HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT # 4559
PERIOD
COVERED: UT March 3, 2008 (DOY 063)
OBSERVATIONS
SCHEDULED
ACS/SBC
11230
HST
FUV Observations of Brightest Cluster Galaxies: The Role of Star
Formation
in Cooling Flows and BCG Evolution
The
intracluster medium (ICM) now appears to be a very dynamic place
where
heating and cooling processes vie for dominance and an uneasy
equilibrium
is maintained. Since these same processes may operate during
the
process of galaxy formation, the centers of clusters of galaxies
provide
low redshift laboratories for studying the critical processes
involved
in galaxy formation and black hole growth. At the present time,
the
main questions are (1) How much gas is cooling out of the ICM? (2)
How
much star formation is ongoing? (3) What is the impact of the gas
and
star formation on the central BCG? In order to measure the current
star
formation in BCGs we have undertaken a program of Spitzer IRAC and
MIPS
observations. We are in process of obtaining observations of a
sample
of Brightest Cluster Galaxies in 70 clusters selected from the
ROSAT
all sky survey. In about 25% of the sources observed so far, we
detect
a mid-IR excess which we attribute to dust heated by star
formation.
We propose to obtain ACS/SBC observations of the Lyman Alpha
emission
line and the adjacent FUV continuum in 7 BCGs which are in
cooling
core clusters of galaxies and have a large mid-IR excess. We
also
propose WFPC2 F606W observations of the two clusters without high
resolution
imaging to allow us to image the dust on the same scale as
the
Far UV continuum. The FUV will allow us to confirm the presense of
ongoing
starformation in these BCGs and will allow us to rule out an AGN
as
the dominant contributer to the mid-IR. The morphology and spatial
extent
of the young stars and the heated dust and CO will constrain the
spatial
scale over which star formation occurs and thus where the
cooling
gas is deposited. The combination of our FUV and IR observations
will
allow us to estimate the star formation rates which must balance
the
rate at which cold gas is deposited in the BCG. Our proposed FUV
observations
will produce unique information about the cooling gas, the
true
mass accretion rates, and the star formation rates in BCGs and its
effect
on the galaxy.
WFPC2
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.
FGS
11295
Trigonometric
Calibration of the Distance Scale for Classical Novae
The
distance scale for classical novae is important for understanding
the
stellar physics of their thermonuclear runaways, their contribution
to
Galactic nucleosynthesis, and their use as extragalactic standard
candles.
Although it is known that there is a relationship between their
absolute
magnitudes at maximum light and their subsequent rates of
decline--the
well-known maximum-magnitude rate-of-decline {MMRD}
relation--it
is difficult to set the zero-point for the MMRD because of
the
very uncertain distances of Galactic novae. We propose to measure
precise
trigonometric parallaxes for the quiescent remnants of the four
nearest
classical novae. We will use the Fine Guidance Sensors, which
are
proven to be capable of measuring parallaxes with errors of ~0.2
mas,
well below what is possible from the ground.
NIC1/NIC2/NIC3
11330
NICMOS
Cycle 16 Extended Dark
This
takes a series of Darks in parallel to other instruments.
NIC1/NIC2/NIC3
8795
NICMOS
Post-SAA calibration - CR Persistence Part 6
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 i
mages.
Each observation will need its own CRMAP, as different SAA
passages
leave different imprints on the NICMOS detectors.
NIC2
10852
Coronagraphic
Polarimetry with NICMOS: Dust grain evolution in T Tauri
stars
The
formation of planetary systems is intimately linked to the dust
population
in circumstellar disks, thus understanding dust grain
evolution
is essential to advancing our understanding of how planets
form.
By combining {1} the coronagraphic polarimetry capabilities of
NICMOS,
{2} powerful 3-D radiative transfer codes, and {3} observations
of
objects known to span the Class II- III stellar evolutionary phases,
we
will gain crucial insight into dust grain growth. By observing
objects
representative of a known evolutionary sequence of YSOs, we will
be
able to investigate how the dust population evolves in size and
distribution
during the crucial transition from a star+disk system to a
system
containing planetesimals. When combine with our previous study on
dust
grain evolution in the Class I-II phase, the proposed study will
help
to establish the fundamental time scales for the depletion of
ISM-like
grains: the first step in understanding the transformation from
small
submicron sized dust grains, to large millimeter sized grains, and
untimely
to planetary bodies.
NIC2
11142
Revealing
the Physical Nature of Infrared Luminous Galaxies at 0.3
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}.
NIC2
11157
NICMOS
Imaging Survey of Dusty Debris Around Nearby Stars Across the
Stellar
Mass Spectrum
Association
of planetary systems with dusty debris disks is now quite
secure,
and advances in our understanding of planet formation and
evolution
can be achieved by the identification and characterization of
an
ensemble of debris disks orbiting a range of central stars with
different
masses and ages. Imaging debris disks in starlight scattered
by
dust grains remains technically challenging so that only about a
dozen
systems have thus far been imaged. A further advance in this field
needs
an increased number of imaged debris disks. However, the technical
challenge
of such observations, even with the superb combination of HST
and
NICMOS, requires the best targets. Recent HST imaging investigations
of
debris disks were sample-limited not limited by the technology used.
We
performed a search for debris disks from a IRAS/Hipparcos cross
correlation
which involved an exhaustive background contamination check
to
weed out false excess stars. Out of ~140 identified debris disks, we
selected
22 best targets in terms of dust optical depth and disk angular
size.
Our target sample represents the best currently available target
set
in terms of both disk brightness and resolvability. For example, our
targets
have higher dust optical depth, in general, than newly
identified
Spitzer disks. Also, our targets cover a wider range of
central
star ages and masses than previous debris disk surveys. This
will
help us to investigate planetary system formation and evolution
across
the stellar mass spectrum. The technical feasibility of this
program
in two-gyro mode guiding has been proven with on-orbit
calibration
and science observations during HST cycles 13, 14, and 15.
WFPC2
11070
WFPC2
CYCLE 15 Standard Darks - part II
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.
WFPC2
11138
The
Physics of the Jets of Powerful Radio Galaxies and Quasars
We
propose to obtain HST polarimetry of the jets of the quasars 1150+497
and
PKS 1136-135. Our goal is to solve the riddle of their high-energy
emission
mechanism, and tackle issues such as particle acceleration and
jet
dynamics. Our targets are the optically brightest quasar jets, and
they
span the range of luminosities and beaming parameters seen in these
objects.
Recent observations with Spitzer, HST and Chandra have shed new
light
on the spectral morphology of quasar jets, throwing wide open the
question
of the nature of their optical and X-ray emission. Three
mechanisms
are possible, including synchrotron emission as well as two
Comptonization
processes. Polarimetry can uniquely determine which of
these
mechanisms operates in the optical. We will compare the optical
polarimetry
to in- hand radio polarimetry as well as in-hand and new
Spitzer,
HST and Chandra imaging to gain new insights on the structure
of
these jets, as well as particle acceleration mechanisms and jet
dynamics.
WFPC2
11201
Systemic
and Internal motions of the Magellanic Clouds: Third Epoch
Images
In
Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields in
the
Magellanic Clouds centered on background quasars. We used these data
to
determine the proper motions of the LMC and SMC to better than 5% and
15%
respectively. These are by far the best determinations of the proper
motions
of these two galaxies. The results have a number of unexpected
implications
for the Milky Way-LMC-SMC system. The implied
three-dimensional
velocities are larger than previously believed, and
are
not much less than the escape velocity in a standard 10^12 solar
mass
Milky Way dark halo. Orbit calculations suggest the Clouds may not
be
bound to the Milky Way or may just be on their first passage, both of
which
would be unexpected in view of traditional interpretations of the
Magellanic
Stream. Alternatively, the Milky Way dark halo may be a
factor
of two more massive than previously believed, which would be
surprising
in view of other observational constraints. Also, the
relative
velocity between the LMC and SMC is larger than expected,
leaving
open the possibility that the Clouds may not be bound to each
other.
To further verify and refine our results we now request an epoch
of
WFPC2/PC data for the fields centered on 40 quasars that have at
least
one epoch of ACS imaging. We request execution in snapshot mode,
as
in our previous programs, to ensure the most efficient use of HST
resources.
A third epoch of data of these fields will provide crucial
information
to verify that there are no residual systematic effects in
our
previous measurements. More importantly, it will increase the time
baseline
from 2 to 5 yrs and will increase the number of fields with at
least
two epochs of data. This will reduce our uncertainties
correspondingly,
so that we can better address whether the Clouds are
indeed
bound to each other and to the Milky Way. It will also allow us
to
constrain the internal motions of various populations within the
Clouds,
and will allow us to determine a distance to the LMC using
rotational
parallax.
WFPC2
11297
Reducing
Systematic Errors on the Hubble Constant: Metallicity
Calibration
of the
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
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.
FLIGHT
OPERATIONS SUMMARY:
Significant
Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
HSTARS:
11205
- GSacq(1,2,1) failed, Search Radius Limit exceeded on FGS 1
Upon acquisition of signal at 18:06:12, vehicle was in gyro control with
FGS1 search radius limit and stop flags set. GSACQ(1,2,1) at 17:55:27
failed to RGA control. One 486 status buffer "A05" message (FGS
Coarse
Track failed- Search Radius Limit exceeded) was received. OBAD map after
GSACQ had RSS error of 53.33 arcseconds. NICMOS 705 status buffer
message (TDF down when a target acquisition SAM request is made) was
posted at 18:05:08.
COMPLETED
OPS REQUEST: (None)
COMPLETED
OPS NOTES:
1647-0
- Reset NICMOS Error Counter @ 063/20:04z
SCHEDULED SUCCESSFUL
FGS
GSacq 09 08
FGS
REacq 05 05
OBAD
with Maneuver 28 28
SIGNIFICANT
EVENTS: (None)