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بررسی حرکات، سرعتها و ویژگیهای ستارگان محلی و در فواصل نزدیک به خورشید راه مناسب و مفیدی است به س... more بررسی حرکات، سرعتها و ویژگیهای ستارگان محلی و در فواصل نزدیک به خورشید راه مناسب و مفیدی است به سوی شناخت ویژگیهای دینامیکی ستارگان کهکشان، سرچشمه دیسک کهکشان و همچنین مراحل مختلف تحول ستارگان. در این زمینه پژوهشهای مختلفی با استفاده از نتایج رصدخانه های بزرگ و کاتالوگهای معتبر نجومی انجام گرفته است. در کار حاضر تلاش گردیده یک نمونه از حرکت ستارگان در نزدیکی خورشید با استفاده از داده های ماهواره Hipparcos بررسی شود. سه جزء سرعت 493 ستاره با فاصله 15 پارسک از خورشید از سرعت انتقالی، سرعت شعاعی و پارالکس آن ها بدست خواهد آمد. همچنین ویژگی های ستارگان محلی از قبیل جرم و توزیع آن در کهکشان، شعاع، دما، موقعیت کهکشانی و رابطه آن ها با سرعت های کهکشانی بررسی شده و در نهایت چگونگی تحول ستارگان در کهکشان پیش بینی شده است.
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yCat, Mar 1, 2020
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Astronomy & Astrophysics, 2020
The INT Galactic Plane Survey (IGAPS) is the merger of the optical photometric surveys, IPHAS and... more The INT Galactic Plane Survey (IGAPS) is the merger of the optical photometric surveys, IPHAS and UVEX, based on data from the Isaac Newton Telescope (INT) obtained between 2003 and 2018. Here, we present the IGAPS point source catalogue. It contains 295.4 million rows providing photometry in the filters, i, r, narrow-band Hα, g, and URGO. The IGAPS footprint fills the Galactic coordinate range, |b| < 5° and 30° < ℓ < 215°. A uniform calibration, referred to as the Pan-STARRS system, is applied to g, r, and i, while the Hα calibration is linked to r and then is reconciled via field overlaps. The astrometry in all five bands has been recalculated in the reference frame of Gaia Data Release 2. Down to i ∼ 20 mag (Vega system), most stars are also detected in g, r, and Hα. As exposures in the r band were obtained in both the IPHAS and UVEX surveys, typically a few years apart, the catalogue includes two distinct r measures, rI and rU. The r 10σ limiting magnitude is approximat...
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ISRN High Energy Physics, 2012
We consider the galactic propagation of cosmic rays with energies below the knee of the cosmic ra... more We consider the galactic propagation of cosmic rays with energies below the knee of the cosmic ray spectrum (at GeV). Lagutin and his colleagues suggested that propagation in a fractal medium would be an appropriate model for such particles and pointed out that a different diffusion equation to that usually assumed is then required. We present results of calculations using a diffusion equation appropriate to an inhomogeneous medium. These results are encouraging and can fit properties of the energy density of cosmic rays using the supernova model of Erlykin and Wolfendale. The containment time of cosmic rays, in such a modeling of propagation in a fractal medium, is discussed.
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Astrophysics and Space Science, 2012
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Serbian Astronomical Journal, 2012
The electron and muon components of extensive air shower (EAS) with energies above 1019 eV are an... more The electron and muon components of extensive air shower (EAS) with energies above 1019 eV are analyzed via various giant EAS arrays. A varying property of showers is observed for two energy ranges; higher and lower than (3 ? 4) x 1019 eV. The age parameter, zenith angle, shower size dependence on muon size and shower size dependence on primary energy show an increment of mass composition (MC) above (3?4)x 1019eV. Comparison of the observed EAS results with the simulations of Capdevielle et al. (2000) and Shinozaki et al. (2005) gives at most 20% photon fraction for primary energies above 1019 eV. The arrival directions of showers above 4x1019 eV indicate an increasing concentration towards the super galactic plane.
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Mass Composition (MC) of Cosmic Rays at high energies is one of the most important issues which a... more Mass Composition (MC) of Cosmic Rays at high energies is one of the most important issues which are significantly related to astrophysical sources. At present work, we have tried to study the spatial parameters, such as age parameter, slope of lateral distribution function of electrons, and muon density of air shower. Each parameter will be discussed separately and also their effect on MC of cosmic rays with energy above 10 18 eV will be considered. The Yakutsk Extensive Air Shower array data was used in our work. Moreover, the present results can be used to distinguish the popular top-down and bottom-up models of astrophysical sources of high energy cosmic rays.
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Mass Composition (MC) of Cosmic Rays at high energies is one of the most important issues which a... more Mass Composition (MC) of Cosmic Rays at high energies is one of the most important issues which are significantly related to astrophysical sources. At present work, we have tried to study the spatial parameters, such as age parameter, slope of lateral distribution function of electrons, and muon density of air shower. Each parameter will be discussed separately and also their effect on MC of cosmic rays with energy above 10eV will be considered. The Yakutsk Extensive Air Shower array data was used in our work. Moreover, the present results can be used to distinguish the popular top-down and bottom-up models of astrophysical sources of high energy cosmic rays.
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New observations of the eclipsing binary system V1848 Ori were carried out using the V filter res... more New observations of the eclipsing binary system V1848 Ori were carried out using the V filter resulting in a determination of new times of minima and new ephemeris were obtained. We presented the first complete analysis of the system’s orbital period behavior and analysis of O-C diagram done by the GA and MCMC approaches in OCFit code. The O-C diagram demonstrates a sinusoidal trend in the data; this trend suggests a cyclic change caused by the LITE effect with a period of 10.57 years and an amplitude of 7.182 minutes. It appears that there is a third body with mass function of f (m3) = 0.0058 M⊙ in this binary system. The light curves were analyzed using the Wilson-Devinney code to determine some geometrical and physical parameters of the system. These results show that V1848 Ori is a contact W UMa binary system with the mass ratio of q = 0.76 and a weak fillout factor of 5.8%. The O’Connell effect was not seen in the light curve and there is no need to add spot.
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The arrival directions of ultra-high energy cosmic rays (UHECR) are considered by using of the da... more The arrival directions of ultra-high energy cosmic rays (UHECR) are considered by using of the data of world extensive air shower (EAS) arrays. It is found that, the arrival directions of showers with energies above 10eV correlate with galactic coordinates of some kind of pulsars. The classification of showers according to their muon component has been done and in comparison with simulation work [1], showers have been divided to the three classes which some of them shows correlation with the galactic coordinates of pulsars. The problem of mass composition and origin of UHECR have been discussed.
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Journal of Physics: Conference Series
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International Journal of Modern Physics D
Unusual and multicore extensive air showers are detected in some experiments. Study of these kind... more Unusual and multicore extensive air showers are detected in some experiments. Study of these kinds of showers is an important issue in nuclear collisions at high energies and need to be interpreted by hadronic interaction models. In the work, taking into account results Sleptsova et al. of which emphasized shower size variations at energies above [Formula: see text][Formula: see text]eV, and also by using of the auger experimental data, some characteristics of multicore events are investigated. Intense nuclear variations are seen in energy range of [Formula: see text]–[Formula: see text][Formula: see text]eV, and nuclear distinctive properties of multicore showers relative to normal showers are shown.
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International Journal of Modern Physics D
Lateral distribution function of extensive air showers of energetic cosmic rays, indicate how sec... more Lateral distribution function of extensive air showers of energetic cosmic rays, indicate how secondary particles spread over a surface detectors. There are many different universal formulas between lateral distribution parameters and shower age parameter which can be used to infer about maximum development of extensive air shower (which is a key parameter to estimate the mass composition of primary cosmic rays). At present work, an estimated percent of mass composition of ultra-high energy cosmic rays is investigated by comparison between Ivanov et al. modeling of simulated data, which has been done by CoRSiKa, and Yakutsk experimental data.
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بررسی حرکات، سرعتها و ویژگیهای ستارگان محلی و در فواصل نزدیک به خورشید راه مناسب و مفیدی است به س... more بررسی حرکات، سرعتها و ویژگیهای ستارگان محلی و در فواصل نزدیک به خورشید راه مناسب و مفیدی است به سوی شناخت ویژگیهای دینامیکی ستارگان کهکشان، سرچشمه دیسک کهکشان و همچنین مراحل مختلف تحول ستارگان. در این زمینه پژوهشهای مختلفی با استفاده از نتایج رصدخانه های بزرگ و کاتالوگهای معتبر نجومی انجام گرفته است. در کار حاضر تلاش گردیده یک نمونه از حرکت ستارگان در نزدیکی خورشید با استفاده از داده های ماهواره Hipparcos بررسی شود. سه جزء سرعت 493 ستاره با فاصله 15 پارسک از خورشید از سرعت انتقالی، سرعت شعاعی و پارالکس آن ها بدست خواهد آمد. همچنین ویژگی های ستارگان محلی از قبیل جرم و توزیع آن در کهکشان، شعاع، دما، موقعیت کهکشانی و رابطه آن ها با سرعت های کهکشانی بررسی شده و در نهایت چگونگی تحول ستارگان در کهکشان پیش بینی شده است.
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yCat, Mar 1, 2020
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Astronomy & Astrophysics, 2020
The INT Galactic Plane Survey (IGAPS) is the merger of the optical photometric surveys, IPHAS and... more The INT Galactic Plane Survey (IGAPS) is the merger of the optical photometric surveys, IPHAS and UVEX, based on data from the Isaac Newton Telescope (INT) obtained between 2003 and 2018. Here, we present the IGAPS point source catalogue. It contains 295.4 million rows providing photometry in the filters, i, r, narrow-band Hα, g, and URGO. The IGAPS footprint fills the Galactic coordinate range, |b| < 5° and 30° < ℓ < 215°. A uniform calibration, referred to as the Pan-STARRS system, is applied to g, r, and i, while the Hα calibration is linked to r and then is reconciled via field overlaps. The astrometry in all five bands has been recalculated in the reference frame of Gaia Data Release 2. Down to i ∼ 20 mag (Vega system), most stars are also detected in g, r, and Hα. As exposures in the r band were obtained in both the IPHAS and UVEX surveys, typically a few years apart, the catalogue includes two distinct r measures, rI and rU. The r 10σ limiting magnitude is approximat...
Bookmarks Related papers MentionsView impact
ISRN High Energy Physics, 2012
We consider the galactic propagation of cosmic rays with energies below the knee of the cosmic ra... more We consider the galactic propagation of cosmic rays with energies below the knee of the cosmic ray spectrum (at GeV). Lagutin and his colleagues suggested that propagation in a fractal medium would be an appropriate model for such particles and pointed out that a different diffusion equation to that usually assumed is then required. We present results of calculations using a diffusion equation appropriate to an inhomogeneous medium. These results are encouraging and can fit properties of the energy density of cosmic rays using the supernova model of Erlykin and Wolfendale. The containment time of cosmic rays, in such a modeling of propagation in a fractal medium, is discussed.
Bookmarks Related papers MentionsView impact
Astrophysics and Space Science, 2012
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Serbian Astronomical Journal, 2012
The electron and muon components of extensive air shower (EAS) with energies above 1019 eV are an... more The electron and muon components of extensive air shower (EAS) with energies above 1019 eV are analyzed via various giant EAS arrays. A varying property of showers is observed for two energy ranges; higher and lower than (3 ? 4) x 1019 eV. The age parameter, zenith angle, shower size dependence on muon size and shower size dependence on primary energy show an increment of mass composition (MC) above (3?4)x 1019eV. Comparison of the observed EAS results with the simulations of Capdevielle et al. (2000) and Shinozaki et al. (2005) gives at most 20% photon fraction for primary energies above 1019 eV. The arrival directions of showers above 4x1019 eV indicate an increasing concentration towards the super galactic plane.
Bookmarks Related papers MentionsView impact
Mass Composition (MC) of Cosmic Rays at high energies is one of the most important issues which a... more Mass Composition (MC) of Cosmic Rays at high energies is one of the most important issues which are significantly related to astrophysical sources. At present work, we have tried to study the spatial parameters, such as age parameter, slope of lateral distribution function of electrons, and muon density of air shower. Each parameter will be discussed separately and also their effect on MC of cosmic rays with energy above 10 18 eV will be considered. The Yakutsk Extensive Air Shower array data was used in our work. Moreover, the present results can be used to distinguish the popular top-down and bottom-up models of astrophysical sources of high energy cosmic rays.
Bookmarks Related papers MentionsView impact
Mass Composition (MC) of Cosmic Rays at high energies is one of the most important issues which a... more Mass Composition (MC) of Cosmic Rays at high energies is one of the most important issues which are significantly related to astrophysical sources. At present work, we have tried to study the spatial parameters, such as age parameter, slope of lateral distribution function of electrons, and muon density of air shower. Each parameter will be discussed separately and also their effect on MC of cosmic rays with energy above 10eV will be considered. The Yakutsk Extensive Air Shower array data was used in our work. Moreover, the present results can be used to distinguish the popular top-down and bottom-up models of astrophysical sources of high energy cosmic rays.
Bookmarks Related papers MentionsView impact
New observations of the eclipsing binary system V1848 Ori were carried out using the V filter res... more New observations of the eclipsing binary system V1848 Ori were carried out using the V filter resulting in a determination of new times of minima and new ephemeris were obtained. We presented the first complete analysis of the system’s orbital period behavior and analysis of O-C diagram done by the GA and MCMC approaches in OCFit code. The O-C diagram demonstrates a sinusoidal trend in the data; this trend suggests a cyclic change caused by the LITE effect with a period of 10.57 years and an amplitude of 7.182 minutes. It appears that there is a third body with mass function of f (m3) = 0.0058 M⊙ in this binary system. The light curves were analyzed using the Wilson-Devinney code to determine some geometrical and physical parameters of the system. These results show that V1848 Ori is a contact W UMa binary system with the mass ratio of q = 0.76 and a weak fillout factor of 5.8%. The O’Connell effect was not seen in the light curve and there is no need to add spot.
Bookmarks Related papers MentionsView impact
The arrival directions of ultra-high energy cosmic rays (UHECR) are considered by using of the da... more The arrival directions of ultra-high energy cosmic rays (UHECR) are considered by using of the data of world extensive air shower (EAS) arrays. It is found that, the arrival directions of showers with energies above 10eV correlate with galactic coordinates of some kind of pulsars. The classification of showers according to their muon component has been done and in comparison with simulation work [1], showers have been divided to the three classes which some of them shows correlation with the galactic coordinates of pulsars. The problem of mass composition and origin of UHECR have been discussed.
Bookmarks Related papers MentionsView impact
Journal of Physics: Conference Series
Bookmarks Related papers MentionsView impact
International Journal of Modern Physics D
Unusual and multicore extensive air showers are detected in some experiments. Study of these kind... more Unusual and multicore extensive air showers are detected in some experiments. Study of these kinds of showers is an important issue in nuclear collisions at high energies and need to be interpreted by hadronic interaction models. In the work, taking into account results Sleptsova et al. of which emphasized shower size variations at energies above [Formula: see text][Formula: see text]eV, and also by using of the auger experimental data, some characteristics of multicore events are investigated. Intense nuclear variations are seen in energy range of [Formula: see text]–[Formula: see text][Formula: see text]eV, and nuclear distinctive properties of multicore showers relative to normal showers are shown.
Bookmarks Related papers MentionsView impact
International Journal of Modern Physics D
Lateral distribution function of extensive air showers of energetic cosmic rays, indicate how sec... more Lateral distribution function of extensive air showers of energetic cosmic rays, indicate how secondary particles spread over a surface detectors. There are many different universal formulas between lateral distribution parameters and shower age parameter which can be used to infer about maximum development of extensive air shower (which is a key parameter to estimate the mass composition of primary cosmic rays). At present work, an estimated percent of mass composition of ultra-high energy cosmic rays is investigated by comparison between Ivanov et al. modeling of simulated data, which has been done by CoRSiKa, and Yakutsk experimental data.
Bookmarks Related papers MentionsView impact