Pub Date : 2024-02-01DOI: 10.1016/j.newast.2024.102198
M. Sharif , M. Sallah
This paper uses the gravitational decoupling through the minimal geometric deformation approach and extends a known isotropic solution for a self-gravitating interior to two types of anisotropic spherical solutions in Rastall gravity in the presence of electromagnetic field. By deforming only the radial metric component, the field equations are decoupled into two sets, the first of which corresponds to an isotropic distribution of matter while the second set contains the anisotropic source. We obtain a solution of the first set by employing the charged isotropic Finch-Skea ansatz, whereas a solution for the second set is obtained by adopting two mimic constraints on the pressure and density. The matching conditions at the stellar surface are explored with the exterior geometry given by the deformed Reissner–Nordström spacetime. For the two fixed values of the Rastall and charge parameters, we investigate physical features of both solutions through graphical analysis of the energy conditions, equation of state parameters, surface redshift and compactness function. The stability of both solutions is also studied through the Herrera cracking approach and causality condition. We deduce that while both solutions are physically viable, only the solution corresponding to the pressure-like constraint is stable.
{"title":"Decoupled charged anisotropic spherical solutions in Rastall gravity","authors":"M. Sharif , M. Sallah","doi":"10.1016/j.newast.2024.102198","DOIUrl":"10.1016/j.newast.2024.102198","url":null,"abstract":"<div><p>This paper uses the gravitational decoupling through the minimal geometric deformation approach and extends a known isotropic solution for a self-gravitating interior to two types of anisotropic spherical solutions in Rastall gravity in the presence of electromagnetic field<span>. By deforming only the radial metric component, the field equations are decoupled into two sets, the first of which corresponds to an isotropic distribution of matter while the second set contains the anisotropic source. We obtain a solution of the first set by employing the charged isotropic Finch-Skea ansatz, whereas a solution for the second set is obtained by adopting two mimic constraints on the pressure and density. The matching conditions at the stellar surface<span> are explored with the exterior geometry given by the deformed Reissner–Nordström spacetime. For the two fixed values of the Rastall and charge parameters, we investigate physical features of both solutions through graphical analysis of the energy conditions, equation of state parameters, surface redshift and compactness function. The stability of both solutions is also studied through the Herrera cracking approach and causality condition. We deduce that while both solutions are physically viable, only the solution corresponding to the pressure-like constraint is stable.</span></span></p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139666613","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}
Pub Date : 2024-01-28DOI: 10.1016/j.newast.2024.102199
Arijit Manna, Sabyasachi Pal
The search for the simplest amino acid, glycine (), in the interstellar medium (ISM) has become a never-ending story for astrochemistry and astrophysics researchers because that molecule plays a possible connection between the Universe and the origin of life. In the last forty years, all searches for in the ISM at millimeter and submillimeter wavelengths have failed. Since the detection of in the ISM is extremely difficult, we aime to search for the possible precursors of . Earlier, many laboratory experiments have suggested that methylamine () plays an important role in the ISM as a possible precursor of . After spectral analysis using the local thermodynamic equilibrium (LTE) model, we identified the rotational emission lines of towards the hot molecular core G358.93–0.03 MM1 using the Atacama Large Millimeter/Submillimeter Array (ALMA). The column density of towards the G358.93–0.03 MM1 is estimated to be (1.10 ± 0.31)1017 cm−2 with an excitation temperature of 180.8 ± 25.5 K. The fractional abundance of with respect to towards the G358.93–0.03 MM1 is (8.80 ± 2.60)10−8. The column density ratio of and towards G358.93–0.03 MM1 is (1.86 ± 0.95)102. The estimated fractional abundance of towards the G358.93–0.03 MM1 agrees fairly well with the previous three-phase warm-up chemical modelling abundance of . We also discuss the possible formation mechanism of , and we find that is most probably formed via the reactions of radical and radical on the grain surface of G358.93–0.03 MM1.
{"title":"Detection of possible glycine precursor molecule methylamine towards the hot molecular core G358.93–0.03 MM1","authors":"Arijit Manna, Sabyasachi Pal","doi":"10.1016/j.newast.2024.102199","DOIUrl":"10.1016/j.newast.2024.102199","url":null,"abstract":"<div><p>The search for the simplest amino acid, glycine (<span><math><mrow><mtext>NH2CH2COOH</mtext></mrow></math></span><span><span>), in the interstellar medium (ISM) has become a never-ending story for </span>astrochemistry and astrophysics researchers because that molecule plays a possible connection between the Universe and the origin of life. In the last forty years, all searches for </span><span><math><mrow><mtext>NH2CH2COOH</mtext></mrow></math></span> in the ISM at millimeter and submillimeter wavelengths have failed. Since the detection of <span><math><mrow><mtext>NH2CH2COOH</mtext></mrow></math></span> in the ISM is extremely difficult, we aime to search for the possible precursors of <span><math><mrow><mtext>NH2CH2COOH</mtext></mrow></math></span>. Earlier, many laboratory experiments have suggested that methylamine (<span><math><mrow><mtext>CH3NH2</mtext></mrow></math></span>) plays an important role in the ISM as a possible precursor of <span><math><mrow><mtext>NH2CH2COOH</mtext></mrow></math></span><span>. After spectral analysis using the local thermodynamic equilibrium (LTE) model, we identified the rotational emission lines of </span><span><math><mrow><mtext>CH3NH2</mtext></mrow></math></span> towards the hot molecular core G358.93–0.03 MM1 using the Atacama Large Millimeter/Submillimeter Array (ALMA). The column density of <span><math><mrow><mtext>CH3NH2</mtext></mrow></math></span> towards the G358.93–0.03 MM1 is estimated to be (1.10 ± 0.31)<span><math><mo>×</mo></math></span>10<sup>17</sup> cm<sup>−2</sup> with an excitation temperature of 180.8 ± 25.5 K. The fractional abundance of <span><math><mrow><mtext>CH3NH2</mtext></mrow></math></span> with respect to <span><math><mrow><mtext>H2</mtext></mrow></math></span> towards the G358.93–0.03 MM1 is (8.80 ± 2.60)<span><math><mo>×</mo></math></span>10<sup>−8</sup>. The column density ratio of <span><math><mrow><mtext>CH3NH2</mtext></mrow></math></span> and <span><math><mrow><mtext>NH2CN</mtext></mrow></math></span> towards G358.93–0.03 MM1 is (1.86 ± 0.95)<span><math><mo>×</mo></math></span>10<sup>2</sup>. The estimated fractional abundance of <span><math><mrow><mtext>CH3NH2</mtext></mrow></math></span> towards the G358.93–0.03 MM1 agrees fairly well with the previous three-phase warm-up chemical modelling abundance of <span><math><mrow><mtext>CH3NH2</mtext></mrow></math></span>. We also discuss the possible formation mechanism of <span><math><mrow><mtext>CH3NH2</mtext></mrow></math></span>, and we find that <span><math><mrow><mtext>CH3NH2</mtext></mrow></math></span> is most probably formed via the reactions of radical <span><math><mrow><mtext>CH3</mtext></mrow></math></span> and radical <span><math><mrow><mtext>NH2</mtext></mrow></math></span> on the grain surface of G358.93–0.03 MM1.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139587992","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}
Pub Date : 2024-01-28DOI: 10.1016/j.newast.2024.102195
Vikash Kumar Sinha, Prashanth Maroju
In this article, we introduce an efficient numerical approach for finding the numerical solution for coupled Lane–Emden–Fower type equations using the variational iteration method combined with the Adomian polynomial. The convergence analysis of the proposed approach is investigated under very general conditions. A couple of numerical examples are included and contrasted with the existing methods (Singh et al., 2021;Sinha et al., 2023;Duan et al., 2015) and the exact solution to check the robustness and effectiveness of the proposed approach. The present method shows faster convergence, computational efficiency, time efficiency and simplicity of implementation.
{"title":"Numerical solution of the coupled Lane–Emden–Fowler type equation using the variational iteration method and the Adomian polynomial","authors":"Vikash Kumar Sinha, Prashanth Maroju","doi":"10.1016/j.newast.2024.102195","DOIUrl":"10.1016/j.newast.2024.102195","url":null,"abstract":"<div><p>In this article, we introduce an efficient numerical approach for finding the numerical solution for coupled Lane–Emden–Fower type equations using the variational iteration method combined with the Adomian polynomial. The convergence analysis of the proposed approach is investigated under very general conditions. A couple of numerical examples are included and contrasted with the existing methods (Singh et al., 2021;Sinha et al., 2023;Duan et al., 2015) and the exact solution to check the robustness and effectiveness of the proposed approach. The present method shows faster convergence, computational efficiency, time efficiency and simplicity of implementation.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139587958","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}
Pub Date : 2024-01-26DOI: 10.1016/j.newast.2024.102194
Yashan Hettiarachchi , Janaka Adassuriya , Chandana Jayaratne , Sasani Jayawardhana , Christian Monstein
Solar radio bursts are sudden peaks in the low-frequency radio emissions originating from the sun. These emissions, while revealing important insights into underlying physical mechanisms in solar physics, can also help predict space weather events that could have adverse effects on satellite communications and the global energy grid. A thorough understanding of this phenomena demands the collection and analysis of solar emission data over vast geographical and time scales. In this regard, the e-CALLISTO network plays a major role through having already archived more than 20 years worth of solar radio burst data. Leveraging on the advances in data analysis techniques, this data can be used to review the statistical significance of burst properties of type II and type III solar radio bursts and hence more importantly the magnetic field measurements of the active regions. In order to process the e-CALLISTO data, a software containing several data reduction processes is introduced to optimize the data analysis via a graphical user interface (GUI). The program is capable of reading out data from any CALLISTO receiving station, while offering visualization capabilities such as the color-corrected spectrum view, the plot of frequencies of the highest intensity, the individual frequency spectrum, the solar burst isolation portal, the fitting model for the radio burst, and the drift rate curve of the burst. These are achieved through using the raw “fits” files of spectra to perform background RFI reduction, identify and isolate solar radio burst regions, model the peak frequency variation using curve fitting, and thereby determine the frequency drift rates. The method can be directly applied to Type II and III solar bursts while providing space for tailoring and modification. In this work, the slow drift type II radio bursts were fitted by exponential decay and the fast drift type III radio bursts were approximated as linear decay. Hence, the frequency drift rates were computed for type II and type III radio bursts. The application is used to analyze several Type II and Type III solar radio bursts and depending on the bust type shock speed and electron velocity were determined. The GUI interface eliminates the time-consuming subjective manual analysis of e-CALLISTO data thereby making the analysis of solar radio bursts a routine and rapid process.
太阳射电暴是源自太阳的低频射电辐射的突然峰值。这些辐射揭示了太阳物理学的基本物理机制,同时也有助于预测可能对卫星通信和全球能源网产生不利影响的空间天气事件。要彻底了解这一现象,就必须收集和分析巨大地理和时间尺度上的太阳辐射数据。在这方面,e-CALLISTO 网络发挥了重要作用,因为它已经将 20 多年的太阳射电暴数据存档。利用数据分析技术的进步,这些数据可用于审查 II 型和 III 型太阳射电暴的暴发特性的统计意义,从而更重要地审查活动区的磁场测量。为了处理 e-CALLISTO 数据,引入了一个包含多个数据还原过程的软件,通过图形用户界面(GUI)优化数据分析。该软件能够从任何一个 CALLISTO 接收站读取数据,同时提供可视化功能,如彩色校正频谱视图、最高强度频率图、单个频谱、太阳爆发隔离门户、无线电爆发拟合模型和爆发漂移率曲线。这些都是通过使用原始的 "拟合 "频谱文件来减少背景射频干扰、识别和隔离太阳射电暴区域、使用曲线拟合建立峰值频率变化模型,从而确定频率漂移率来实现的。该方法可直接应用于 II 型和 III 型太阳射电暴,同时提供了定制和修改的空间。在这项工作中,慢漂移 II 型射电暴采用指数衰减拟合,快漂移 III 型射电暴近似采用线性衰减拟合。因此,计算出了 II 型和 III 型射电暴的频率漂移率。该应用软件用于分析多个 II 类和 III 类太阳射电暴,并根据不同的射电暴类型确定冲击速度和电子速度。图形用户界面省去了对 e-CALLISTO 数据进行耗时的主观手工分析,从而使太阳射电暴分析成为一个常规和快速的过程。
{"title":"The analysis of type II and type III solar radio bursts: GUI for the e-CALLISTO data","authors":"Yashan Hettiarachchi , Janaka Adassuriya , Chandana Jayaratne , Sasani Jayawardhana , Christian Monstein","doi":"10.1016/j.newast.2024.102194","DOIUrl":"10.1016/j.newast.2024.102194","url":null,"abstract":"<div><p>Solar radio bursts are sudden peaks in the low-frequency radio emissions originating from the sun. These emissions, while revealing important insights into underlying physical mechanisms in solar physics, can also help predict space weather<span><span><span> events that could have adverse effects on satellite communications and the global energy grid. A thorough understanding of this phenomena demands the collection and analysis of solar emission data over vast geographical and time scales. In this regard, the e-CALLISTO network plays a major role through having already archived more than 20 years worth of solar radio burst data. Leveraging on the advances in data analysis techniques, this data can be used to review the statistical significance of burst properties of type II and type III solar radio bursts and hence more importantly the magnetic field measurements of the active regions. In order to process the e-CALLISTO data, a software containing several </span>data reduction processes is introduced to optimize the data analysis via a graphical user interface (GUI). The program is capable of reading out data from any CALLISTO receiving station, while offering visualization capabilities such as the color-corrected spectrum view, the plot of frequencies of the highest intensity, the individual frequency spectrum, the solar burst isolation portal, the fitting model for the radio burst, and the drift rate curve of the burst. These are achieved through using the raw “fits” files of spectra to perform background </span>RFI reduction, identify and isolate solar radio burst regions, model the peak frequency variation using curve fitting, and thereby determine the frequency drift rates. The method can be directly applied to Type II and III solar bursts while providing space for tailoring and modification. In this work, the slow drift type II radio bursts were fitted by exponential decay and the fast drift type III radio bursts were approximated as linear decay. Hence, the frequency drift rates were computed for type II and type III radio bursts. The application is used to analyze several Type II and Type III solar radio bursts and depending on the bust type shock speed and electron velocity were determined. The GUI interface eliminates the time-consuming subjective manual analysis of e-CALLISTO data thereby making the analysis of solar radio bursts a routine and rapid process.</span></p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139587959","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}
Pub Date : 2024-01-26DOI: 10.1016/j.newast.2024.102197
Y.H. Chen
LAMOST DR10 low resolution catalog (LRC) v1.0 has released 7,478,650 AFGK type stars with corresponding parameters and small parameter errors. These spectra are observed from October 2011 to July 2022. These AFGK stars are a large sample with very small stellar parameter errors, which are very suitable for statistical research work. The stars with [Fe/H] from -2.5 to -2.0, -1.5 to -1.3, and 0.5 to 1.0 were selected as representations for a statistical research. We analyze these stars with the distribution of effective temperature and surface gravity. In addition, we perform a cross-match research between our samples and the red giant branch (RGB) stars and red clump (RC) stars identified by Wang et al. Some low mass stars and medium mass stars are evolved using the stellar evolution code MESA. The calculated theoretical results are compared with the observed statistical data. Most of the stars are main-sequence (MS) stars with log around 4.0. The other stars are probably RGB stars or RC stars with log 3.0. The very metal-poor stars ([Fe/H] from -2.5 to -2.0) probably are -generation stars with a small value of , which can help us to study the early universe. The stars with [Fe/H] from 0.5 to 1.0 are super metal-rich stars, which probably are -generation stars with a large value of . There is a gap around log = 3.8 for the super metal-rich stars, which corresponds to the MS stars around 1.2 . This will help us to study the formation process of super metal-rich stars. Rich observational data will greatly enhance our understanding to the truth of the universe.
{"title":"The preliminary statistical analysis of LAMOST DR10 low resolution AFGK stars based on different metal abundances","authors":"Y.H. Chen","doi":"10.1016/j.newast.2024.102197","DOIUrl":"10.1016/j.newast.2024.102197","url":null,"abstract":"<div><p>LAMOST DR10 low resolution catalog (LRC) v1.0 has released 7,478,650 AFGK type stars with corresponding parameters and small parameter errors. These spectra are observed from October 2011 to July 2022. These AFGK stars are a large sample with very small stellar parameter errors, which are very suitable for statistical research work. The stars with [Fe/H] from -2.5 to -2.0, -1.5 to -1.3, and 0.5 to 1.0 were selected as representations for a statistical research. We analyze these stars with the distribution of effective temperature and surface gravity. In addition, we perform a cross-match research between our samples and the red giant branch (RGB) stars and red clump (RC) stars identified by Wang et al. Some low mass stars and medium mass stars are evolved using the stellar evolution code MESA. The calculated theoretical results are compared with the observed statistical data. Most of the stars are main-sequence (MS) stars with log<span><math><mi>g</mi></math></span> around 4.0. The other stars are probably RGB stars or RC stars with log<span><math><mi>g</mi></math></span> <span><math><mo>≤</mo></math></span> 3.0. The very metal-poor stars ([Fe/H] from -2.5 to -2.0) probably are <span><math><mi>n</mi></math></span>-generation stars with a small value of <span><math><mi>n</mi></math></span>, which can help us to study the early universe. The stars with [Fe/H] from 0.5 to 1.0 are super metal-rich stars, which probably are <span><math><mi>n</mi></math></span>-generation stars with a large value of <span><math><mi>n</mi></math></span>. There is a gap around log<span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>e</mi><mi>f</mi><mi>f</mi></mrow></msub></math></span> = 3.8 for the super metal-rich stars, which corresponds to the MS stars around 1.2<!--> <span><math><msub><mrow><mi>M</mi></mrow><mrow><mo>⨀</mo></mrow></msub></math></span>. This will help us to study the formation process of super metal-rich stars. Rich observational data will greatly enhance our understanding to the truth of the universe.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1384107624000113/pdfft?md5=78b9b61b60159daf32b280da519072ea&pid=1-s2.0-S1384107624000113-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139587961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We study the Morris-Thorne traversable asymptotically flat and non-flat wormholes in the galactic halo of the Milky Way Galaxy(MWG) based on the Einasto dark matter(DM) density profile. Our reported shape function is positive and increasing in nature, moreover, satisfies all the essential wormhole representing conditions i.e. the reported shape function forms wormhole like structures in the galactic halo region of the MWG. Furthermore, the wormhole containing the DM candidate of the halo shelters wormholes by violating the null energy condition(NEC) with respect to three different redshift functions. The wormholes, namely, WH1 and WH2 corresponding to the first two choices of redshift functions are asymptotically flat while the WH3 corresponding to the third choice of redshift function is asymptotically non-flat. We, here, also analyze the ANEC violating matter content, embedding surface, and proper radial distance for our solutions.
{"title":"Dark matter supporting traversable wormholes in the Galactic halo","authors":"Susmita Sarkar , Nayan Sarkar , Somi Aktar , Moumita Sarkar , Farook Rahaman , Anil Kumar Yadav","doi":"10.1016/j.newast.2023.102183","DOIUrl":"10.1016/j.newast.2023.102183","url":null,"abstract":"<div><p>We study the Morris-Thorne traversable asymptotically flat and non-flat wormholes in the galactic halo of the Milky Way Galaxy(MWG) based on the Einasto dark matter(DM) density profile. Our reported shape function is positive and increasing in nature, moreover, satisfies all the essential wormhole representing conditions i.e. the reported shape function forms wormhole like structures in the galactic halo region of the MWG. Furthermore, the wormhole containing the DM candidate of the halo shelters wormholes by violating the null energy condition(NEC) with respect to three different redshift functions. The wormholes, namely, WH1 and WH2 corresponding to the first two choices of redshift functions are asymptotically flat while the WH3 corresponding to the third choice of redshift function is asymptotically non-flat. We, here, also analyze the ANEC violating matter content, embedding surface, and proper radial distance for our solutions.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139538096","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}
Pub Date : 2024-01-11DOI: 10.1016/j.newast.2023.102186
Yutong Chen , Tingfeng Yi , Junping Chen , He Lu , Yuncai Shen , Junjie Wang , Liang Wang , Shun Zhang , Lisheng Mao , Liang Dong
The blazar PG 1553+113 is hypothesized to harbor a supermassive black hole binary system, a scenario that aligns with its observed physical characteristics. In this study, we re-examine the authenticity of the periodicity of PG 1553+113 by conducting a comprehensive analysis of multi-wavebands periodic light variations, using the updated light curve data of more than 15 years. We used two methods to search for the light curves data of this blazar in -ray, -ray, optical and radio bands. The multi-wavebands analysis approach enables a thorough verification of the observed periodic patterns. The result of -ray detection showed a quasi-periodic oscillation (QPO) of 2.16 years, which verified the results given by Ackermann et al. (2015). And the optical band shows a QPO of 2.24 years. We analyzed the correlation among -ray, optical and radio bands, and we found that there is a strong correlation among them, and the emission of different bands coming from the same region (the same electron group). Finally, we estimated the black hole mass of PG 1553+113 to be based on the binary black hole model.
{"title":"Revisiting the quasi-periodic oscillations in blazar PG 1553+113 with multi-wavebands data","authors":"Yutong Chen , Tingfeng Yi , Junping Chen , He Lu , Yuncai Shen , Junjie Wang , Liang Wang , Shun Zhang , Lisheng Mao , Liang Dong","doi":"10.1016/j.newast.2023.102186","DOIUrl":"10.1016/j.newast.2023.102186","url":null,"abstract":"<div><p><span>The blazar PG 1553+113 is hypothesized to harbor a supermassive black hole binary system, a scenario that aligns with its observed physical characteristics. In this study, we re-examine the authenticity of the periodicity of PG 1553+113 by conducting a comprehensive analysis of multi-wavebands periodic light variations, using the updated light curve data of more than 15 years. We used two methods to search for the light curves data of this blazar in </span><span><math><mi>γ</mi></math></span>-ray, <span><math><mi>X</mi></math></span>-ray, optical and radio bands. The multi-wavebands analysis approach enables a thorough verification of the observed periodic patterns. The result of <span><math><mi>γ</mi></math></span>-ray detection showed a quasi-periodic oscillation (QPO) of 2.16 years, which verified the results given by Ackermann et al. (2015). And the optical band shows a QPO of 2.24 years. We analyzed the correlation among <span><math><mi>γ</mi></math></span>-ray, optical and radio bands, and we found that there is a strong correlation among them, and the emission of different bands coming from the same region (the same electron group). Finally, we estimated the black hole mass of PG 1553+113 to be <span><math><mrow><mi>M</mi><mo>≃</mo><mn>4</mn><mo>.</mo><mn>3</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>9</mn></mrow></msup><mspace></mspace><msub><mrow><mi>M</mi></mrow><mrow><mo>⨀</mo></mrow></msub></mrow></math></span> based on the binary black hole model.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139456928","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}
Pub Date : 2024-01-05DOI: 10.1016/j.newast.2024.102187
S K Narasimhamurthy, Praveen J
This present work delves into the study of cosmological constant roll inflation, approaching it through the lens of Finsler-Barthel-Kropina geometry. This novel framework explains the conventional understanding of the large-scale structure of universe's homogeneity and isotropy with small-scale presence of anisotropy. The methodology employed in this work involves translating the concept of osculating Riemannian space into the context of Finsler spaces. By harnessing the unique metric structure of Kropina space, the primary focus is on unravelling the intricacies of the inflationary phenomenon. The study reveals that by introducing the anisotropic parameter into the metric structure and Hubble parameter, a comprehensive explanation for the anisotropic expansion of the universe can be achieved. Through a careful analysis of slow roll parameters, the research delves into the dynamics of inflation on a macroscopic scale, shedding light on the influence of anisotropy on both scalar and tensor perturbations within the power spectrum. Ultimately, the core aim of this study is to establish that the Finslerian analogy of inflation finds a coherent explanation within the framework of Kropina geometry.
{"title":"Cosmological constant roll of inflation within Finsler-barthel-Kropina geometry: A geometric approach to early universe dynamics","authors":"S K Narasimhamurthy, Praveen J","doi":"10.1016/j.newast.2024.102187","DOIUrl":"10.1016/j.newast.2024.102187","url":null,"abstract":"<div><p>This present work delves into the study of cosmological constant roll inflation, approaching it through the lens of Finsler-Barthel-Kropina geometry. This novel framework explains the conventional understanding of the large-scale structure of universe's homogeneity and isotropy with small-scale presence of anisotropy. The methodology employed in this work involves translating the concept of osculating Riemannian space into the context of Finsler spaces. By harnessing the unique metric structure of Kropina space, the primary focus is on unravelling the intricacies of the inflationary phenomenon. The study reveals that by introducing the anisotropic parameter <span><math><mi>η</mi></math></span> into the metric structure and Hubble parameter, a comprehensive explanation for the anisotropic expansion of the universe can be achieved. Through a careful analysis of slow roll parameters, the research delves into the dynamics of inflation on a macroscopic scale, shedding light on the influence of anisotropy on both scalar and tensor perturbations within the power spectrum. Ultimately, the core aim of this study is to establish that the Finslerian analogy of inflation finds a coherent explanation within the framework of Kropina geometry.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139375586","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}
Pub Date : 2024-01-04DOI: 10.1016/j.newast.2023.102184
M. Sharif, Saba Naz
This paper presents complexity measure of a dynamical spherical configuration with anisotropic distribution in energy–momentum squared gravity. The self-gravitating bodies become complex due to non-uniform energy density, asymmetrical pressure, heat loss and contribution of modified terms. By orthogonally decomposing the Riemann tensor, we analyze the structure scalars and obtain the complexity factor that accounts for all the fundamental characteristics of the system. Furthermore, by using the homologous mode as the simplest pattern of evolution, we study the dynamics of the celestial configuration. We also discuss dissipative/non-dissipative fluids in the context of homologous and complexity-free cases. Finally, we investigate a criterion for which the complexity-free condition remains stable throughout evolutionary process. It is concluded that the contribution of product as well as squared components of the considered framework leads to a more complex system.
{"title":"Complexity of dynamical spherical system in f(R,T2) gravity","authors":"M. Sharif, Saba Naz","doi":"10.1016/j.newast.2023.102184","DOIUrl":"10.1016/j.newast.2023.102184","url":null,"abstract":"<div><p>This paper presents complexity measure of a dynamical spherical configuration with anisotropic distribution in energy–momentum squared gravity. The self-gravitating bodies become complex due to non-uniform energy density, asymmetrical pressure, heat loss and contribution of modified terms. By orthogonally decomposing the Riemann tensor, we analyze the structure scalars and obtain the complexity factor that accounts for all the fundamental characteristics of the system. Furthermore, by using the homologous mode as the simplest pattern of evolution, we study the dynamics of the celestial configuration. We also discuss dissipative/non-dissipative fluids in the context of homologous and complexity-free cases. Finally, we investigate a criterion for which the complexity-free condition remains stable throughout evolutionary process. It is concluded that the contribution of product as well as squared components of the considered framework leads to a more complex system.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139102568","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}
Pub Date : 2024-01-03DOI: 10.1016/j.newast.2023.102185
Farzan Mushtaq , Xia Tiecheng , Allah Ditta , Farruh Atamurotov , Alisher Abduvokhidov , Alimova Asalkhon
This paper is suggested to analyze the gravitational weak lensing and fundamental frequencies in the framework of the Einstein–Euler–Heisenberg (EEH) black hole. We compute the deflection angle of light by the EEH black hole in weak field limits. Which represents that the bending of light is a global and topological effect. For this purpose, we deduce the Gaussian curvature and apply the Gauss–Bonnet theorem (GBT). Furthermore, we determine the deflection angle at which light is deflected by a plasma medium. We also look into how an EEH black hole behaves graphically in vacuum and plasma medium. Moreover, we study the fundamental frequencies with three different models of EEH black hole.
{"title":"Weak gravitational lensing and fundamental frequencies of Einstein–Euler–Heisenberg black hole","authors":"Farzan Mushtaq , Xia Tiecheng , Allah Ditta , Farruh Atamurotov , Alisher Abduvokhidov , Alimova Asalkhon","doi":"10.1016/j.newast.2023.102185","DOIUrl":"10.1016/j.newast.2023.102185","url":null,"abstract":"<div><p>This paper is suggested to analyze the gravitational weak lensing and fundamental frequencies in the framework of the Einstein–Euler–Heisenberg (EEH) black hole. We compute the deflection angle of light by the EEH black hole in weak field limits. Which represents that the bending of light is a global and topological effect. For this purpose, we deduce the Gaussian curvature and apply the Gauss–Bonnet theorem (GBT). Furthermore, we determine the deflection angle at which light is deflected by a plasma medium. We also look into how an EEH black hole behaves graphically in vacuum and plasma medium. Moreover, we study the fundamental frequencies with three different models of EEH black hole.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139102191","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}