2MASSJ22560844+5954299: the newly discovered cataclysmic star with the deepest eclipse

Context: The SW Sex stars are assumed to represent a distinguished stage in CV evolution, making it especially important to study them. Aims: We discovered a new cataclysmic star and carried out prolonged and precise photometric observations, as well as medium-resolution spectral observations. Modelling these data allowed us to determine the psysical parameters and to establish its peculiarities. Results: The newly discovered vataclysmic variable 2MASSJ22560844+5954299 shows the deepest eclipse amongst the known nova-like stars. It was reproduced by totally covering a very luminous accretion disk by a red secondary component. The temperature distribution of the disk is flatter than that of steady-state disk. The target is unusual with the combination of a low mass ratio q~1.0 (considerably below the limit q=1.2 of stable mass transfer of CVs) and an M-star secondary. The intensity of the observed three emission lines, H_alpha, He 5875, and He 6678, sharply increases around phase 0.0, accompanied by a Doppler jump to the shorter wavelength. The absence of eclipses of the emission lines and their single-peaked profiles means that they originate mainly in a vertically extended hot-spot halo. The emission H_alpha line reveals S-wave wavelength shifts with semi-amplitude of around 210 km/s and phase lag of 0.03. Conclusions: The non-steady-state emission of the luminous accretion disk of 2MASSJ22560844+5954299 was attributed to the low viscosity of the disk matter caused by its unusually high temperature. The star shows all spectral properties of an SW Sex variable apart from the 0.5 central absorption.Comment: Accepted for publication in Astronomy & Astrophysics. 12 pages, 11 figures, 6 table

Jacobi Identity for Vertex Algebras in Higher Dimensions

Vertex algebras in higher dimensions provide an algebraic framework for investigating axiomatic quantum field theory with global conformal invariance. We develop further the theory of such vertex algebras by introducing formal calculus techniques and investigating the notion of polylocal fields. We derive a Jacobi identity which together with the vacuum axiom can be taken as an equivalent definition of vertex algebra.Comment: 35 pages, references adde

WASP-4b Transit Observations With GROND

This is the author accepted manuscript. The final version is available from EDP Sciences via the DOI in this recordGround-based simultaneous multiband transit observations allow an accurate system parameters determination and may lead to the detection and characterization of additional bodies via the transit timing variations (TTVs) method. We aimed to (i) characterize the heavily bloated WASP-4b hot Jupiter and its star by measuring system parameters and the dependence of the planetary radius as a function of four (Sloan g', r', i', z') wavelengths and (ii) search for TTVs. We recorded 987 images during three complete transits with the GROND instrument, mounted on the MPG/ESO-2.2m telescope at La Silla Observatory. Assuming a quadratic law for the stellar limb darkening we derive system parameters by fitting a composite transit light curve over all bandpasses simultaneously. To compute uncertainties of the fitted parameters, we employ the Bootstrap Monte Carlo Method. The three central transit times are measured with precision down to 6 s. We find a planetary radius Rp = 1.413+/-0.020 RJup, an orbital inclination i = 88deg57'+/-0.45deg and calculate a new ephemeris, a period P = 1.33823144+/-0.00000032days and a reference transit epoch T0 = 2454697.798311+/-0.000046 (BJD). Analysis of the new transit mid-times in combination with previous measurements shows no sign of a TTV signal greater than 20s. We perform simplified numerical simulations to place upper-mass limits of a hypothetical perturber in the WASP-4b system.Part of the funding for GROND (both hardware as well as personnel) was generously granted from the Leibniz-Prize to Prof. G. Hasinger (DFG grant HA 1850/28-1). N.N. acknowledges the Klaus Tschira Stiftung (KTS) and the Heidelberg Graduate School of Fundamental Physics (HGSFP) for the financial support of his Ph.D. research. G.M. acknowledges the financial support from the Polish Ministry of Science and Higher Education through the Iuventus Plus grant IP2010 023070

Departure from the constant-period ephemeris for the transiting exoplanet WASP-12 b

Most hot Jupiters are expected to spiral in towards their host stars due to transfering of the angular momentum of the orbital motion to the stellar spin. Their orbits can also precess due to planet-star interactions. Calculations show that both effects could be detected for the very-hot exoplanet WASP-12 b using the method of precise transit timing over a timespan of the order of 10 yr. We acquired new precise light curves for 29 transits of WASP-12 b, spannning 4 observing seasons from November 2012 to February 2016. New mid-transit times, together with literature ones, were used to refine the transit ephemeris and analyse the timing residuals. We find that the transit times of WASP-12 b do not follow a linear ephemeris with a 5 sigma confidence level. They may be approximated with a quadratic ephemeris that gives a rate of change in the orbital period of -2.56 +/- 0.40 x 10^{-2} s/yr. The tidal quality parameter of the host star was found to be equal to 2.5 x 10^5 that is comparable to theoretical predictions for Sun-like stars. We also consider a model, in which the observed timing residuals are interpreted as a result of the apsidal precession. We find, however, that this model is statistically less probable than the orbital decay.Comment: Accepted for publication in A&A Letter

Two regularizations - two different models of Nambu-Jona-Lasinio

Two variants of the Nambu--Jona-Lasinio model -- the model with 4-dimensional cutoff and the model with dimensionally-analytical regularization -- are systematically compared. It is shown that they are, in essence, two different models of light-quark interaction. In the mean-field approximation the distinction becomes apparent in a behavior of scalar amplitude near the threshold. For 4-dimensional cutoff the pole term can be extracted, which corresponds to sigma-meson. For dimensionally-analytical regularization the singularity of the scalar amplitude is not pole, and this singularity is quite disappeared at some value of the regularization parameter. Still more essential distinction of these models exists in the next-to-leading order of mean-field expansion. The calculations of meson contributions in the quark chiral condensate and in the dynamical quark mass demonstrate, that these contributions though their relatively smallness can destabilize the Nambu--Jona-Lasinio model with 4-dimensional cutoff. On the contrary, the Nambu--Jona-Lasinio model with dimensionally-analytical regularization is stabilized with the next-to-leading order, i.e. the value of the regularization parameter shifts to the stability region, where these contributions decrease.Comment: 14 pages; Journal version; parameter fixing procedure is modifie

Refined physical properties and g',r',i',z',J,H,K transmission spectrum of WASP-23b from the ground

This is the author accepted manuscript. The final version is available from EDP Sciences via the DOI in this recordMulti-band observations of planetary transits using the telescope defocus technique may yield high-quality light curves suitable for refining the physical properties of exoplanets even with small or medium size telescopes. Such observations can be used to construct a broad-band transmission spectrum of transiting planets and search for the presence of strong absorbers. We have thoroughly characterised the orbital ephemeris and physical properties of the transiting planet and host star in the WASP-23b system, constructed a broad-band transmission spectrum of WASP-23b and performed a comparative analysis with theoretical models of hot Jupiters. We observed a complete transit of WASP-23b in seven bands simultaneously, using the GROND instrument on the MPG/ESO 2.2m telescope at La Silla Observatory and telescope defocussing. The optical data were taken in the Sloan g',r',i' and z' bands. The resulting light curves are of high quality, with a root-mean-square scatter of the residual as low as 330ppm in the z'-band, with a cadence of 90s. Near-infrared data were obtained in the JHK bands. We performed MCMC analysis of our photometry plus existing radial velocity data to refine measurements of the ephemeris and physical properties of the WASP-23. We constructed a broad-band transmission spectrum of WASP-23b and compared it with a theoretical transmission spectrum of a Hot Jupiter. We measured the central transit time with a precision about 8s. From this and earlier observations we obtain an orbital period of P=2.9444300+/-0.0000011d. Our analysis also yielded a larger radius and mass for the planet (Rp=1.067+0.045-0.038 RJup and, Mp=0.917+0.040-0.039MJup). The transmission spectrum is marginally flat, given the limited precision of the measurements for the planet radius and poor spectral resolution of the data.N.N. acknowledges support from an STFC consolidated grant. J.S. acknowledges STFC for the award of an Advanced Fellowship

The magnetic properties of 177^{\rm 177}Hf and 180^{\rm 180}Hf in the strong coupling deformed model

This paper reports NMR measurements of the magnetic dipole moments of two high-K isomers, the 37/2$^-$, 51.4 m, 2740 keV state in $^{\rm 177}$Hf and the 8$^-$, 5.5 h, 1142 keV state in $^{\rm 180}$Hf by the method of on-line nuclear orientation. Also included are results on the angular distributions of gamma transitions in the decay of the $^{\rm 177}$Hf isotope. These yield high precision E2/M1 multipole mixing ratios for transitions in bands built on the 23/2$^+$, 1.1 s, isomer at 1315 keV and on the 9/2$^+$, 0.663 ns, isomer at 321 keV. The new results are discussed in the light of the recently reported finding of systematic dependence of the behavior of the g$_{\rm R}$ parameter upon the quasi-proton and quasi-neutron make up of high-K isomeric states in this region.Comment: 9 pages, 9 figures, accepted for publication in Physical Review

Four Dimensional CFT Models with Rational Correlation Functions

Recently established rationality of correlation functions in a globally conformal invariant quantum field theory satisfying Wightman axioms is used to construct a family of soluble models in 4-dimensional Minkowski space-time. We consider in detail a model of a neutral scalar field $\phi$ of dimension 2. It depends on a positive real parameter c, an analogue of the Virasoro central charge, and admits for all (finite) c an infinite number of conserved symmetric tensor currents. The operator product algebra of $\phi$ is shown to coincide with a simpler one, generated by a bilocal scalar field $V(x_1,x_2)$ of dimension (1,1). The modes of V together with the unit operator span an infinite dimensional Lie algebra $L_V$ whose vacuum (i.e. zero energy lowest weight) representations only depend on the central charge c. Wightman positivity (i.e. unitarity of the representations of $L_V$) is proven to be equivalent to $c \in N$.Comment: 28 pages, LATEX, amsfonts, latexsym. Proposition 2.3, and Conjecture in Sec. 6 are revised. Minor errors are correcte

A continuous source of translationally cold dipolar molecules

The Stark interaction of polar molecules with an inhomogeneous electric field is exploited to select slow molecules from a room-temperature reservoir and guide them into an ultrahigh vacuum chamber. A linear electrostatic quadrupole with a curved section selects molecules with small transverse and longitudinal velocities. The source is tested with formaldehyde (H2CO) and deuterated ammonia (ND3). With H2CO a continuous flux is measured of approximately 10^9/s and a longitudinal temperature of a few K. The data are compared with the result of a Monte Carlo simulation.Comment: 4 pages, 4 figures v2: small changes in the abstract, text and references. Figures 1 & 2 regenerated to prevent errors in the pd