroscopy, we will
observe
about 40 deep (4-5 orbit) fields with the combination of G102
and
G141, and about 20 shallow (2-3 orbit) fields with G141 alone.
Our
primary science goals at the highest redshifts are: (1) Detect Lya
in
~100 galaxies with z>5.6 and measure the evolution of the Lya
luminosity
function, independent of of cosmic variance; 2) Determine the
connection
between emission line selected and continuum-break selected
galaxies
at these high redshifts, and 3) Search for the proposed
signature
of neutral hydrogen absorption at re-ionization. At
intermediate
redshifts we will (4) Detect more than 1000 galaxies in
Halpha
at 0.5<z<1.8 to measure the evolution of the extinction-corrected
star
formation density across the peak epoch of star formation. This is
over
an order-of-magnitude improvement in the current statistics, from
the
NICMOS Parallel grism survey. (5) Trace ``cosmic downsizing" from
0.5<z<2.2;
and (6) Estimate the evolution in reddening and metallicty in
star-
forming galaxies and measure the evolution of the Seyfert
population.
For hundreds of spectra we will be able to measure one or
even
two line pair ratios -- in particular, the Balmer decrement and
[OII]/[OIII]
are sensitive to gas reddening and metallicity. As a bonus,
the
G102 grism offers the possibility of detecting Lya emission at
z=7-8.8.
To
identify single-line Lya emitters, we will exploit the wide
0.8--1.9um
wavelength coverage of the combined G102+G141 spectra. All
[OII]
and [OIII] interlopers detected in G102 will be reliably separated
from
true LAEs by the detection of at least one strong line in the G141
spectrum,
without the need for any ancillary data. We waive all
proprietary
rights to our data and will make high-level data products
available
through the ST/ECF.
WFC3/IR
11694
Mapping
the Interaction Between High-Redshift Galaxies and the
Intergalactic
Environment
With
the commissioning of the high-throughput large-area camera WFC3/IR,
it
is possible for the first time to undertake an efficient survey of
the
rest-frame optical morphologies of galaxies at the peak epoch of
star
formation in the universe. We therefore propose deep WFC3/IR
imaging
of over 320 spectroscopically confirmed galaxies between
redshift
1.6 < z < 3.4 in well-studied fields which lie along the line
of
sight to bright background QSOs. The spectra of these bright QSOs
probe
the IGM in the vicinity of each of the foreground galaxies along
the
line of sight, providing detailed information on the physical state
of
the gas at large galactocentric radii. In combination with our
densely
sampled UV/IR spectroscopy, stellar population models, and
kinematic
data in these fields, WFC3/IR imaging data will permit us to
construct
a comprehensive picture of the structure, dynamics, and star
formation
properties of a large population of galaxies in the early
universe
and their effect upon their cosmological environment.
WFC3/UVIS
11657
The
Population of Compact Planetary Nebulae in the Galactic Disk
We
propose to secure narrow- and broad-band images of compact planetary
nebulae
(PNe) in the Galactic Disk to study the missing link of the
early
phases of post-AGB evolution. Ejected AGB envelopes become PNe
when
the gas is ionized. PNe expand, and, when large enough, can be
studied
in detail from the ground. In the interim, only the HST
capabilities
can resolve their size, morphology, and central stars. Our
proposed
observations will be the basis for a systematic study of the
onset
of morphology. Dust properties of the proposed targets will be
available
through approved Spitzer/IRS spectra, and so will the
abundances
of the alpha- elements. We will be able thus to explore the
interconnection
of morphology, dust grains, stellar evolution, and
populations.
The target selection is suitable to explore the nebular and
stellar
properties across the galactic disk, and to set constraints on
the
galactic evolutionary models through the analysis of metallicity and
population
gradients.
WFC3/IR
11631
Binary
Brown Dwarfs and the L/T Transition
Brown
dwarfs traverse spectral types M, L and T as their atmospheric
structure
evolves and they cool into oblivion. This SNAPSHOT program
will
obtain WFC3-IR images of 45 nearby late-L and early-T dwarfs to
investigate
the nature of the L/T transition. Recent analyses have
suggested
that a substantial proportion of late-L and early-T dwarfs are
binaries,
comprised of an L dwarf primary and T dwarf secondary. WFC3-IR
observations
will let us quantify this suggestion by expanding coverage
to
a much larger sample, and permitting comparison of the L/T binary
fraction
against ‘normal’ ultracool dwarfs. Only eight L/T binaries are
currently
known, including several that are poorly resolved: we
anticipate
at least doubling the number of resolved systems. The
photometric
characteristics of additional resolved systems will be
crucial
to constraining theoretical models of these late-type ultracool
dwarfs.
Finally, our data will also be eminently suited to searching for
extremely
low luminosity companions, potentially even reaching the Y
dwarf
regime.
WFC3/ACS/UVIS
11613
GHOSTS:
Stellar Outskirts of Massive Spiral Galaxies
We
propose to continue our highly successful GHOSTS HST survey of the
resolved
stellar populations of nearby, massive disk galaxies using
SNAPs.
These observations provide star counts and color-magnitude
diagrams
2-3 magnitudes below the tip of the Red Giant Branch of the
outer
disk and halo of each galaxy. We will measure the metallicity
distribution
functions and stellar density profiles from star counts
down
to very low average surface brightnesses, equivalent to ~32 V-mag
per
square arcsec.
This
proposal will substantially improve our unique sampling of galaxy
outskirts.
Our targets cover a range in galaxy mass, luminosity,
inclination,
and morphology. As a function of these galaxy properties,
this
survey provides: - the most extensive, systematic measurement of
radial
light profiles and axial ratios of the diffuse stellar halos and
outer
disks of spiral galaxies; - a comprehensive analysis of halo
metallicity
distributions as function of galaxy type and position within
the
galaxy; - an unprecedented study of the stellar metallicity and age
distribution
in the outer disk regions where the disk truncations occur;
-
the first comparative study of globular clusters and their field
stellar
populations.
We
will use these fossil records of the galaxy assembly process to test
halo
formation models within the hierarchical galaxy formation scheme.
ACS/SBC/COS/NUV/FUV
11579
The
Difference Between Neutral- and Ionized-Gas Metal Abundances in
Local
Star-Forming Galaxies with COS
The
metallicity of galaxies and its evolution with redshift is of
paramount
importance for understanding galaxy formation. Abundances in
the
interstellar medium (ISM) are typically determined using
emission-line
spectroscopy of HII regions. However, since HII regions
are
associated with recent SF they may not have abundances typical for
the
galaxy as a whole. This is true in particular for star-forming
galaxies
(SFGs), in which the bulk of the metals may be contained in the
neutral
gas. It is therefore important to directly probe the metal
abundances
in the neutral gas. This can be done using absorption lines
in
the Far UV. We have developed techniques to do this in SFGs, where
the
absorption is measured for sightlines toward bright SF regions
within
the galaxy itself. We have successfully applied this technique to
a
sample of galaxies observed with FUSE. The results have been very
promising,
suggesting in I Zw 18 that abundances in the neutral gas may
be
up to 0.5 dex lower than in the ionized gas. However, the
interpretation
of the FUSE data is complicated by the very large FUSE
aperture
(30 arcsec), the modest S/N, and the limited selection of
species
available in the FUSE bandpass. The advent of COS on HST now
allows
a significant advance in all of these areas. We will therefore
obtain
absorption line spectroscopy with G130M in the same sample for
which
we already have crude constraints from FUSE. We will obtain
ACS/SBC
images to select the few optimal sightlines to target in each
galaxy.
The results will be interpreted through line-profile fitting to
determine
the metal abundances constrained by the available lines. The
results
will provide important new insights into the metallicities of
galaxies,
and into outstanding problems at high redshift such as the
observed
offset between the metallicities of Lyman Break Galaxies and
Damped
Lyman Alpha systems.
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 z>7, 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.