HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT # 4302
PERIOD COVERED: UT February 16,17,18,19, 2007 (DOY
047,048,049,050)
OBSERVATIONS SCHEDULED
NIC1/NIC2/NIC3 8794
NICMOS Post-SAA calibration - CR Persistence Part 5
A new procedure proposed to alleviate the CR-persistence
problem of
NICMOS. Dark frames will be obtained immediately upon
exiting the SAA
contour 23, and every time a NICMOS exposure is scheduled
within 50
minutes of coming out of the SAA. The darks will be
obtained in parallel
in all three NICMOS Cameras. The POST-SAA darks will be
non- standard
reference files available to users with a USEAFTER
date/time mark. The
keyword 'USEAFTER=date/time' will also be added to the
header of each
POST-SAA DARK frame. The keyword must be populated with
the time, in
addition to the date, because HST crosses the SAA ~8 times
per day so
each POST-SAA DARK will need to have the appropriate time
specified, for
users to identify the ones they need. Both the raw and
processed images
will be archived as POST-SAA DARKSs. Generally we expect
that all NICMOS
science/calibration observations started within 50 minutes
of leaving an
SAA will need such maps to remove the CR persistence from
the science
images. Each observation will need its own CRMAP, as
different SAA
passages leave different imprints on the NICMOS detectors.
WFPC2 11096
Hubble Heritage imaging of Jupiter during the New Horizons
encounter HST
Proposal 11096
WFPC2 images of Jupiter in Feb 2007 in support of New
Horizons flyby of
Jupiter. This Hubble Heritage DD program is working in
concert with the
existing GO programs by John Clarke {10862} and John
Spencer {10871}.
S/C 11094
SBC Filter Wheel Checkout
Following the side 2 electronics failure it is proposed to
return to
side 1 and operate the SBC. Several tests will be
performed before
resuming normal operations. The following proposal is one
of these and
should be held until the return to side 1 is approved.
This proposal's
purpose is to command the SBC Filter Wheel to each of its
positions in
both directions of motion and verify {via the mechanism's
positional
encoding readout} proper execution of the commands.
WFPC2 11093
Hubble Heritage Observations of PNe with WFPC2
This is a proposal for observation of a set of PNe using a
common WFPC2
observation sequence.
WFPC2 11089
WFPC2 UV Throughput Check after 27-Jan-2007 Safemode
Check UV throughput of standard star GRW+70D5824 in all
four chips
following safemode caused by ACS Side 2 failure.
NIC3 11082
NICMOS Imaging of GOODS: Probing the Evolution of the
Earliest Massive
Galaxies, Galaxies Beyond
Deep near-infrared imaging provides the only avenue
towards
understanding a host of astrophysical problems, including:
finding
galaxies and AGN at z > 7, the evolution of the most
massive galaxies,
the triggering of star formation in dusty galaxies, and
revealing
properties of obscured AGN. As such, we propose to observe
60 selected
areas of the GOODS North and South fields with NICMOS
Camera 3 in the
F160W band pointed at known massive M > 10^11 M_0
galaxies at z > 2
discovered through deep Spitzer imaging. The depth we will
reach {26.5
AB at 5 sigma} in H_160 allows us to study the internal
properties of
these galaxies, including their sizes and morphologies,
and to
understand how scaling relations such as the Kormendy
relationship
evolved. Although NIC3 is out of focus and undersampled,
it is currently
our best opportunity to study these galaxies, while also
sampling enough
area to perform a general NIR survey 1/3 the size of an
ACS GOODS field.
These data will be a significant resource, invaluable for
many other
science goals, including discovering high redshift
galaxies at z > 7,
the evolution of galaxies onto the Hubble sequence, as
well as examining
obscured AGN and dusty star formation at z > 1.5. The
GOODS fields are
the natural location for HST to perform a deep NICMOS
imaging program,
as extensive data from space and ground based
observatories such as
Chandra, GALEX, Spitzer, NOAO, Keck, Subaru, VLT, JCMT,
and the VLA are
currently available for these regions. Deep
high-resolution
near-infrared observations are the one missing ingredient
to this
survey, filling in an important gap to create the deepest,
largest, and
most uniform data set for studying the faint and distant
universe. The
importance of these images will increase with time as new
facilities
come on line, most notably WFC3 and ALMA, and for the
planning of future
JWST observations.
NIC3 11080
Exploring the Scaling Laws of Star Formation
As a variety of surveys of the local and distant Universe
are
approaching a full census of galaxy populations, our
attention needs to
turn towards understanding and quantifying the physical
mechanisms that
trigger and regulate the large-scale star formation rates
{SFRs} in
galaxies.
NIC3 11064
CYCLE 15 NICMOS SPECTROPHOTOMETRY CALIBRATION PROGRAM
Now that the spectrophotometric capabilities of the NICMOS
grism have
been established, cycle 15 observations are needed to
refine the
sensitivity estimates, to check for sensitivity loss with
time, to
improve the accuracy of the linearity correction, to
improve the
secondary flux standards by re-observation, and to expand
the G206 data
set now that the sky subtraction technique has been shown
to produce
useful fluxes for some of the fainter secondary standards.
These faint
secondary IR standards will be a significant step towards
establishing
flux standards for JWST, as well as for SNAP, Spitzer, and
SOFIA. 1.Re-
observe the 3 primary WDs GD71, G191B2b, & GD153 twice
each, once at the
beginning and once near the end of the 18 month cycle. To
date, we have
only 2 observation of each star, while the corresponding
STIS data set
for these primary standards ranges from 6 to 23 obs. No
observations
exist for GD71 or GD153 with G206, so that the current
G206 sensitivity
is defined solely by G191B2B. Purposes: Refine
sensitivities, measure
sens losses. Orbits: 2 for each of 6 visits = 12 2.
Re-observe WD1057 &
WD1657 plus another P041C lamp-on visit to improve the
scatter in the
non-lin measurements per Fig. 8 of NIC ISR 2006-02. The WD
stars require
2 orbits each, while the lamp-on test is done in one. The
very faintest
and most crucial standard WD1657 has 2 good visits
already, so to
substantially improve the S/N, two visits of two orbits
are needed.
Include G206 for P041C in the lamp-off baseline part of
that orbit.
Orbits: WD1057-2, WD1657-4, P041C-1 --> 7 3. Re-observe
9 secondary
standards to improve S/N of the faint ones and to include
G206 for all
9. BD+17 {3 obs} is not repeated in this cycle. Four are
bright enough
to do in one orbit: VB8, 2M0036+18, P330E, and P177D.
Orbits:2*5+4=14
Grand Total orbits over 18 month cycle 15 is 12+6+14=32
{Roelof will
submit the P041C lamp-on visit in a separate program.}
NIC1 11061
NICMOS Imaging of Grism Spectrophotometric Standards
In this program we will take imaging observations with all
3 cameras
with a range of filters of a significant number of stars
that are part
of the spectroscopic standard star project. These stars
will form the
fainter reference star backbone for programs as JWST,
Sophia, and SNAP.
With this program we will: 1. Accurately calibrate
relative brightness
of standard stars, which can be done more accurately with
photometry
than with spectroscopy. This has been proven to be vary
valuable to
straighten out the problems in the spectroscopic data
reduction and
calibrations so far. 2. Increase the number of stars over
a large
magnitude range to provide a more accurate cross check of
our count rate
dependent non-linearity correction 3. Include stars with
radically
different {very red} spectra to investigate whether the
filter curves as
measured before flight are still valid by comparing the
throughput
estimates from these stars to those used for the standard
calibration.
4. Repeat a few standard star observations from cycle 7
and post-NCS
installation SMOV, to increase the accuracy in the change
in sensitivity
measurement with just a few observations thanks to the
long baseline.
ACS/WFC 11052
Internal Flat Fields
The stability of the CCD P-flat fields will be monitored
using the
calibration lamps and a sub-sample of the filter set. High
signal
observations will be used to assess the stability of the
pixel-to-pixel
flat field structure and to monitor the position of the dust
motes.
ACS/SBC 11048
SBC MAMA Recovery
Procedure to be used when ACS MAMA anomalously shuts down.
Recovery
procedure is designed to carefully bring the MAMA back to
operating
condition while watching for possible problems. The final
step is to do
a fold analysis which gives detailed information about how
well the
instrument is performing. Only the first four visits are
to be executed.
Visits 5 to 7 whih are a repaeat of 1 to 4 are to be kept
on hold.
WFPC2 11029
WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation
Anomaly
Monitor
Intflat observations will be taken to provide a linearity
check: the
linearity test consists of a series of intflats in F555W,
in each gain
and each shutter. A combination of intflats, visflats, and
earthflats
will be used to check the repeatability of filter wheel
motions.
{Intflat sequences tied to decons, visits 1-18 in prop
10363, have been
moved to the cycle 15 decon proposal xxxx for easier
scheduling.} Note:
long-exposure WFPC2 intflats must be scheduled during ACS
anneals to
prevent stray light from the WFPC2 lamps from
contaminating long ACS
external exposures.
ACS/WFC 11024
WFPC2 CYCLE 15 INTERNAL MONITOR
This calibration proposal is the Cycle 15 routine internal
monitor for
WFPC2, to be run weekly to monitor the health of the
cameras. A variety
of internal exposures are obtained in order to provide a
monitor of the
integrity of the CCD camera electronics in both bays {both
gain 7 and
gain 15 -- to test stability of gains and bias levels}, a
test for
quantum efficiency in the CCDs, and a monitor for possible
buildup of
contaminants on the CCD windows. These also provide raw
data for
generating annual super-bias reference files for the
calibration
pipeline.
WFPC2 11023
WFPC2 CYCLE 15 Standard Darks - part 1
This dark calibration program obtains dark frames every
week in order to
provide data for the ongoing calibration of the CCD dark
current rate,
and to monitor and characterize the evolution of hot
pixels. Over an
extended period these data will also provide a monitor of
radiation
damage to the CCDs.
FGS 10989
Astrometric Masses of Extrasolar Planets and Brown Dwarfs
We propose observations with HST/FGS to estimate the
astrometric
elements {perturbation orbit semi-major axis and
inclination} of
extra-solar planets orbiting six stars. These companions
were originally
detected by radial velocity techniques. We have
demonstrated that FGS
astrometry of even a short segment of reflex motion, when
combined with
extensive radial velocity information, can yield useful
inclination
information {McArthur et al. 2004}, allowing us to
determine companion
masses. Extrasolar planet masses assist in two ongoing
research
frontiers. First, they provide useful boundary conditions
for models of
planetary formation and evolution of planetary systems.
Second, knowing
that a star in fact has a plantary mass companion,
increases the value
of that system to future extrasolar planet observation
missions such as
SIM PlanetQuest, TPF, and GAIA.
ACS/WFC 10918
Reducing Systematic Errors on the Hubble Constant:
Metallicity
Calibration of the Cepheid PL Relation
Reducing the systematic errors on the Hubble constant is
still of
significance and of immediate importance to modern
cosmology. One of the
largest remaining uncertainties in the Cepheid-based
distance scale
{which itself is at the foundation of the HST Key Project
determination
of H_o} which can now be addressed directly by HST, is the
effect of
metallicity on the Cepheid Period-Luminosity relation.
Three chemically
distinct regions in M101 will be used to directly measure
and thereby
calibrate the change in zero point of the Cepheid PL relation
over a
range of metallicities that run from SMC-like, through
Solar, to
metallicities as high as the most metal-enriched galaxies
in the pure
Hubble flow. ACS for the first time offers the opportunity
to make a
precise calibration of this effect which currently
accounts for at least
a third of the total systematic uncertainty on Ho. The
calibration will
be made in the V and I bandpasses so as to be immediately
and directly
applicable to the entire HST Cepheid-based distance scale
sample, and
most especially to the highest-metallicity galaxies that
were hosts to
the Type Ia supernovae, which were then used to extend the
the distance
scale calibration out to cosmologically significant
distances.
WFPC2 10890
Morphologies of the Most Extreme High-Redshift
Mid-IR-Luminous Galaxies
The formative phase of the most massive galaxies may be
extremely
luminous, characterized by intense star- and
AGN-formation. Till now,
few such galaxies have been unambiguously identified at
high redshift,
restricting us to the study of low-redshift ultraluminous
infrared
galaxies as possible analogs. We have recently discovered
a sample of
objects which may indeed represent this early phase in
galaxy formation,
and are undertaking an extensive multiwavelength study of
this
population. These objects are bright at mid-IR wavelengths
{F[24um]>0.8mJy}, but deep ground based imaging
suggests extremely faint
{and in some cases extended} optical counterparts
{R~24-27}. Deep K-band
images show barely resolved galaxies. Mid-infrared
spectroscopy with
Spitzer/IRS reveals that they have redshifts z ~ 2-2.5,
suggesting
bolometric luminosities ~10^{13-14}Lsun! We propose to
obtain deep ACS
F814W and NIC2 F160W images of these sources and their environs
in order
to determine kpc-scale morphologies and surface photometry
for these
galaxies. The proposed observations will help us determine
whether these
extreme objects are merging systems, massive obscured
starbursts {with
obscuration on kpc scales!} or very reddened {locally
obscured} AGN
hosted by intrinsically low-luminosity galaxies.
NIC1 10879
A search for planetary-mass companions to the nearest L
dwarfs -
completing the survey
We propose to extend the most sensitive survey yet
undertaken for very
low-mass companions to ultracool dwarfs. We will use
NICMOS to complete
imaging of an all-sky sample of 87 L dwarfs in 80 systems
within 20
parsecs of the Sun. The combination of infrared imaging
and proximity
allows us to search for companions with mass ratios
q>0.25 at
separations exceeding ~3 AU, while probing companions with
q>0.5 at ~1.5
AU separation. This resolution is crucial, since no
ultracool binaries
are known in the field with separations exceeding 15 AU.
Fifty L dwarfs
from the 20-parsec sample have high- resolution imaging,
primarily
through our Cycle 13 HST proposal which identified six new
binaries,
including an L/T system. Here, we propose to target the
remaining 30
dwarfs
WFPC2 10871
Observations of the Galilean Satellites in Support of the
New Horizons
Flyby
On February 28 2007 the New Horizons {NH} spacecraft will
fly by Jupiter
on its way to Pluto, and will conduct an extensive series
of
observations of the Jupiter system, including the Galilean
satellites.
We propose HST observations to support and complement the
New Horizons
observations in four ways: 1} Determine the distribution
and variability
of Io's plumes in the two weeks before NH closest
approach, to look for
correlations with Io- derived dust streams that may be
detected by New
Horizons, to understand the origin of the dust streams; 2}
Imaging of
SO2 and S2 gas absorption in Io's plumes in Jupiter
transit, which
cannot be done by NH; 3} Color imaging of Io's surface to
determine the
effects of the plumes and volcanos seen by New Horizons on
the surface-
New Horizons cannot image the sunlit surface in color due
to saturation;
4} Imaging of far-UV auroral emissions from the
atmospheres of Io,
Europa, and Ganymede in Jupiter eclipse, near-
simultaneously with
disk-integrated NH UV spectra, to locate the source of the
UV emissions
seen by NH and use the response of the satellite
atmospheres to the
eclipse to constrain production mechanisms.
NIC2, ACS/WFC 10802
SHOES-Supernovae, HO, for the Equation of State of Dark
energy
The present uncertainty in the value of the Hubble
constant {resulting
in an uncertainty in Omega_M} and the paucity of Type Ia
supernovae at
redshifts exceeding 1 are now the leading obstacles to
determining the
nature of dark energy. We propose a single, integrated set
of
observations for Cycle 15 that will provide a 40%
improvement in
constraints on dark energy. This program will observe
known Cepheids in
six reliable hosts of Type Ia
supernovae with NICMOS, reducing the
uncertainty in H_0 by a factor of two because of the
smaller dispersion
along the instability strip, the diminished extinction,
and the weaker
metallicity dependence in the infrared. In parallel with
ACS, at the
same time the NICMOS observations are underway, we will
discover and
follow a sample of Type
Ia supernovae at z > 1.
Together, these
measurements, along with prior constraints from WMAP, will
provide a
great improvement in HST's ability to distinguish between
a static,
cosmological constant and dynamical dark energy. The
Hubble Space
Telescope is the only instrument in the world that can
make these IR
measurements of Cepheids beyond the Local Group, and it is
the only
telescope in the world that can be used to find and follow
supernovae at
z > 1. Our program exploits both of these unique
capabilities of HST to
learn more about one of the greatest mysteries in science.
ACS/WFC 10798
Dark Halos and Substructure from Arcs & Einstein Rings
The surface brightness distribution of extended
gravitationally lensed
arcs and Einstein rings contains super-resolved
information about the
lensed object, and, more excitingly, about the smooth and
clumpy mass
distribution of the lens galaxies. The source and lens
information can
non-parametrically be separated, resulting in a direct
"gravitational
image" of the inner mass-distribution of
cosmologically-distant galaxies
{Koopmans 2005; Koopmans et al. 2006 [astro-ph/0601628]}.
With this goal
in mind, we propose deep HST ACS-F555W/F814W and
NICMOS-F160W WFC
imaging of 20 new gravitational-lens systems with
spatially resolved
lensed sources, of the 35 new lens systems discovered by
the Sloan Lens
ACS Survey {Bolton et al. 2005} so far, 15 of which are
being imaged in
Cycle-14. Each system has been selected from the SDSS and
confirmed in
two time- efficient HST-ACS snapshot programs {cycle
13&14}.
High-fidelity multi-color HST images are required {not
delivered by the
420s snapshots} to isolate these lensed images {properly
cleaned,
dithered and extinction-corrected} from the lens galaxy
surface
brightness distribution, and apply our "gravitational
maging" technique.
Our sample of 35 early-type lens galaxies to date is by
far the largest,
still growing, and most uniformly selected. This minimizes
selection
biases and small-number statistics, compared to smaller,
often
serendipitously discovered, samples. Moreover, using the
WFC provides
information on the field around the lens, higher S/N and a
better
understood PSF, compared with the HRC, and one retains
high spatial
resolution through drizzling. The sample of galaxy mass
distributions -
determined through this method from the arcs and Einstein
ring HST
images - will be studied to: {i} measure the smooth mass
distribution of
the lens galaxies {dark and luminous mass are separated
using the HST
images and the stellar M/L values derived from a joint
stellar-dynamical
analysis of each system}; {ii} quantify statistically and
individually
the incidence of mass-substructure {with or without
obvious luminous
counter- parts such as dwarf galaxies}. Since dark-matter
substructure
could be more prevalent at higher redshift, both results
provide a
direct test of this prediction of the CDM hierarchical
structure-formation model.
NIC3 10792
Quasars at Redshift z=6 and Early Star Formation History
We propose to observe four high-redshift quasars {z=6} in
the NIR in
order to estimate relative Fe/Mg abundances and the
central black hole
mass. The results of this study will critically constrain
models of
joint quasar and galaxy formation, early star formation,
and the growth
of supermassive black holes. Different time scales and
yields for
alpha-elements {like O or Mg} and for iron result into an
iron
enrichment delay of ~0.3 to 0.6 Gyr. Hence, despite the
well-known
complexity of the FeII emission line spectrum, the ratio
iron/alpha -
element is a potentially useful cosmological clock. The
central black
hole mass will be estimated based on a recently revised
back hole mass -
luminosity relationship. The time delay of the iron
enrichment and the
time required to form a supermassive black hole {logM>8
Msol, tau
~0.5Gyr} as evidenced by quasar activity will be used to
date the
beginning of the first intense star formation, marking the
formation of
the first massive galaxies that host luminous quasars, and
to constrain
the epoch when supermassive black holes start to grow by
accretion.
FGS 10610
Astrometric Masses of Extrasolar Planets and Brown Dwarfs
We propose observations with HST/FGS to estimate the
astrometric
elements {perturbation orbit semi-major axis and
inclination} of
extra-solar planets orbiting six stars. These companions
were originally
detected by radial velocity techniques. We have
demonstrated that FGS
astrometry of even a short segment of reflex motion, when
combined with
extensive radial velocity information, can yield useful
inclination
information {McArthur et al. 2004}, allowing us to
determine companion
masses. Extrasolar planet masses assist in two ongoing
research
frontiers. First, they provide useful boundary conditions
for models of
planetary formation and evolution of planetary systems.
Second, knowing
that a star in fact has a plantary mass companion,
increases the value
of that system to future extrasolar planet observation
missions such as
SIM PlanetQuest, TPF, and GAIA.
ACS/WFC 10520
Resolving the Complex Star Formation History of the Leo I
Dwarf
Spheroidal Galaxy
Determining the star formation histories {SFHs} and
chemical evolution
of nearby galaxies gives us powerful constrains on the
physical
processes that regulate galaxy evolution. The SFHs can be
measured most
accurately by comparing the observed densities of stars in
color-magnitude diagrams {CMDs} to predictions from
stellar evolutionary
models. WFPC2 imaging of the Leo I dSph shows it is unique
because its
stellar population is relatively young. Approximately 68%
of its stars
formed between 1 and 7 Gyr ago and only 12% of its stars
formed >~ 10
Gyr ago. We propose to vastly improve the derived SFH of
Leo I by
exploiting ACS/WFC's higher quantum efficiency at bluer
wavelengths,
higher spatial resolution, and larger field-of-view. The
figure of merit
for our proposed observations, defined as the age
resolution times the
number of stars detected, will be a factor of 12 higher
than existing
WFPC2 observations. To surmount the degeneracy of age and
metallicity in
the CMD, we have independently measured the metallicity
distribution of
its stars using spectroscopy. Simultaneously modeling the
metallicity
distribution and CMD, we will firmly constrain the
evolution of the Leo
I dSph, a unique example of an isolated dwarf galaxy that
has not been
influenced by interactions with the Milky Way or M31.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
10694 - GSAcq (2,3,3) results in fine lock backup (2,0,2)
REAcq (2,3,3) scheduled at
047/10:38:25-10:45:34 resulted in fine lock
backup (2,0,2) using FGS 2, due to (QF3STOPF)
stop flag indication on
secondary FGS 3.
10696 - GSacq(2,1,1) failed to RGA control
GSacq(2,1,1) scheduled at 047/14:02:15 failed
to RGA control due to
receiving stop flag QF2STOPF on FGS 2 at
14:05:41.
10697 - Multiple REacq(1,3,3) failures to RGA control
REacq failed at 13:46:57 with a STOP flag for
FGS 1. F3SSCEB (F3 Star
Select Compensation Error B) flagged out at
13:47:56.
REacq scheduled at 15:18:26 also failed with a
STOP flag for FGS1.
REacq scheduled at 16:55:24 also failed with a
STOP flag for FGS1.
Monitoring all three failures the following was
noted:
The failure occurred after fine lock for both
FGS's and during the
vehicle offset maneuver. The star used for FGS
1 tracks outside the FGS
FOV during this maneuver.
Upon AOS @ 19:17, the REacq scheduled at
18:30:14 failed with a STOP
flag for FGS1.
Upon AOS @ 20:29, the REacq scheduled at
20:06:07 failed with a STOP
flag for FGS1.
10699 - GSAcq(2,1,2) failed to RGA Hold (Gyro Control)
Upon acquisition of signal at 050/11:51:21, the
GSAcq(2,1,2) scheduled
at 050/11:43:25 - 11:51:30 had failed to RGA
Hold due to (QF2STOPF) stop
flag indication on FGS2.
10702 - GSAcq (2,1,2) failed due to Search Radius Limit
Exceeded on FGS 2
At AOS (051/09:12:16) GSAcq (2,1,2) scheduled
051/08:29:56-08:37:10 had
failed due to search radius limit exceeded on
FGS 2.
COMPLETED OPS REQUEST:
18018-4 - Configure ACS to Side 1 Safe Mode
18017-0 - SMAC20 Version 'M' Install
18019-4 - Configure ACS for Side 1 Operations
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 26 23
FGS REacq 29 24
OBAD with Maneuver 107 107
SIGNIFICANT EVENTS:
Flash Report:
As of 047/16:22:43 ACS is configured to its Safe mode on
Side 1, and the
on-board SMAC20 has been updated to the new version M to
support ACS
Side 1 SBC-only operations.
Flash Report:
As of 048/00:28:33. ACS CS FSW 4.02A has been successfully
loaded,
validated, and activated in the transition to the Operate
state. ACS is
configured to intercept the 050 SMS and resume SBC science
activities.
Flash Report:
Results of the ACS SBC Filter Wheel Test ACS completed the
SBC filter wheel test.
Flash Report:
The SI SEs at GSFC have been notified that ACS Flag 2 can
be cleared for
normal SBC operations.