Journal of Astrophysics and Astronomy最新文献_第5页

UVIT/AstroSat observation of TW Hya TW Hya的UVIT/AstroSat观测

IF 1.5 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2026-07-03 DOI: 10.1007/s12036-026-10154-3

Prasanta K. Nayak, Mayank Narang, P. Manoj, D. K. Ojha, U. S. Kamath, Blesson Mathew, T. Baug, S. Vig, S. Chandra, G. Maheswar

{"title":"UVIT/AstroSat observation of TW Hya","authors":"Prasanta K. Nayak, Mayank Narang, P. Manoj, D. K. Ojha, U. S. Kamath, Blesson Mathew, T. Baug, S. Vig, S. Chandra, G. Maheswar","doi":"10.1007/s12036-026-10154-3","DOIUrl":"10.1007/s12036-026-10154-3","url":null,"abstract":"<div><p>The paper demonstrates the spectroscopic and photometric capabilities of the Ultra-Violet Imaging Telescope (UVIT) to study T-Tauri stars (TTSs). We present the first UVIT/Far-UV (FUV) spectrum of a TTS, TW Hya. Based on C <span>iv</span> line luminosity, we estimated accretion luminosity (0.12±0.03 <span>(L_odot )</span>) and mass accretion rate (2.4±0.6 <span>(times )</span> <span>(10^{-8} M_odot /yr)</span>) of TW Hya, and compared these values with the accretion luminosity (0.031±0.002 <span>(L_odot )</span>) and mass accretion rate (0.62±0.04 <span>(times )</span> <span>(10^{-8} M_odot /yr)</span>) derived from spectral energy distribution (SED). From the SED, we derive best-fitted parameters for TW Hya: <span>(T_{eff})</span> = 3900±50 K, radius = 1.2±0.03 <span>(R_odot )</span>, <span>(log , g = 4.0)</span> and equivalent black-body temperatures corresponding to accretion luminosity as 14100±25 K. The parameters of TW Hya derived from UVIT observations were found to be matched well with the literature. Comparison with International Ultraviolet Explorer (IUE) and Hubble Space Telescope (HST) spectra suggests that UVIT can be used to study the spectroscopic variability of young stars. This study proposes leveraging the FUV spectroscopic capabilities of UVIT to contribute to the advancement of upcoming UV spectroscopic missions, including the Indian Spectroscopic Imaging Space Telescope.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"47 2","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148380638","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

The extreme solar transient events as observed by the MAG payload onboard Aditya-L1 spacecraft around L1 point Aditya-L1航天器上MAG有效载荷在L1点附近观测到的极端太阳瞬变事件

IF 1.5 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2026-06-30 DOI: 10.1007/s12036-026-10151-6

Vipin K. Yadav, Srikar P. Tadepalli, Geeta Vichare, Nandita Srivastava, Y. Vijaya, B. Krishnam Prasad, Monika Mahajan, K. V. L. N. Mallikarjun, Syeeda N. Zamani, K. A. Lohar, M. M. Kandpal, S. Narendra, Abhijit A. Adoni, Vijay Shankar Rai, D. R. Veeresha

{"title":"The extreme solar transient events as observed by the MAG payload onboard Aditya-L1 spacecraft around L1 point","authors":"Vipin K. Yadav, Srikar P. Tadepalli, Geeta Vichare, Nandita Srivastava, Y. Vijaya, B. Krishnam Prasad, Monika Mahajan, K. V. L. N. Mallikarjun, Syeeda N. Zamani, K. A. Lohar, M. M. Kandpal, S. Narendra, Abhijit A. Adoni, Vijay Shankar Rai, D. R. Veeresha","doi":"10.1007/s12036-026-10151-6","DOIUrl":"10.1007/s12036-026-10151-6","url":null,"abstract":"<div><p>Aditya-L1 is the first Indian spacecraft placed in a halo-orbit around the first Lagrangian (L1) point to continuously observe the Sun. A fluxgate magnetometer (MAG) is also onboard with other payloads to measure the interplanetary magnetic field (IMF) coming from the Sun towards the Earth which is an important parameter in monitoring the near-Earth space weather. The MAG is a dual triaxial sensor set mounted on a 6 m long boom, deployed along the negative roll direction of Aditya-L1, with one set at the tip of boom and the other set at the centre of the boom around 3 m away from the spacecraft towards the boom-tip on the sun-viewing panel deck. The MAG boom was deployed (downwards from the spacecraft) on January 11, 2024 and since then MAG is measuring the IMF. MAG observations are found to match well with the magnetic field measurements of the Deep Space Climate Observatory (DSCOVR) from NOAA, USA. During its continuous operations since then MAG has observed several extreme solar transient events such as the Interplanetary Coronal Mass Ejections (ICMEs), Magnetic Clouds etc. In this paper we report MAG observations of passage of three ICMEs during September–October, 2024 which occurred due to extreme solar transient events. As the selected events led to severe geomagnetic storms Dst < − 100 nT, the impact of these events on the Earth’s magnetosphere are presented.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"47 2","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148380907","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

Black hole-Neutron star distinction based on long-term MAXI and Swift study of 42 low mass X-ray binaries 基于42个低质量x射线双星长期MAXI和Swift研究的黑洞-中子星区分

IF 1.5 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2026-06-25 DOI: 10.1007/s12036-026-10152-5

Prakhar Maheshwari, Mayukh Pahari, Anish Sarkar, Saurabh Sharma

{"title":"Black hole-Neutron star distinction based on long-term MAXI and Swift study of 42 low mass X-ray binaries","authors":"Prakhar Maheshwari, Mayukh Pahari, Anish Sarkar, Saurabh Sharma","doi":"10.1007/s12036-026-10152-5","DOIUrl":"10.1007/s12036-026-10152-5","url":null,"abstract":"<div><p>In this study, we analysed about <span>(sim )</span>13 years of publicly available data from <i>MAXI</i> and <i>Swift</i>/BAT to examine the long-term source evolution of 42 transient low-mass X-ray binaries. The sample consists of 11 confirmed black hole X-ray binaries (BHXBs), 10 black hole candidates (BHC), and 21 neutron star X-ray binaries (NSXBs). Outbursts and flaring activities studied over 13 years show that 19/21 NSXBs spend significantly longer time in the hard state (observations for which hardness ratio is <span>(ge )</span> 0.2) while 15/21 BHXB+XRC spend substantially longer time in the soft state (observations for which hardness ratio is < 0.2). The frequency distribution of the hardness ratio clearly shows two distinct distributions for BHXBs and NSXBs, with their peaks separated: NSXBs prefer harder values, while BHXBs prefer softer values of hardness. Our model-independent analysis for 42 transient sources shows that statistically NSXBs do not prefer to show a canonical high soft state as observed in BHXBs. Additionally, the probability distribution of the duration of the 2-20 keV X-ray outburst is observed to peak at a significantly longer duration (>100 days) for BHXBs than for NSXBs (15-60 days). Our analysis shows that among candidate sources, Swift J1728.9-3613, MAXI J1535-571, MAXI J1659-152, EXO 1846-031 show a ‘q’ diagram in the HID and prefer to align with the HID frequency distribution of BHXBs that show ‘q’ diagram, MAXI J1305-704 and MAXI J1836-194 align with frequency distribution of black hole sources without ‘q’ diagram while MAXI J1848-015 shows the HID distribution similar to NSXBs, indicating a neutron star accretor. Therefore, a long-term statistical study of <i>MAXI</i> and <i>Swift</i>/BAT X-ray outbursts from a large sample of transient sources may be used to distinguish BHXB from NSXB.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"47 2","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148323769","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

Sun-to-Earth evolution and space weather impact of the 21 April 2023 CME: validation of a space weather modeling framework 2023年4月21日CME的日地演化和空间天气影响：空间天气模型框架的验证

IF 1.5 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2026-06-15 DOI: 10.1007/s12036-026-10138-3

Ranadeep Sarkar, Shanmugha Balan, Nandita Srivastava

{"title":"Sun-to-Earth evolution and space weather impact of the 21 April 2023 CME: validation of a space weather modeling framework","authors":"Ranadeep Sarkar, Shanmugha Balan, Nandita Srivastava","doi":"10.1007/s12036-026-10138-3","DOIUrl":"10.1007/s12036-026-10138-3","url":null,"abstract":"<div><p>The first severe geomagnetic storm of Solar Cycle 25 occurred on 23-24 April 2023, reaching a minimum Dst of -213 nT. Utilizing the state-of-the-art observational and modeling techniques, we investigate the Sun-to-Earth evolution of the coronal mass ejection (CME) that caused this severe geomagnetic storm. We use multi-wavelength and multi-vantage point remote sensing observations to constrain the near-Sun CME properties, which serve as input for the interplanetary flux rope simulator (INFROS) model to simulate the magnetic vectors of the ICME at 1 AU. Utilizing multi-point in situ observations of the ICME detected by both STEREO-A and Wind, we validate the INFROS model results at each spacecraft. We further couple INFROS with the Drag-Based Model (DBM) and empirical Dst prediction models, presenting a space weather modeling framework to estimate the intensity of the associated geomagnetic storm. Based on the remote sensing observations, we find that the CME eruption was associated with the partial eruption of a pre-existing filament structure, which led to an underestimation of the poloidal flux when determined using the post-eruption arcade (PEA) method. In contrast, empirical model-based estimations provide more accurate results on constraining the poloidal flux of the CME. The INFROS model successfully captures the magnetic structure of the ICME observed near Earth but fails to reproduce the trailing part of the flux rope as observed at STEREO-A, likely due to distortion caused by a following interacting high-speed stream. Validation of the space weather modeling framework with the observed SYM/H index for this event shows good agreement between the observed and predicted SYM/H profiles. These results highlight that the INFROS-based space weather modeling framework could serve as an operational space weather forecasting tool for predicting the intensity of geomagnetic storms.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"47 2","pages":""},"PeriodicalIF":1.5,"publicationDate":"2026-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148281155","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

Investigating the effect of temperature and pairing gaps on electron capture cross-sections in neutron-rich (N = 50) nuclei 研究温度和配对间隙对富中子(N = 50)核中电子捕获截面的影响

IF 1.6 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2026-06-11 DOI: 10.1007/s12036-026-10150-7

Muhammad Riaz, Jameel-Un Nabi, Arslan Mehmood, Abdul Kabir, Syeda Anmol Rida

引用次数: 0

Structure and evolution of multi-cluster within Galactic disc: Gaia DR3 insights into eight open clusters 银河系盘内多星团的结构与演化：盖亚DR3对8个疏散星团的洞察

IF 1.6 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2026-06-03 DOI: 10.1007/s12036-026-10143-6

A AHMED, W H ELSANHOURY, D C ÇINAR, A A HAROON, M S ALENAZI, E A ELKHOLY

{"title":"Structure and evolution of multi-cluster within Galactic disc: Gaia DR3 insights into eight open clusters","authors":"A AHMED, W H ELSANHOURY, D C ÇINAR, A A HAROON, M S ALENAZI, E A ELKHOLY","doi":"10.1007/s12036-026-10143-6","DOIUrl":"10.1007/s12036-026-10143-6","url":null,"abstract":"<div><p>In this study, we present a comprehensive analysis of the structural, astrophysical, and dynamical properties of eight open clusters: NGC 559, NGC 1817, NGC 2141, NGC 7245, Ruprecht 15, Ruprecht 137, Ruprecht 142, and Ruprecht 169, utilizing the precise astrometric and photometric data from <i>Gaia</i> Data Release 3. By fitting King’s model to the radial density profiles, we determined their structural parameters, including core and cluster limiting radii, which were found to be in the ranges of 3.07 – 16.21 arcmin and 9.97 – 25.97 arcmin, respectively. The fundamental astrophysical parameters were derived by fitting <span>PARSEC</span> isochrones to the colour-magnitude diagrams. Our analysis indicates that the clusters’ logarithmic ages span from 7.95 to 9.34 years, with metallicities ranging between 0.007 – 0.015 and heliocentric distances from 1640 to 5203 pc. The total stellar masses for the clusters were calculated to be within the range of 257 – 1916 <span>(M_{odot })</span>. The slopes of the mass function for most clusters were found to be consistent with the Salpeter initial mass function. Furthermore, our dynamical analysis suggests that all investigated clusters except Ruprecht 15 show signs of being dynamically relaxed. Notably, the spatial distribution and bimodal structure observed in the radial density profile of NGC 7245 provide strong evidence that it is a binary cluster candidate. Finally, our kinematic analysis and orbit integration show that the clusters possess dynamical properties that are fully consistent with their membership in the Galactic thin disc.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"47 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148172451","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

Exactly solved model of a one dimensional self gravitating system 一维自引力系统的精确解模型

IF 1.6 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2026-04-21 DOI: 10.1007/s12036-026-10139-2

RAJARAM NITYANANDA

引用次数: 0

Constraining the onset height of coronal mass ejection driven shocks using near-Sun observations in visible and radio wavelengths 利用可见光和无线电波长的近日观测来限制日冕物质抛射驱动激波的起始高度

IF 1.6 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2026-04-21 DOI: 10.1007/s12036-026-10147-2

C Kathiravan, V Muthu priyal, R Ramesh

引用次数: 0

Template-fitting meets deep learning: redshift estimation using physics-guided neural networks 模板拟合满足深度学习：使用物理引导的神经网络进行红移估计

IF 1.6 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2026-04-13 DOI: 10.1007/s12036-026-10144-5

Jonas Chris Ferrao, Dickson Dias, Pranav Naik, Glory D’cruz, Anish Naik, Siya Khandeparkar, Manisha Gokuldas Fal Dessai

{"title":"Template-fitting meets deep learning: redshift estimation using physics-guided neural networks","authors":"Jonas Chris Ferrao, Dickson Dias, Pranav Naik, Glory D’cruz, Anish Naik, Siya Khandeparkar, Manisha Gokuldas Fal Dessai","doi":"10.1007/s12036-026-10144-5","DOIUrl":"10.1007/s12036-026-10144-5","url":null,"abstract":"<div><p>Accurate photometric redshift estimation is essential for large-scale cosmological surveys, enabling studies of galaxy evolution and the large-scale structure of the Universe, when spectroscopic measurements are impractical. Template fitting and machine learning are the two primary methods for estimating photometric redshifts, each with its own set of advantages and drawbacks. We present a hybrid framework that unifies the two through a Physics-Guided Neural Network (PGNN), integrating Spectral Energy Distribution (SED) templates with a multimodal deep learning architecture. The model combines Convolutional Neural Networks (CNNs) to extract morphological information from galaxy images, bidirectional LSTM (BiLSTM) layers to capture wavelength-ordered dependencies among photometric bands, and a cross-attention mechanism that adaptively fuses photometric and image-derived features for enhanced redshift inference. Bayesian layers further provide uncertainty estimates. Using the publicly available “GalaxiesML” dataset, which comprises <span>(sim )</span>300,000 galaxies from the Hyper Suprime-Cam survey’s PDR2 release, our method achieves an RMS error of 0.0942, a catastrophic outlier rate of 1.28%, and a bias of 0.0002, surpassing existing approaches on the same dataset. By embedding physical priors, spectral correlations, and cross-modal interactions within a unified architecture, this work establishes a robust, interpretable, and scalable framework for photometric redshift estimation in next-generation surveys such as LSST and Euclid .</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"47 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737619","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

Disk dynamics in X-ray pulsars with Hall diffusion and mass-loss outflows 具有霍尔扩散和质量损失外流的x射线脉冲星盘动力学

IF 1.6 4区物理与天体物理

Journal of Astrophysics and Astronomy Pub Date : 2026-04-13 DOI: 10.1007/s12036-026-10146-3

Kazem Faghei

{"title":"Disk dynamics in X-ray pulsars with Hall diffusion and mass-loss outflows","authors":"Kazem Faghei","doi":"10.1007/s12036-026-10146-3","DOIUrl":"10.1007/s12036-026-10146-3","url":null,"abstract":"<div><p>We present a semi-analytical model of magnetized accretion disks around neutron stars that extends previous disk-magnetosphere interaction frameworks by including Hall diffusion and disk-driven mass outflows. The modified induction and angular momentum equations are solved numerically to investigate the rotational structure of the disk. The results show that Hall diffusion significantly alters the angular momentum transport within the disk, broadening the transition region between Keplerian rotation and corotation with the neutron star. In contrast, the impact of disk outflows is twofold and critically depends on the specific angular momentum extracted from or delivered to the disk by the outflows, as parameterized by <span>(l)</span>. Outflows that remove angular momentum from the disk (<span>(l < 0)</span>) reduce the fastness parameter and broaden the transition zone, while outflows that supply angular momentum to the disk (<span>(l > 0)</span>) increase the fastness parameter and narrow the transition zone. When both effects of Hall diffusion and outflows operate together, they establish a competitive interplay that dictates the final disk configuration. Hall diffusion tends to expand the region of sub-Keplerian rotation, while outflows can either counteract or reinforce this broadening depending on the sign and magnitude of <span>(l)</span>. These findings highlight the importance of non-ideal MHD processes and outflows in determining the structure and dynamics of accretion disks around magnetized compact objects.</p></div>","PeriodicalId":610,"journal":{"name":"Journal of Astrophysics and Astronomy","volume":"47 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737621","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