Journal of Astrophysics and Astronomy最新文献_第4页

Detection of continuum emission and atomic hydrogen from comet C/2020 F3 NEOWISE using GMRT 利用全球红外辐射计探测C/2020 F3 NEOWISE彗星的连续发射和原子氢

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2024-03-14 DOI: 10.1007/s12036-024-09998-4

Sabyasachi Pal, Arijit Manna

{"title":"Detection of continuum emission and atomic hydrogen from comet C/2020 F3 NEOWISE using GMRT","authors":"Sabyasachi Pal, Arijit Manna","doi":"10.1007/s12036-024-09998-4","DOIUrl":"10.1007/s12036-024-09998-4","url":null,"abstract":"<div>Comets are the most primordial objects in our solar system. Comets are icy bodies that release gas and dust when moving close to the Sun. The C/2020 F3 (Near-Earth Object Wide-field Infrared Survey Explorer: NEOWISE) is a nearly isotropic comet moving near-parabolic orbit. The C/2020 F3 (NEOWISE) was the brightest comet in the northern hemisphere after comet Hale–Bopp in 1997 and comet McNaught in 2006. This paper presents the first interferometric high-resolution detection of the comet C/2020 F3 (NEOWISE) using the Giant Metrewave Radio Telescope (GMRT). We detected the radio continuum emission from the comet C/2020 F3 (NEOWISE) with a flux density level 2.84 (±0.56)–3.89 (±0.57) mJy in the frequency range of 1050–1450 MHz. We also detected the absorption line of atomic hydrogen (HI) with a signal-to-noise ratio (SNR) (sim )5.7. The column density of the detected HI absorption line is (N_{textrm{HI}} = (3.46pm 0.60)times (T_{s}/100)times 10^{21},hbox {cm}^{-2}), where we assume the spin temperature (T_{s} = 100) K and filling factor (f = 1). The significant detection of continuum emission from the comet C/2020 F3 (NEOWISE) at (sim )21 cm wavelength indicated that it arose from the large icy grains halo (IGH) region.</div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"45 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140151542","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}

引用次数: 0

Markov Chain Monte Carlo optimization applied to double stars from Miller & Pitman research 将马尔可夫链蒙特卡洛优化技术应用于米勒和皮特曼研究的双星

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2024-03-05 DOI: 10.1007/s12036-024-09997-5

Maksym Ersteniuk, Timothy Banks, Edwin Budding, Michael D. Rhodes

引用次数: 0

Optical design studies for national large optical-IR telescope 国家大型光学-红外望远镜光学设计研究

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2024-02-29 DOI: 10.1007/s12036-024-09995-7

Varun Padikal, Amirul Hasan, Vineeth Valsan, S. Sriram, Athul Kurian, Vishnu C. Unni, Alikhan Basheer, Pramod Panchal, Maheswar Gopinathan, B. S. Remya, Totan Chand

引用次数: 0

Luminosity dependent cyclotron line in Swift J1626.6−5156 Swift J1626.6-5156 中与光度相关的回旋线

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2024-02-14 DOI: 10.1007/s12036-023-09994-0

Binay Rai, Biswajit Paul, Mohammed Tobrej, Manoj Ghising, Ruchi Tamang, Bikash Chandra Paul

引用次数: 0

Exploring the collinear Lagrangian points of exoplanet systems with P–R drag and oblateness 探索具有P-R阻力和扁圆度的系外行星系统的共线拉格朗日点

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2024-02-08 DOI: 10.1007/s12036-023-09993-1

Ibtisam Shaikh, Priya Hasan, S. N. Hasan

{"title":"Exploring the collinear Lagrangian points of exoplanet systems with P–R drag and oblateness","authors":"Ibtisam Shaikh, Priya Hasan, S. N. Hasan","doi":"10.1007/s12036-023-09993-1","DOIUrl":"10.1007/s12036-023-09993-1","url":null,"abstract":"<div>In this paper, we study the location and stability of the collinear Lagrangian points for the RTBP case in which one of the primary bodies radiates and the other is oblate. We consider the effect of Poynting–Roberson drag and investigate how the location and stability of the Lagrangian points change with changes in the radiation parameter (beta ) and oblateness a. We apply our results to ten exoplanet systems: CoRoT-2 b, TOI-1278 b, HAT-P-20 b, Kepler-75 b, WASP-89 b, TIC 172900988 b, NGTS 9 b, LP 714-47 b, WASP-162 b and XO-3 b, data of which has been taken from NASA exoplanet archives, to find locations in these exoplanet systems where one can detect asteroids, primordial material or seeds where planet formation can take place. We find that the location of the collinear Lagrangian points changes with variations in radiation pressure and oblateness. Further, for all the ten planetary systems studied in this paper, the Lagrangian points are unstable and can be locations where we expect to find minor planets, asteroids or debris. The unstability of the Lagrangian points can be a possible cause of relocation and migration of planetesimals.</div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"45 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139751628","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}

引用次数: 0

Possibilities of identifying members from Milky Way satellite galaxies using unsupervised machine learning algorithms 利用无监督机器学习算法识别银河卫星星系成员的可能性

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2024-01-17 DOI: 10.1007/s12036-023-09990-4

Devika K. Divakar, Pallavi Saraf, Thirupathi Sivarani, Vijayakumar H. Doddamani

{"title":"Possibilities of identifying members from Milky Way satellite galaxies using unsupervised machine learning algorithms","authors":"Devika K. Divakar, Pallavi Saraf, Thirupathi Sivarani, Vijayakumar H. Doddamani","doi":"10.1007/s12036-023-09990-4","DOIUrl":"10.1007/s12036-023-09990-4","url":null,"abstract":"<div>A detailed study of stellar populations in Milky Way (MW) satellite galaxies remains an observational challenge due to their faintness and fewer spectroscopically confirmed member stars. We use unsupervised machine learning methods to identify new members for nine nearby MW satellite galaxies using Gaia data release-3 (Gaia DR3) astrometry, the Dark Energy Survey (DES) and the DECam Local Volume Exploration Survey (DELVE) photometry. Two density-based clustering algorithms, DBSCAN and HDBSCAN, have been used in the four-dimensional astrometric parameter space ((alpha _{2016}), (delta _{2016}), (mu _{alpha } cos delta ), (mu _delta )) to identify member stars belonging to MW satellite galaxies. Our results indicate that we can recover more than 80% of the known spectroscopically confirmed members in most satellite galaxies and also reject 95–100% of spectroscopic non-members. We have also added many new members using this method. We compare our results with previous studies using photometric and astrometric data and discuss the suitability of density-based clustering methods for MW satellite galaxies.</div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"45 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139498532","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}

引用次数: 0

Performance analysis of NeQuick2 and IRI-Plas models during quiet geomagnetic and low solar activity conditions at Thanjavur equatorial location: Preliminary results 在 Thanjavur 赤道位置的安静地磁和低太阳活动条件下对 NeQuick2 和 IRI-Plas 模型的性能分析：初步结果

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2024-01-09 DOI: 10.1007/s12036-023-09992-2

Veera Kumar Maheswaran, James A. Baskaradas, Venkata Ratnam Devanaboyina, Sriram Subramanian, Rupesh M. Das

{"title":"Performance analysis of NeQuick2 and IRI-Plas models during quiet geomagnetic and low solar activity conditions at Thanjavur equatorial location: Preliminary results","authors":"Veera Kumar Maheswaran, James A. Baskaradas, Venkata Ratnam Devanaboyina, Sriram Subramanian, Rupesh M. Das","doi":"10.1007/s12036-023-09992-2","DOIUrl":"10.1007/s12036-023-09992-2","url":null,"abstract":"<div>The ionosphere’s dynamic fluctuations are a persistent challenge to satellite navigation and communication. The total electron content (TEC) information from global navigation satellite system (GNSS) signals provides the status of the ionosphere for fail-safe transionospheric communication. The equatorial ionization anomaly (EIA) and equatorial plasma bubble (EPB) dominate in low latitude and equatorial ionosphere. The low solar activity's fast varying pre-reversal enhancement is low, and slow varying gravity waves can seed ionospheric disturbances. This study analyses the vertical TEC (VTEC) variations using a ground-based global positioning system (GPS) receiver at Thanjavur (10.72° N, 79.02° E), Tamil Nadu, India, for the years 2019 and 2020, with specific emphasis on the Equinox and Solstice conditions during low solar activity. The suitability of global ionospheric models such as IRI-Plas and NeQuick2 models is investigated with low solar activity GPS VTEC observations. VTEC variations are more during the Vernal Equinox compared to other seasons. The NeQuick2 model underestimates the VTEC content during the night hours and overestimates the day's evening hours regardless of the month, perhaps due to higher ITU-R coefficients. The results help us improve IRI-Plas and NeQuick prediction models' accuracy.</div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"45 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139412618","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}

引用次数: 0

Square Kilometre Array—India Consortium: Education and Public Outreach 平方公里阵列-印度联合会：教育和公众宣传

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-12-22 DOI: 10.1007/s12036-023-09984-2

Niruj Mohan Ramanujam, Prasun Dutta, Indulekha Kavila, Manoneeta Chakraborty, Samir Dhurde, Ananda Hota, Chiranjib Konar, Divya Oberoi, Mamta Pandey-Pommier, Mayuri Sathyanarayana Rao

引用次数: 0

ACA observation and chemical modeling of phosphorus nitride towards hot molecular cores G10.47(varvec {+})0.03 and G31.41(varvec {+})0.31 对热分子核心 G10.47$varvec {+}$0.03 和 G31.41$varvec {+}$0.31 氮化磷的 ACA 观测和化学建模

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-12-22 DOI: 10.1007/s12036-023-09989-x

ARIJIT MANNA, SABYASACHI PAL

{"title":"ACA observation and chemical modeling of phosphorus nitride towards hot molecular cores G10.47(varvec {+})0.03 and G31.41(varvec {+})0.31","authors":"ARIJIT MANNA, SABYASACHI PAL","doi":"10.1007/s12036-023-09989-x","DOIUrl":"10.1007/s12036-023-09989-x","url":null,"abstract":"<div>Phosphorus (P) is one of the important elements for the formation of life and plays a crucial role in several biochemical processes. Recent spectral line surveys have confirmed the existence of P-bearing molecules, especially PN and PO, in the star-formation regions, but their formation mechanisms are poorly understood. The P-bearing molecule phosphorus nitride (PN) is detected in several star-forming regions, but this molecule has been poorly studied at high gas densities ((ge )10(^{6}) cm(^{-3})) hot molecular cores. In this paper, we presented the detection of rotational emission line of PN with transition (J = 3)–2 towards the hot molecular cores G10.47(+)0.03 and G31.41(+)0.31, using the Atacama Compact Array (ACA). The estimated column densities of PN for G10.47(+)0.03 and G31.41(+)0.31 using the local thermodynamic equilibrium model are ((3.60pm 0.2)times 10^{13}) cm(^{-2}) and ((9.10pm 0.1)times 10^{12}) cm(^{-2}) with an excitation temperature of (150pm 25) K. The fractional abundance of PN relative to H(_{2}) is (2.76times 10^{-10}) for G10.47(+)0.03 and (5.68times 10^{-11}) for G31.41(+)0.031. We computed the two-phase warm-up chemical model of PN to understand the chemical evolution in the environment of hot molecular cores. After chemical modeling, we claimed that PN is created in the gas phase via the neutral–neutral reaction between PO and N in the warm-up stage. Similarly, PN is destroyed via the ion–neutral reaction between H(_{3})O(^{+}) and PN.</div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"45 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138947667","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}

引用次数: 0

Propagation of nonlinear wave in 2-D planar and axisymmetric non-ideal radiating gas flow under the influence of magnetic field 磁场影响下二维平面和轴对称非理想辐射气流中非线性波的传播

IF 1.1 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2023-12-21 DOI: 10.1007/s12036-023-09985-1

Shobhit Kumar Srivastava, Rahul Kumar Chaturvedi, L. P. Singh

{"title":"Propagation of nonlinear wave in 2-D planar and axisymmetric non-ideal radiating gas flow under the influence of magnetic field","authors":"Shobhit Kumar Srivastava, Rahul Kumar Chaturvedi, L. P. Singh","doi":"10.1007/s12036-023-09985-1","DOIUrl":"10.1007/s12036-023-09985-1","url":null,"abstract":"<div>Influence of magnetic field on the propagation of shock waves in radiation gasdynamics is analysed by using wavefront analysis method. We examined behavior of the waves propagated into the two-dimensional (2-D) steady supersonic magnetogasdynamic flow of non-ideal gas with radiation. The transport equations are derived, which determine the condition for the shock formation. The effect of non-idealness and thermal radiation and their consequences under the influence of magnetic field is studied and examined how the flow patterns of the disturbance vary with respect to the variation in the parameters of the flow. It is found that the presence of a magnetic field plays an essential role in the wave propagation phenomena. Nature of the solution with respect to Mach number is analysed, and it is examined how the shock formation distance changes with an increase or decrease in the value of Mach number. Also, the effect of non-idealness on the shock formation distance is elucidated and examined how the shock formation affects the increase in the value of non-ideal parameter in the presence of magnetic field with thermal radiation.</div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"45 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138951770","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}

引用次数: 0