Astrophysics最新文献

{"title":"Swampland Criteria and Neutrino Generation in a Non-Cold Dark Matter Universe","authors":"M. Khurshudyan","doi":"10.1007/s10511-023-09800-3","DOIUrl":"10.1007/s10511-023-09800-3","url":null,"abstract":"<div><div><p>In this paper, the implications of string Swampland criteria for a dark energy-dominated universe, where we have a deviation from the cold dark matter model, will be discussed. In particular, we have considered two models. One of them is one parameter model, while the second one has been crafted to reveal the dynamics in the deviation. The analysis has been obtained through the use of Gaussian processes (GPs) and <i>H</i>(<i>z</i>) expansion rate data (a 30-point sample deduced from a differential age method and a 10- point sample obtained from the radial BAO method). We learned that the tension with the Swampland criteria still will survive as in the cases of the models where dark matter is cold. In the analysis besides mentioned 40-point <i>H</i>(<i>z</i>) data, we used the latest values of <i>H</i>₀ reported by the Planck and Hubble missions to reveal possible solutions for the <i>H</i>₀ tension problem. Finally, the constraints on the neutrino generation number have been obtained revealing interesting results to be discussed yet. This and various related questions have been left to be discussed in forthcoming papers.</p></div></div>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"66 3","pages":"423 - 440"},"PeriodicalIF":0.5,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41087385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface Photometry of 50 Dwarf Galaxies in the Local Volume","authors":"K. A. Kryzhanovsky,&nbsp;M. E. Sharina,&nbsp;I. D. Karachentsev,&nbsp;G. M. Karataeva","doi":"10.1007/s10511-023-09791-1","DOIUrl":"10.1007/s10511-023-09791-1","url":null,"abstract":"<div><div><p>Results of surface photometry of 50 galaxies in the Local Volume based on archived images obtained with the Hubble Space Telescope are presented. Integrated magnitudes in the V and I bands are introduced for the chosen galaxies, along with brightness and color profiles. The obtained photometric parameters are compared with the measurements of other authors.</p></div></div>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"66 3","pages":"291 - 303"},"PeriodicalIF":0.5,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41087380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On a Possible Mechanism for the Start or Resumption of Activity of Radio Galaxies in Clusters of Galaxies","authors":"R. R. Andreasyan,&nbsp;H. V. Abrahamyan,&nbsp;G. M. Paronyan,&nbsp;G. A. Mikayelyan,&nbsp;A. M. Mickaelian","doi":"10.1007/s10511-023-09792-0","DOIUrl":"10.1007/s10511-023-09792-0","url":null,"abstract":"<div><div><p>We study the close proximity of the well-known and well-studied 3C31 class FRI radio galaxy in order to reveal the influence of the environment on an extragalactic radio source. It was shown that about 110 million years ago the galaxies NGC 380 and NGC 386 were located near the galaxy NGC 383 (the parent galaxy of 3C31). On the other hand, the modeling of the spectral characteristics of the radio emission of the central part of the radio galaxy 3C31 gives an estimate of the age of the central jet of about 100 million years. Therefore, it can be assumed that one of the possible reasons for the appearance or resumption of the radioactivity of the galaxy NGC 383 may be a triple close passage of galaxies.</p></div></div>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"66 3","pages":"304 - 310"},"PeriodicalIF":0.5,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41087369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ephemeris Updates for Seven Selected Hatnet Survey Transiting Exoplanets","authors":"A. Poro,&nbsp;F. A. Farahani,&nbsp;E. Jahangiri,&nbsp;A. Sarostad,&nbsp;M. Gozarandi,&nbsp;M. Haghgou,&nbsp;F. Abolhassani,&nbsp;A. Fakhrabadi,&nbsp;Y. Jongen,&nbsp;A. Wünsche,&nbsp;R Naves,&nbsp;P. Guerra,&nbsp;A. Marchini,&nbsp;M. Salisbury,&nbsp;R. Ehrenberger,&nbsp;V-P. Hentunen","doi":"10.1007/s10511-023-09794-y","DOIUrl":"10.1007/s10511-023-09794-y","url":null,"abstract":"<div><div><p>We refined the ephemeris of seven transiting exoplanets HAT-P-6b, HAT-P-12b, HAT-P-18b, HAT-P-22b, HAT-P-32b, HAT-P-33b, and HAT-P-52b. We observed 11 transits from eight observatories in different filters for HAT-P-6b and HAT-P-32b. Also, the Exoplanet Transit Database (ETD) observations for each of the seven exoplanets were analyzed, and the light curves of five systems were studied using Transiting Exoplanet Survey Satellite (TESS) data. We used Exofast-v1 to simulate these ground- and space-based light curves and estimate mid-transit times. We obtained a total of 11, 175 and 67 mid-transit times for these seven exoplanets from our observations, ETD and TESS data, respectively, along with 155 midtransit times from the literature. Then, we generated transit timing variation (TTV) diagrams for each using derived mid-transit times as well as those found in the literature. The systems’ linear ephemeris was then refined and improved using the Markov Chain Monte Carlo (MCMC) method. All of the studied exoplanets, with the exception of the HAT-P-12b system, displayed an increasing trend in the orbital period in the TTV diagrams.</p></div></div>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"66 3","pages":"324 - 343"},"PeriodicalIF":0.5,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41087379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Renyi Holographic Dark Energy and Its Behaviour in f(G) Gravity","authors":"M. K. Alam,&nbsp;S. S. Singh,&nbsp;L. A. Devi","doi":"10.1007/s10511-023-09798-8","DOIUrl":"10.1007/s10511-023-09798-8","url":null,"abstract":"<div><div><p>In this work, the Renyi holographic dark energy (RHDE) and its behaviour has been explored with the anisotropic and spatially homogeneous Bianchi type-I Universe in the framework of <i>f</i> (<i>G</i>) gravity. We use IR cutoff as the Hubble and Granda-Oliveros (GO) horizons. To find a consistent solutions of the field equations of the models, it is assumed that the deceleration parameter is defined in terms of function of Hubble parameter <i>H</i>. With reference to current cosmological data, the behaviors of the cosmological parameters relating to the dark energy model are evaluated and their physical significance is examined. It is observed that for both the models, the equation of state parameter approaches to -1 at late times. However, the RHDE model with the Hubble horizon exhibits stability from the squared sound speed, but the RHDE model with the GO horizon exhibits instability. In both the models, deceleration parameter and statefinder diagnostic confirm the accelerated expansion of the Universe and also correspond to the ΛCDM model at late times.</p></div></div>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"66 3","pages":"383 - 410"},"PeriodicalIF":0.5,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41087386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plane Symmetric String Cosmological Model with Zero Mass Scalar Field in f (R) Gravity","authors":"Kalpana Pawar,&nbsp;A. K. Dabre,&nbsp;Pallavi Makode","doi":"10.1007/s10511-023-09796-w","DOIUrl":"10.1007/s10511-023-09796-w","url":null,"abstract":"<div><div><p>In this article, an anisotropic Locally Rotationally Symmetric (LRS) Bianchi type I metric in the presence of cloud string fluid and zero mass scalar field in reference to <i>f</i> (<i>R</i>) gravity have been investigated. To obtain the deterministic solutions we assumed the weak field limit for a point-like source <i>f</i> (<i>R</i>) = <i>R</i>^3/2 and the very well-known expansion-shear scalar proportionality relation. Furthermore, some physical and kinematical parameters have been calculated to study the astrophysical consequences of obtained model, which shows a good resemblance to the recent observational data.</p></div></div>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"66 3","pages":"353 - 365"},"PeriodicalIF":0.5,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41087373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Поверхностная фотометрия 50 карликовых галактик в местном объеме","authors":"К. А. Крыжановский, М. Е. Шарина, Игорь Дмитриевич Караченцев, Г. М. Каратаева","doi":"10.54503/0571-7132-2023.66.3-317","DOIUrl":"https://doi.org/10.54503/0571-7132-2023.66.3-317","url":null,"abstract":"Представлены результаты поверхностной фотометрии 50-ти галактик в Местном объеме на основе архивных изображений, полученных на космическом телескопе Хаббла. Для выборки галактик приводятся интегральные величины в полосах V и I, а также профили яркости и цвета. Проведено сравнение полученных фотометрических параметров с измерениями других авторов.\u0000The results of surface photometry of 50 galaxies in the Local Volume based on archival images obtained with the Hubble Space Telescope are presented. For the sample of galaxies, the integrated magnitudes in the V and I bands are given, as well as the brightness and color profiles. The obtained photometric parameters are compared with the measurements of other authors.","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"44 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74955448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Движение частицы в поле бесконечного плоского слоя","authors":"Р. М. Авакян, А. А. Саарян, С. С. Джибилян","doi":"10.54503/0571-7132-2023.66.3-441","DOIUrl":"https://doi.org/10.54503/0571-7132-2023.66.3-441","url":null,"abstract":"В настоящей работе в рамках общей теории относительности исследуется движение светового сигнала и пробной частицы в поле бесконечного плоского слоя. Рассмотрены оба случая внешнего решения для гравитационного поля в вакууме, соответствующие метрикам Риндлера и Тауба. Определяются время движения и путь, пройденный частицей до ее остановки. Показано, что в геометрии Тауба, в отличие от светового сигнала, материальная частица не достигает сингулярности. Определено минимальное расстояние от сингулярности в зависимости от энергии частицы. Для сравнения приводятся результаты в рамках специальной теории относительности.\u0000In this paper we investigate the motion of a light signal and a test particle in the field of an infinite flat slab within the framework of the general relativity. Both cases of the external solution for the gravitational field in the vacuum, corresponding to the Rindler and Taub metrics, are considered. The time of motion and the path traveled by the particle before it stops are determined. It is shown that in the Taub geometry, in contrast to the light signal, a material particle does not reach a singularity. The minimum distance from the singularity is determined depending on the energy of the particle. For comparison, results are given within the framework of the special relativity.","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"46 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84644040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Активность молодой звезды EPIC 204376071 из ассоциации Upper Sco","authors":"И. С. Саванов","doi":"10.54503/0571-7132-2023.66.3-373","DOIUrl":"https://doi.org/10.54503/0571-7132-2023.66.3-373","url":null,"abstract":"По наблюдениям миссии К2 космического телескопа Кеплер выполнено исследование активности EPIC 204376071-молодого объекта, члена ассоциации Upper Sco с возрастом 11±3 млн лет, кривая блеска которого обладает единичным затмением суточной продолжительности с глубиной около 80%. EPIC 204376071 является маломассивным М-карликом с массой 0.16 M . По наблюдениям кампании С15 миссии К2 мы уточнили период вращения и амплитуду переменности блеска звезды, а также по стандартной методике оценили величину параметра запятненности A в абсолютной мере. Величина периода вращения звезды Р равна 1.6270 ±0.030 сут. Площадь пятен на поверхности EPIC 204376071 превосходит максимальную площадь пятен на Солнце и составляет величину порядка 7900 м.д.п. Представлены результаты восстановления температурных неоднородностей на поверхности EPIC 204376071. На построенной карте хорошо различимы две холодные области, разделенные по долготе примерно на 150o. Для оценки свойств вспышечной активности EPIC 204376071 была рассмотрена одна наиболее достоверная вспышка с амплитудой блеска около 4%.\u0000Using the observations of the K2 mission of the Kepler Space Telescope we studied the activity of EPIC 204376071 - a young object in the Upper Sco association with the age of 11 ± 3 million years, whose light curve has a single occultation of daily duration with a depth of about 80%. EPIC 204376071 is a M-dwarf of mass 0.16  M . On the base on the observations of the C15 campaign of the K2 mission we estimated the rotation period, amplitude of the variability of the brightness of the star and the spottedness parameter A in absolute measure using the standard method. The magnitude of the rotation period of the star P is 1.6270 ± 0.030 days. The area of spots on the surface of EPIC 204376071 exceeds the maximum area of spots on the Sun and is about 7900 MSH. The results of the restoration of temperature inhomogeneities on the surface of EPIC 204376071 are presented. Two cool regions separated in longitude by about 150o are clearly distinguishable on the constructed map. Characteristics stellar flare activity are estimated on the base of one of the most reliable flare. The flare amplitude is about 4%. The measured relative energy RE of the flare was 212 sec. The calculated energy of the flare Efl equal to 1.1·1034 erg (logEfl = 34.05). The corresponding probable value of the coronal mass ejection can reach 4.1·1020 g. Possible explanations of a single occultation of 1-day duration with a depth of about 80% on the EPIC 204376071 light curve are discussed.","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"39 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85494454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Environmental Dependence of Different Colors of Active Galactic Nucleus (AGN) Host Galaxies","authors":"Xin-Fa Deng,&nbsp;Zhi-Yong Wu","doi":"10.1007/s10511-023-09790-2","DOIUrl":"10.1007/s10511-023-09790-2","url":null,"abstract":"<div><div><p>Using the apparent-magnitude limited active galactic nucleus (AGN) host galaxy sample of the Sloan Digital Sky Survey Data Release 12 (SDSS DR12), we investigate the environmental dependence of the u-r, u-g, g-r, r-i and i-z colors of AGN host galaxies. We divide the whole apparent-magnitude limited AGN sample into many subsamples with a redshift binning size of ?z = 0.01, and analyze the environmental dependence of all five galaxy colors of subsamples in each redshift bin. It turns out that overall, all five galaxy colors of AGN host galaxies are weakly correlated with the local environment.</p></div></div>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"66 2","pages":"173 - 180"},"PeriodicalIF":0.5,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4113374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}