HUBBLE
SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY
REPORT #5020
PERIOD
COVERED: 5am January 26 - 5am January 27, 2010 (DOY 026/10:00z-027/10:00z)
OBSERVATIONS
SCHEDULED
NIC2/WFC3/IR
11548
Infrared
Imaging of Protostars in the Orion A Cloud: The Role of
Environment
in Star Formation
We
propose NICMOS and WFC3/IR observations of a sample of 252 protostars
identified
in the Orion A cloud with the Spitzer Space Telescope. These
observations
will image the scattered light escaping the protostellar
envelopes,
providing information on the shapes of outflow cavities, the
inclinations
of the protostars, and the overall morphologies of the
envelopes.
In addition, we ask for Spitzer time to obtain 55-95 micron
spectra
of 75 of the protostars. Combining these new data with existing
3.6
to 70 micron photometry and forthcoming 5-40 micron spectra measured
with
the Spitzer Space Telescope, we will determine the physical
properties
of the protostars such as envelope density, luminosity,
infall
rate, and outflow cavity opening angle. By examining how these
properties
vary with stellar density (i.e. clusters vs. groups vs.
isolation)
and the properties of the surrounding molecular cloud; we can
directly
measure how the surrounding environment influences protostellar
evolution,
and consequently, the formation of stars and planetary
systems.
Ultimately, this data will guide the development of a theory of
protostellar
evolution.
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.
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
11567
Boron
Abundances in Rapidly Rotating Early-B Stars
Models
of rotation in early-B stars predict that rotationally driven
mixing
should deplete surface boron abundances during the main-sequence
lifetime
of many stars. However, recent work has shown that many boron
depleted
stars are intrinsically slow rotators for which models predict
no
depletion should have occurred, while observations of nitrogen in
some
more rapidly rotating stars show less mixing than the models
predict.
Boron can provide unique information on the earliest stages of
mixing
in B stars, but previous surveys have been biased towards narrow-
lined
stars because of the difficulty in measuring boron abundances in
rapidly
rotating stars. The two targets observed as part of our Cycle 13
SNAP
program 10175, just before STIS failed, demonstrate that it is
possible
to make useful boron abundance measurements for early-B stars
with
Vsin(i) above 100 km/s. We propose to extend that survey to a large
enough
sample of stars to allow statistically significant tests of
models
of rotational mixing in early-B stars.
STIS/CCD
11844
CCD
Dark Monitor Part 1
The
purpose of this proposal is to monitor the darks for the STIS CCD.
STIS/CCD
11846
CCD
Bias Monitor-Part 1
The
purpose of this proposal is to 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
11849
STIS
CCD Hot Pixel Annealing
This
purpose of this activity is to repair radiation induced hot pixel
damage
to the STIS CCD by warming the CCD to the ambient instrument
temperature
and annealing radiation-damaged pixels.
Radiation
damage creates hot pixels in the STIS CCD Detector. Many of
these
hot pixels can be repaired by warming the CCD from its normal
operating
temperature near -83 deg. C to the ambient instrument
temperature
(~ +5 deg. C) for several hours. The number of hot pixels
repaired
is a function of annealing temperature. The effectiveness of
the
CCD hot pixel annealing process is assessed by measuring the dark
current
behavior before and after annealing and by searching for any
window
contamination effects.
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.
WFC3/ACS/IR
11142
Revealing
the Physical Nature of Infrared Luminous Galaxies at 0.3<z<2.7
Using
HST and Spitzer We aim to determine physical properties of IR
luminous
galaxies at 0.3<z<2.7 by requesting coordinated HST/NIC2 and
MIPS
70um observations of a unique, 24um flux-limited sample with
complete
Spitzer mid-IR spectroscopy. The 150 sources investigated in
this
program have S(24um) > 0.8mJy and their mid-IR spectra have already
provided
the majority targets with spectroscopic redshifts (0.3<z<2.7).
The
proposed 150~orbits of NIC2 and 66~hours of MIPS 70um will provide
the
physical measurements of the light distribution at the rest-frame
~8000A
and better estimates of the bolometric luminosity. Combining
these
parameters together with the rich suite of spectral diagnostics
from
the mid-IR spectra, we will (1) measure how common mergers are
among
LIRGs and ULIRGs at 0.3<z<2.7, and establish if major mergers are
the
drivers of z>1 ULIRGs, as in the local Universe, (2) study the
co-evolution
of star formation and blackhole accretion by investigating
the
relations between the fraction of starburst/AGN measured from mid-IR
spectra
vs. HST morphologies, L(bol) and z, and (3) obtain the current
best
estimates of the far-IR emission, thus L(bol) for this sample, and
establish
if the relative contribution of mid-to-far IR dust emission is
correlated
with morphology (resolved vs. unresolved).
WFC3/ACS/IR
11677
Is
47 Tuc Young? Measuring its White Dwarf Cooling Age and Completing a
Hubble
Legacy
With
this proposal we will firmly establish the age of 47 Tuc from its
cooling
white dwarfs. 47 Tuc is the nearest and least reddened of the
metal-rich
disk globular clusters. It is also the template used for
studying
the giant branches of nearby resolved galaxies. In addition,
the
age sensitive magnitude spread between the main sequence turnoff and
horizontal
branch is identical for 47 Tuc, two bulge globular clusters
and
the bulge field population. A precise relative age constraint for 47
Tuc,
compared to the halo clusters M4 and NGC 6397, both of which we
recently
dated via white dwarf cooling, would therefore constrain when
the
bulge formed relative to the old halo globular clusters. Of
particular
interest is that with the higher quality ACS data on NGC
6397,
we are now capable with the technique of white dwarf cooling of
determining
ages to an accuracy of +/-0.4 Gyrs at the 95% confidence
level.
Ages derived from the cluster turnoff are not currently capable
of
reaching this precision. The important role that 47 Tuc plays in
galaxy
formation studies, and as the metal-rich template for the
globular
clusters, makes the case for a white dwarf cooling age for this
metal-rich
cluster compelling.
Several
recent analyses have suggested that 47 Tuc is more than 2 Gyrs
younger
than the Galactic halo. Others have suggested an age similar to
that
of the most metal poor globular clusters. The current situation is
clearly
uncertain and obviously a new approach to age dating this
important
cluster is required.
With
the observations of 47 Tuc, this project will complete a legacy for
HST.
It will be the third globular cluster observed for white dwarf
cooling;
the three covering almost the full metallicity range of the
cluster
system. Unless JWST has its proposed bluer filters (700 and 900
nm)
this science will not be possible perhaps for decades until a large
optical
telescope is again in space. Ages for globular clusters from the
main
sequence turnoff are less precise than those from white dwarf
cooling
making the science with the current proposal truly urgent.
WFC3/IR
11189
Probing
the Early Universe with GRBs
Cosmology
is beginning to constrain the nature of the earliest stars and
galaxies
to form in the Universe, but direct observation of galaxies at
z>6
remains highly challenging due to their scarcity, intrinsically
small
size, and high luminosity distance. GRB afterglows, thanks to
their
extreme luminosities, offer the possibility of circumventing these
normal
constraints by providing redshifts and spectral information which
couldn't
be obtained through direct observation of the host galaxies
themselves.
In addition, the association of GRBs with massive stars
means
that they are an indicator of star formation, and that their hosts
are
likely responsible for a large proportion of the ionizing radiation
during
that era. Our collaboration is conducting a campaign to rapidly
identify
and study candidate very high redshift bursts, bringing to bear
a
network of 2, 4 and 8m telescopes with near-IR instrumentation. Swift
has
proven capable of detecting faint, distant GRBs, and reporting
accurate
positions for many bursts in near real-time. Here we propose to
continue
our HST program of targeting GRBs at z~6 and above. HST is
crucial
to this endeavor, allowing us (a) to characterize the basic
properties,
such as luminosity and color, and in some cases
morphologies,
of the hosts, which is essential to understanding these
primordial
galaxies and their relationship to other galaxy populations;
and
(b) to monitor the late time afterglows and hence compare them to
lower-z
bursts and test the use of GRBs as standard candles.
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
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.
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: (None)
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSAcq
6
6
FGS
REAcq
8
8
OBAD
with Maneuver 6
6
SIGNIFICANT
EVENTS: (None)