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  • The first light curve solutions and period study of two contact binary systems: V1370 Tau and QQ Boo
    New Astron. (IF 1.058) Pub Date : 2020-09-19
    Jabar Rahimi; Elahe Lashgari; Morteza Ghanbarzadehchaleshtori; Amin Boudesh; Fatemeh Davoudi; Ahmad Farahani; Filip Walter; Bohuslav Hladík; Peter Nosal; Atila Poro

    The first light curve solutions of the binary systems V1370 Tau and QQ Boo are presented. The periodic changes are calculated, and a new ephemeris presented for each of these two binary systems. O-C analysis is performed using the MCMC method in OCFit code. The changing rate of period was measured as dP/dt= 0.2423 days/year for V1370 Tau and dP/dt= -0.1363 days/year for QQ Boo. The light curve solutions

    更新日期:2020-09-23
  • The comparative analysis of dense stellar models governed by quadratic and linear equations of state
    New Astron. (IF 1.058) Pub Date : 2020-09-21
    Kiran Pant; Pratibha Fuloria

    In the present article we construct physically viable models of anisotropic charged compact stellar objects admitting quadratic equation of state and linear equation of state. We analyze the physical behavior of compact star models 4U1538-52, LMCX-4, and Vela X-1 with in the frame work of general relativity. Our stellar models are free from singularities, satisfy all energy conditions and exhibit physically

    更新日期:2020-09-23
  • Effect of Moon perturbation on the energy curves and equilibrium points in the Sun–Earth–Moon system
    New Astron. (IF 1.058) Pub Date : 2020-09-23
    Ashok Kumar Pal; Elbaz I. Abouelmagd; Ram Kishor

    In this paper, we have considered that the Moon motion around the Earth is a source of a perturbation for the infinitesimal body motion in the Sun–Earth system. The perturbation effect is analyzed by using the Sun–Earth–Moon bi–circular model (BCM). We have determined the effect of this perturbation on the Lagrangian points and zero velocity curves. We have obtained the motion of infinitesimal body

    更新日期:2020-09-23
  • Michel Accretion Onto a Non-Commutative Black Hole
    New Astron. (IF 1.058) Pub Date : 2020-09-23
    G. Abbas; A. Ditta

    The matter accretion onto a noncommutative (NC) inspired Schwarzschild black hole is addressed for a polytropic fluid and results are compared with Schwarzschild black hole. The flow parameters - critical velocity u(r), sonic speed cs2 and accretion rate M˙ are derived from the NC static black hole and are related to the outcomes acquired for the standard Schwarzschild black hole. Due to the effect

    更新日期:2020-09-23
  • Common envelope episodes that lead to double neutron star formation
    Publ. Astron. Soc. Aust. (IF 5.067) Pub Date : 2020-09-23
    Alejandro Vigna-Gómez; Morgan MacLeod; Coenraad J. Neijssel; Floor S. Broekgaarden; Stephen Justham; George Howitt; Selma E. de Mink; Serena Vinciguerra; Ilya Mandel

    Close double neutron stars (DNSs) have been observed as Galactic radio pulsars, while their mergers have been detected as gamma-ray bursts and gravitational wave sources. They are believed to have experienced at least one common envelope episode (CEE) during their evolution prior to DNS formation. In the last decades, there have been numerous efforts to understand the details of the common envelope

    更新日期:2020-09-23
  • Search for low-energy neutrinos from astrophysical sources with Borexino
    Astropart. Phys. (IF 2.61) Pub Date : 2020-09-01
    M. Agostini; K. Altenmüller; S. Appel; V. Atroshchenko; Z. Bagdasarian; D. Basilico; G. Bellini; J. Benziger; D. Bick; G. Bonfini; D. Bravo; B. Caccianiga; F. Calaprice; A. Caminata; L. Cappelli; P. Cavalcante; F. Cavanna; A. Chepurnov; G. Zuzel

    We report on searches for neutrinos and antineutrinos from astrophysical sources performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. Electron antineutrinos (ν¯e) are detected in an organic liquid scintillator through the inverse β-decay reaction. In the present work we set model-independent upper limits in the energy range 1.8–16.8 MeV on neutrino fluxes from unknown

    更新日期:2020-09-23
  • ℋolographic 𝒩aturalness
    Int. J. Mod. Phys. D (IF 2.154) Pub Date : 2020-09-11
    Andrea Addazi

    The ℋolographic 𝒩aturalness (ℋ𝒩) is a new paradigm towards an explanation of the Cosmological Constant (CC) and the Higgs Hierarchy (HH) in the Universe. Motivated by the Holographic Principle, and inspired by the (A)dS/CFT correspondence, we elaborate on the possibility and on the cosmological consequences of a fundamental intrinsic disorder and temperature in vacuo. We postulate that the zero vacuum

    更新日期:2020-09-23
  • Lorentzian quintessential inflation
    Int. J. Mod. Phys. D (IF 2.154) Pub Date : 2020-08-12
    David Benisty; Eduardo I. Guendelman

    From the assumption that the slow-roll parameter 𝜖 has a Lorentzian form as a function of the e-folds number N, a successful model of a quintessential inflation is obtained. The form corresponds to the vacuum energy both in the inflationary and in the dark energy epochs. The form satisfies the condition to climb from small values of 𝜖 to 1 at the end of the inflationary epoch. At the late universe

    更新日期:2020-09-23
  • Spurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitons
    Int. J. Mod. Phys. A (IF 1.486) Pub Date : 2020-09-23
    Massimo Giovannini

    In the same way as the energy density associated with the tensor modes of the geometry modifies the evolution of the curvature perturbations, the scalar modes may also indirectly affect the cosmic backgrounds of relic gravitons by inducing higher-order corrections that are only superficially gauge-invariant. This spurious gauge-invariance gets manifest when the effective anisotropic stresses, computed

    更新日期:2020-09-23
  • Study of the branching ratios and CP asymmetries in Bs0¯ → K∗0ρ0(ω) decays within QCD factorization
    Int. J. Mod. Phys. A (IF 1.486) Pub Date : 2020-09-21
    E. H. Raslan; H. R. Khan

    We study analytically the branching ratio (BR) and charge parity (CP) asymmetries of the Bs0¯→K∗0ρ0 and K∗0ω decay modes within QCDF approach. We find the BR(Bs0¯→K∗0ρ0)=(1.28±0.23)×10−6 and BR(Bs0¯→K∗0ω)=(1.12±0.58)×10−6. We also find the values of CP asymmetries are 𝒜CPdir(Bs0¯→K∗0ρ0)=0.214±0.087, 𝒜CPmix(Bs0¯→K∗0ρ0)=0.377±0.147, 𝒜CPΔΓ(Bs0¯→K∗0ρ0)=0.901±0.051, 𝒜CPdir(Bs0¯→K∗0ω)=0.284±0.038, 𝒜CPmix(Bs0¯→K∗0ω)=0

    更新日期:2020-09-23
  • Spectral Emission Features of SiO 2 Spheres
    Res. Notes AAS Pub Date : 2020-09-21
    Dmitry Petrov, Alexander Savushkin, and Elena Zhuzhulina

    Silicate dust particles are part of many astronomical objects such as comets and circumstellar discs. In the spectrum, silicates exhibit a number of characteristic emission features. In this paper, we studied the contribution of quartz (SiO 2 ) particles to these features. Using the Mie theory, calculations were made of the intensity of light scattered by such particles. Two spectral features were

    更新日期:2020-09-23
  • The Equatorial Jet Speed on Tidally Locked Planets. I. Terrestrial Planets
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    Mark Hammond, Shang-Min Tsai, and Raymond T. Pierrehumbert

    The atmospheric circulation of tidally locked planets is dominated by a superrotating eastward equatorial jet. We develop a predictive theory for the formation of this jet, proposing a mechanism in which the three-dimensional stationary waves induced by the day–night forcing gradient produce an equatorial acceleration. This is balanced in equilibrium by an interaction between the resulting jet and

    更新日期:2020-09-23
  • Investigation of Coronal Properties of X-Ray Bright G-dwarf Stars Based on the Solar Surface Magnetic Field–Corona Relationship
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    Shinsuke Takasao, Ikuyuki Mitsuishi, Takuma Shimura, Atsushi Yoshida, Masanobu Kunitomo, Yuki A. Tanaka, and Daisuke Ishihara

    We investigated the coronal properties of G-dwarf stars including the Sun over a wide range of X-ray luminosity L X (3 × 10 26 to 2 × 10 30 erg s −1 ). We analyzed the archival data of 10 X-ray bright ( L X > 10 28 erg s −1 ) G-dwarf stars to derive their emission measure (EM) and the coronal temperature ( T ) during the periods when no prominent stellar flares were observed. We attempted to explain

    更新日期:2020-09-23
  • X-Ray Spectroscopy in the Microcalorimeter Era. II. A New Diagnostic on Column Density from the Case A to B Transition in H- and He-like Iron
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    P. Chakraborty, G. J. Ferland, M. Chatzikos, F. Guzmán, and Y. Su

    The Soft X-ray Spectrometer on board Hitomi, with the unprecedented resolving power of R ∼ 1250, allowed the detection of members of the Fe xxv K α complex emission spectra from the center of the Perseus Cluster. In this paper, we introduce a novel method of measuring the column density using the optically thin (Case A) to optically thick (Case B) transition for one- and two-electron systems. We compare

    更新日期:2020-09-23
  • To Power the X-Ray Plateaus of Gamma-Ray Bursts through Larger Amplitude Electromagnetic Waves
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    Shuang Du

    The origin of the gamma-ray burst (GRB) X-ray plateau, especially the internal plateau, is still unclear, but it could be related to a GRB’s magnetar central engine. It is generally believed that the spin-down power of the magnetar is injected into forward external shock; however, we propose here that most of the power will be dissipated behind the GRB jet through a larger amplitude electromagnetic

    更新日期:2020-09-23
  • Reaction Rate Sensitivity of the Production of γ -Ray Emitting Isotopes in Core-collapse Supernovae
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    Kirby Hermansen, Sean M. Couch, Luke F. Roberts, Hendrik Schatz, and MacKenzie L. Warren

    Radioactive isotopes produced in core-collapse supernovae (CCSNe) provide useful insights into the underlying processes driving the collapse mechanism and the origins of elemental abundances. Their study generates a confluence of major physics research, including experimental measurements of nuclear reaction rates, astrophysical modeling, and γ -ray observations. Here we identify the key nuclear reaction

    更新日期:2020-09-23
  • Monitoring the Morphology of M87* in 2009–2017 with the Event Horizon Telescope
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    Maciek Wielgus, Kazunori Akiyama, Lindy Blackburn, Chi-kwan Chan, Jason Dexter, Sheperd S. Doeleman, Vincent L. Fish, Sara Issaoun, Michael D. Johnson, Thomas P. Krichbaum, Ru-Sen Lu, Dominic W. Pesce, George N. Wong, Geoffrey C. Bower, Avery E. Broderick, Andrew Chael, Koushik Chatterjee, Charles F. Gammie, Boris Georgiev, Kazuhiro Hada, Laurent Loinard, Sera Markoff, Daniel P. Marrone, Richard Plambeck

    The Event Horizon Telescope (EHT) has recently delivered the first resolved images of M87*, the supermassive black hole in the center of the M87 galaxy. These images were produced using 230 GHz observations performed in 2017 April. Additional observations are required to investigate the persistence of the primary image feature—a ring with azimuthal brightness asymmetry—and to quantify the image variability

    更新日期:2020-09-23
  • Low-level Carbon Monoxide Line Polarization in Two Protoplanetary Disks: HD 142527 and IM Lup
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    Ian W. Stephens, Manuel Fernández-López, Zhi-Yun Li, Leslie W. Looney, and Richard Teague

    Magnetic fields are expected to play an important role in accretion processes for circumstellar disks. However, measuring the magnetic field morphology is difficult, especially when given that polarimetric (sub)millimeter continuum observations may not trace the fields in most disks. The Goldreich–Kylafis effect suggests that line polarization is perpendicular or parallel to the magnetic field direction

    更新日期:2020-09-23
  • Delayed Photons from Binary Evolution Help Reionize the Universe
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    Amy Secunda, Renyue Cen, Taysun Kimm, Ylva Götberg, and Selma E. de Mink

    High-resolution numerical simulations including feedback and aimed at calculating the escape fraction ( f esc ) of hydrogen-ionizing photons often assume stellar radiation based on single-stellar population synthesis models. However, strong evidence suggests the binary fraction of massive stars is ≳70%. Moreover, simulations so far have yielded values of f esc falling only on the lower end of the ∼10%–20%

    更新日期:2020-09-23
  • Structural Evolution in Massive Galaxies at z ∼ 2
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    Ken-ichi Tadaki, Sirio Belli, Andreas Burkert, Avishai Dekel, Natascha M. Förster Schreiber, Reinhard Genzel, Masao Hayashi, Rodrigo Herrera-Camus, Tadayuki Kodama, Kotaro Kohno, Yusei Koyama, Minju M. Lee, Dieter Lutz, Lamiya Mowla, Erica J. Nelson, Alvio Renzini, Tomoko L. Suzuki, Linda J. Tacconi, Hannah Übler, Emily Wisnioski, and Stijn Wuyts

    We present 0.″2 resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations at 870 μ m in a stellar mass–selected sample of 85 massive ( ##IMG## [http://ej.iop.org/images/0004-637X/901/1/74/apjabaf4aieqn1.gif] {${M}_{\star }\gt {10}^{11}\,{M}_{\odot }$} ) star-forming galaxies (SFGs) at ##IMG## [http://ej.iop.org/images/0004-637X/901/1/74/apjabaf4aieqn2.gif] {$z=1.9\mbox{--}2.6$} in

    更新日期:2020-09-23
  • Formation of Foreshock Transients and Associated Secondary Shocks
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    Xin An, Terry Z. Liu, Jacob Bortnik, Adnane Osmane, and Vassilis Angelopoulos

    Upstream of shocks, the foreshock is filled with hot ions. When these ions are concentrated and thermalized around a discontinuity, a diamagnetic cavity bounded by compressional boundaries, referred to as a foreshock transient, forms. Sometimes, the upstream compressional boundary can further steepen into a secondary shock, which has been observed to accelerate particles and contribute to the primary

    更新日期:2020-09-23
  • On the Generation of Compressible Mirror-mode Fluctuations in the Inner Heliosheath
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    Horst Fichtner, Jens Kleimann, Peter H. Yoon, Klaus Scherer, Sean Oughton, and N. Eugene Engelbrecht

    Measurements made with the Voyager 1 spacecraft indicate that significant levels of compressive fluctuations exist in the inner heliosheath. Some studies have already been performed with respect to the mirror-mode instability in the downstream region close to the solar wind termination shock, and here we extend the investigation to the whole inner heliosheath. We employ quasilinear theory and results

    更新日期:2020-09-23
  • X-Ray Spectroscopy in the Microcalorimeter Era. I. Effects of Fe xxiv Resonant Auger Destruction on Fe xxv K α Spectra
    Astrophys. J.  (IF 5.745) Pub Date : 2020-09-22
    P. Chakraborty, G. J. Ferland, M. Chatzikos, F. Guzmán, and Y. Su

    We discuss the importance of Fe 23+ in determining the line intensities of the Fe xxv K α complex in an optically thick cloud, and investigate resonant auger destruction (RAD) with CLOUDY. Although initially motivated by the Perseus cluster, our calculations are extended to the wide range of column densities encountered in astronomy. A Fe xxv line photon can change/lose its identity upon absorption

    更新日期:2020-09-23
  • Erratum: Search for photons with energies above 18 eV using the hybrid detector of the Pierre Auger Observatory
    J. Cosmol. Astropart. Phys. (IF 5.21) Pub Date : 2020-09-22
    A. Aab, P. Abreu, M. Aglietta, I. Al Samarai, I.F.M. Albuquerque, I. Allekotte, A. Almela, J. Alvarez Castillo, J. Alvarez-Muñiz, G.A. Anastasi, L. Anchordoqui, B. Andrada, S. Andringa, C. Aramo, F. Arqueros, N. Arsene, H. Asorey, P. Assis, J. Aublin, G. Avila, A.M. Badescu, A. Balaceanu, R.J. Barreira Luz, J.J. Beatty, K.H. Becker, J.A. Bellido, C. Berat, M.E. Bertaina, X. Bertou, P.L. Biermann, P

    Please see the PDF file for details.

    更新日期:2020-09-23
  • Demographics of Neutron Stars in Young Massive and Open Clusters
    Astrophys. J. Lett. (IF 8.198) Pub Date : 2020-09-22
    Giacomo Fragione and Sambaran Banerjee

    Star clusters appear to be the ideal environment for the assembly of neutron star–neutron star (NS–NS) and black hole–neutron star (BH–NS) binaries. These binaries are among the most interesting astrophysical objects, being potential sources of gravitational waves (GWs) and gamma-ray bursts. We use for the first time high-precision N -body simulations of young massive and open clusters to study the

    更新日期:2020-09-23
  • Archival VLBA Observations of the Cygnus A Nuclear Radio Transient (Cyg A-2) Strengthen the Tidal Disruption Event Interpretation
    Astrophys. J. Lett. (IF 8.198) Pub Date : 2020-09-22
    Steven J. Tingay, James C. A. Miller-Jones, and Emil Lenc

    We have analyzed archival Very Long Baseline Array (VLBA) data for Cygnus A between 2002 and 2013, to search for radio emission from the transient discovered in 2015 by Perley et al. approximately 0.″4 from the nucleus of Cygnus A (Cyg A-2). Perley et al. use Very Large Array and VLBA archival data (between 1989 and 1997) to show that the transient rises in flux density by a factor of at least 5 in

    更新日期:2020-09-23
  • A New Candidate Luminous Blue Variable
    Astrophys. J. Lett. (IF 8.198) Pub Date : 2020-09-22
    Donald F. Figer, Francisco Najarro, Maria Messineo, J. Simon Clark, and Karl M. Menten

    We identify IRAS 16115−5044, which was previously classified as a protoplanetary nebula (PPN), as a candidate luminous blue variable (LBV). The star has high luminosity (≳10 5.75 L ⊙ ), ensuring supergiant status, has a temperature similar to LBVs, is photometrically and spectroscopically variable, and is surrounded by warm dust. Its near-infrared spectrum shows the presence of several lines of H i

    更新日期:2020-09-23
  • A Helium-flash-induced Mixing Event Can Explain the Lithium Abundances of Red Clump Stars
    Astrophys. J. Lett. (IF 8.198) Pub Date : 2020-09-22
    Josiah Schwab

    Observations demonstrate that the surface abundance of ##IMG## [http://ej.iop.org/images/2041-8205/901/1/L18/apjlabb45fieqn1.gif] {${}^{7}\mathrm{Li}$} in low-mass stars changes dramatically between the tip of the red giant branch and the red clump. This naturally suggests an association with the helium core flash, which occurs between these two stages. Using stellar evolution models and a simple,

    更新日期:2020-09-23
  • INTEGRAL results on the electron-positron annihilation radiation and X-ray & Gamma-ray diffuse emission of the Milky Way
    New Astron. Rev. (IF 4.2) Pub Date : 2020-09-22
    Eugene Churazov; Laurent Bouchet; Pierre Jean; Elisabeth Jourdain; Jürgen Knödlseder; Roman Krivonos; Jean-Pierre Roques; Sergey Sazonov; Thomas Siegert; Andrew Strong; Rashid Sunyaev

    This review summarizes INTEGRAL results on two topics: the electron-positron annihilation line and X-ray & Gamma-ray diffuse emission of the Milky Way. The electron-positron annihilation line at 511 keV is the most prominent spectral feature in the gamma-ray spectrum of the Milky Way. From the observational perspective, INTEGRAL has already provided constraints on the total flux, morphology of the

    更新日期:2020-09-22
  • Improving performance of zoom-in cosmological simulations using initial conditions with customized grids
    New Astron. (IF 1.058) Pub Date : 2020-09-18
    Gillen Brown; Oleg Y. Gnedin

    We present a method for customizing the root grid of zoom-in initial conditions used for simulations of galaxy formation. Starting from the white noise used to seed the structures of an existing initial condition, we cut out a smaller region of interest and use this trimmed white noise cube to create a new root grid. This new root grid contains similar structures as the original, but allows for a smaller

    更新日期:2020-09-22
  • A novel early dark energy model
    New Astron. (IF 1.058) Pub Date : 2020-09-18
    Luz Ángela García; Leonardo Castañeda; Juan Manuel Tejeiro

    We present a theoretical study of an early dark energy (EDE) model. The equation of state ω(z) evolves during the thermal history in a framework of a Friedmann-Lemaitre-Robertson-Walker Universe, following an effective parametrization that is a function of redshift z. We explore the evolution of the system from the radiation domination era to the late times, allowing the EDE model to have a non-negligible

    更新日期:2020-09-22
  • Plane-symmetric dark energy model with a massive scalar field
    New Astron. (IF 1.058) Pub Date : 2020-09-20
    Y. Aditya; U.Y. Divya Prasanthi; D.R.K. Reddy

    Investigation of dark energy models in the presence of scalar fields are attracting several kinds of research because they play a vital role in the discussion of a new scenario of accelerated expansion of the universe. In this paper, we obtain an exact plane-symmetric dark energy cosmological model in the presence of an attractive massive scalar field by solving Einstein field equations using some

    更新日期:2020-09-22
  • A survey of spatially and temporally resolved radio frequency interference in the FM band at the Murchison Radio-astronomy Observatory
    Publ. Astron. Soc. Aust. (IF 5.067) Pub Date : 2020-09-22
    S. J. Tingay; M. Sokolowski; R. Wayth; D. Ung

    We present the first survey of radio frequency interference (RFI) at the future site of the low frequency Square Kilometre Array (SKA), the Murchison Radio-astronomy Observatory (MRO), that both temporally and spatially resolves the RFI. The survey is conducted in a 1 MHz frequency range within the FM band, designed to encompass the closest and strongest FM transmitters to the MRO (located in Geraldton

    更新日期:2020-09-22
  • Nature does not play Dice at the Planck scale
    Int. J. Mod. Phys. D (IF 2.154) Pub Date : 2020-09-19
    Tejinder P. Singh

    We start from classical general relativity coupled to matter fields. Each configuration variable and its conjugate momentum, as also spacetime points are raised to the status of matrices [equivalently operators]. These matrices obey a deterministic Lagrangian dynamics at the Planck scale. By coarse-graining this matrix dynamics over time intervals much larger than Planck time, one derives quantum theory

    更新日期:2020-09-22
  • A symmetry principle for emergent spacetime
    Int. J. Mod. Phys. D (IF 2.154) Pub Date : 2020-09-19
    Edgar Shaghoulian

    There are many examples where geometry and gravity are concepts that emerge from a theory of quantum mechanics without gravity. This suggests thinking of gravity as an exotic phase of matter. Quantifying this phase in the Landau paradigm requires some sort of symmetry principle or order parameter that captures its appearance. In this essay, we propose higher-form symmetries as a symmetry principle

    更新日期:2020-09-22
  • Erratum: Dispersion of gravitational waves in cold spherical interstellar medium
    Int. J. Mod. Phys. D (IF 2.154) Pub Date : 2020-09-19
    Dániel Barta; Mátyás Vasúth

    The study published in IJMPD27(4):1850040, 2018 provided a numerical result for the frequency-shift of GWs due to dispersion in interstellar medium. In order to adjust the metric functions of the originally improperly matched ‘background’ spacetime in Sec. 2.1, the authors have adopted Darmois–Israel junction conditions. In Sec. 4.1 the code used in the original paper erroneously computed the magnitude

    更新日期:2020-09-22
  • BRST–BFV and BRST–BV descriptions for bosonic fields with continuous spin on R1,d−1
    Int. J. Mod. Phys. A (IF 1.486) Pub Date : 2020-09-21
    Č. Burdík; V. K. Pandey; A. Reshetnyak

    Gauge-invariant descriptions for a free bosonic scalar field of continuous spin in a d-dimensional Minkowski space–time using a metric-like formulation are constructed on the basis of a constrained BRST–BFV approach we propose. The resulting BRST–BFV equations of motion for a scalar field augmented by ghost operators contain different sets of auxiliary fields, depending on the manner of a partial gauge-fixing

    更新日期:2020-09-22
  • Deflection of light by a rotating black hole surrounded by “quintessence”
    Int. J. Mod. Phys. A (IF 1.486) Pub Date : 2020-09-11
    Prateek Sharma; Hemwati Nandan; Radouane Gannouji; Rashmi Uniyal; Amare Abebe

    We present a detailed analysis of a rotating black hole surrounded by “quintessence.” This solution represents a fluid with a constant equation of state, w, which can for example describe an effective warm dark matter fluid around a black hole. We clarify the conditions for the existence of such a solution and study its structure by analyzing the existence of horizons as well as the extremal case.

    更新日期:2020-09-22
  • Coarse-graining of the Einstein–Hilbert action rewritten by the Fisher information metric
    Int. J. Mod. Phys. A (IF 1.486) Pub Date : 2020-09-21
    Shingo Takeuchi

    In this study, considering the Fisher information metric (Fisher metric) given by a specific form, which is the form of weights in statistics, we rewrite the Einstein–Hilbert (EH) action. Then, determining the transformation rules of the Fisher metric, etc under the coarse-graining, we perform the coarse-graining toward that rewritten EH action. We finally show an existence of a trivial fixed-point

    更新日期:2020-09-22
  • Holographic map for cosmological horizons
    Int. J. Mod. Phys. A (IF 1.486) Pub Date : 2020-09-14
    Chang Liu; David A. Lowe

    We propose a holographic map between Einstein gravity coupled to matter in a de Sitter background and large N quantum mechanics of a system of spins. Holography maps a spin model with a finite-dimensional Hilbert space defined on a version of the stretched horizon into bulk gravitational dynamics. The full Hamiltonian of the spin model contains a nonlocal piece which generates chaotic dynamics, widely

    更新日期:2020-09-22
  • On interpolations between Jordanian twists
    Int. J. Mod. Phys. A (IF 1.486) Pub Date : 2020-09-21
    D. Meljanac; S. Meljanac; Z. Škoda; R. Štrajn

    We consider two families of Drinfeld twists generated from a simple Jordanian twist further twisted with 1-cochains. Using combinatorial identities, they are presented as a series expansion in the dilatation and momentum generators. These twists interpolate between two simple Jordanian twists. For an expansion of a family of twists ℱL,u, we also show directly that the 2-cocycle condition reduces to

    更新日期:2020-09-22
  • Statefinder diagnostic for exponential harmonic field
    Int. J. Mod. Phys. A (IF 1.486) Pub Date : 2020-09-21
    A. D. Kanfon; F. Mavoa; G. Koto N’Gobi

    The dynamic study of the harmonic exponential field has been made using the statefinder diagnostic. By the use of a specific method, we find out the statefinder parameters r, s according to the deceleration parameter and the redshift. The numerical analysis of these parameters brings out the transition between the accelerated and decelerated phases of the universe. There is also an attracting effect

    更新日期:2020-09-22
  • Existence of conserved quantities and their algebra in curved spacetime
    Int. J. Mod. Phys. A (IF 1.486) Pub Date : 2020-09-21
    Susobhan Mandal

    In general relativity, finding out the geodesics of a given spacetime manifold is an important task because it determines which classical processes are dynamically forbidden. Conserved quantities play an important role in solving the geodesic equations of a general spacetime manifold. Furthermore, knowing all possible conserved quantities of a system gives information about the hidden symmetries of

    更新日期:2020-09-22
  • Resonances ϕ(1020) and ϕ(1680) contributions for the three-body decays B+ → Ds+KK̄
    Int. J. Mod. Phys. A (IF 1.486) Pub Date : 2020-09-21
    Ai-Jun Ma

    We study the resonances ϕ(1020) and ϕ(1680) contributions for the three-body decays B+→Ds+KK̄ in the perturbative QCD approach. The branching ratios for B+→Ds+ϕ(1020)→Ds+K+K− and B+→Ds+ϕ(1020)→Ds+K0K̄0 are predicted to be (1.53±0.23)×10−7 and (1.02−0.13+0.19)×10−7, respectively. The decay B+→Ds+ϕ(1680) with ϕ(1680) decays into K+K− or K0K̄0, has the branching fraction (6.94−2.02+1.83)×10−9, which is

    更新日期:2020-09-22
  • Rational nonlinear electrodynamics causes the inflation of the universe
    Int. J. Mod. Phys. A (IF 1.486) Pub Date : 2020-09-21
    S. I. Kruglov

    The source of the universe inflation is electromagnetic fields obeying rational nonlinear electrodynamics proposed earlier. Within this model the singularities of the electric field at the center of charges, the Ricci scalar, the Ricci tensor squared and the Kretschmann scalar are absent. We consider the universe which is filled by stochastic magnetic fields. It is demonstrated that the inflation lasts

    更新日期:2020-09-22
  • Power-law energy distributions of small-scale impulsive events on the active Sun: Results from IRIS
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-09-22
    Nived Vilangot Nhalil; Chris J Nelson; Mihalis Mathioudakis; J Gerry Doyle; Gavin Ramsay

    Numerous studies have analysed inferred power-law distributions between frequency and energy of impulsive events in the outer solar atmosphere in an attempt to understand the predominant energy supply mechanism in the corona. Here, we apply a burst detection algorithm to high-resolution imaging data obtained by the Interface Region Imaging Spectrograph to further investigate the derived power-law index

    更新日期:2020-09-22
  • The efficiency of nuclear burning during thermonuclear (Type I) bursts as a function of accretion rate
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-09-22
    Y Cavecchi; D K Galloway; A J Goodwin; Z Johnston; A Heger

    We measured the thermonuclear burning efficiency as a function of accretion rate for the Type I X-ray bursts of five low-mass X-ray binary systems. We chose sources with measured neutron star spins and a substantial population of bursts from a large observational sample. The general trend for the burst rate is qualitatively the same for all sources; the burst rate first increases with the accretion

    更新日期:2020-09-22
  • Near-Gaussian distributions for modelling discrete stellar velocity data with heteroskedastic uncertainties
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-09-22
    Jason L Sanders; N Wyn Evans

    The velocity distributions of stellar tracers in general exhibit weak non-Gaussianity encoding information on the orbital composition of a galaxy and the underlying potential. The standard solution for measuring non-Gaussianity involves constructing a series expansion (e.g. the Gauss-Hermite series) which can produce regions of negative probability density. This is a significant issue for the modelling

    更新日期:2020-09-22
  • Tidally Trapped Pulsations in Binary Stars
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-09-22
    J Fuller; D W Kurtz; G Handler; S Rappaport

    A new class of pulsating binary stars was recently discovered, whose pulsation amplitudes are strongly modulated with orbital phase. Stars in close binaries are tidally distorted, so we examine how a star’s tidally induced asphericity affects its oscillation mode frequencies and eigenfunctions. We explain the pulsation amplitude modulation via tidal mode coupling such that the pulsations are effectively

    更新日期:2020-09-22
  • A Flexible Analytic Model of Cosmic Variance in the First Billion Years
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-09-22
    A C Trapp; Steven R Furlanetto

    Cosmic variance is the intrinsic scatter in the number density of galaxies due to fluctuations in the large-scale dark matter density field. In this work, we present a simple analytic model of cosmic variance in the high redshift Universe (z ∼ 5–15). We assume that galaxies grow according to the evolution of the halo mass function, which we allow to vary with large-scale environment. Our model produces

    更新日期:2020-09-22
  • The first shear measurements from precision weak lensing
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-09-22
    Pol Gurri; Edward N Taylor; Christopher J Fluke

    We present an end-to-end methodology to measure the effects of weak lensing on individual galaxy-galaxy systems exploiting their kinematic information. Using this methodology, we have measured a shear signal from the velocity fields of 18 weakly-lensed galaxies. We selected a sample of systems based only on the properties of the sources, requiring them to be bright (apparent i-band magnitude <17.4)

    更新日期:2020-09-22
  • Asteroseismic Inference of Subgiant Evolutionary Parameters with Deep Learning
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-09-22
    Marc Hon; Earl P Bellinger; Saskia Hekker; Dennis Stello; James S Kuszlewicz

    With the observations of an unprecedented number of oscillating subgiant stars expected from NASA’s TESS mission, the asteroseismic characterization of subgiant stars will be a vital task for stellar population studies and for testing our theories of stellar evolution. To determine the fundamental properties of a large sample of subgiant stars efficiently, we developed a deep learning method that estimates

    更新日期:2020-09-22
  • Reionization inference from the CMB optical depth and E-mode polarization power spectra
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-09-22
    Yuxiang Qin; Vivian Poulin; Andrei Mesinger; Bradley Greig; Steven Murray; Jaehong Park

    The Epoch of Reionization (EoR) depends on the complex astrophysics governing the birth and evolution of the first galaxies and structures in the intergalactic medium. EoR models rely on cosmic microwave background (CMB) observations, and in particular the large-scale E-mode polarization power spectra (EE PS), to help constrain their highly uncertain parameters. However, rather than directly forward-modelling

    更新日期:2020-09-22
  • WASP-186 and WASP-187: two hot Jupiters discovered by SuperWASP and SOPHIE with additional observations by TESS
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-09-22
    N Schanche; G Hébrard; A Collier Cameron; S Dalal; B Smalley; T G Wilson; I Boisse; F Bouchy; D J A Brown; O Demangeon; C A Haswell; C Hellier; U C Kolb; T Lopez; P F L Maxted; D L Pollacco; R G West; P J Wheatley

    We present the discovery of two new hot Jupiters identified from the WASP survey, WASP-186b and WASP-187b (TOI-1494.01 and TOI-1493.01). Their planetary nature was established from SOPHIE spectroscopic observations, and additional photometry was obtained from TESS. Stellar parameters for the host stars are derived from spectral line, IRFM, and isochrone placement analyses. These parameters are combined

    更新日期:2020-09-22
  • Galaxies in the Zone of Avoidance with the Spitzer Space Telescope
    Res. Notes AAS Pub Date : 2020-09-21
    Melina Thévenot, Claude Cornen, Brian L. Goodwin, Christine Macmillan, Andrés Guillermo Stenner, and Barbara Téglás

    In this work we describe 59 galaxies discovered in the talk-forum of the Milky Way Project (MWP) by volunteers of the project. The MWP is based on infrared images by the Spitzer Space Telescope and primarily probes the Zone of Avoidance for star-forming regions located in the Milky Way. The list of galaxies found here include 35 galaxies previously not described, a possible galaxy cluster and two galaxies

    更新日期:2020-09-22
  • The Large Far Ultraviolet Variations of α Cir A and α Cir B as Recorded by IUE and FUSE
    Res. Notes AAS Pub Date : 2020-09-21
    Richard Monier

    Inspection of archival IUE spectra of the bright rapidly oscillating Ap star α Cir A reveal large flux variations from 1600 to 2000 Å over the 4.4790 day rotational period. At 1965 Å, where the flux reaches a maximum, the flux more than doubles between phases of maximum and minimum flux. These large flux variations are most likely caused by the passage of spots or belts of overabundant elements in

    更新日期:2020-09-22
  • Detection of Coherent Pulsation Modes in the Strongly Magnetic Of?p Star NGC 1624-2 using TESS Observation
    Res. Notes AAS Pub Date : 2020-09-20
    D. W. Kurtz, S. Hubrig, S. P. Järvinen, and M. Schöller

    High-cadence Transiting Exoplanet Survey Satellite (TESS) observations are promising for studies of short-term pulsational variability in magnetic O stars, which usually have long rotation periods of the order of months or years. The Of?p star NGC 1624-2 is of special interest as it possesses the strongest magnetic field measured among O stars, together with a giant magnetosphere. We detect three significant

    更新日期:2020-09-22
  • All Known SN Ia Models Fail to Reproduce the Observed t 0 – M N I 56 Correlation
    Res. Notes AAS Pub Date : 2020-09-20
    Amir Sharon and Doron Kushnir

    SNe Ia are likely the thermonuclear explosions of carbon–oxygen white-dwarf stars, but their progenitor systems remain elusive. A few theoretical scenarios for the progenitor systems have been suggested, which have been shown to agree with some observational properties of SNe Ia. However, several computational challenges prohibit a robust comparison to the observations. We focus on the observed ##IMG##

    更新日期:2020-09-22
  • The mass of a dark matter WIMP derived from the Hubble constant conflict
    Res. Astron. Astrophys. Pub Date : 2020-09-21
    John Baruch

    There continues to be good reason to believe that dark matter particles, which only “feel” the gravitational force, influence the local and distant Universe, despite drawing a complete blank in the search for such a particle. The expansion rate of the Universe is defined by the Hubble constant h . Measurements of the Hubble constant at different wavelengths produce different results, differing well

    更新日期:2020-09-22
  • The gravitational wave emission of double white dwarf coalescences
    Res. Astron. Astrophys. Pub Date : 2020-09-21
    Ze-Cheng Zou邹 泽成, Xiao-Long Zhou周 小龙 and Yong-Feng Huang黄 清敏

    Type Ia Supernovae (SNe Ia) are widely used as standard candles to probe the Universe. However, how these fierce explosions are produced itself is still a highly debated issue. There are mainly two popular models for SNe Ia: the double-degenerate scenario and the single-degenerate scenario. The double-degenerate scenario suggests that SNe Ia are produced by the coalescence of two degenerate white dwarfs

    更新日期:2020-09-22
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