HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT #4914
PERIOD
COVERED: 5am August 20 - 5am August 21, 2009 (DOY 232/09:00z-233/09:00z)
OBSERVATIONS
SCHEDULED
ACS/WFC3
11465
ACS
CCD Monitoring and Calibration for WFC3
This
program is a smaller version of our routine CCD monitoring program,
designed
to run throughout SMOV, after which our regular Cycle 17 CAL
proposal
will begin. This program obtains the bias and dark frames
needed
to generate reference files for calibrating science data, and
allows
us to monitor detector noise and the growth of hot pixels.
ACS/WFC3
11695
Searching
for the Bottom of the Initial Mass Function
The
measurement of the minimum mass of the IMF would provide a
fundamental
test of theories of star and planet formation. In a Cycle 13
program,
we used ACS and ground- based near-IR imaging and spectroscopy
to
measure the IMF down to a completeness limit of 10 M_Jup (i~24) in a
800"x1000"
area in the southern subcluster of the Chamaeleon I
star-forming
region (2 Myr, 160 pc). There is no sign of a low-mass
cutoff
in this IMF measurement. To provide a better constraint on the
minimum
mass of the IMF, we propose to obtain ACS images of this field
again
and use the two ACS epochs to identify substellar cluster members
down
to the detection limit of the data (i~27) via their proper motions.
In
this way, we will improve the completeness limit of our IMF
measurement
to 3 M_Jup. In addition, to improve the number statistics of
our
measurement of the substellar IMF in Chamaeleon I, we propose to
double
the number of objects in the IMF sample by performing ACS imaging
of
a second field toward the northern subcluster.
ACS/WFC3
11887
CCD
Stability Monitor
This
program will verify that the low frequency flat fielding, the
photometry,
and the geometric distortion are stable in time and across
the
field of view of the CCD arrays. A moderately crowded stellar field
in
the cluster 47 Tuc is observed with the ACS (at the cluster core) and
WFC3
(6 arcmin West of the cluster core) using the full suite of broad
and
narrow band imaging filters. The positions and magnitudes of objects
will
be used to monitor local and large scale variations in the plate
scale
and the sensitivity of the detectors and to derive an independent
measure
of the detector CTE. The UV sensitivity for the SBC and ACS will
be
addressed in the UV contamination monitor program (11886, PI=Smith).
One
additional orbit will be obtained at the beginning of the cycle will
allow
a verification of the CCD gain ratios for WFC3 using gain 2.0,
1.4,
1.0, 0.5 and for ACS using gain 4.0 and 2.0. In addition, one
subarray
exposure with the WFC3 will allow a verification that
photometry
obtained in full-frame and in sub-array modes are repeatable
to
better than 1%. This test is important for the ACS Photometric Cross-
Calibration
program (11889, PI=Bohlin) which uses sub-array exposures.
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 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.
NIC2/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. {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}.
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
Monitor
the darks for the STIS CCD.
STIS/CCD
11846
CCD
Bias Monitor-Part 1
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
11852
STIS
CCD Spectroscopic Flats C17
Obtain
pixel-to-pixel lamp flat fields for the STIS CCD in spectroscopic
mode.
STIS/CCD
11858
CCD
Spectroscopic Dispersion Solution
Constrain
wavelength and spatial distortion maps using internal wavecals
obtained
with all 6 gratings (G230LB, G230MB, G430L, G430M, G750L,
G750M)
supported for use with the CCD. Data will be obtained for the
nearly
identical set of 38 central wavelengths used in the 9617 and
10025
programs.
STIS/MA1/MA2
11859
MAMA
Dispersion Solutions
Wavelength
dispersion solutions will be determined on a yearly basis as
part
of a long- term monitoring program. Deep engineering wavecals for
each
MAMA grating will be obtained at common cenwaves. Intermediate
settings
will also be taken to check the reliability of derived
dispersion
solutions. Final selection was determined on basis of past
monitoring
and C17 requirements. The internal wavelength calibrations
will
be taken using the LINE line lamp. Extra-deep wavecals are included
for
some echelle modes and first order modes to ensure detection of weak
lines.
STIS20
11402
STIS-20
NUV MAMA Dark Monitor
The
STIS NUV-MAMA dark current is dominated by a phosphorescent glow
from
the detector window. Meta-stable states in this window are
populated
by cosmic ray impacts, which, days later, can be thermally
excited
to an unstable state from which they decay, emitting a UV
photon.
The equilibrium population of these meta-stable states is larger
at
lower temperatures; so warming up the detector from its cold safing
will
lead to a large, but temporary, increase in the dark current.
To
monitor the decay of this glow, and to determine the equilibrium dark
current
for Cycle 17, four 1380s NUV-MAMA ACCUM mode darks should be
taken
each week during the SMOV period. Once the observed dark current
has
reached an approximate equilibrium with the mean detector
temperature,
the frequency of this monitor can be reduced to one pair of
darks
per week.
WFC3/IR
11915
IR
Internal Flat Fields
This
program is the same as 11433 (SMOV) and depends on the completion
of
the IR initial alignment (program 11425). This version contains three
instances
of 37 internal orbits; to be scheduled early, middle, and near
the
end of Cycle 17, in order to use the entire 110-orbit allocation.
In
this test, we will study the stability and structure of the IR
channel
flat field images through all filter elements in the WFC3-IR
channel.
Flats will be monitored, i.e. to capture any temporal trends in
the
flat fields, and delta flats produced. High signal observations will
provide
a map of the pixel-to-pixel flat field structure, as well as
identify
the positions of any dust particles.
WFC3/UVI
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 (11909), will be
used
to generate the necessary superbias and superdark reference files
for
the calibration pipeline (CDBS).
WFC3/UVI
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.
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:
18683-5
- Install WFC3 CS FSW 4.00 and NSSC-I BQ 9.0.6 @ 232/1830z
COMPLETED
OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS
GSAcq
12
12
FGS
REAcq
03
03
OBAD
with Maneuver 06
06
SIGNIFICANT
EVENTS:
Flash
Report:
Wide
Field Camera 3 CS Flight Software version 4.00 and NSSC-I Flight
Software
version BQ 9.0.6 have been successfully loaded via Ops Request
18683-5