http://xxx.lanl.gov/abs/1205.3088

http://www.sciencemag.org.oca.ucsc.edu/content/early/2012/05/10/science.1221141.full

abstract
Alan Coley, Woei Chet Lim
(Submitted on 10 May 2012)
In this Letter we discuss a natural general relativistic mechanism that causes inhomogeneities and hence generates matter perturbations in the early universe. We concentrate on spikes, both incomplete spikes and recurring spikes, that naturally occur in the initial oscillatory regime of general cosmological models. In particular, we explicitly show that spikes occurring in a class of G_2 models lead to inhomogeneities that, due to gravitational instability, leave small residual imprints on matter in the form of matter perturbations. The residual matter overdensities from recurring spikes are not local but form on surfaces. We discuss the potential physical consequences of the residual matter imprints and their possible effect on the subsequent formation of large scale structure.

Dark Matter vs. Modified Gravity: A Trialogue

paper

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.

Link
Kourosh Nozari, M. Shoukrani
(Submitted on 8 Apr 2012)
We study the effects of the non-minimal coupling on the dissipative dynamics of the warm inflation in a braneworld setup, where the inflaton field is non-minimally coupled to induced gravity on the warped DGP brane. We study with details the effects of the non-minimal coupling and dissipation on the inflationary dynamics on the normal DGP branch of this scenario in the high-dissipation and high-energy regime. We show that incorporation of the non-minimal coupling in this setup decreases the number of e-folds relative to the minimal case. We also compare our model parameters with recent observational data.

pdf. Dvali, et al.

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://www.ifa.hawaii.edu/~reipurth/newsletter/newsletter232.pdf

Amol Upadhye, Wayne Hu, Justin Khoury
http://arxiv.org/abs/1204.3906

http://scienceblogs.com/catdynamics/upload/2012/04/esa_makes_a_choice/ESA-SPC.pdf

José Fonseca, David Wands (ICG, Portsmouth)
(Submitted on 16 Apr 2012)
We characterise the primordial perturbations produced due to both inflaton and curvaton fluctuations in models where the curvaton has a quadratic, cosine or hyperbolic potential, and the inflaton potential is characterised by the usual slow-roll parameters. Isocurvature curvaton field perturbations can produce significant non-Gaussianity in the primordial density field, in contrast with adiabatic inflaton field perturbations which produce negligible non-Gaussianity for canonical scalar fields. A non-self-interacting curvaton with quadratic potential produces a local-type non-Gaussianity that is well described by the non-linearity parameter fNL, which may be scale-dependent when the inflaton perturbations dominate the power spectrum. We show how observational bounds on non-linearity parameters and the tensor-scalar ratio can be used to constrain curvaton and inflaton parameters. We find a consistency relation between the bispectrum and trispectrum parameters in a mixed inflaton-curvaton model for a quadratic curvaton potential. Self-interaction terms in the curvaton potential can lead to both a large trispectrum parameter, gNL, and scale-dependence of the non-linearity parameters.

http://arxiv.org/abs/1204.3443

Shining Light into Black Boxes
A. Morin, J. Urban, P. D. Adams, I. Foster, A. Sali, D. Baker, P. Sliz

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

In single clock models of inflation the coupling between modes of very different scales does not have any significant dynamical effect during inflation. It leads to interesting projection effects. Larger and smaller modes change the relation between the scale a mode of interest will appear in the post-inflationary universe and will also change the time of horizon crossing of that mode. We argue that there are no infrared projection effects in physical questions, that there are no effects from modes of longer wavelength than the one of interest. These potential effects cancel when computing fluctuations as a function of physically measurable scales. Modes on scales smaller than the one of interest change the mapping between horizon crossing time and scale. The correction to the mapping computed in the absence of fluctuations is enhanced by a factor N_e, the number of e-folds of inflation between horizon crossing and reheating. The new mapping is stochastic in nature but its variance is not enhanced by N_e.
Leonardo Senatore, Matias Zaldarriaga

http://arxiv.org/abs/1203.6354

Studying loop corrections to inflationary perturbations, with particular emphasis on infrared factors, is important to understand the consistency of the inflationary theory, its predictivity and to establish the existence of the slow-roll eternal inflation phenomena and its recently found volume bound. In this paper we prove that the zeta correlation function is time-independent at one-loop level in single clock inflation. While many of the one-loop diagrams lead to a time-dependence when considered individually, the time-dependence beautifully cancels out in the overall sum. We identify two subsets of diagrams that cancel separately due to different physical reasons. The first cancellation is related to the change of the background cosmology due to the renormalization of the stress tensor. It results in a cancellation between the non-1PI diagrams and some of the diagrams made with quartic vertices. The second subset of diagrams that cancel is made up of cubic operators, plus the remaining quartic ones. We are able to write the sum of these diagrams as the integral over a specific three-point function between two very short wavelengths and one very long one. We then apply the consistency condition for this three-point function in the squeezed limit to show that the sum of these diagrams cannot give rise to a time dependence. This second cancellation is thus a consequence of the fact that in single clock inflation the attractor nature of the solution implies that a long wavelength zeta perturbation is indistinguishable from a trivial rescaling of the background, and so results in no physical effect on short wavelength modes.

Guilherme L. Pimentel, Leonardo Senatore, Matias Zaldarriaga

http://arxiv.org/abs/1203.6651

We expound ten principles in an attempt to clarify the debate over infrared loop corrections to the primordial scalar and tensor power spectra from inflation. Among other things we note that existing proposals for nonlinear extensions of the scalar fluctuation field $\zeta$ introduce new ultraviolet divergences which no one understands how to renormalize. Loop corrections and higher correlators of these putative observables would also be enhanced by inverse powers of the slow roll parameter $\epsilon$. We propose an extension which should be better behaved.
S. P. Miao (Utrecht), R. P. Woodard (Florida)

http://arxiv.org/abs/1204.1784

http://arxiv.org/abs/1204.1352

http://arxiv.org/abs/1204.1456

http://science.nasa.gov/astrophysics/2012-senior-review/

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

L. Weng, A. Flammini, A. Vespignani & F. Menczer
Scientific Reports 2, Article number: 335 doi:10.1038/srep00335
Received 19 September 2011 Accepted 08 March 2012 Published 29 March 2012

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

the abstract

http://voxcharta.org/wp-admin/post-new.php

http://xxx.lanl.gov/abs/1203.5476

http://xxx.lanl.gov/abs/1203.5719

Clifford Cheung, Michele Papucci, Kathryn M. Zurek
http://arxiv.org/abs/1203.5106

Authors: Miguel F. Paulos, Andrew J. Tolley
http://arxiv.org/abs/1203.4268

In this paper we provide a general framework based on $\delta N$ formalism to estimate the cosmological observables pertaining to the cosmic microwave background radiation for non-separable potentials, and for generic \emph{end of inflation} boundary conditions. We provide analytical and numerical solutions to the relevant observables by decomposing the cosmological perturbations along the curvature and the isocurvature directions, \emph{instead of adiabatic and entropy directions}. We then study under what conditions large bi-spectrum and tri-spectrum can be generated through phase transition which ends inflation. In an illustrative example, we show that large $f_{NL}\sim {\cal O}(80)$ and $\tau_{NL}\sim {\cal O}(20000)$ can be obtained for the case of separable and non-separable inflationary potentials.

Anupam Mazumdar, Lingfei Wang

http://arxiv.org/abs/1203.3558

We analyse the multifield behaviour in D-brane inflation when contributions from the bulk are taken into account. For this purpose, we study a large number of realisations of the potential; we find the nature of the inflationary trajectory to be very consistent despite the complex construction. Inflation is always canonical and occurs in the vicinity of an inflection point. Extending the transport method to non-slow-roll and to calculate the running, we obtain distributions for observables. The spectral index is typically blue and the running positive, putting the model under moderate pressure from WMAP7 constraints. The local f_NL and tensor-to-scalar ratio are typically unobservably small, though we find approximately 0.5% of realisations to give observably large local f_NL. Approximating the potential as sum-separable, we are able to give fully analytic explanations for the trends in observed behaviour. Finally we find the model suffers from the persistence of isocurvature perturbations, which can be expected to cause further evolution of adiabatic perturbations after inflation. We argue this is a typical problem for models of multifield inflation involving inflection points and renders models of this type technically unpredictive without a description of reheating.

Mafalda Dias, Jonathan Frazer, Andrew R. Liddle

http://arxiv.org/abs/1203.3792

(Dvali, Gomez)

Recently we have suggested that the microscopic quantum description of a black hole is an overpacked self-sustained Bose-condensate of N weakly-interacting soft gravitons, which obeys the rules of ‘t Hooft’s large-N physics. In this note we derive an effective Landau-Ginzburg Lagrangian for the condensate and show that it becomes an exact description in a semi-classical limit that serves as the black hole analog of ‘t Hooft’s planar limit. The role of a weakly-coupled Landau-Ginzburg order parameter is played by N. This description consistently reproduces the known properties of black holes in semi-classical limit. Hawking radiation, as the quantum depletion of the condensate, is described by the slow-roll of the field N. In the semiclassical limit, where black holes of arbitrarily small size are allowed, the equation of depletion is self similar leading to a scaling law for the black hole size with critical exponent 1/3.

pdf link

http://arxiv.org/abs/1203.1669 (hep-ex)

Measurement claim of non-zero θ_13 neutrino mixing angle.

http://xxx.lanl.gov/pdf/1203.1619.pdf

Ian Kimpton, Antonio Padilla

http://arxiv.org/abs/1203.1040

http://www.nature.com/nature/journal/v483/n7387/full/nature10778.html

• 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.

http://arxiv.org/abs/1203.1173

Kyungjoon Lee, John S. Brownstein, Richard G. Mills, Isaac S. Kohane

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://xxx.lanl.gov/abs/1203.0033

http://xxx.lanl.gov/abs/1203.0016

http://arxiv.org/pdf/1202.6364v1.pdf
Gregory Gabadadze, Kurt Hinterbichler, David Pirtskhalava

Kurt Hinterbichler, Austin Joyce, Justin Khoury

http://arxiv.org/abs/1202.6056

http://adsabs.harvard.edu/abs/2012Icar..217..474M

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.

http://arxiv.org/abs/1202.3388

by

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

http://xxx.lanl.gov/abs/1202.1167

http://arxiv.org/abs/1202.0892

Philippe Brax

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

Roberto Gobbetti, Matthew Kleban
http://arxiv.org/pdf/1201.6380v1.pdf

http://arxiv.org/abs/1201.5732

http://arxiv.org/abs/1201.5961

http://arxiv.org/abs/1201.5926

Authors: Ana Achucarro, Jinn-Ouk Gong, Sjoerd Hardeman, Gonzalo A. Palma, Subodh P. Patil

http://arxiv.org/abs/1201.6342

Authors: Stephan J.G. Gift
Ether drift resulting from the rotation of the Earth has been detected. This was accomplished using GPS technology in a modified Michelson-Morley experiment. The original Michelson-Morley experiment searched for ether drift by observing round-trip light travel time differences using interference fringe shifts. This method is limited by length contraction effects that significantly reduce any fringe shifts. In the modified approach elapsed time for one-way light transmission is directly determined using GPS clocks. The method yields travel time differences for light transmission in the East-West direction but not in the North-South direction consistent with rotationally-induced ether drift.
Comments: 12 Pages. Accepted for publication in Applied Physics Research

http://vixra.org/abs/1201.0058

Can gravity distinguish between Dirac and Majorana Neutrinos?

Satellites around massive galaxies since z~2

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.

http://www.scirp.org/journal/PaperInformation.aspx?paperID=16372

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.

http://arxiv.org/abs/1112.4821

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.

Including the effects of electric currents in any description of the origin, shape, or motion of cosmic magnetized plasma is crucial for understanding many observed astronomical phenomena. The Maxwell (Heaviside) equations are based on real experimental measurements. These fundamental expressions clearly link electric current densities, magnetic flux densities, and electric fields into a unified conceptual whole. Examples are presented to demonstrate the pitfalls of omitting the contribution and effects of currents from descriptions of the behavior of magnetic fields. An example suggests a possible electrical explanation of the enigmatic cyclical reversal of magnetic polarities near sunspots and demonstrates the unique insight afforded by including the causal effects of currents.

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

http://www.nytimes.com/2011/12/14/science/tantalizing-hints-but-no-direct-proof-in-search-for-higgs-boson.html

http://arxiv.org/pdf/1112.1435

A proof of the Riemann Hypothesis:

http://arxiv.org/abs/1110.2952

The Riemann Hypothesis is Unprovable:

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

http://astrojournalclub.wordpress.com/2011/11/27/this-weeks-meeting-mentoring-for-young-scientists/

Come discuss!

http://arxiv.org/abs/1111.5378

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.

Quantum states are the key mathematical objects in quantum theory. It is therefore surprising that physicists have been unable to agree on what a quantum state represents. There are at least two opposing schools of thought, each almost as old as quantum theory itself. One is that a pure state is a physical property of system, much like position and momentum in classical mechanics. Another is that even a pure state has only a statistical significance, akin to a probability distribution in statistical mechanics. Here we show that, given only very mild assumptions, the statistical interpretation of the quantum state is inconsistent with the predictions of quantum theory. This result holds even in the presence of small amounts of experimental noise, and is therefore amenable to experimental test using present or near-future technology. If the predictions of quantum theory are confirmed, such a test would show that distinct quantum states must correspond to physically distinct states of reality.

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

Jonathan Gair,1 Nicola ́s Yunes,2, 3 and Carl M. Bender4

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.

An update on OPERA’s observation of superluminal neutrinos has been posted on the hep-ex arxiv: http://arxiv.org/abs/1109.4897

See some discussion on this here.

This paper did not appear on astro-ph, nonetheless i’d like to discuss it.

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

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

Paul Hartogh, Dariusz C. Lis, Dominique Bockelée-Morvan, Miguel de Val-Borro, Nicolas Biver, Michael Küppers, Martin Emprechtinger, Edwin A. Bergin, Jacques Crovisier, Miriam Rengel, Raphael Moreno, Slawomira Szutowicz & Geoffrey A. Blake

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

Awarded to Saul Perlmutter, Brian P. Schmidt, and Adam G. Riess.

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.

http://arxiv.org/abs/1109.0081

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.

http://www.nature.com/nature/journal/v477/n7362/full/nature10377.html

And for commentary:

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

ATel #3581: Young Type Ia Supernova PTF11kly in M101

http://arxiv.org/pdf/1107.0766v1

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.

1105.3069

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.

A. P. Jones and J. A. Nuth III

(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.

This week’s issue of Nature has a special on the future of the PhD. In a series of articles the academic pyramid (Ph.D. student/post-doc/permanent staff) is being discussed, in particular the perceived overproduction of PhDs, induced by funding systems around the world. The editorial provides a good summary of various viewpoints: http://www.nature.com/nature/journal/v472/n7343/full/472259b.html

http://scienceblogs.com/catdynamics/2011/04/nasa_wiping_the_slate_clean.php

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.

F. Francisco, O. Bertolami, P. J. S. Gil, J. Páramos

(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.

http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys1907.html

http://arxiv.org/pdf/1101.2451v2

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.

http://www.nature.com/nature/journal/v469/n7331/full/nature09717.html

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.

http://xxx.lanl.gov/abs/1101.3765

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://www.nature.com/nature/journal/v468/n7325/full/nature09601.html

http://arxiv.org/abs/1012.5622

http://arxiv.org/abs/1012.5172

For some reason this has not appeared normally.

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.

Special introductions of new postdocs and their research. Come ready for wipeboard action.
10:45am, CfAO atrium

In next week’s discussion group (2010-11-30), we’ll spend a few minutes hearing about

• 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.

Johny Setiawan1,∗, Rainer J. Klement1, Thomas Henning1, Hans-Walter Rix1 , Boyke Rochau1, Jens Rodmann2 and Tim Schulze-Hartung1

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

Not on arXiv (yet?):

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.

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.

Cenko et al. 2010 published:

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?

An analysis of over 50,000 Science papers suggests that it could pay to include more references:

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

http://www.strudel.org.uk/blog/astro/images//20100719_astronomer_HR_diagram.png

Press release:
http://hubblesite.org/newscenter/archive/releases/2010/17/

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).

Some pretty cool movies and pictures from this new spacecraft:

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

Astro-ph will not have any new postings today due to maintenance on the arXiv website. UPDATE: Astro-ph did in fact update tonight, but at a bizarre time (after 10pm PST). The new listings are now posted.

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.

A population of extrasolar planets has been uncovered with minimum masses of 1.9–10 times the Earth’s mass, called super-Earths, but atmospheric studies can be precluded by the distance and size of their stars. Here, observations of the transiting planet GJ 1214b are reported; it has a mass 6.55 times that of the Earth and a radius 2.68 times the Earth’s radius. The star is small and only 13 parsecs away, permitting the study of the planetary atmosphere with current observatories.

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

Also known as “How do you organize your pdfs and other electronic data?”

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!

http://www.nasa.gov/mission_pages/LCROSS/main/prelim_water_results.html