HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4671
PERIOD COVERED: 5am August 8 - 5am August 11, 2008 (DOY
221/0900z-224/0900z)
OBSERVATIONS SCHEDULED
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.
WFPC2 11807
Hubble WFPC2 Imaging of NGC 2074 in the Large Magellanic
Cloud
We propose HST WFPC2 observations of the diffuse nebula
NGC 2074 (which
is possibly a SNR) in the LMC. We will exploit the spatial
resolution
provided by HST to image circumstellar ejecta of hot stars
, where
ground- based imaging is difficult, and cannot provide
meaningful
spatial information. The distribution of the ionized gas
and dust will
allow us to determine the morphology of the circumstellar
nebulae. In
addition, the image promises to be quite spectacular,
endowing it with
great outreach potential.
WFPC2 11804
WFPC2 Closeout Calibration -- CTE Effects on Standard Star
Observations of the primary standard star GRW+70D5824 are
made at
several different places on the CCD to directly estimate
the impact of
CTE. All four CCDs are evaluated. Filters F170W and F555W
are used to
evaluate the effects of background and different PSF
shapes / sizes.
WFPC2 11796
WFPC2 Cycle 16 Decontaminations and Associated
Observations
This proposal is for the WFPC2 decons. Also included are
instrument
monitors tied to decons: photometric stability check,
focus monitor,
pre- and post-decon internals (bias, intflats, kspots,
& darks), UV
throughput check, VISFLAT sweep, and internal UV flat
check.
NIC2 11548
NICMOS Imaging of Protostars in the Orion A Cloud: The
Role of
Environment in Star Formation
We propose NICMOS 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.
NIC3 11334
NICMOS Cycle 16 Spectrophotometry
Observation of the three primary WD flux standards must be
repeated to
refine the NICMOS absolute calibration and monitor for
sensitivity
degradation. So far, NICMOS grism spectrophotometry is
available for
only ~16 stars with good STIS spectra at shorter
wavelengths. There are
more in the HST CALSPEC standard star data base with good
STIS spectra
that would also become precise IR standards with NICMOS
absolute SED
measurements. Monitoring the crucial three very red stars
(M, L, T) for
variability and better S/N in the IR. Apparent variability
was
discovered at shorter wavelengths during the ACS
cross-calibration work
that revealed a ~2% discrepancy of the cool star fluxes
with respect to
the hot primary WD standards. About a third of these stars
are bright
enough to do in one orbit, the rest require 2 orbits.
NIC1/NIC2/NIC3 11318
NICMOS Cycle 16 Multiaccum Darks
The purpose of this proposal is to monitor the dark
current, read noise,
and shading profile for all three NICMOS detectors
throughout the
duration of Cycle 16. This proposal is a slightly modified
version of
proposal 10380 of cycle 13 and 9993 of cycle12 and is the
same as Cycle
15. Covers the period from April 08 to November 08
(inclusive)
WFPC2 11227
The Orbital Period for an Ultraluminous X-ray Source in
NGC1313
The ultraluminous X-ray sources {ULXs} are extragalactic
point sources
with luminosities that exceed the Eddington luminosity for
conventional
stellar-mass black holes by factors of 10 - 100. It has
been hotly
debated whether the ULXs are just common stellar-mass
black hole sources
with beamed emission or whether they are sub-Eddington
sources that are
powered by the long-sought intermediate mass black holes
{IMBH}. To
firmly decide this question, one must obtain dynamical
mass measurements
through photometric and spectroscopic monitoring of the
secondaries of
these system. The crucial first step is to establish the
orbital period
of a ULX, and arguably the best way to achieve this goal
is by
monitoring its ellipsoidal light curve. The extreme ULX
NGC1313 X-2
provides an outstanding target for an orbital period
determination
because its relatively bright optical counterpart {V =
23.5} showed a
15% variation between two HST observations separated by
three months.
This level of variability is consistent with that expected
for a tidally
distorted secondary star. Here we propose a set of 20
imaging
observations with HST/WFPC2 to define the orbital period.
This would be
the first photometric measurement of the orbital period of
a ULX binary.
Subsequently, we will propose to obtain spectroscopic
observations to
obtain its radial velocity amplitude and thereby a dynamical
estimate of
its mass.
WFPC2 11222
Direct Detection and Mapping of Star Forming Regions in
Nearby, Luminous
Quasars
We propose to carry out narrow-band emission line imaging
observations
of 8 quasars at z=0.05-0.15 with the WFPC2 ramp filters
and with the
NICMOS narrow-band filters. We will obtain images in the
[O II], [O
III], H-beta, and Pa-alpha emission line bands to carry
out a series of
diagnostic tests aimed at detecting and mapping out
star-forming regions
in the quasar host galaxies. This direct detection of
star-forming
regions will confirm indirect indications for star
formation in quasar
host galaxies. It will provide a crucial test for models
of quasar and
galaxy evolution, that predict the co-existence of
starbursts and
"monsters" and will solve the puzzle of why
different indicators of star
formation give contradictory results. A secondary science
goal is to
assess suggested correlations between quasar luminosity
and the size of
the narrow-line region.
WFPC2 11218
Snapshot Survey for Planetary Nebulae in Globular Clusters
of the Local
Group
Planetary nebulae {PNe} in globular clusters {GCs} raise a
number of
interesting issues related to stellar and galactic
evolution. The number
of PNe known in Milky Way GCs, 4, is surprisingly low if
one assumes
that all stars pass through a PN stage. However, it is
likely that the
remnants of stars now evolving in Galactic GCs leave the
AGB so slowly
that any ejected nebula dissipates long before the star
becomes hot
enough to ionize it. Thus there should not be ANY PNe in
Milky Way
GCs--but there are four! It has been suggested that these
PNe are the
result of mergers of binary stars within GCs, i.e., that
they are
descendants of blue stragglers. The frequency of
occurrence of PNe in
external galaxies poses more questions, because it shows a
range of
almost an order of magnitude. I propose a Snapshot survey
aimed at
discovering PNe in the GC systems of Local Group galaxies
more distant
than the Magellanic Clouds. These clusters, some of which
may be much
younger than their counterparts in the Milky Way, might
contain many
more PNe than those of our own galaxy. I will use the
standard technique
of emission-line and continuum imaging, which easily
discloses PNe.
WFPC2 11203
A Search for Circumstellar Disks and Planetary-Mass
Companions around
Brown Dwarfs in Taurus
During a 1-orbit program in Cycle 14, we used WFPC2 to
obtain the first
direct image of a circumstellar disk around a brown dwarf.
These data
have provided fundamental new constraints on the formation
process of
brown dwarfs and the properties of their disks. To search
for additional
direct detections of disks around brown dwarfs and to
search for
planetary-mass companions to these objects, we propose a
WFPC2 survey of
32 brown dwarfs in the Taurus star-forming region.
WFPC2 11202
The Structure of Early-type Galaxies: 0.1-100 Effective
Radii
The structure, formation and evolution of early-type
galaxies is still
largely an open problem in cosmology: how does the
Universe evolve from
large linear scales dominated by dark matter to the highly
non-linear
scales of galaxies, where baryons and dark matter both
play important,
interacting, roles? To understand the complex physical
processes
involved in their formation scenario, and why they have
the tight
scaling relations that we observe today {e.g. the
Fundamental Plane}, it
is critically important not only to understand their
stellar structure,
but also their dark-matter distribution from the smallest
to the largest
scales. Over the last three years the SLACS collaboration
has developed
a toolbox to tackle these issues in a unique and
encompassing way by
combining new non-parametric strong lensing techniques,
stellar
dynamics, and most recently weak gravitational lensing,
with
high-quality Hubble Space Telescope imaging and VLT/Keck
spectroscopic
data of early-type lens systems. This allows us to break
degeneracies
that are inherent to each of these techniques separately
and probe the
mass structure of early-type galaxies from 0.1 to 100
effective radii.
The large dynamic range to which lensing is sensitive
allows us both to
probe the clumpy substructure of these galaxies, as well
as their
low-density outer haloes. These methods have convincingly
been
demonstrated, by our team, using smaller pilot-samples of
SLACS lens
systems with HST data. In this proposal, we request
observing time with
WFPC2 and NICMOS to observe 53 strong lens systems from
SLACS, to obtain
complete multi-color imaging for each system. This would
bring the total
number of SLACS lens systems to 87 with completed HST
imaging and
effectively doubles the known number of galaxy-scale
strong lenses. The
deep HST images enable us to fully exploit our new techniques,
beat down
low-number statistics, and probe the structure and
evolution of early-
type galaxies, not only with a uniform data-set an order
of magnitude
larger than what is available now, but also with a fully
coherent and
self-consistent methodological approach!
NIC2 11197
Sweeping Away the Dust: Reliable Dark Energy with an
Infrared Hubble
Diagram
We propose building a high-z Hubble Diagram using type Ia
supernovae
observed in the infrared rest-frame J-band. The infrared
has a number of
exceptional properties. The effect of dust extinction is
minimal,
reducing a major systematic that may be biasing dark
energy
measurements. Also, recent work indicates that type Ia
supernovae are
true standard candles in the infrared meaning that our
Hubble diagram
will be resistant to possible evolution in the Phillip's
relation over
cosmic time. High signal-to-noise measurements of 16 type
Ia events at
z~0.4 will be compared with an independent optical Hubble
diagram from
the ESSENCE project to test for a shift in the derived
dark energy
equation of state due to a systematic bias. In Cycle 15 we
obtained
NICMOS photometry of 8 ESSENCE supernovae and are awaiting
template
observations to place them on the IR Hubble diagram. Here
we request
another 8 supernovae be studied in the final season of the
ESSENCE
search. Because of the bright sky background, H-band
photometry of z~0.4
supernovae is not feasible from the ground. Only the
superb image
quality and dark infrared sky seen by HST makes this test
possible. This
experiment may also lead to a better, more reliable way of
mapping the
expansion history of the universe with the Joint Dark
Energy Mission.
NIC1/NIC2 11172
Defining Classes of Long Period Variable Stars in M31
We propose a thrifty but information-packed investigation
{1440
exposures total} with NICMOS F205W, F160W and F110W
providing crucial
information about Long Period Variables in M31, at a level
of detail
that has recently allowed the discovery of new variable
star classes in
the Magellanic Clouds, a very different stellar
population. These
observations are buttressed by an extensive map of the
same fields with
ACS and WFPC2 exposures in F555W and F814W, and a massive
ground-based
imaging patrol producing well-sampled light curves for
more than 400,000
variable stars. Our primary goal is to collect sufficient
NIR data in
order to analyze and classify the huge number of
long-period variables
in our catalog {see below} through Period-Luminosity {P/L}
diagrams. We
will produce accurate P/L diagrams for both the bulge and
a progression
of locations throughout the disk of M31. These diagrams
will be similar
in quality to those currently in the Magellanic Clouds,
with their lower
metallicity, radically different star formation history,
and larger
spread in distance to the variables. M31 offers an
excellent chance to
study more typical disk populations, in a manner which
might be extended
to more distant galaxies where such variables are still
visible, probing
a much more evenly spread progenitor age distribution than
cepheids {and
perhaps useful as a distance scale alternative or
cross-check}. Our data
will also provide a massive and unique color-magnitude
dataset, and
allow us to confirm the microlensing nature of a large
sample of
candidate lensed sources in M31. We expect that this study
will produce
several important results, among them a better
understanding of P/L and
P/L-color relations for pulsating variables which are
essential to the
extragalactic distance ladder, will view these variables
at a common
distance over a range of metallicities {eliminating the
distance- error
vs. metallicity ambiguity between the LMC and SMC}, allow
further
insight into possible faint-variable mass-loss for higher
metallicities,
and in general produce a sample more typical of giant disk
galaxies
predominant in many studies.
ACS/SBC 11151
Evaluating the Role of Photoevaporation of Protoplanetary
Disk Dispersal
Emission produced by accretion onto the central star leads
to
photoevaporation, which may play a fundamental role in
disk dispersal.
Models of disk photoevaporation by the central star are
challenged by
two potential problems: the emission produced by accretion
will be
substantially weaker for low-mass stars, and
photoevaporation must
continue as accretion slows. Existing FUV spectra of CTTSs
are biased to
solar-mass stars with high accretion rates, and are
therefore
insufficient to address these problems. We propose use
HST/ACS SBC
PR130L to obtain FUV spectra of WTTSs and of CTTSs at low
masses and
mass accretion rates to provide crucial data to evaluate
photoevaporation models. We will estimate the FUV and EUV
luminosities
of low-mass CTTSs with small mass accretion rates, CTTSs
with transition
disks and slowed accretion, and of magnetically-active
WTTSs.
NIC3 11147
The Origin of Diffuse UV Light from Spiral Disks
The ultraviolet light from galaxies has been used as a
beacon for
tracing the cosmic star formation history of the Universe,
yet we have
an incomplete understanding of many characteristics of
this light. Most
of the UV emission from nearby, normal star--forming
galaxies is
unresolved and "diffuse", and GALEX has shown
that in spiral disks it
permeates the inter-arm regions. The nature of this
diffuse inter- arm
component is under debate. Recent results suggest that it
may arise from
non- ionizing UV photons which originate in star forming
regions in the
spiral arms, travel in the plane of the galaxy, and then
scatter off of
diffusely distributed cold dust grains. Alternatively, an
in-situ,
unresolved stellar population could produce the observed
inter-arm UV
emission. This project seeks to establish which of the two
competing
scenarios is responsible for the bulk of this diffuse
emission. We
propose to use HST's UV imaging capability (ACS/SBC) to
obtain deep
observations of selected fields in the nearby spiral
galaxy M101, for
which available (low angular resolution) data favor the
'scattered
light' scenario. Our observations are designed to detect
any faint,
UV-luminous stellar population down to main sequence B5
stars. With
these data, we will establish the nature of the bulk of
the diffuse UV
light in this spiral galaxy by: (i) quantifying the
contribution from
dust-scattered light; (ii) measuring the contribution to
the ubiquitous
diffuse ionized medium from in- situ ionizing stars; and
(iii) providing
constraints on the observed stellar mass function in the
field. Only HST
has the UV sensitivity and angular resolution to
discriminate in-situ
stellar populations from scattered light. The ultimate
goal of this
project is to re-'calibrate' the UV emission as a star
formation rate
indicator, which will need to account for any scattered
component.
NIC1 11136
Resolving Ultracool Astrophysics with Brown Dwarf Binaries
We propose to obtain resolved far-red and near-IR
photometry of 13 brown
dwarf binaries with HST/NICMOS in order to study one of
the
long-standing puzzles in ultracool astrophysics, namely
the rapid change
in spectra from L dwarfs to T dwarfs at nearly constant
effective
temperature (a.k.a. the "L/T transition''). While
many nearby brown
dwarfs have been studied, use of such samples is
inevitably hindered by
the unknown ages, masses, and metallicities of the field
population.
Characterization of resolved ultracool binaries is a
promising avenue
for addressing this problem, by providing coeval systems
of the same
composition with comparable masses and temperatures. Our
proposed
HST/NICMOS (0.9-1.6 micron) observations will be combined
with longer
wavelength ground-based photometry and spectroscopy from
Keck laser
guide star adaptive optics. The resulting multiband (0.9-2.5
micron)
dataset will be a unique resource for measuring the
evolution of
spectral energy distributions across the L/T transition,
to test
state-of-the-art atmospheric models, and to determine the
physical
process(es) that dominate the L/T transition.
Understanding the L/T
transition is important not only for testing brown dwarf
atmospheres,
but also provides a key pathway for understanding the same
physical
effects, namely the formation and removal of clouds, in
the atmospheres
of the extrasolar planets.
WFPC2 11134
WFPC2 Tidal Tail Survey: Probing Star Cluster Formation on
the Edge
The spectacular HST images of the interiors of merging
galaxies such as
the Antennae and NGC 7252 have revealed rich and diverse
populations of
star clusters created over the course of the interaction.
Intriguingly,
our WFPC2 study of tidal tails in these and other
interacting pairs has
shown that star cluster birth in the tails does not follow
a similarly
straightforward evolution. In fact, cluster formation in
these
relatively sparse environments is not guaranteed -- only
one of six
tails in our initial study showed evidence for a
significant population
of young star clusters. The tail environment thus offers
the opportunity
to probe star cluster formation on the edge of the
physical parameter
space {e.g., of stellar and gas mass, density, and
pressure} that
permits it to occur. We propose to significantly extend
our pilot sample
of optically bright, gas-rich tidal tails by a factor of 4
in number to
include a more diverse population of tails, encompassing
major and minor
mergers, gas-rich and gas-poor tails, as well as early,
late, and merged
interaction stages. With 21 orbits of HST WFPC2 imaging in
the F606W and
F814W filters, we can identify, roughly age-date, and
measure sizes of
star clusters to determine what physical parameters affect
star cluster
formation. WFPC2 imaging has been used effectively in our
initial study
of four mergers, and it will be possible in this program
to reach
similar limits of Mv=-8.5 for each of 16 more tails. With
the much
larger sample we expect to isolate which factors, such as
merger stage,
HI content, and merger mass ratio, drive the formation of
star clusters.
ACS/SBC 11110
Searching for Lyman Apha Emission from FUSE Lyman
Continuum Candidates
We have recently been granted time on FUSE to characterize
the escape
fraction of hydrogen Lyman continuum (Lyc) photons from a
morphologically diverse set of star forming galaxies. The
FUSE program
is designed to provide ~ 5 sigma detections of Lyc photons
emitted from
star forming galaxies with escape fractions ~5%. With this
proposal we
seek hydrogen Lyman alpha (Lya) observations of a
representative subset
of the FUSE program targets to constrain the observational
relationship
between Lyc, Lya, and hydrogen Balmer line emission in
these systems.
Such observations explore the detailed balance between the
simple
optically thin (Case A) and optically thick (Case B)
limits in
recombination theory. The ultimate goal of this program is
to quantify
the relationship between escaping Lya and Lyc emission and
the first
structures that form in the early universe.
NIC2 11101
The Relevance of Mergers for Fueling AGNs: Answers from
QSO Host
Galaxies
The majority of QSOs are known to reside in centers of
galaxies that
look like ellipticals. Numerical simulations have shown
that remnants of
galaxy mergers often closely resemble elliptical galaxies.
However, it
is still strongly debated whether the majority of QSO host
galaxies are
indeed the result of relatively recent mergers or whether
they are
completely analogous to inactive ellipticals to which
nothing
interesting has happened recently. To address this
question, we recently
obtained deep HST ACS images for five QSO host galaxies
that were
classified morphologically as ellipticals {GO-10421}. This
pilot study
revealed striking signs of tidal interactions such as
ripples, tidal
tails, and warped disks that were not detected in previous
studies. Our
observations show that at least some
"elliptical" QSO host galaxies are
the products of relatively recent merger events rather
than old galaxies
formed at high redshift. However, the question remains
whether the host
galaxies of classical QSOs are truly distinct from
inactive ellipticals
and whether there is a connection between the merger
events we detect
and the current nuclear activity. We must therefore place
our results
into a larger statistical context. We are currently
conducting an HST
archival study of inactive elliptical galaxies {
control sample. We now propose to obtain deep HST/WFPC2
images of 13
QSOs whose host galaxies are classified as normal
ellipticals. Comparing
the results for both samples will help us determine
whether classical
QSOs reside in normal elliptical galaxies or not. Our
recent pilot study
of five QSOs indicates that we can expect exciting results
and deep
insights into the host galaxy morphology also for this
larger sample of
QSOs. A statistically meaningful sample will help us
determine the true
fraction of QSO hosts that suffered strong tidal
interactions and thus,
whether a merger is indeed a requirement to trigger
nuclear activity in
the most luminous AGNs. In addition to our primary science
observations
with WFPC2, we will obtain NICMOS3 parallel observations
with the
overall goal to select and characterize galaxy populations
at high
redshifts. The imaging will be among the deepest NICMOS
images: These
NICMOS images are expected to go to a limit a little over
1 magnitude
brighter than HUDF-NICMOS data, but over 13 widely
separated fields,
with a total area about 1.5 times larger than HUDF-
NICMOS. This
separation means that the survey will tend to average out
effects of
cosmic variance. The NICMOS3 images will have sufficient
resolution for
an initial characterization of galaxy morphologies, which
is currently
one of the most active and promising areas in approaching
the problem of
the formation of the first massive galaxies. The depth and
area coverage
of our proposed NICMOS observations will also allow a
careful study of
the mass function of galaxies at these redshifts. This
provides a large
and unbiased sample, selected in terms of stellar mass and
unaffected by
cosmic variance, to study the on-going star formation
activity as a
function of mass {i.e. integrated star formation} at this
very important
epoch.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
11428 - FGS 1 Loss of Lock
Following a successful GSACQ(1,2,1) at
222/13:10:37, loss of lock was
observed at 13:30:47 with QF1STOPF and QSTOP
flags set and take data
flag down.
Observation affected: WFPC 100 to 105, proposal
11101, NICMOS 135,
proposal #08795.
11429 - GSACQ(2,0,2) failed, scan step limit exceeded on
FGS 2
GSACQ(2,0,2) at 223/18:10:27 failed to RGA hold
due to scan step limit
exceeded on FGS 2. No 486 ESB or NSSCI status
buffer messages were
received, #44 commands did not update from
their values prior to LOS.
QF2SSLEX and QF2STOPF stop flags were received
at 18:14:34.
Observations affected: NICMOS 173 to 175,
proposal 11548.
11430 - GSACQ(1,0,1) failed
GSACQ(1,0,1) at 223/19:46:26 failed to RGA
control with QF1STOPF and
QSTOP flags set at 19:51:10. Two 486 ESB
"1805" messages
(T2G_MOVING_TARGET_DETECTED) were received at
19:52:51.
Observations affected: NICMOS 177 to 178,
proposal 11548.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FAILURE TIMES
FGS GSacq 27 25
FGS REacq 14 14
OBAD with Maneuver 82 82
LOSS of LOCK @222/1331z
SIGNIFICANT EVENTS: (None)