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  • Thermonuclear X-ray bursts detected in Cyg X-2 using AstroSat/LAXPC
    New Astron. (IF 1.058) Pub Date : 2020-08-11
    Jincy Devasia; Gayathri Raman; Biswajit Paul

    We report the detection of 5 Type-1 thermonuclear X-ray bursts and one burst-like event in the neutron star LMXB source, Cyg X-2 using X-ray data obtained with the Large Area X-ray Proportional Counter (LAXPC) instrument on board AstroSat. We carry out an energy resolved burst profile analysis as well as time resolved spectral analysis for each of the bursts and characterize their properties. All bursts

  • AB Andromedae – An Overcontact Eclipsing Binary
    New Astron. (IF 1.058) Pub Date : 2020-08-10
    Robert H. Nelson

    In an effort to resolve the discrepancy between two earlier studies, new radial velocity and photometric data have been obtained and analyzed by Roche modelling for AB Andromedae, an overcontact W-subtype eclipsing binary. The new values for the basic data, m1 = 0.60 (3) Mʘ, m2 = 1.14 (3) Mʘ, R1 = 0.81 (1) Rʘ, R2 = 1.08 (1) Rʘ, L1 = 0.73 (6) Lʘ, and L2 = 1.02 (7) Lʘ, mostly lie close to a given set

  • Accelerating universe with varying Λ in f(R, T) theory of gravity
    New Astron. (IF 1.058) Pub Date : 2020-08-09
    Rishi Kumar Tiwari; Değer Sofuoğlu; Sateesh Kumar Mishra

    In this paper we have investigated Bianchi Type-I cosmological model with varying cosmological constant Λ in f(R, T) theory of gravity. In order to obtain an exact solution of the field equations, we have used a special law of Hubble parameter proposed by Banerjee and Das (Gen Relat Gravit 37 (2005) 1695-1703), which leads to a time dependent deceleration parameter. We have discussed the physical and

  • Monitoring of transiting exoplanets and their host stars with small aperture telescopes
    New Astron. (IF 1.058) Pub Date : 2020-08-09
    M.A. Salisbury; U.C. Kolb; A.J. Norton; C.A. Haswell

    Exoplanet research is now target rich with a wide diversity of systems making it difficult for high demand observatories to undertake follow up observations over extended periods of time. We investigate the effectiveness of using 0.4m-class telescopes for monitoring transiting hot Jupiters and their host stars. We consider two representative case studies: WASP-52b with 13 new transits, and HAT-P-23b

  • Dynamical analysis with thermodynamic aspects of anisotropic dark energy bounce cosmological model in f(R, G) gravity
    New Astron. (IF 1.058) Pub Date : 2020-08-02
    S.H. Shekh

    Present analysis dedicated to the dynamical investigation of anisotropic dark energy LRS Bianchi type-I cosmological model in the context of modified gravity in which Langrangian be the arbitrary function of Ricci scalar and Gouss-Bonnet invariant say f(R, G) gravity in the way of anisotropic fluid. The classification of the field equations towards f(R,G)=f0RmG1−m make available that the model is purely

  • Capricious basins of attraction in photogravitational magnetic binary problem
    New Astron. (IF 1.058) Pub Date : 2020-08-09
    Vinay Kumar; Md. Arif; M. Shahbaz Ullah

    Abstract: The present paper deals with the magnetic binary problem in the framework of restricted problem of three bodies. The bigger primary is taken as the source of radiation pressure and smaller primary is taken as point mass. The parametric evolution of the position and existence of libration points are explored. The study of zero velocity curves and the stability of libration points are one of

  • Non-commutative wormhole solutions in exponential gravity with matter coupling
    New Astron. (IF 1.058) Pub Date : 2020-08-01
    M. Farasat Shamir; G. Mustafa; Anum Fazal

    In the present article, we use non-commutative geometry to investigate the wormhole solutions in modified f(R, T) theory of gravity. In particular, we consider Gaussian and Lorentzian source with f(R,T)=f1(R)+λT model to discuss the wormhole solutions existence. We choose two different models of f1(R) i.e. f1(R)=R−αγ(1−e−Rγ) known as exponential gravity model and f1(R)=R−αγtanh(Rγ) known as Tsujikawa

  • First Lunar Occultations Results from the Trebur Observatory
    New Astron. (IF 1.058) Pub Date : 2020-08-07
    A. Richichi; J.M. Ohlert

    A program of routine observations of lunar occultations has been initiated at the Michael Adrian Observatorium using a 1.2 m telescope equipped with a commercial CMOS camera. The goal is mainly the direct measurement of the angular diameter of late-type stars, as well as of binary stars with small separations. Among the results reported in this first paper, we discuss a measurement of Aldebaran (α Tau)

  • Anisotropic universe and observational constraint on the dark energy models with the cosmological redshift drift
    New Astron. (IF 1.058) Pub Date : 2020-08-06
    H. Hossienkhani; N. Azimi; S. Gheysari; Z. Zarei

    This study set out to examine the effect of anisotropy on the various dark energy models by using the observational data, including the Sandage-Loeb test, Strongly gravitationally lensing, observational Hubble data, and Baryon Acoustic Oscillations data. In particular, we consider three cases of dark energy models: the cosmological constant model, which is most favored by current observations, the

  • Self-similar orbit-averaged Fokker-Planck equation for isotropic spherical dense star clusters (i) accurate pre-collapse solution
    New Astron. (IF 1.058) Pub Date : 2020-08-06
    Yuta Ito

    This is the first paper of a series of our works on the self-similar orbit-averaged Fokker-Planck (OAFP) equation to model distribution function for stars in isotropic dense spherical star clusters. At the late stage of the relaxation evolution of the clusters, standard stellar dynamics predicts that the clusters evolve in a self-similar fashion forming collapsing cores. However, the corresponding

  • Dynamics of some cosmological solutions in modified f(R) gravity
    New Astron. (IF 1.058) Pub Date : 2020-07-26
    Adnan Malik; M. Farasat Shamir

    This paper is devoted to investigate the modified f(R) theory of gravity, where R represents the Ricci scalar respectively. For our current work, we consider the Friedmann-Robertson-Walker (FRW) space-time for finding solutions of field equations. Furthermore, some numerical solutions are examined by taking the Klein-Gordon Equation and using distinct values of the equation of state (EoS) parameter

  • GalRotpy: a tool to parametrize the gravitational potential of disc-like galaxies
    New Astron. (IF 1.058) Pub Date : 2020-07-22
    Andrés Granados; Daniel Torres; Leonardo Castañeda; Lady Henao; Santiago Vanegas

    GalRotpy is a Python3-based tool, intended to determine the contribution of each mass component to the gravitational potential of disc-like galaxies by means of their rotation curve. Besides, GalRotpy allows to perform a parametric fit of a given rotation curve, which relies on a MCMC procedure implemented by using emcee package. Here the gravitational potential of disc-like galaxies is built from

  • Reaction rate calculation of d(α, γ)6Li process at low energy in framework of effective field theory
    New Astron. (IF 1.058) Pub Date : 2020-07-27
    S. Nahidinezhad; H. Sadeghi; M. Khoddam

    Reaction rate of the process d(α, γ)6Li has been calculated in the framework of Effective Field Theory (EFT) at low energy. Deuteron is assumed as a dibaryon in the initial state. The reaction amplitude for the initial P-wave states of deuteron-alpha and reaction rate for sum of E1 and E2 transitions are found in the framework of EFT up to NLO. Our results are in good agreement with the recent experimental

  • Irregular emission cycles in the Oe star HD 60 848
    New Astron. (IF 1.058) Pub Date : 2020-07-30
    Gregor Rauw; Yaël Nazé; Fran Campos; Joan Guarro Fló; Umberto Sollecchia

    We analyse the spectroscopic and photometric variability of the Oe star HD 60 848 over the last twenty five years. The spectra reveal recurrent, but irregular cycles of increased circumstellar emission lines. These cycles are highly asymmetric displaying a slow increase over about 6 years, followed by a fast decay within about 6 months. Our analysis focuses on the most recent cycle (2013 – 2020). The

  • The Late-Type Detached Binary DU Leonis
    New Astron. (IF 1.058) Pub Date : 2020-07-29
    Robert H. Nelson

    New radial velocity and photometric data for DU Leonis have been obtained, and Roche-based simultaneous analysis of RV and light curve data for DU Leo has been accomplished for the first time, using the 2003 and 2015 versions of the Wilson-Devinney code. Values for the masses and radii have been obtained: M1 = 0.937 (5) Mʘ, M2 = 0.921 (5) Mʘ, and R1 = 1.25 (1) Rʘ, R2 = 1.21 (1) Rʘ. For the luminosities

  • Exact analytic solution of an unsolvable class of first Lane–Emden equation for polytropic gas sphere
    New Astron. (IF 1.058) Pub Date : 2020-07-24
    Rafael Torres-Córdoba; Edgar A. Martínez-García

    This article provides for the first time a general analytical solution to the Lane-Emden equation of the first kind. So far only three known analytical solutions are found in the literature, for the following values of n: 0, 1 and 5. A common feature these three solutions share is their boundary conditions: θ(ξ)∣ξ=0=1 and dθ(ξ)dξ∣ξ=0 =0. If a third boundary condition d2θ(ξ)dξ2∣ξ=0,= −1 is used, only

  • A new approximate coupling function: The case of Forbush decreases
    New Astron. (IF 1.058) Pub Date : 2020-07-17
    L. Xaplanteris; M. Livada; H. Mavromichalaki; L. Dorman

    We attempt the derivation of a new coupling function between ground level and primary cosmic rays for the case of Forbush decreases. The calculations for the new function are based on basic Quantum Field Theory theoretical tools, something that has not been attempted till now in other widely used cosmic ray coupling functions. The use of Quantum Field Theory calculations in cosmic rays events in general

  • The study of runaway candidate stars in the 30 Doradus region: Using Gaia DR2 data
    New Astron. (IF 1.058) Pub Date : 2020-07-22
    Yikdem Mengesha Gebrehiwot; Berhe Tewelde Teklehaimanot

    We explore the Gaia DR2 relative proper motions of seven young, massive, OB type runaway candidate stars presented by Platais et al. (2018) in the 30 Doradus (30 Dor) region of the Large Magellanic Cloud (LMC). The stars are slow runaways in the tangential plane of the 30 Dor region with relative proper motions μ≤0.4masyr−1 that correspond to a tangential velocity of 100 kms−1 with respect to their

  • Elliptic restricted synchronous three-body problem (ERS3BP) with a mass dipole model
    New Astron. (IF 1.058) Pub Date : 2020-07-12
    M. Javed Idrisi; M. Shahbaz Ullah; Vinay Kumar

    The goal of the present manuscript is to determine the points of libration and their linear stability in the elliptic restricted synchronous three-body problem with a mass dipole model. The dipole system consists of two-point masses connected with a massless rod in a constant characteristic distance. To execute this study, we acquire the equations of motion of a spacecraft having negligible mass travelling

  • A study of non-collinear libration points under the combined effects of radiation pressure and Stokes drag
    New Astron. (IF 1.058) Pub Date : 2020-06-25
    M. Javed Idrisi; M. Shahbaz Ullah

    We study the non-collinear libration points in the frame work of photo-gravitational circular restricted three-body problem with Stokes drag acting as a dissipative force and considering the more massive primary as a radiating body and the less massive primary as a triaxial rigid body. The combined effects of radiation pressure and Stokes drag on the existence and stability of non-collinear libration

  • Detection of high energy showers by the Astroneu extensive air shower array
    New Astron. (IF 1.058) Pub Date : 2020-07-11
    A. Leisos; T. Avgitas; G. Bourlis; G.K. Fanourakis; I. Gkialas; I. Manthos; A.G. Tsirigotis; S.E. Tzamarias

    The Astroneu Extensive Air Shower (EAS) array comprises autonomous detection stations; each station consisting of 3 large scintillator detectors and one or more Radio Frequency (RF) antennas. The scintillator detectors of a station are able to detect showers with a low energy threshold of 20−30 TeV, at a rate of 10−20 showers per hour depending on the station geometrical layout. The RF antennas are

  • New photometric analysis of hot Jupiter: WASP-135b
    New Astron. (IF 1.058) Pub Date : 2020-07-17
    Oğuz Öztürk; Ahmet Erdem

    We report photometric follow-up observations of WASP-135b obtained using the 1.23-m telescope at Calar Alto Observatory and 1.00-m telescope at TÜBİTAK National Observatory during the 2017 and 2018 observational seasons. Eight new transit light curves of WASP-135b were analyzed with jktebop code. The ratio of the planet radius to radius of host star, fractional radius of host star, and orbital inclination

  • An association of CMEs with solar flares detected by Fermi γ-ray burst monitor during solar cycle 24
    New Astron. (IF 1.058) Pub Date : 2020-07-14
    Ramy Mawad; Walid Abdel-Sattar; Hussein M. Farid

    By performing certain spatial and temporal criteria, we obtained 492 CME events simultaneously associated with GBM solar flare events (hereafter, GBM-flare–CME) from the total number 5123 Gamma-ray Burst Monitor (GBM) solar flares and 15228 Coronal Mass Ejections (CMEs) detected during the solar cycle 24 (2008–2019). Among these 492 events, which represent about 9.6% of the total number of the detected

  • Unpredictable basin boundaries in restricted six-body problem with square configuration
    New Astron. (IF 1.058) Pub Date : 2020-07-14
    Vinay Kumar; M. Javed Idrisi; M. Shahbaz Ullah

    The present work deals with the recently introduced restricted six body-problem with square configuration. We have computed and verified the position of libration points with the help of Newton-Raphson method. It is observed that the total number of libration points are either twelve or twenty depends upon the mass parameter μ ∈ (0, 0.25). The multivariate form of Newton-Raphson scheme is used to discuss

  • Absolute parameters of the W UMa binaries CSS J223614+311343, V523 Aur and V783 And
    New Astron. (IF 1.058) Pub Date : 2020-07-18
    Diana Kjurkchieva; Raul Michel; Shijie Zhao; Carmen Ayala-Loera; Luis C. Bermudez-Bustamante; Velimir A. Popov

    Photometric BVRc observations of the stars CSS J223614+311343, V523 Aur and V783 And were carried out and their absolute parameters (masses, radii and luminosities) were determined based on light curve modeling and Gaia distances. The main results are: (i) The components of CSS J223614+311343 and V783 And are of K spectral type while those of V523 Aur are G stars; (ii) The three systems have middle

  • Photoionization features of the ground and excited levels of Cl II and benchmarking with experiment
    New Astron. (IF 1.058) Pub Date : 2020-07-11
    Sultana N. Nahar

    This report presents i) various characteristic features in photoionization cross sections (σPI) of Cl II + hν → Cl III + e for many fine structure levels of Cl II, 392 in total with n ≤ 10 and l ≤ 9, ii) comparison of features with those observed in an experiment carried out at the Advanced Light Source at Lawrence Berkeley National Lab, and iii) partial photoionization cross sections of the ground

  • Late-time viscous cosmology in f(R, T) gravity
    New Astron. (IF 1.058) Pub Date : 2020-07-12
    Simran Arora; Snehasish Bhattacharjee; P.K. Sahoo

    The article communicates an alternative route to suffice the late-time acceleration considering a bulk viscous fluid with viscosity coefficient ζ=ζ0+ζ1H+ζ2H2, where ζ0, ζ1, ζ2 are constants in the framework of f(R, T) modified gravity. We presume the f(R, T) functional form to be f=R+2αT where α is a constant. We then solve the field equations for the Hubble Parameter and study the cosmological dynamics

  • Photometric study of five kepler contact binaries
    New Astron. (IF 1.058) Pub Date : 2020-07-02
    Xu-Zhi Li; Liang Liu

    A lot of data in time domain were obtained by the Kepler mission, including many contact binaries. Long-term observation lets us obtain more information about the short time scale variation in their light curves or in their orbital periods. Unfortunately, the exposure time is too long (most of them are 30 minutes). Hence, many variations in light curves are smoothed. To avoid this problem, we analyzed

  • Hawking-Unruh effect associated with primordial black holes and maximum acceleration of elementary particles
    New Astron. (IF 1.058) Pub Date : 2020-06-22
    V. Vipindas; T.E. Girish; C. Radhakrishnan Nair

    Three decades ago an expression for the maximum acceleration of elementary particles was derived using quantum theory. There is no experimental confirmation of this so far. In this paper we study the phenomenon of acceleration of elementary particles by the surface gravity of primordial black holes (PBH) formed in the early universe and the associated Hawking-Unruh effect. From a heuristic theory we

  • First photometric study of two contact binaries: 1SWASP J15133589-3725239, 1SWASP J22310605-1940584
    New Astron. (IF 1.058) Pub Date : 2020-06-26
    Mehmet Tanriver; Carlos Alberto Guerrero Pena; Raul Michel Murillo; Roberto Pires

    We present the results of our investigation and first analysis of the geometrical and physical parameters of the 1SWASP J15133589-3725239 and 1SWASP J22310605-1940584 W UMa-type binary systems. Light curve analysis was performed with the PHOEBE0.31a interface program based on the Wilson-Devinney code. New times of minima and light elements have been determined. According to our solution, the 1SWASP

  • Introducing a new version of the restricted three-body problem with a continuation fraction potential
    New Astron. (IF 1.058) Pub Date : 2020-06-27
    Euaggelos E. Zotos; Elbaz I. Abouelmagd; N. S. Abd El Motelp

    The on-plane version of the restricted problem of 3 bodies with a continuation fraction potential is numerically investigated. The idea is to consider that one of the primaries is a radiation source and the secondary one is not spherical. By adopting the grid classification method we locate the coordinates, on the XY−plane, of all the points of equilibrium, for several values of the involved parameters

  • Cosmic Ray RF detection with the Astroneu array
    New Astron. (IF 1.058) Pub Date : 2020-06-22
    I. Manthos; G. Bourlis; I. Gkialas; A. Leisos; A. Papaikonomou; A.G. Tsirigotis; S.E. Tzamarias

    Results will be shown from the Astroneu array developed and operated in the outskirts of Patras, Greece. An array of 9 scintillator detectors and 3 antennas were deployed to study Extensive Air Showers (EAS) as a tool for calibrating an underwater neutrino telescope, possible other applications in muon tomography, education purposes, and last but not least, for the detection of air showers via their

  • Jet-driven AGN feedback in galaxy formation before black hole formation
    New Astron. (IF 1.058) Pub Date : 2020-06-19
    Ealeal Bear; Noam Soker

    We propose a scenario where during galaxy formation an active galactic nucleus (AGN) feedback mechanism starts before the formation of a supermassive black hole (SMBH). The supermassive star (SMS) progenitor of the SMBH accretes mass as it grows and launches jets. We simulate the evolution of SMSs and show that the escape velocity from their surface is ≈several×103kms−1, with large uncertainties. We

  • Astrophysical accretion near Hayward regular black hole
    New Astron. (IF 1.058) Pub Date : 2020-06-15
    A. Ditta; G. Abbas

    We have studied the steady state accretion process of perfect fluids onto a regular Hayward black hole (BH) corresponding to Schwarzschild spacetime. It has been found that the accretion rate of regular Hayward BH differ from Schwarzschild BH. The graphical results of our problem depend on fluid’s radial velocity u(r), speed of sound cs2 and the mass accretion rate M˙. We see the physical behaviors

  • The First Light Curve Solutions and Period Changes of EW Psc and HN Psc
    New Astron. (IF 1.058) Pub Date : 2020-06-20
    F. Davoudi; A. Poro; F. Alicavus; J. Rahimi; E. Lashgari; M. Ghanbarzadehchaleshtori; A. Boudesh; S. Hoshyar; D. Asgarian; N. Pilghush; S. Modarres; S. Ebadi; A. Sojoudizadeh; S.Z. Azarniur; H. Karami; A. Dehghani Ghanatghestani

    The first light curve solutions of the stars EW and HN in the Pisces constellation are presented. Photometry, and its’ periodic changes are calculated and discussed. The analysis of the O-C diagram is done by the MCMC approach in the OCFit code and a new ephemeris is provided for the two binary systems. The results show that EW Psc is a near contact eclipsing binary system with a photometric mass ratio

  • Study of the structure of the inflow/outflow region in the self-gravitating standard accretion disks
    New Astron. (IF 1.058) Pub Date : 2020-06-07
    M. Eskandari Cherati; A. Khesali

    The structure of self-gravitating accretion disks is investigated. In order to describe this, we establish the quantitative changes in the θ direction by solving a set of ordinary differential equations in the spherical coordinates (r, θ, φ). The use of a spherical coordinate system causes a positive radial velocity to indicate the presence of an outflow region and a negative radial velocity to indicate

  • d−α Radiative capture process by effective field theory
    New Astron. (IF 1.058) Pub Date : 2020-05-23
    S. Nahidinezhad; H. Sadeghi; H. Khalili

    Two of the main components of nuclear fusion processes which occur in stars are the radiative capture of deuteron-alpha and its inverse reaction during which helium transforms into larger elements. One of the reactions occuring is the production of 6Li through the d(α, γ)6Li reaction that is supported by the Big Bang model. The process of radiation in the energy region 0.07 MeV ≤ Ecm ≤ 0.41 MeV has

  • Redshift Drift in f(R, T) Gravity
    New Astron. (IF 1.058) Pub Date : 2020-05-23
    Snehasish Bhattacharjee; P.K. Sahoo

    Redshift drift refers to the phenomena that redshift of cosmic objects is a function of time. Measurement of redshift drift is of fundamental importance in physical cosmology and can be utilized to distinguish different cosmological models. Redshift drift can be expressed in two distinct methods. The first method is related to cosmography, where the Redshift drift is given as a series expansion of

  • Relativistic parametric embedding class I solutions of cold stars in Karmarkar space-time continuum
    New Astron. (IF 1.058) Pub Date : 2020-05-19
    Jaya Upreti; Satyanarayana Gedela; Neeraj Pant; R.P. Pant

    The aim of this paper is to explore a new parametric class of relativistic solutions to the Einstein field equations describing a spherically symmetric, static distribution of anisotropic fluid spheres to study the behavior of some of the cold stars in the setting of Karmarkar space-time continuum. We develop models of stellar objects for a range of parameter values of n and analyze their behavior

  • Holographic Dark Energy Cosmological Models in f(G) Theory
    New Astron. (IF 1.058) Pub Date : 2020-05-17
    A.Y. Shaikh; S.V. Gore; S.D. Katore

    In this paper, Locally Rotationally Symmetric (LRS) Bianchi type-I models with holographic dark energy within the framework of f(G) theory of gravitation are thought about. So as to get determinate solutions, volumetric exponential expansion, power law expansion and hybrid expansion law are mentioned. The physical interpretations of the solution have been studied by using some physical quantizes. Additionally

  • A robust determination of halo environment in the cosmic field
    New Astron. (IF 1.058) Pub Date : 2020-05-15
    Peng Wang; Xi Kang; Noam I. Libeskind; Quan Guo; Stefan Gottlöber; Wei Wang

    A number of methods for studying the large-scale cosmic matter distribution exist in the literature. One particularly common method employed to define the cosmic web is to examine the density, velocity or potential field. Such methods are advantageous since a Hessian matrix can be constructed whose eigenvectors (and eigenvalues) indicate the principal directions (and strength) of local collapse or

  • A photometric study of HAT 141-03513: another twin of the V361 Lyr system
    New Astron. (IF 1.058) Pub Date : 2020-05-15
    M. Wolf; H. Kučáková

    The BVRI light curves were measured for the eclipsing binary HAT 141-03513 as a part of our long-term observational project for studying low-mass eclipsing binaries with a short orbital period. The asymmetric light curve and the difference in brightness in maxima, are probably the result of presence of a hot region on the surface of one component. The light curve solution in Phoebe results to the semidetached

  • Statefinder diagnostic for the Re´nyi holographic dark energy
    New Astron. (IF 1.058) Pub Date : 2020-05-13
    Umesh Kumar Sharma; Vipin Chandra Dubey

    In this paper, we have examined the Re´nyi holographic dark energy (RHDE) model in the framework of flat FRW universe by considering different values of non - extensive parameter δ. The deceleration parameter (q) of RHDE model justifies the recent phase transition of cosmos because of q changes sign from +ve to −ve i.e. deceleration to accelerated phase. We calculated and plotted the trajectories of

  • Wormhole model with a hybrid shape function in f(R, T) gravity
    New Astron. (IF 1.058) Pub Date : 2020-05-12
    Parbati Sahoo; Sanjay Mandal; P.K. Sahoo

    In the present article we propose a new hybrid shape function for wormhole (WH)s in the modified f(R, T) gravity. The proposed shape function satisfied the conditions of WH geometry. Geometrical behavior of WH solutions are discussed in both anisotropic and isotropic cases respectively. Also, the stability of this model is obtained by determining the equilibrium condition. The radial null energy condition

  • Random fragmentation of turbulent molecular clouds lying in the central region of giant galaxies
    New Astron. (IF 1.058) Pub Date : 2020-05-12
    Suman Paul; Tanuka Chattopadhyay

    A stochastic model of fragmentation of molecular clouds has been developed for studying the resulting Initial Mass Function (IMF) where the number of fragments, inter-occurrence time of fragmentation, masses and velocities of the fragments are random variables. Here two turbulent patterns of the velocities of the fragments have been considered, namely, Gaussian and Gamma distributions. It is found

  • Some bianchi type cosmological models in f(R, ϕ) gravity
    New Astron. (IF 1.058) Pub Date : 2020-05-12
    Adnan Malik; Shahzad Ahmed; Saqib Mahmood

    In this paper, we study three different Bianchi type line elements, like Bianchi type-I (BT-I), Bianchi type-III (BT-III) and Kantowski Sachs space-time in the framework of f(R, ϕ) theory of gravity, where R and ϕ represent the Ricci scalar and the scalar potential function respectively. We find the exact solution of vacuum field equations of f(R, ϕ) theory by taking valuable assumption that the expansion

  • The study of Gödel type solutions in f(R, ϕ) gravity
    New Astron. (IF 1.058) Pub Date : 2020-05-12
    Adnan Malik; M. Farasat Shamir

    The aim of this paper is to study the Gödel type universe in modified f(R, ϕ) theory of gravity, where R stands for Ricci scalar and ϕ be the scalar potential. We investigate the modified field equations by using anisotropic and perfect fluid distributions. In particular, we consider two proposed models with some fixed values of parameters and investigate the exact solutions. The behaviour of energy

  • Age and metallicity of galaxies in different environments of the Coma supercluster
    New Astron. (IF 1.058) Pub Date : 2020-05-11
    Juhi Tiwari; Smriti Mahajan; Kulinder Pal Singh

    We analyse luminosity-weighted ages and metallicity (Z) of galaxies in a continuous range of environments, i.e. clusters, filaments and voids prevalent in the Coma supercluster (∼100h−1 Mpc). Specifically, we employ two absorption line indices, Hβ and ⟨Fe⟩ as tracers of age and metallicity of galaxies. We find that the stellar-phase metallicity of galaxies declines with increasing age as a function

  • First study of a low-amplitude eclipsing binary KIC11496078
    New Astron. (IF 1.058) Pub Date : 2020-05-06
    S. Soomandar; A. Abedi

    We investigate a low-amplitude W UMa binary KIC 11496078 based on Kepler photometric data, and the diagrams of OC maxima and minima of light curves are plotted. The anti-correlated nature of the curves indicates that KIC 11496078 is a binary. We use short cadence mode (SC) data for analyzing the light curve. By performing some analyses, the parameters of the system are determined. The results show

  • New CCD photometry and light curve analysis of two WUMaBinaries: 1SWASP J133417.80+394314.4 and V2790 Orion
    New Astron. (IF 1.058) Pub Date : 2020-05-04
    A. Shokry; I.Z. Zead; M.H. El-Depsey; M.S. Darwish; I.A. Hassan; A.M.K. Shaltout; M.S. Saad; M.I. Nouh

    We present a new multicolor CCD photometry and light curve analysis of two eclipsing binary systems, 1SWASP J133417.80 + 394314.4 and V2790 Orion. The photometric solutions for both binaries were carried out using the updated version of the Wilson– Devinney code. The results showed that first systems is A- type W UMa with mass ratios q = 0.158 while the second system is W- type with q = 3.2. The systems

  • Crossing the phantom divide line in universal extra dimensions
    New Astron. (IF 1.058) Pub Date : 2020-05-01
    Nasr Ahmed; Anirudh Pradhan

    We investigate the cosmic acceleration and the evolution of dark energy across the cosmological constant boundary in universal extra dimensions UED. We adopt an empirical approach to solve the higher-dimensional cosmological equations so that the deceleration parameter q is consistent with observations. The expressions for the jerk and deceleration parameters are independent of the number of dimensions

  • Multiwavelength study of the radio galaxy NGC 1275 with TACTIC, Fermi and Swift during December, 2016 – February, 2017
    New Astron. (IF 1.058) Pub Date : 2020-04-28
    B. Ghosal; A. Tolamatti; K.K. Singh; K.K. Yadav; R.C. Rannot; A.K. Tickoo; P. Chandra; A. Goyal; N. Kumar; P. Marandi; N.K. Agarwal; M. Kothari; K.K. Gaur; N. Chouhan; C. Borwankar; V.K. Dhar; M.K. Koul; K. Venugopal; M. Sharma

    Located in the Perseus galaxy cluster, NGC 1275 (z=0.0179), is the brightest radio galaxy detected in both high energy (HE ; E > 100 MeV) and very high energy (VHE ; E > 100 GeV) regimes. Here we present the results from the observations of NGC 1275 with TACTIC for 37.1 h between December, 2016 and February, 2017. In the absence of a statistically significant VHE γ-ray detection from the TACTIC observations

  • First photometric investigation of two short-period eclipsing binaries NSVS 7377756 and for UCAC3 276-106147
    New Astron. (IF 1.058) Pub Date : 2020-04-28
    Carlo Barani; Massimiliano Martignoni; Francesco Acerbi

    We present the first CCD sets of complete light curves for two W Ursae Majoris Systems, UCAC3 276-106147 and NSVS 7377756. These light curves are here analyzed and modelled using the latest version of the Wilson-Devinney Code. We found that UCAC3 276-106147 is a W-subtype shallow-contact eclipsing binary (fill-out factor 7.5%), with a mass ratio of q = 2.88 (1/q = 0.347), a small temperature difference

  • Traversable wormholes in f(R) gravity with constant and variable redshift functions
    New Astron. (IF 1.058) Pub Date : 2020-04-15
    Nisha Godani; Gauranga C. Samanta

    The present paper is aimed at the study of traversable wormholes in f(R) gravity with a viable f(R) function defined as f(R)=R−μRc(RRc)p, where R is scalar curvature, μ, Rc and p are constants with μ, Rc > 0 and 0 < p < 1 (Amendola et al., 2007a). The metric of wormhole is dependent on shape function b(r) and redshift function ϕ(r), which characterize its properties, so the shape function and redshift

  • Elliptic Sitnikov five-body problem under radiation pressure
    New Astron. (IF 1.058) Pub Date : 2020-04-17
    M. Shahbaz Ullah; M. Javed Idrisi; Vinay Kumar

    We consider the square configuration of photo-gravitational elliptic restricted five-body problem and study the Sitnikov motions. The four radiating primaries are of equal mass placed at the vertices of square and the fifth body having negligible mass performs oscillations along a straight line perpendicular to the orbital plane of the primaries. The motion of the fifth body is called vertical periodic

  • Effects of electromagnetic field on the stability of locally isotropic gravastars
    New Astron. (IF 1.058) Pub Date : 2020-04-22
    K. Majeed; Z. Yousaf; G. Abbas

    We have studied a new solution of charged gravastars with isotropic matter configuration in the framework of f(R, T) theory of gravity. For this purpose, we have assumed the electric charge as a constant. This stellar structure divided into three different regions: The preliminary part shows the interior charged region in which pressure equals to the negative density, second is the intermediate charged

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