HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5066
PERIOD
COVERED: 5am April 1 - 5am April 2, 2010 (DOY 091/09:00z-092/09:00z)
OBSERVATIONS
SCHEDULED
ACS/WFC
11679
Probing
The Globular Cluster / Low Mass X-ray Binary Connection in
Early-type
Galaxies At Low X-ray Luminosities
Combined
high-resolution images from Hubble and Chandra (CXO) have
revolutionized
our understanding of extragalactic low-mass X-ray
binaries
(LMXBs) and globular clusters (GCs), yet their connection in
early-type
galaxies has remained unstudied at the luminosities of the
Galactic
LMXBs in GCs. NGC 3379 and NGC 4278 are be the first
prototypical
elliptical galaxies with complete, deep CXO observations
enabling
the study of LMXBs at lower luminosities. We propose completing
mosaic
ACS observations of both galaxies (5 fields per galaxy) that will
provide
the most comprehensive view into the connection between GCs and
LMXBs
in early-type galaxies. We will detect ~860 and ~270 GCs in all of
NGC
4278 and NGC 3379, respectively. These two galaxies will have among
the
greatest number of detected GC-LMXBs to date (~130 & 50) and will
include
the faintest GC-LMXBs in a normal early-type galaxy. We will
measure
the fraction of GCs which contain LMXBs, as a function of X-ray
luminosity,
galactocentric distance, color, and GC half-light radius.
Using
the radial profiles of optical light, GCs, and LMXBs, we will
determine
the percentage of field LMXBs which may have originated in
GCs.
We will use the measured GC properties over the entire extent of
both
galaxies to constrain theories of GC formation and evolution. This
is
a resubmission of an approved Cycle 15 program (10835) which was only
partially
completed.
COS/FUV
11897
FUV
Spectroscopic Sensitivity Monitoring
The
purpose of this proposal is to monitor sensitivity in each FUV
grating
mode to detect any changes due to contamination or other causes.
COS/FUV/STIS/CCD/MA1
11592
Testing
the Origin(s) of the Highly Ionized High-Velocity Clouds: A
Survey
of Galactic Halo Stars at z>3 kpc
Cosmological
simulation predicts that highly ionized gas plays an
important
role in the formation and evolution of galaxies and their
interplay
with the intergalactic medium. The NASA HST and FUSE missions
have
revealed high-velocity CIV and OVI absorption along extragalactic
sightlines
through the Galactic halo. These highly ionized high-velocity
clouds
(HVCs) could cover 85% of the sky and have a detection rate
higher
than the HI HVCs. Two competing, equally exciting, theories may
explain
the origin of these highly ionized HVCs: 1) the "Galactic"
theory,
where the HVCs are the result of feedback processes and trace
the
disk-halo mass exchange, perhaps including the accretion of matter
condensing
from an extended corona; 2) the "Local Group" theory, where
they
are part of the local warm-hot intergalactic medium, representing
some
of the missing baryonic matter of the Universe. Only direct
distance
determinations can discriminate between these models. Our group
has
found that some of these highly ionized HVCs have a Galactic origin,
based
on STIS observations of one star at z<5.3 kpc. We propose an HST
FUV
spectral survey to search for and characterize the high velocity NV,
CIV,
and SiIV interstellar absorption toward 24 stars at much larger
distances
than any previous searches (4<d<21 kpc, 3<|z|<13 kpc). COS
will
provide atomic to highly ionized species (e.g.,OI, CII, CIV, SiIV)
that
can be observed at sufficient resolution (R~22, 000) to not only
detect
these highly ionized HVCs but also to model their properties and
understand
their physics and origins. This survey is only possible
because
of the high sensitivity of COS in the FUV spectral range.
COS/NUV
11561
An
Intensive COS Spectroscopic Study of the Planetary Debris Disks
Around
two Warm White Dwarfs
It
is very likely that the gas giants in our Solar system will survive
the
evolution of the Sun into a white dwarf, and the same is thought to
be
generally true for Jovian planets around solar-like stars if their
initial
orbits are wider than ~3AU. Despite this prediction, no
unambiguous
detection of a planet around a white dwarf has been
announced
so far. However, over the past few years, about a dozen white
dwarfs
have been identified which host metal-rich debris disks that are
thought
to stem from the tidal disruption of asteroids. In most cases
the
debris disks are observed in the form of an infrared flux excess,
and
offer relatively little diagnostic potential for the study of their
structure.
We have discovered three warm (T~20000K) white dwarfs with
metal-rich
debris disks in a gaseous phase which display strong
double-peaked
CaII emission lines in the I-band and weak Fe 5169A
emission.
The line profiles can be modeled in terms of Keplerian disks
with
an extension of ~1Rsun around the white dwarfs. Photospheric MgII
4481A
absorption demonstrates that the white dwarfs are accreting from
the
debris disks. Besides these spectral features, the optical
wavelength
range is devoid of other useful metal transitions. Here, we
propose
an intensive spectroscopic ultraviolet study of these systems,
which
will provide (a) ~1000 photospheric absorption lines of 15
chemical
elements, allowing an accurate abundance study of the material
accreted
from the debris disks, and (b) ~2 dozen additional emission
lines
of Mg, Cr, Ti, and Fe that will provide detailed insight into the
dynamical,
thermal, and density structure of these exo-planetary debris
disks.
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.
FGS
11704
The
Ages of Globular Clusters and the Population II Distance Scale
Globular
clusters are the oldest objects in the universe whose age can
be
accurately determined. The dominant error in globular cluster age
determinations
is the uncertain Population II distance scale. We propose
to
use FGS 1R to obtain parallaxes with an accuracy of 0.2
milliarcsecond
for 9 main sequence stars with [Fe/H] < -1.5. This will
determine
the absolute magnitude of these stars with accuracies of 0.04
to
0.06mag. This data will be used to determine the distance to 24
metal-poor
globular clusters using main sequence fitting. These
distances
(with errors of 0.05 mag) will be used to determine the ages
of
globular clusters using the luminosity of the subgiant branch as an
age
indicator. This will yield absolute ages with an accuracy of 5%,
about
a factor of two improvement over current estimates. Coupled with
existing
parallaxes for more metal-rich stars, we will be able to
accurately
determine the age for globular clusters over a wide range of
metallicities
in order to study the early formation history of the Milky
Way
and provide an independent estimate of the age of the universe.
The
Hipparcos database contains only 1 star with [Fe/H] < -1.4 and an
absolute
magnitude error less than 0.18 mag which is suitable for use in
main
sequence fitting. Previous attempts at main sequence fitting to
metal-poor
globular clusters have had to rely on theoretical
calibrations
of the color of the main sequence. Our HST parallax program
will
remove this source of possible systematic error and yield distances
to
metal-poor globular clusters which are significantly more accurate
than
possible with the current parallax data. The HST parallax data will
have
errors which are 10 times smaller than the current parallax data.
Using
the HST parallaxes, we will obtain main sequence fitting distances
to
11 globular clusters which contain over 500 RR Lyrae stars. This will
allow
us to calibrate the absolute magnitude of RR Lyrae stars, a
commonly
used Population II distance indicator.
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/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
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/S/C
12097
Additional
IR Subarray Dark Current Measurements (in support of GO
programs
11205, 11580)
This
proposal will produce IR dark images necessary to calibrate GO
science
observations (already taken, see proposals 11205 and 11580) that
use
observing modes not supported by the existing IR dark current
monitor
(proposal 11929). These modes are as follows: SQ256SUB/SPARS100,
SQ256SUB/SPARS200,
SQ512SUB/SPARS10, SQ512SUB/SPARS100, and
SQ512SUB/SPARS200.
WFC3/UV/IR
11709
Stretching
the Diversity of Cosmic Explosions: The Supernovae of
Gamma-ray
Bursts
While
the association between gamma-ray bursts (GRBs) and massive stars
is
robust, there is a large diversity of properties among supernovae
(SNe)
associated with GRBs. The converse is also true: Several recent
events
show that there is a large brightness range among high energy
transients
associated with SNe. As part of a comprehensive program, we
propose
to use HST in order to search for and characterize the SNe
associated
with GRB.
HST
offers the means to cleanly separate the light curve of the GRB
afterglow
from the supernova, and to remove the contamination from the
host
galaxy, opening a clear path to the fundamental parameters of the
SN,
and thence to the progenitor. From these observations, we will
determine
the absolute magnitude at maximum, the shape of the spectral
energy
distribution, and any change over time of the energy
distribution.
We will also measure the rate of decay of the exponential
tail.
Merged
with the ground-based data that we will obtain for each event, we
will
be able to compare our data set to models and constrain the energy
of
the explosion, the mass of the ejecta and the mass of Nickel
synthesized
during the explosion. These results will shed light on the
apparent
variety of supernovae associated with gamma-ray bursts and
X-ray
flashes, and on the relation between these SNe and other, more
common,
types of core-collapse explosions.
WFC3/UVIS
11594
A
WFC3 Grism Survey for Lyman Limit Absorption at z=2
We
propose to conduct a spectroscopic survey of Lyman limit absorbers at
redshifts
1.8 < z < 2.5, using WFC3 and the G280 grism. This proposal
intends
to complete an approved Cycle 15 SNAP program (10878), which was
cut
short due to the ACS failure. We have selected 64 quasars at 2.3 < z
<
2.6 from the Sloan Digital Sky Survey Spectroscopic Quasar Sample, for
which
no BAL signature is found at the QSO redshift and no strong metal
absorption
lines are present at z > 2.3 along the lines of sight. The
survey
has three main observational goals. First, we will determine the
redshift
frequency dn/dz of the LLS over the column density range 16.0 <
log(NHI)
< 20.3 cm^-2. Second, we will measure the column density
frequency
distribution f(N) for the partial Lyman limit systems (PLLS)
over
the column density range 16.0 < log(NHI) < 17.5 cm^-2. Third, we
will
identify those sightlines which could provide a measurement of the
primordial
D/H ratio. By carrying out this survey, we can also help
place
meaningful constraints on two key quantities of cosmological
relevance.
First, we will estimate the amount of metals in the LLS using
the
f(N), and ground based observations of metal line transitions.
Second,
by determining f(N) of the PLLS, we can constrain the amplitude
of
the ionizing UV background at z~2 to a greater precision. This survey
is
ideal for a snapshot observing program, because the on-object
integration
times are all well below 30 minutes, and follow-up
observations
from the ground require minimal telescope time due to the
QSO
sample being bright.
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
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/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 warm up, 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.
WFC3/UV
12077
Monitoring
the Aftermath of an Asteroid Impact Event
Our
Director's Discretionary program (GO-12053) to image the newly
discovered
object P/2010 A2 executed successfully on 2010 Jan 25 and 29
with
spectacular results. Hubble has apparently borne witness to the
first
detection of a collision in the asteroid belt. Hubble imaging with
the
WFC3 has revealed an object unlike anything ever seen before and
with
details impossible to detect with any other facility. We request 6
more
orbits of Hubble time (1 orbit every 20 days over the next few
months,
until the object enters Hubble's solar exclusion zone in
late-June
2010) to monitor the evolution of this remarkable object and
further
clarify the nature of this event. These observations may usher
in
a new era of searching for and characterizing collisional events
within
the asteroid belt.
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
(None)
COMPLETED
OPS REQUEST:
18837-0
- Null Genslew for proposal 12077 - slot 13 @ 091/1345z
COMPLETED
OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS
GSAcq
10
10
FGS
REAcq
5
5
OBAD
with Maneuver 4
4
SIGNIFICANT
EVENTS: (None)