H-alpha observations of the gamma-ray-emitting Be/X-ray binary LSI+61303: orbital modulation, disk truncation, and long-term variability

We report 138 spectral observations of the H-alpha emission line of the radio- and gamma-ray-emitting Be/X-ray binary LSI+61303 obtained during the period of September 1998 -- January 2013. From measuring various H-alpha parameters, we found that the orbital modulation of the H-alpha is best visible in the equivalent width ratio EW(B)/EW(R), the equivalent width of the blue hump, and in the radial velocity of the central dip. The periodogram analysis confirmed that the H-alpha emission is modulated with the orbital and superorbital periods. For the past 20 years the radius of the circumstellar disk is similar to the Roche lobe size at the periastron. It is probably truncated by a 6:1 resonance. The orbital maximum of the equivalent width of H-alpha emission peaks after the periastron and coincides on average with the X-ray and gamma-ray maxima. All the spectra are available upon request from the authors and through the CDS.Comment: 11 pages, accepted for publication in A&

Time series irreversibility: a visibility graph approach

We propose a method to measure real-valued time series irreversibility which combines two differ- ent tools: the horizontal visibility algorithm and the Kullback-Leibler divergence. This method maps a time series to a directed network according to a geometric criterion. The degree of irreversibility of the series is then estimated by the Kullback-Leibler divergence (i.e. the distinguishability) between the in and out degree distributions of the associated graph. The method is computationally effi- cient, does not require any ad hoc symbolization process, and naturally takes into account multiple scales. We find that the method correctly distinguishes between reversible and irreversible station- ary time series, including analytical and numerical studies of its performance for: (i) reversible stochastic processes (uncorrelated and Gaussian linearly correlated), (ii) irreversible stochastic pro- cesses (a discrete flashing ratchet in an asymmetric potential), (iii) reversible (conservative) and irreversible (dissipative) chaotic maps, and (iv) dissipative chaotic maps in the presence of noise. Two alternative graph functionals, the degree and the degree-degree distributions, can be used as the Kullback-Leibler divergence argument. The former is simpler and more intuitive and can be used as a benchmark, but in the case of an irreversible process with null net current, the degree-degree distribution has to be considered to identifiy the irreversible nature of the series.Comment: submitted for publicatio

Classification of qubit entanglement: SL(2,C) versus SU(2) invariance

The role of SU(2) invariants for the classification of multiparty entanglement is discussed and exemplified for the Kempe invariant I_5 of pure three-qubit states. It is found to being an independent invariant only in presence of both W-type entanglement and threetangle. In this case, constant I_5 admits for a wide range of both threetangle and concurrences. Furthermore, the present analysis indicates that an SL^3 orbit of states with equal tangles but continuously varying I_5 must exist. This means that I_5 provides no information on the entanglement in the system in addition to that contained in the tangles (concurrences and threetangle) themselves. Together with the numerical evidence that I_5 is an entanglement monotone this implies that SU(2) invariance or the monotone property are too weak requirements for the characterization and quantification of entanglement for systems of three qubits, and that SL(2,C) invariance is required. This conclusion can be extended to general multipartite systems (including higher local dimension) because the entanglement classes of three-qubit systems appear as subclasses.Comment: 9 pages, 10 figures, revtex

The Partition Function of Multicomponent Log-Gases

We give an expression for the partition function of a one-dimensional log-gas comprised of particles of (possibly) different integer charge at inverse temperature {\beta} = 1 (restricted to the line in the presence of a neutralizing field) in terms of the Berezin integral of an associated non- homogeneous alternating tensor. This is the analog of the de Bruijn integral identities [3] (for {\beta} = 1 and {\beta} = 4) ensembles extended to multicomponent ensembles.Comment: 14 page

Revisión del género Cantabrogeus Salgado, 2000, con la descripción de tres nuevas especies hipogeas endémicas de la Cordillera Cantábrica (Coleoptera, Leiodidae, Cholevinae, Leptodirini)

Se revisan las dos especies previamente descritas del género Cantabrogeus (Coleoptera, Leiodidae, Cholevinae, Leptodirini), y se describen tres especies nuevas: Cantabrogeus antimachus sp. n., C. cultellus sp. n. y C. fresnedai sp. n. Una de ellas (C. antimachus sp. n.) es triploide (3n = 33) y la primera especie partenogenética conocida de Leiodidae. Se analizan y se discuten las relaciones existentes entre los diferentes taxones a partir de los caracteres morfológicos externos y las estructuras de los aparatos genitales masculino y femenino, así como las áreas cársticas que colonizan las diferentes especies en la zona cantábrica (NO ibérico). El análisis de datos moleculares (fragmentos de siete genes mitocondriales y nucleares) confirma la monofilia de Cantabrogeus y su proximidad filogenética con el género Fresnedaella, así como su inclusión dentro de la serie Quaestus, que es parafilética. La especie partenogenética (C. antimachus sp. n.) ocupa una posición derivada dentro del género Cantabrogeus, que, de acuerdo con estimas de la tasa de variación molecular basadas en estudios previos, probablemente se diversificó durante el Plioceno–Pleistoceno en las zonas cársticas cántabras, que son de una alta complejidad tectónica.The two previously known species of the genus Cantabrogeus (Coleoptera, Leiodidae, Cholevinae, Leptodirini) are redescribed, and three new species are described: Cantabrogeus antimachus n. sp., C. cultellus n. sp. and C. fresnedai n. sp. One of these (C. antimachus n. sp.) is tripliod (3n = 33) and the first known parthenogenetic species of Leiodidae. The relationships between the different taxa are discussed based on external morphological characters and the structure of male and female genitalia, as well as the distribution of the species in the different areas in the Cantabrian mountains (NW Iberia). Analyses of molecular data (fragments of seven mitochondrial and nuclear genes) confirms the monophyly of Cantabrogeus and its sister–group relationship with Fresnedaella, as well as its inclusion within the paraphyletic series Quaestus. The parthenogenetic species (C. antimachus n. sp.) has a derived position within Cantabrogeus, which, according to previous estimates of the molecular rate, probably diversified during the Pliocene–Pleistocene in the Cantabrian karst areas, of a high tectonic complexity.Se revisan las dos especies previamente descritas del género Cantabrogeus (Coleoptera, Leiodidae, Cholevinae, Leptodirini), y se describen tres especies nuevas: Cantabrogeus antimachus sp. n., C. cultellus sp. n. y C. fresnedai sp. n. Una de ellas (C. antimachus sp. n.) es triploide (3n = 33) y la primera especie partenogenética conocida de Leiodidae. Se analizan y se discuten las relaciones existentes entre los diferentes taxones a partir de los caracteres morfológicos externos y las estructuras de los aparatos genitales masculino y femenino, así como las áreas cársticas que colonizan las diferentes especies en la zona cantábrica (NO ibérico). El análisis de datos moleculares (fragmentos de siete genes mitocondriales y nucleares) confirma la monofilia de Cantabrogeus y su proximidad filogenética con el género Fresnedaella, así como su inclusión dentro de la serie Quaestus, que es parafilética. La especie partenogenética (C. antimachus sp. n.) ocupa una posición derivada dentro del género Cantabrogeus, que, de acuerdo con estimas de la tasa de variación molecular basadas en estudios previos, probablemente se diversificó durante el Plioceno–Pleistoceno en las zonas cársticas cántabras, que son de una alta complejidad tectónica

Asymptotics of Selberg-like integrals: The unitary case and Newton's interpolation formula

We investigate the asymptotic behavior of the Selberg-like integral $$\frac1{N!}\int_{[0,1]^N}x_1^p\prod_{i<j}(x_i-x_j)^2\prod_ix_i^{a-1}(1-x_i)^{b-1}dx_i$$, as $N\to\infty$ for different scalings of the parameters $a$ and $b$ with $N$. Integrals of this type arise in the random matrix theory of electronic scattering in chaotic cavities supporting $N$ channels in the two attached leads. Making use of Newton's interpolation formula, we show that an asymptotic limit exists and we compute it explicitly

An X-ray study of the SNR G344.7-0.1 and the central object CXOU J170357.8-414302

Aims. We report results of an X-ray study of the supernova remnant (SNR) G344.7-0.1 and the point-like X-ray source located at the geometrical center of the SNR radio structure. Methods. The morphology and spectral properties of the remnant and the central X-ray point-like source were studied using data from the XMM-Newton and Chandra satellites. Archival radio data and infrared Spitzer observations at 8 and 24 $\mu$m were used to compare and study its multi-band properties at different wavelengths. Results. The XMM-Newton and Chandra observations reveal that the overall X-ray emission of G344.7-0.1 is extended and correlates very well with regions of bright radio and infrared emission. The X-ray spectrum is dominated by prominent atomic emission lines. These characteristics suggest that the X-ray emission originated in a thin thermal plasma, whose radiation is represented well by a plane-parallel shock plasma model (PSHOCK). Our study favors the scenario in which G344.7-0.1 is a 6 x 10^3 year old SNR expanding in a medium with a high density gradient and is most likely encountering a molecular cloud on the western side. In addition, we report the discovery of a soft point-like X-ray source located at the geometrical center of the radio SNR structure. The object presents some characteristics of the so-called compact central objects (CCO). However, its neutral hydrogen absorption column (N_{H}) is inconsistent with that of the SNR. Coincident with the position of the source, we found infrared and optical objects with typical early-K star characteristics. The X-ray source may be a foreground star or the CCO associated with the SNR. If this latter possibility were confirmed, the point-like source would be the farthest CCO detected so far and the eighth member of the new population of isolated and weakly magnetized neutron stars.Comment: 9 pages, 8 figures, accepted for publication in Astronomy and Astrophysics. Higher resolution figures can be seen on A&

Nuevos registros de monogeneos (Platyhelminthes: Monogenea) infectando algunos peces marinos del litoral peruano

A parasitological survey searching monogeneans infesting marine fish was carried out during June 2018 and January 2020 from the coastal zone of Puerto Pizarro, Tumbes (northern Peru) and from the coastal zone of Chorrillos, Lima (central Peru). The gills, skin, nasal cavities, or branchial gill-cover of seven species were sampled. Ten monogenean species assigned to six families and nine genera were identified. The monogeneans Callorhynchocotyle callorhynchi (Manter, 1955); Capsala biparasiticum (Goto, 1894) Price, 1938; Euryhaliotrema sagmatum Kritsky &amp; Boeger, 2002; Listrocephalos kearni Bullard, Payne &amp;Braswell, 2004; Magniexcipula lamothei Bravo-Hollis, 1981; Nasicola klawei (Stunkard, 1962) Yamaguti, 1968; and Pseudorhabdosynochus anulus Violante-Gonzalez &amp; Rojas-Herrera, 2011 are registered for the first time in Peru. While Capsala gregalis (Wagner &amp; Carter, 1967) Chisholm &amp; Whittington, 2007; Heterocotyle margaritae Chero, Cruces, Sáez, Santos &amp; Luque, 2020; and Monocotyle luquei Chero, Cruces, Iannacone, Sanchez, Minaya, Sáez &amp; Alvariño, 2016 have been previously registered in Peruvian waters, however, the region of Tumbes (northern Peru) represent a new locality record for these species.Durante junio de 2018 y enero de 2020 se realizó un levamiento parasitológico para buscar monogeneos que infectan peces marinos en la zona costera de Puerto Pizarro, departamento de Tumbes (norte de Perú) y en la zona costera de Chorrillos, departamento de Lima (centro de Perú). Se analizaron las branquias, la piel, las cavidades nasales o el opérculo de siete especies. Se identificaron diez especies de monogeneos, asignadas a seis familias y nueve géneros. Los monogeneos Callorhynchocotyle callorhynchi (Manter, 1955); Capsala biparasitica (Goto, 1894) Price, 1938; Euryhaliotrema sagmatum Kritsky y Boeger, 2002; Listrocephalos kearni Bullard, Payne y Braswell, 2004; Magniexcipula lamothei Bravo-Hollis, 1981; Nasicola klawei (Stunkard, 1962) Yamaguti, 1968; y Pseudorhabdosynochus anulus Violante-Gonzalez &amp; Rojas-Herrera, 2011 son registrados por primera vez en Perú. Mientras que, Capsala gregalis (Wagner y Carter, 1967) Chisholm y Whittington, 2007; Heterocotyle margaritae Chero, Cruces, Sáez, Santos &amp; Luque, 2020; y Monocotyle luquei Chero, Cruces, Iannacone, Sanchez, Minaya, Sáez &amp; Alvariño, 2016 han sido previamente registrados en aguas peruanas, sin embargo, la región de Tumbes (norte de Perú) representa un nuevo registro de localidad para estas especies

Invariant and polynomial identities for higher rank matrices

We exhibit explicit expressions, in terms of components, of discriminants, determinants, characteristic polynomials and polynomial identities for matrices of higher rank. We define permutation tensors and in term of them we construct discriminants and the determinant as the discriminant of order $d$, where $d$ is the dimension of the matrix. The characteristic polynomials and the Cayley--Hamilton theorem for higher rank matrices are obtained there from

The invariant-comb approach and its relation to the balancedness of multipartite entangled states

The invariant-comb approach is a method to construct entanglement measures for multipartite systems of qubits. The essential step is the construction of an antilinear operator that we call {\em comb} in reference to the {\em hairy-ball theorem}. An appealing feature of this approach is that for qubits (or spins 1/2) the combs are automatically invariant under SL(2,\CC), which implies that the obtained invariants are entanglement monotones by construction. By asking which property of a state determines whether or not it is detected by a polynomial SL(2,\CC) invariant we find that it is the presence of a {\em balanced part} that persists under local unitary transformations. We present a detailed analysis for the maximally entangled states detected by such polynomial invariants, which leads to the concept of {\em irreducibly balanced} states. The latter indicates a tight connection with SLOCC classifications of qubit entanglement. \\ Combs may also help to define measures for multipartite entanglement of higher-dimensional subsystems. However, for higher spins there are many independent combs such that it is non-trivial to find an invariant one. By restricting the allowed local operations to rotations of the coordinate system (i.e. again to the SL(2,\CC)) we manage to define a unique extension of the concurrence to general half-integer spin with an analytic convex-roof expression for mixed states.Comment: 17 pages, revtex4. Substantially extended manuscript (e.g. proofs have been added); title and abstract modified