Journal of Astrophysics and Astronomy最新文献

The article ‘Confirmation of interstellar phosphine towards asymptotic giant branch star IRC(+)10216’ by A. Manna and S. Pal uses ALMA data of the C-star envelope IRC(+)10216 to claim a confirmation of the detection of (hbox {PH}_3) in this source. The article, however, incorrectly assigns an emission feature observed in the ALMA spectrum of IRC(+)10216 to (hbox {PH}_3), while we find that it arises from a highly vibrationally excited state of HCN. Concretely the feature can be confidently assigned to the (J=3)–2, (ell =0) transition of HCN in the (nu _1 + 4nu _2) vibrational state based on the observation of the (ell = +2) and (ell = -2) components of the same rotational transition, (J=3)–2, with the observed relative intensities in agreement with the relative line strengths. The detection of (hbox {PH}_3) in IRC(+)10216 remains confirmed based on the observation of the (J=1)–0 and (J=2)–1 lines with the single-dish telescopes IRAM 30m, ARO SMT 10m, and Herschel (Agúndez et al. 2008, 2014; Tenenbaum & Ziurys 2008).

The Be X-ray binary pulsar RX J0520.5(-)6932 in the Large Magellanic Cloud recently underwent an outburst after a gap of about 10 years. This paper presents the timing and spectral analysis of this transient system using the NuSTAR observation that was made near the peak of the outburst. Coherent pulsations were detected with a period of 8.029877(9) s (at MJD 60412.87) up to 50 keV. The pulse profile was single-peaked and asymmetric, with the presence of two local minima on the slowly rising edge up to about 18 keV. The hard X-ray pulse profiles were relatively smooth. The 3–50 keV FPMA–FPMB energy spectrum was well described by a thermally comptonized continuum with an electron temperature of (sim )5.3 keV and a photon index of (sim )1.36. A broad (sim )6.32 keV Fe emission line and a cyclotron resonant scattering feature (CRSF) with (sim )32.3 keV central energy, corresponding to a surface magnetic field strength of (sim ) (2.8times 10^{12}) G were also required to describe the energy spectrum. The pulse phase resolved spectroscopy indicated significant variation in energy and width of the CRSF and iron emission line. A (sim )14.6 keV absorption feature was also detected at specific pulse phases.

In contemporary astronomy and astrophysics (A&A), the integration of high-performance computing (HPC), big data analytics, and artificial intelligence/machine learning (AI/ML) has become essential for advancing research across a wide range of scientific domains. These tools are playing an increasingly pivotal role in accelerating discoveries, simulating complex astrophysical phenomena, and analyzing vast amounts of observational data. For India to maintain and enhance its competitive edge in the global landscape of computational astrophysics and data science, the Indian A&A community must embrace these transformative technologies fully. Despite limited resources, the expanding Indian community has made significant scientific contributions. However, to remain globally competitive in the coming years, it is vital to establish a robust national framework that provides researchers with reliable access to state-of-the-art computational resources. This system should involve the regular solicitation of computational proposals, which can be assessed by domain experts and HPC specialists, ensuring that high-impact research receives the necessary support. India can develop the talent, infrastructure, and collaborative environment necessary for world-class research in computational astrophysics and data science.

With the evolution of radio astronomy and related education and training, the demand for scalable, efficient, and remote systems in data acquisition, storage, and analysis has significantly increased. Addressing this need, we have developed a web interface for a log-periodic dipole antenna array integral to the SKA Test activities at the Gauribidanur Radio Observatory (77.428 E, 13.603 N). This interface, employing Python-based technologies such as Streamlit and PyVISA, along with Standard Commands for Programmable Instruments (SCPI) commands, offers a seamless and user-friendly experience. Our solution introduces a unique data acquisition approach, employing SCPI through Python to communicate with the setup’s data acquisition system. The web interface, accessible remotely via a secure WLAN network or VPN, facilitates user-initiated observations and comprehensive logging and offers advanced features like manual radio frequency interference masking, transit plotting, and fringe plot analysis. Additionally, it acts as a data hub, allowing for the remote downloading of observational data. These capabilities significantly enhance the user’s ability to conduct detailed post-observation data analysis. The effectiveness of this interface is further demonstrated through a successful solar transit observation, validating its utility and accuracy in real-world astronomical applications. The applications of this web tool are expandable. They can be tailored according to the Observatory’s goals and instrumentation, as well as the growing radio astronomy instrumentation and observing facilities at various educational institutions.

Chandrayaan-2 Large Area soft X-ray Spectrometer (CLASS) is a remote X-ray Fluorescence experiment to map the lunar surface elemental abundances. With its large effective area and low energy threshold, CLASS generates the highest spatial resolution maps of all major rock-forming elements on the Moon, such as Mg, Al, Si, Ca, Ti, and Fe. Five years of operation in lunar orbit has resulted in global coverage. With several lunar missions planned for this decade for in situ exploration and sample returns, the (15 times 15) km geochemical maps from CLASS will serve as an important dataset. This article highlights the scientific results of CLASS in the last five years and discusses its potential applications.

In this article, we present the current state of observing facilities available for Indian astronomers in various wavelength bands existing in the country. We also mention a few state-of-the-art astronomical facilities across the globe and contrast them with the Indian facilities. We then present a vision for improving our facilities to raise world-class capabilities. This process involves (a) upgrading the current facilities, (b) partnering in mega-science projects across the globe, (c) continued involvement in International projects, and (d) creating our large-scale facilities. These steps are divided into short, medium, and long-term tasks/projects. Recommendations for building large telescopes with versatile back-end instruments on Indian soil for Indian astronomers have been provided for each wavelength band. All these world-class astronomical observing facilities warrant cutting-edge technologies ranging from signal/image processing, high-performance computing, algorithms, and AI/ML. We hope this exercise will start a discussion and eventually lead to the initiation of these projects, which will result in significant scientific breakthroughs in the coming decades.

The procedures followed for computations of eclipses in the classical treatises are best understood with a practical demonstration of the technique. Here, we have studied manuscripts describing the computations. These are authored by Ekanātha of the 14th century, whose works are not well known. We demonstrate the procedure by practical verification of each step and finally comparing the results with currently available computations. In the process, the finer details of valuable tools, like the iteration method, are brought to light. The drawings of the eclipses are presented as per the procedure. The possible causes for the observed discrepancies in the results are discussed.

Astronomy, of all the sciences, is possibly the one with the most public appeal across all age groups. This is also evidenced by the existence of a large number of planetaria and amateur astronomy societies, which are unique to the field. Astronomy is known as a ‘gateway science’, with the ability to attract students who then proceed to explore their interest in other STEM fields. Astronomy’s link to society is, therefore, substantive and diverse. This white paper analyses six key areas: outreach and communication, astronomy education, history and heritage, astronomy for development, diversity, and hiring practices for outreach personnel.

The current status of each of these areas is described, followed by an analysis of what is needed for the future. A set of recommendations for institutions, funding agencies, and individuals are evolved for each specific area. This work outlines how the future astronomy-society connection should take shape and provides a road map for the various stakeholders involved.

In this study, I re-examine the question of whether a hypothetical planet, Vulcan, could explain the anomalous advance of Mercury’s perihelion. I propose that Vulcan might be considered a type of primordial black hole with a planetary mass. The detection of this type of celestial body has become possible through modern experimental techniques, including the Optical Gravitational Lensing Experiment. Recently, an excess of ultra-short microlensing events with crossing times of 0.1–0.3 days has been reported, suggesting the possible existence of sub-Earth-mass primordial black holes in our solar system. The primordial black hole Vulcan planetary mass hypothesis could then explain the anomalous advance of Mercury’s perihelion under the influence of its gravitational attraction, remaining hidden from astronomers’ telescopes. But in this case, it will also influence the perihelion advance of the other planets. To this end, I first calculate the mutual partial contributions to the perihelion motion of all the planets by two different methods without Vulcan in a model of the simplified solar system consisting of the Sun and eight planets. Next, I include Vulcan in this model within the framework of the Newtonian theory of classical gravitation and analyze Vulcan’s influence on the perihelion advance of the inner planets, using Vulcan parameters from my previous work. These results are compared with the perihelion advances of the inner planets predicted by the theory of general relativity and with the data obtained by modern observations.

This study examines the characterization of binary star systems using Spectral Energy Distributions (SEDs), a technique increasingly essential with the rise of large-scale astronomical surveys. Binaries can emit flux at different regions of the electromagnetic spectrum, making SEDs a valuable tool in identifying and characterizing unresolved binary systems. However, fitting multi-component models to SEDs and recovering accurate stellar parameters remains challenging due to nonlinear fitting methods and inherent uncertainties in the data and the spectral models. In this work, a simplified approach was used to model stars as blackbodies, and we tested the accuracy of parameter recovery from SEDs, particularly by focusing on secondary stars. We explored a range of primary properties, filter sets, and noise models. Special attention was given to two case studies: one examining the detection of unresolved binaries using Gaia XP spectra, and the other focusing on identifying hotter companions in binary systems using UV-IR SEDs. Although an analytic prescription for recoverability is impossible, we present a simplified model and the necessary python tools to analyze any potential binary system. Finally, we propose using blackbody models as a baseline for error estimation in SED fitting. We offer a possible method for measuring fitting errors and improving the precision of binary star characterizations.