Search Publications
The Deeper Studies of IC 2488 and IC 2714
Li, Xu-Zhi; Zhu, Qing-Feng; Xu, Xiao-Hui +2 more
In this paper, we use two methods, an algorithm of the density-based spatial clustering of applications with noise combined with the Gaussian mixture model, and the maximum likelihood method, to study two open clusters: IC 2488 and IC 2714 with Gaia Data Release 3 data. We compare the two methods in terms of cluster star number, isochrone fitting,…
What excites the optical emission in X-ray-selected galaxies?
Rix, H. -W.; Tugay, A. V.; Zadorozhna, L. V. +3 more
We present a study of 1347 galaxies at z < 0.35 with detected nuclear X-ray emission and optical emission line diagnostics in the Baldwin-Phillips-Terlevich (BPT) diagram. This sample was obtained by cross-matching the XMM-Newton DR10 catalogue with Sloan Digital Sky Survey (SDSS) DR17 galaxies with well-measured line ratios. The distribution o…
Characterization of the Dust and Sodium Tails of Comet C/2020 F3 (NEOWISE) from Parker Solar Probe and Amateur Observations
Coates, Andrew J.; Afghan, Qasim; Jones, Geraint H. +2 more
Comet C/2020 F3 (NEOWISE) reached perihelion on 2020 July 3 at 0.29 au and exhibited a highly structured dust tail. Using a simplified Finson–Probstein model, structures such as striae, observed in the tail in images obtained by the Parker Solar Probe spacecraft and amateur observers, are characterized in this work and parameterized in terms of du…
Tracing shock waves: type II radio emission on 27th of September 2001
Al-Hamadani, Firas; Al-Sawad, Amjad
This study focus on atypical Type II radio bursts observed in conjunction with three simultaneous coronal mass ejections (CMEs) on September 27, 2001. These CMEs originated from a single active region (AR) and were linked to relatively weak solar flares. Analysis of the CME sequences revealed distinct periods of interplanetary (IP) Type II radio e…
Coronal Signatures of Flare Generated Fast-Mode Wave at EUV and Radio Wavelengths
Vasanth, V.
This paper presents a detailed study of the type II solar radio burst that occurred on 06 March 2014 using combined data analysis. It is a classical radio event consisting of type III radio burst and a following type II radio burst in the dynamic spectrum. The type II radio burst is observed between 235 – 130 MHz (120 – 60 MHz) in harmonic (fundam…
Haro 5-2: A New Pre-main-sequence Quadruple Stellar System
Flores, C.; Geballe, T. R.; Reipurth, Bo +9 more
We have discovered that the Hα emission-line star Haro 5-2, located in the 3–6 Myr old Ori OB1b association, is a young quadruple system. The system has a 2+2 configuration, with an outer separation of 2.″6 and with resolved subarcsecond inner binary components. The brightest component, Aa, dominates the A-binary; it is a weak-line T Tauri star wi…
Ultraviolet NO and Visible O2 Nightglow in the Mars Southern Winter Polar Region: Statistical Study and Model Comparison
Vandaele, A. C.; Daerden, F.; Thomas, I. R. +8 more
The Mars NO and the O2 nightglow are produced by the recombination of atoms produced on the dayside by photodissociation and transported to the nightside. These emissions are tracers of the summer to winter pole dynamics in the upper Mars atmosphere. The UV-visible (UVIS) channel of the Nadir and Occultation for MArs Discovery (NOMAD) s…
Investigating Ionization in the Intergalactic Medium
Borthakur, Sanchayeeta; Koplitz, Brad; Ramesh, Anjali
The intergalactic medium (IGM) contains >50% of the baryonic mass of the Universe, yet the mechanisms responsible for keeping the IGM ionized have not been fully explained. Hence, we investigate ion abundances from the largest blind QSO absorption catalog for clouds that show C IV, N V, and O VI simultaneously. The wavelength range of present U…
A robust automated machine-learning method for the identification of star clusters in the central region of the Small Magellanic Cloud
Hatzidimitriou, D.; Zezas, A.; Antoniou, V. +3 more
Aims: We developed a cluster-detection method based on the code DBSCAN to identify star clusters in the central region of the Small Magellanic Cloud (SMC).
Methods: Two approaches were used to determine the values of the free parameters of DBSCAN. They agree well with each other and can be used in the fields that are studied without any …
A photometric study of a total-eclipse contact binary V458 Mon
Zhu, Liying; Matekov, Azizbek; Zubairi, Ahmed Waqas +3 more
We present light curve solution of V458 Mon firstly by using the Wilson-Devinney code. The total eclipse and deep minima of the light curves of V458 Monenable us to determine reliable orbital parameters of the binary system. The solution suggests that V458 Monis a low mass ratio binary system with about 0.2 possessing a moderate degree of contact.…