U. D. Jentschura, B. J. Wundt
(Submitted on 2 May 2012)
Superluminal spin-1/2 particles are analyzed under the assumption that the equation of motion is compatible with Lorentz invariance (tachyonic particles). It is found that tachyonic spin-1/2 particles can only be observed in left-handed helicity states, and that tachyonic spin-1/2 antiparticles are always right-handed. This result is independent of the numerical value of the tachyonic mass term, holds even for a tiny tachyonic mass of a few eV and may eventually be verified or falsified by experiments in the long-term future. We propose a superluminal character of the neutrino as an alternative explanation for the lack of a right-handed helicity state. This conclusion is connected with the superluminal Dirac algebra (Gordon identities) for spin-1/2 tachyonic particles. In particular, we derive the decomposition of the superluminal vector and axial vector current into convective and spin parts. Finally, we complement the discussion by giving bispinor solutions for generalized Dirac equations with mixed tachyonic and tardyonic mass terms, of the form m_1 + gamma5*m2, and m1 + i*gamma5*m2. These solutions and corresponding sums over the fundamental spinor solutions may be useful in a wider context.

We confront the concepts of Wilsonian UV-completion versus self-completion by Classicalization in theories with derivatively-coupled scalars. We observe that the information about the UV-completion road is encoded in the sign of the derivative terms. We note that the sign of the derivative couplings for which there is no consistent Wilsonian UV-completion is the one that allows for consistent classicalons. This is an indication that for such a sign the vertex must be treated as fundamental and the theory self-protects against potential inconsistencies, such as superluminality, via self-completion by classicalization. Applying this reasoning to the UV-completion of the Standard Model, we see that the information about the Higgs versus classicalization is encoded in the sign of the scattering amplitude of longitudinal W-bosons. Negative sign excludes Higgs or any other weakly-coupled Wilsonian physics.

http://arxiv.org/abs/1204.3443

The publication and open exchange of knowledge and material form the backbone of scientific progress and reproducibility and are obligatory for publicly funded research. Despite increasing reliance on computing in every domain of scientific endeavor, the computer source code critical to understanding and evaluating computer programs is commonly withheld, effectively rendering these programs “black boxes” in the research work flow. Exempting from basic publication and disclosure standards such a ubiquitous category of research tool carries substantial negative consequences. Eliminating this disparity will require concerted policy action by funding agencies and journal publishers, as well as changes in the way research institutions receiving public funds manage their intellectual property (IP).

http://www.sciencemag.org/content/336/6078/159.summary

http://arxiv.org/abs/1203.6354

Guilherme L. Pimentel, Leonardo Senatore, Matias Zaldarriaga

http://arxiv.org/abs/1203.6651

http://arxiv.org/abs/1204.1784

We show that the number of gods in a universe must equal the Euler characteristics of its underlying manifold. By incorporating the classical cosmological argument for creation, this result builds a bridge between theology and physics and makes theism a testable hypothesis. Theological implications are profound since the theorem gives us new insights in the topological structure of heavens and hells. Recent astronomical observations can not reject theism, but data are slightly in favor of atheism.

http://arxiv.org/abs/1203.6902

The wide adoption of social media has increased the competition among ideas for our finite attention. We employ a parsimonious agent-based model to study whether such a competition may affect the popularity of different memes, the diversity of information we are exposed to, and the fading of our collective interests for specific topics. Agents share messages on a social network but can only pay attention to a portion of the information they receive. In the emerging dynamics of information diffusion, a few memes go viral while most do not. The predictions of our model are consistent with empirical data from Twitter, a popular microblogging platform. Surprisingly, we can explain the massive heterogeneity in the popularity and persistence of memes as deriving from a combination of the competition for our limited attention and the structure of the social network, without the need to assume different intrinsic values among ideas

http://www.nature.com/srep/2012/120329/srep00335/full/srep00335.html

Anupam Mazumdar, Lingfei Wang

http://arxiv.org/abs/1203.3558

Mafalda Dias, Jonathan Frazer, Andrew R. Liddle

http://arxiv.org/abs/1203.3792

Measurement claim of non-zero θ_13 neutrino mixing angle.

http://arxiv.org/abs/1203.1040

• Michael F. Sterzik,
• Stefano Bagnulo
• & Enric Palle

Low-resolution intensity spectra of Earth’s atmosphere obtained from space reveal strong signatures of life (‘biosignatures’), such as molecular oxygen and methane with abundances far from chemical equilibrium, as well as the presence of a ‘red edge’ (a sharp increase of albedo for wavelengths longer than 700 nm) caused by surface vegetation¹. Light passing through the atmosphere is strongly linearly polarized by scattering (from air molecules, aerosols and cloud particles) and by reflection (from oceans and land²). Spectropolarimetric observations of local patches of Earth’s sky light from the ground contain signatures of oxygen, ozone and water, and are used to characterize the properties of clouds and aerosols^3, 4. When applied to exoplanets, ground-based spectropolarimetry can better constrain properties of atmospheres and surfaces than can standard intensity spectroscopy^{5, 6, 7, 8, 9}. Here we report disk-integrated linear polarization spectra of Earthshine, which is sunlight that has been first reflected by Earth and then reflected back to Earth by the Moon^{10, 11, 12, 13}. The observations allow us to determine the fractional contribution of clouds and ocean surface, and are sensitive to visible areas of vegetation as small as 10 per cent. They represent a benchmark for the diagnostics of the atmospheric composition, mean cloud height and surfaces of exoplanets.

Background
It has been shown that large interdisciplinary teams working across geography are more likely to be impactful. We asked whether the physical proximity of collaborators remained a strong predictor of the scientific impact of their research as measured by citations of the resulting publications.

Methodology/Principal Findings
Articles published by Harvard investigators from 1993 to 2003 with at least two authors were identified in the domain of biomedical science. Each collaboration was geocoded to the precise three-dimensional location of its authors. Physical distances between any two coauthors were calculated and associated with corresponding citations. Relationship between distance of coauthors and citations for four author relationships (first-last, first-middle, last-middle, and middle-middle) were investigated at different spatial scales. At all sizes of collaborations (from two authors to dozens of authors), geographical proximity between first and last author is highly informative of impact at the microscale (i.e. within building) and beyond. The mean citation for first-last author relationship decreased as the distance between them increased in less than one km range as well as in the three categorized ranges (in the same building, same city, or different city). Such a trend was not seen in other three author relationships.

Conclusions/Significance
Despite the positive impact of emerging communication technologies on scientific research, our results provide striking evidence for the role of physical proximity as a predictor of the impact of collaborations.

http://arxiv.org/abs/1202.6056

The 1.02 μm wavelength thermal emission of the nightside of Venus is strongly anti-correlated to the elevation of the surface. The VIRTIS instrument on Venus Express has mapped this emission and therefore gives evidence for the orientation of Venus between 2006 and 2008. The Magellan mission provided a global altimetry data set recorded between 1990 and 1992. Comparison of these two data sets reveals a deviation in longitude indicating that the rotation of the planet is not fully described by the orientation model recommended by the IAU. This deviation is sufficiently large to affect estimates of surface emissivity from infrared imaging. A revised period of rotation of Venus of 243.023 ± 0.002 d aligns the two data sets. This period of rotation agrees with pre-Magellan estimates but is significantly different from the commonly accepted value of 243.0185 ± 0.0001 d estimated from Magellan radar images. It is possible that this discrepancy stems from a length of day variation with the value of 243.023 ± 0.002 d representing the average of the rotation period over 16 years.

Sachiko Kuroyanagi, Koichi Miyamoto, Toyokazu Sekiguchi, Keitaro Takahashi, Joseph Silk

http://arxiv.org/pdf/1202.0740v1.pdf

http://arxiv.org/abs/1201.6342

http://vixra.org/abs/1201.0058

Accretion of minor satellites has been postulated as the most likely mechanism to explain the significant size evolution of the massive galaxies over cosmic time. Using a sample of 629 massive (Mstar~10^11 Msun) galaxies from the near-infrared Palomar/DEEP-2 survey, we explore which fraction of these objects has satellites with 0.01 Msat < Mcentral < 1 (1:100) up to z=1 and which fraction has satellites with 0.1 Msat < Mcentral < 1 (1:10) up to z=2 within a projected radial distance of 100 kpc. We find that the fraction of massive galaxies with satellites, after the background correction, remains basically constant and close to ~30% for satellites with a mass ratio down to 1:100 up to z=1, and ~15% for satellites with a 1:10 mass ratio up to z=2. The family of spheroid-like massive galaxies presents a 2-3 times larger fraction of objects with satellites than the group of disk-like massive galaxies. A crude estimation of the number of 1:3 mergers a massive spheroid-like galaxy experiences since z~2 is around 2. For a disk-like galaxy this number decreases to ~1.

It is shown that in order that the fluid pressure and acceleration are uniform and finite in Einstein’s Static
Universe (ESU),  , the cosmological constant, is zero.  being a fundamental constant, should be the
same everywhere including the Friedman model. Independent proofs show that it must be so. Accordingly,
the supposed acceleration of the universe and the attendant concept of a “Dark Energy” (DE) could be an
illusion; an artifact of explaining cosmological observations in terms of an oversimplified model which is
fundamentally inappropriate. Indeed observations show that the actual universe is lumpy and inhomogeneous
at the largest scales. Further in order that there is no preferred centre, such an inhomogeneity might be ex-
pressed in terms of infinite hierarchial fractals. Also, the recent finding that the Friedman model intrinsically
corresponds to zero pressure (and hence zero temperature) in accordance with the fact that an ideal Hubble
flow implies no collision, no randomness (Mitra, Astrophys. Sp. Sc., 333,351, 2011) too shows that the
Friedman model cannot represent the real universe having pressure, temperature and radiation. Dark Energy
might also be an artifact of the neglect of dust absorption of distant Type 1a supernovae coupled with likely
evolution of supernovae luminosities or imprecise calibration of cosmic distance ladders or other systemetic
errors (White, Rep. Prog. Phys., 70, 883, 2007). In reality, observations may not rule out an inhomogeneous
static universe (Ellis, Gen. Rel. Grav. 9, 87, 1978), if the fundamental “constants” are indeed constant.

The motion of a charged particle is influenced by the self-force arising from the particle’s interaction with its own field. In a curved spacetime, this self-force depends on the entire past history of the particle and is difficult to evaluate. As a result, all existing self-force evaluations in curved spacetime are for particles moving along a fixed trajectory. Here, for the first time, we overcome this longstanding limitation and present fully self-consistent orbits and waveforms of a scalar charged particle around a Schwarzschild black hole.

http://www.benthamscience.com/open/toaaj/openaccess2.htm

http://arxiv.org/abs/1110.2952

The Riemann Hypothesis is Unprovable:

http://arxiv.org/abs/math/0309367v4

Come discuss!

Alexandre Le Tiec, Luc Blanchet, Bernard F. Whiting

First laws of black hole mechanics, or thermodynamics, come in a variety of different forms. In this paper, from a purely post-Newtonian (PN) analysis, we obtain a first law for binary systems of point masses moving along an exactly circular orbit. Our calculation is valid through 3PN order and includes, in addition, the contributions of logarithmic terms at 4PN and 5PN orders. This first law of binary point-particle mechanics is then derived from first principles in general relativity, and analogies are drawn with the single and binary black hole cases. Some consequences of the first law are explored for PN spacetimes. As one such consequence, a simple relation between the PN binding energy of the binary system and Detweiler’s redshift observable is established. Through it, we are able to determine with high precision the numerical values of some previously unknown high order PN coefficients in the circular-orbit binding energy. Finally, we propose new gauge invariant notions for the energy and angular momentum of a particle in a binary system.

http://xxx.lanl.gov/abs/1111.3328v1

http://arxiv.org/pdf/1111.3605v1

An expected source of gravitational waves for future detectors in space are the inspirals of small compact objects into much more massive black holes. . On short timescales the orbit of the small object is approximately geodesic. Over the course of an inspiral, a typical system will pass through resonances where two of these frequencies become commensurate. The effect of the resonance will be to alter significantly the rate of inspiral for the duration of the resonance.

See some discussion on this here.

It is about the perception of astrology and other unscientific views.

http://adsabs.harvard.edu/abs/2011AEdRv..10a0101S

Herschel discovery on the D/H ratio in water molecules in comet Hartley 2.

http://www.nobelprize.org/nobel_prizes/physics/laureates/2011/index.html

The OPERA Collaboraton: T. Adam, N. Agafonova, A. Aleksandrov, O. Altinok, P. Alvarez Sanchez, S. Aoki, A. Ariga, T. Ariga, D. Autiero, A. Badertscher, A. Ben Dhahbi, A. Bertolin, C. Bozza, T. Brugiére, F. Brunet, G. Brunetti, S. Buontempo, F. Cavanna, A. Cazes, L. Chaussard, M. Chernyavskiy, V. Chiarella, A. Chukanov, G. Colosimo, M. Crespi, N. D’Ambrosios, Y. Déclais, P. del Amo Sanchez, G. De Lellis, M. De Serio, F. Di Capua, F. Cavanna, A. Di Crescenzo, D. Di Ferdinando, N. Di Marco, S. Dmitrievsky, M. Dracos, D. Duchesneau, S. Dusini, J. Ebert, I. Eftimiopolous, O. Egorov, A. Ereditato, L.S. Esposito, J. Favier, T. Ferber, R.A. Fini, T. Fukuda, A. Garfagnini, G. Giacomelli, C. Girerd, M. Giorgini, M. Giovannozzi, J. Goldberga, C. Göllnitz, L. Goncharova, Y. Gornushkin, et al. (117 additional authors not shown)

(Submitted on 22 Sep 2011)

The OPERA neutrino experiment at the underground Gran Sasso Laboratory has measured the velocity of neutrinos from the CERN CNGS beam over a baseline of about 730 km with much higher accuracy than previous studies conducted with accelerator neutrinos. The measurement is based on high-statistics data taken by OPERA in the years 2009, 2010 and 2011. Dedicated upgrades of the CNGS timing system and of the OPERA detector, as well as a high precision geodesy campaign for the measurement of the neutrino baseline, allowed reaching comparable systematic and statistical accuracies. An early arrival time of CNGS muon neutrinos with respect to the one computed assuming the speed of light in vacuum of (60.7 \pm 6.9 (stat.) \pm 7.4 (sys.)) ns was measured. This anomaly corresponds to a relative difference of the muon neutrino velocity with respect to the speed of light (v-c)/c = (2.48 \pm 0.28 (stat.) \pm 0.30 (sys.)) \times 10-5.

Nichols and Chen, Caltech

We adapt a method of matching post-Newtonian and black-hole-perturbation theories on a timelike surface (which proved useful for understanding head-on black-hole-binary collisions) to treat equal-mass, inspiralling black-hole binaries. We first introduce a radiation-reaction potential into this method, and we show that it leads to a self-consistent set of equations that describe the simultaneous evolution of the waveform and of the timelike matching surface. This allows us to produce a full inspiral-merger-ringdown waveform of the l=2, m=2,-2 modes of the gravitational waveform of an equal-mass black-hole-binary inspiral. These modes match those of numerical-relativity simulations well in phase, though less well in amplitude for the inspiral. As a second application of this method, we study a merger of black holes with spins antialigned in the orbital plane (the “superkick” configuration). During the ringdown of the superkick, the phases of the mass- and current-quadrupole radiation become locked together, because they evolve at the same quasinormal mode frequencies. We argue that this locking begins during merger, and we show that if the spins of the black holes evolve via geodetic precession in the perturbed black-hole spacetime of our model, then the spins precess at the orbital frequency during merger. In turn, this gives rise to the correct behavior of the radiation, and produces a kick similar to that observed in numerical simulations.

And for commentary:

http://www.nature.com/nature/journal/v477/n7362/full/477037a.html

The motion of a small compact (SCO) object in a background spacetime is investigated further in the context of a class of model nonlinear scalar field theories that have a perturbative structure analogous to the General Relativistic description of extreme mass ratio inspirals (EMRIs). We derive regular expressions for the scalar perturbations generated by the motion of the compact object that are valid through third order in ε, the size of the SCO to the background curvature length scale. Our results for the field perturbations are compared to those calculated through second order in ε by Rosenthal in [1] and found to agree. However, our procedure for regularizing the scalar perturbations is considerably simpler. Following the Detweiler-Whiting scheme, we use our results for the regular expressions for the field and derive the regular self-force corrections through third order. We find agreement with our previous derivation based on a variational principle of an effective action for the worldline associated with the SCO thereby demonstrating the internal consistency of our formalism. This also explicitly demonstrates that the Detweiler-Whiting decomposition of Green’s functions is a valid and practical method of self force computation at higher orders in perturbation theory and, more generally, at all orders in perturbation theory, as we show in an appendix. Finally, we identify a central quantity, which we call a master source, from which all other physically relevant quantities are derivable. Specifically, knowing the master source through some order in ε allows one to construct the waveform measured by an observer, the regular part of the field and its derivative on the worldline, the regular part of the self force, and various orbital quantities such as shifts of the innermost stable circular orbit, etc., when restricting to conservative dynamics. The existence of a master source together with the regularization methods implemented in this series should be indispensable for derivations of higher-order gravitational self force corrections in the future.

http://lanl.arxiv.org/abs/1105.3069v1

The stability properties of relativistic stars against gravitational collapse to black hole is a classical problem in general relativity. A sufficient criterion for secular instability was established by Friedman, Ipser and Sorkin (1988), who proved that a sequence of uniformly rotating barotropic stars is secularly unstable on one side of a turning point and then argued that a stronger result should hold: that the sequence should be stable on the opposite side, with the turning point marking the onset of secular instability. We show here that this expectation is not met. By computing in full general relativity the $F$-mode frequency for a large number of rotating stars, we show that the neutral-stability point, i.e., where the frequency becomes zero, differs from the turning point for rotating stars. Using numerical simulations we validate that the new criterion can be used to assess the dynamical stability of relativistic rotating stars.

(PDF)

Context. There is a long-standing conundrum in interstellar dust studies relating to the discrepancy between the time-scales for dust
formation from evolved stars and the apparently more rapid destruction in supernova-generated shock waves.
Aims. We re-examine some of the key issues relating to dust evolution and processing in the interstellar medium.
Methods. We use recent and new constraints from observations, experiments, modelling and theory to re-evaluate dust formation in
the interstellar medium (ISM).
Results. We find that the discrepancy between the dust formation and destruction time-scales may not be as significant as has previ-
ously been assumed because of the very large uncertainties involved.
Conclusions. The derived silicate dust lifetime could be compatible with its injection time-scale, given the inherent uncertainties in
the dust lifetime calculation. The apparent need to re-form significant quantities of silicate dust in the tenuous interstellar medium
may therefore not be a strong requirement. Carbonaceous matter, on the other hand, appears to be rapidly recycled in the ISM and,
in contrast to silicates, there are viable mechanisms for its re-formation in the ISM.

IXO and LISA are dead and disbanded as NASA missions.
We are looking at a very thin pipeline and few new missions for a while, unless there is drastic new direction from above and strong guidance on funding.

(Submitted on 27 Mar 2011)

Comments: 11 pages, 7 figures, 3 tables

Subjects: Space Physics (physics.space-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM); General Relativity and Quantum Cosmology (gr-qc)

arXiv:1103.5222v1

We present an improved method to compute the radiative momentum transfer in the Pioneer 10 & 11 spacecraft that takes into account both diffusive and specular reflection. The method allows for more reliable results regarding the thermal acceleration of the deep-space probes, confirming previous findings. A parametric analysis is performed in order to set an upper and lower-bound for the thermal acceleration and its evolution with time.

We show by explicit construction that for every solution of the incompressible Navier-Stokes equation in $p+1$ dimensions, there is a uniquely associated “dual” solution of the vacuum Einstein equations in $p+2$ dimensions. The dual geometry has an intrinsically flat timelike boundary segment $\Sigma_c$ whose extrinsic curvature is given by the stress tensor of the Navier-Stokes fluid. We consider a “near-horizon” limit in which $\Sigma_c$ becomes highly accelerated. The near-horizon expansion in gravity is shown to be mathematically equivalent to the hydrodynamic expansion in fluid dynamics, and the Einstein equation reduces to the incompressible Navier-Stokes equation. For $p=2$, we show that the full dual geometry is algebraically special Petrov type II. The construction is a mathematically precise realization of suggestions of a holographic duality relating fluids and horizons which began with the membrane paradigm in the 70’s and resurfaced recently in studies of the AdS/CFT correspondence.

Searches for very-high-redshift galaxies over the past decade have yielded a large sample of more than 6,000 galaxies existing just 900–2,000 million years (Myr) after the Big Bang (redshifts 6 > z > 3; ref. 1). The Hubble Ultra Deep Field (HUDF09) data have yielded the first reliable detections of z ≈ 8 galaxies that, together with reports of a γ-ray burst at z ≈ 8.2 (refs 10, 11), constitute the earliest objects reliably reported to date. Observations of z ≈ 7–8 galaxies suggest substantial star formation at z > 9–10 (refs 12, 13). Here we use the full two-year HUDF09 data to conduct an ultra-deep search for z ≈ 10 galaxies in the heart of the reionization epoch, only 500 Myr after the Big Bang. Not only do we find one possible z ≈ 10 galaxy candidate, but we show that, regardless of source detections, the star formation rate density is much smaller (~10%) at this time than it is just ~200 Myr later at z ≈ 8. This demonstrates how rapid galaxy build-up was at z ≈ 10, as galaxies increased in both luminosity density and volume density from z ≈ 10 to z ≈ 8. The 100–200 Myr before z ≈ 10 is clearly a crucial phase in the assembly of the earliest galaxies.

We introduce a reduced basis approach as a new paradigm for modeling, representing and searching for gravitational waves. We construct waveform catalogs for non-spinning compact binary coalescences, and we find that for accuracies of $99\%$ and $99.999\%$ the method generates a factor of about $10-10^5$ fewer templates than standard placement methods. The continuum of gravitational waves can be represented by a finite and comparatively compact basis. The method is robust under variations in the noise of detectors, implying that only a single catalog needs to be generated.

http://xxx.lanl.gov/abs/1011.6142

Dany Page (1), Madappa Prakash (2), James M. Lattimer (3), Andrew W. Steiner (4)

We propose that the recently observed cooling of the neutron star in Cassiopeia A is due to enhanced neutrino emission from the onset of the breaking and formation of neutron Cooper pairs in the 3P2 channel. To account for the observed cooling rate, which is significantly faster than that expected from the modified Urca process, the critical temperature for this superfluid transition is required to be ~ 0.5×10^9 K. Our prediction that this cooling will continue for several decades at an almost constant rate can be tested by continuous monitoring of this neutron star.

• http://www.nature.com/nature/journal/v468/n7320/full/nature09506.html

Quantum electrodynamics describes the interactions of electrons and photons. Electric charge (the gauge coupling constant) is energy dependent, and there is a previous claim that charge is affected by gravity (described by general relativity) with the implication that the charge is reduced at high energies. However, that claim has been very controversial and the matter has not been settled. Here I report an analysis (free from the earlier controversies) demonstrating that quantum gravity corrections to quantum electrodynamics have a quadratic energy dependence that result in the electric charge vanishing at high energies, a result known as asymptotic freedom.

1Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany.
2European Space Agency, Space Environment and Effects Section, ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, Netherlands.

Stars in their late stage of evolution, such as Horizontal Branch stars, are still largely unexplored for planets. We report the detection of a planetary companion around HIP 13044, a very metal-poor star on the red Horizontal Branch, based on radial velocity observations with a high-resolution spectrograph at the 2.2-m MPG/ESO telescope. The star’s periodic radial velocity variation of P = 16.2 days caused by the planet can be distinguished from the periods of the stellar activity indicators. The minimum mass of the planet is 1.25 Mjup and its orbital semimajor axis 0.116 AU. Because HIP 13044 belongs to a group of stars that have been accreted from a disrupted satellite galaxy of the Milky Way, the planet most likely has an extragalactic origin.

Abstract
PDF

http://iopscience.iop.org/0004-637X/724/2/1402/

The study of cold atomic hydrogen (H I) in molecular clouds has the potential to significantly improve our understanding of the formation of molecular clouds, the atomic to molecular hydrogen conversion process, and star formation. Results from the first large survey of H I Narrow Self Absorption (HINSA) features outside of the Taurus Molecular Cloud Complex are presented. Previous hypotheses that cold atomic hydrogen represents the third largest constituent of molecular clouds are confirmed with a mean abundance of 10^–2.8 in comparison with the total proton column density. HINSA features are observed in over 80% of the observed clouds, accompanied by indications that cold H I probably exists in all clouds. We find that HINSA features are observable to distances of at least 700 pc. Nine clouds have been mapped in detail revealing that HINSA abundances can vary significantly within a cloud both spatially and in an individual velocity component. Possible explanations for this phenomenon are briefly discussed.

Nature | Letter

A two-solar-mass neutron star measured using Shapiro delay

http://www.nature.com/nature/journal/v467/n7319/abs/nature09466.html

P. B. Demorestp, T. Pennucc, S. M. Ransom, M. S. E. Roberts, & J. W. T. Hessels

Journal name:

Nature  467  1081–1083 (28 October 2010)

Neutron stars are composed of the densest form of matter known to exist in our Universe, the composition and properties of which are still theoretically uncertain. Measurements of the masses or radii of these objects can strongly constrain the neutron star matter equation of state and rule out theoretical models of their composition^{1, 2}. The observed range of neutron star masses, however, has hitherto been too narrow to rule out many predictions of ‘exotic’ non-nucleonic components^{3, 4, 5, 6}. The Shapiro delay is a general-relativistic increase in light travel time through the curved space-time near a massive body⁷. For highly inclined (nearly edge-on) binary millisecond radio pulsar systems, this effect allows us to infer the masses of both the neutron star and its binary companion to high precision^{8, 9}. Here we present radio timing observations of the binary millisecond pulsar J1614-2230^{10, 11} that show a strong Shapiro delay signature. We calculate the pulsar mass to be (1.97 ± 0.04)M_⊙, which rules out almost all currently proposed^{2, 3, 4, 5} hyperon or boson condensate equations of state (M_⊙, solar mass). Quark matter can support a star this massive only if the quarks are strongly interacting and are therefore not ‘free’ quarks¹².

The Collimation and Energetics of the Brightest Swift Gamma-ray Bursts

A paper I missed at the time on astro-ph.

They get E_gamma for a few bright GRBs, and claim a clear jet break for them, and then infer an E_gamma for each that is higher than the early Frail and Bloom results. None of the breaks seem very compelling to me; e.g. GRB050904, where they claim an X-ray and optical break in Tagliaferri et al. (2005), where the X-rays are totally flare-dominated, and Tagliaferri says nothing about the X-rays.

Is this type of collimation work meaningless?

http://www.nature.com/news/2010/100813/full/news.2010.406.html

Science paper:
http://hubblesite.org/pubinfo/pdf/2010/17/pdf.pdf

This paper is notable because it presents the first exo-planetary system where the inclination between the orbits of two different planets has been determined (30 degrees).

http://science.nasa.gov/science-news/science-at-nasa/2010/21apr_firstlight/

The maintenance overhauls the submission system on arXiv, and has resulted in a change in how post order on astro-ph is determined:

Submissions are assigned identifiers and appear in the listings in order based on the submission time (the last time the “Submit” button was selected at the end of the submission process). An edit and subsequent “Submit” will reset this time and thus change position in the listings. Edits are permitted between 16:00 and the 20:00 announcement time (EST). However, doing this will remove the submission from that day’s announcements and delay it until the next day.

In other words, (I think) your article has to correctly parse when you first submit it in order to appear at the top of the list. Additionally, posts are forced to appear the next day if there are any edits after 1pm PST. I do not know if these posts automatically appear at the top of the next day’s listing.

More info on the new submission process is available here.

http://www.nature.com/nature/journal/v462/n7275/pdf/nature08679.pdf

Has JafRef changed your life, or maybe it’s BibDesk?  Anyone out there think it’s worth to shell out for Papers?  Do you use online services like Bibsonomy?  Are all your pdfs marked up with Skim?  Come share your favorite tips to get the masses of papers organized!