DAILY REPORT #4914 - Fri 21 Aug 2009 10:27:AM
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
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