1,571 research outputs found
Hourly Variability in Q0957+561
We have continued our effort to re-reduce archival Q0957+561 brightness
monitoring data and present results for 1629 R-band images using the methods
for galaxy subtraction and seeing correction reported previously. The new
dataset comes from 4 observing runs, several nights apiece, with sampling of
typically 5 minutes, which allows the first measurement of the structure
function for variations in the R-band from timescales of hours to years.
Comparison of our reductions to previous reductions of the same data, and to
r-band photometry produced at Apache Point Observatory shows good overall
agreement. Two of the data runs, separated by 417 days, permit a sharpened
value for the time delay of 417.4 days, valid only if the time delay is close
to the now-fashionable 417-day value; our data do not constrain a delay if it
is more than three days from this 417-day estimate. Our present results show no
unambiguous signature of the daily microlensing, though a suggestive feature is
found in the data. Both time delay measurement and microlensing searches suffer
from from the lack of sampling at half-day offsets, inevitable at a single
observatory, hence the need for round-the-clock monitoring with participation
by multiple observatories.Comment: AASTeX 4.0 preprint style, 21 pages, 8 EPS figure
Why don't clumps of cirrus dust gravitationally collapse?
We consider the Herschel-Planck infrared observations of presumed
condensations of interstellar material at a measured temperature of
approximately 14 K (Juvela et al., 2012), the triple point temperature of
hydrogen. The standard picture is challenged that the material is cirrus-like
clouds of ceramic dust responsible for Halo extinction of cosmological sources
(Finkbeiner, Davis, and Schlegel 1999). Why would such dust clouds not collapse
gravitationally to a point on a gravitational free-fall time scale of
years? Why do the particles not collide and stick together, as is fundamental
to the theory of planet formation (Blum 2004; Blum and Wurm, 2008) in pre-solar
accretion discs? Evidence from 3.3 m and UIB emissions as well as ERE
(extended red emission) data point to the dominance of PAH-type macromolecules
for cirrus dust, but such fractal dust will not spin in the manner of rigid
grains (Draine & Lazarian, 1998). IRAS dust clouds examined by Herschel-Planck
are easily understood as dark matter Proto-Globular-star-Cluster (PGC) clumps
of primordial gas planets, as predicted by Gibson (1996) and observed by Schild
(1996).Comment: 8 pages, 2 figures, Conference FQMT'1
Evolution of primordial planets in relation to the cosmological origin of life
We explore the conditions prevailing in primordial planets in the framework
of the HGD cosmologies as discussed by Gibson and Schild. The initial stages of
condensation of planet-mass H-4He gas clouds in trillion-planet clumps is set
at 300,000 yr (0.3My) following the onset of plasma instabilities when ambient
temperatures were >1000K. Eventual collapse of the planet-cloud into a solid
structure takes place against the background of an expanding universe with
declining ambient temperatures. Stars form from planet mergers within the
clumps and die by supernovae on overeating of planets. For planets produced by
stars, isothermal free fall collapse occurs initially via quasi equilibrium
polytropes until opacity sets in due to molecule and dust formation. The
contracting cooling cloud is a venue for molecule formation and the sequential
condensation of solid particles, starting from mineral grains at high
temperatures to ice particles at lower temperatures, water-ice becomes
thermodynamically stable between 7 and 15 My after the initial onset of
collapse, and contraction to form a solid icy core begins shortly thereafter.
Primordial-clump-planets are separated by ~ 1000 AU, reflecting the high
density of the universe at 30,000 yr. Exchanges of materials, organic molecules
and evolving templates readily occur, providing optimal conditions for an
initial origin of life in hot primordial gas planet water cores when adequately
fertilized by stardust. The condensation of solid molecular hydrogen as an
extended outer crust takes place much later in the collapse history of the
protoplanet. When the object has shrunk to several times the radius of Jupiter,
the hydrogen partial pressure exceeds the saturation vapour pressure of solid
hydrogen at the ambient temperature and condensation occurs.Comment: 14 pages 7 figures SPIE Conference 7819 Instruments, Methods, and
Missions for Astrobiology XIII Proceedings, Aug 3-5, 2010, San Diego, Ed.
Richard B. Hoove
Functional analysis of a missense mutation in the serine protease inhibitor SPINT2 associated with congenital sodium diarrhea.
Membrane-bound serine proteases play important roles in different biological processes. Their regulation by endogenous inhibitors is poorly understood. A Y163C mutation in the SPINT2 gene encoding the serine protease inhibitor Hepatocyte Growth Factor Inhibitor HAI-2 is associated with a congenital sodium diarrhea. The functional consequences of this mutation on HAI-2 activity and its physiological targets are unknown. We established a cellular assay in Xenopus laevis oocytes to study functional interactions between HAI-2 and candidate membrane-bound serine proteases expressed in the gastro-intestinal tract. We found that the wild-type form of HAI-2 is a potent inhibitor of nine gastro-intestinal serine proteases. The Y163C mutation in the second Kunitz domain of HAI-2 resulted in a complete loss of inhibitory activity on two intestinal proteases, prostasin and tmprss13. The effect of the mutation of the homologous Y68C in the first Kunitz domain of HAI-2 is consistent with a differential contribution of the two Kunitz domains of HAI-2 in the inhibition of serine proteases. By contrast to the Tyr to Cys, the Tyr to Ser substitution did not change the inhibitory potency of HAI-2, indicating that the thiol-group of the cysteine rather than the Tyr deletion is responsible for the HAI-2 loss of function. Our functional assay allowed us to identify membrane-bound serine proteases as cellular target for inhibition by HAI-2 wild type and mutants, and to better define the role of the Tyr in the second Kunitz domain in the inhibitory activity of HAI-2
Q2237+0305 source structure and dimensions from light curves simulation
Assuming a two-component quasar structure model consisting of a central
compact source and an extended outer feature, we produce microlensing
simulations for a population of star-like objects in the lens galaxy. Such a
model is a simplified version of that adopted to explain the brightness
variations observed in Q0957 (Schild & Vakulik 2003). The microlensing light
curves generated for a range of source parameters were compared to the light
curves obtained in the framework of the OGLE program. With a large number of
trials we built, in the domain of the source structure parameters, probability
distributions to find "good" realizations of light curves. The values of the
source parameters which provide the maximum of the joint probability
distribution calculated for all the image components, have been accepted as
estimates for the source structure parameters. The results favour the
two-component model of the quasar brightness structure over a single compact
central source model, and in general the simulations confirm the Schild-Vakulik
model that previously described successfully the microlensing and other
properties of Q0957. Adopting 3300 km/s for the transverse velocity of the
source, the effective size of the central source was determined to be about
2x10^15 cm, and Epsilon =2 was obtained for the ratio of the integral
luminosity of the outer feature to that of the central source.Comment: 7 pages, 4 figures, LaTe
Discovery of a candidate protoplanetary disk around the embedded source IRc9 in Orion
We report the detection of spatially-extended mid-infrared emission around
the luminous embedded star IRc9 in OMC-1, as seen in 8.8, 11.7, and 18.3 micron
images obtained with T-ReCS on Gemini South. The extended emission is
asymmetric, and the morphology is reminiscent of warm dust disks around other
young stars. The putative disk has a radius of roughly 1.5 arcsec (700 AU), and
a likely dust mass of almost 10 Earth masses. The infrared spectral energy
distribution of IRc9 indicates a total luminosity of about 100 Lsun, implying
that it shall become an early A-type star when it reaches the main sequence.
Thus, the candidate disk around IRc9 may be a young analog of the planetary
debris disks around Vega-like stars and the disks of Herbig Ae stars, and may
provide a laboratory in which to study the earliest phases of planet formation.
A disk around IRc9 may also add weight to the hypothesis that an enhanced T
Tauri-like wind from this star has influenced the molecular outflow from the
OMC-1 core.Comment: 7 pages, 2 figs, Accepted by ApJ Letter
Turbulence and turbulent mixing in natural fluids
Turbulence and turbulent mixing in natural fluids begins with big bang
turbulence powered by spinning combustible combinations of Planck particles and
Planck antiparticles. Particle prograde accretions on a spinning pair releases
42% of the particle rest mass energy to produce more fuel for turbulent
combustion. Negative viscous stresses and negative turbulence stresses work
against gravity, extracting mass-energy and space-time from the vacuum.
Turbulence mixes cooling temperatures until strong-force viscous stresses
freeze out turbulent mixing patterns as the first fossil turbulence. Cosmic
microwave background temperature anisotropies show big bang turbulence fossils
along with fossils of weak plasma turbulence triggered as plasma photon-viscous
forces permit gravitational fragmentation on supercluster to galaxy mass
scales. Turbulent morphologies and viscous-turbulent lengths appear as linear
gas-proto-galaxy-clusters in the Hubble ultra-deep-field at z~7. Proto-galaxies
fragment into Jeans-mass-clumps of primordial-gas-planets at decoupling: the
dark matter of galaxies. Shortly after the plasma to gas transition,
planet-mergers produce stars that explode on overfeeding to fertilize and
distribute the first life.Comment: 23 pages 12 figures, Turbulent Mixing and Beyond 2009 International
Center for Theoretical Physics conference, Trieste, Italy. Revision according
to Referee comments. Accepted for Physica Scripta Topical Issue to be
published in 201
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