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(Abridged) We carried out an extensive search to identify the counterparts of all the sources listed in the WMAP 3-yr catalogue using literature and archival data. Our work led to the identification of 309 WMAP sources, 98% of which are…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 P. Giommi , S. Colafrancesco , P. Padovani , D. Gasparrini , E. Cavazzuti , S. Cutini

Blazars represent dominant population of the extragalactic $\gamma$-ray sources in the Universe. These sources exhibit some characteristic properties like strong and non-thermal continuum emission over the entire electromagnetic spectrum…

High Energy Astrophysical Phenomena · Physics 2020-10-07 K. K. Singh , P. J. Meintjes

Clustering is an important tool to describe gamma-ray bursts (GRBs). We analyzed the Final BATSE Catalog using Gaussian-mixture-models-based clustering methods for six variables (durations, peak flux, total fluence and spectral hardness…

High Energy Astrophysical Phenomena · Physics 2019-06-05 B. G. Tóth , I. I. Rácz , I. Horváth

The processes governing the production of astrophysical high-energy neutrinos are still debated, and the sources originating them remain an open question. Among the putative emitters, active galactic nuclei have gained increasing attention.…

Blazars are among the most studied sources in high-energy astrophysics as they form the largest fraction of extragalactic gamma-ray sources and are considered prime candidates for being the counterparts of high-energy astrophysical…

Detecting stellar clusters have always been an important research problem in Astronomy. Although images do not convey very detailed information in detecting stellar density enhancements, we attempt to understand if new machine learning…

Machine Learning · Computer Science 2021-09-28 Arnab Karmakar , Deepak Mishra , Anandmayee Tej

In this paper, we consider the task of clustering a set of individual time series while modeling each cluster, that is, model-based time series clustering. The task requires a parametric model with sufficient flexibility to describe the…

Machine Learning · Computer Science 2023-02-23 Ryohei Umatani , Takashi Imai , Kaoru Kawamoto , Shutaro Kunimasa

Blazars are active galactic nuclei with relativistic jets pointed almost directly at Earth. Blazars are characterized by strong, apparently stochastic flux variability at virtually all observed wavelengths and timescales, from minutes to…

High Energy Astrophysical Phenomena · Physics 2023-02-16 Aryeh Brill

Blazars, a unique class of active galactic nuclei, exhibit highly variable emission across the electromagnetic spectrum. This variability frequently manifests as intense flaring events, sparking an ongoing debate in recent literature about…

High Energy Astrophysical Phenomena · Physics 2025-04-08 Pablo Peñil , Nuria Torres-Albà , Alba Rico , Marco Ajello , Sara Buson , Sagar Adhikari

We analyse Very Long Baseline Interferometry (VLBI) observations of the blazar CGRaBS J0809+5341 using Bayesian inference methods. The observation was carried out at 5 GHz using 8 telescopes that form part of the European VLBI Network.…

Instrumentation and Methods for Astrophysics · Physics 2016-10-18 Iniyan Natarajan , Zsolt Paragi , Jonathan Zwart , Simon Perkins , Oleg Smirnov , Kurt van der Heyden

Blazars are the most violent steady/recurrent sources of high-energy gamma-ray emission in the known Universe. They are prominent emitters of electromagnetic radiation throughout the entire electromagnetic spectrum. The observable radiation…

Astrophysics · Physics 2008-11-26 Markus Boettcher

With their emission mainly coming from a relativistic jet pointing towards us, blazars are fundamental sources to study extragalactic jets and their central engines, consisting of supermassive black holes (SMBHs) fed by accretion discs.…

Blazars are characterized by rapid variability at virtually all wavelengths from radio through TeV gamma-rays. The challenge since their discovery has been to understand the origin of their luminous, apparently nonthermal, nuclear emission.…

Astrophysics · Physics 2007-05-23 C. Megan Urry

The evolutionary classification of molecular clumps, crucial for understanding star formation, is commonly based on human-assigned categories derived from infrared (IR) emission and well-established morphological criteria. However, due to…

Astrophysics of Galaxies · Physics 2026-02-27 K. V. Plakitina , M. S. Kirsanova , A. B. Ostrovskii , A. D. Gimalieva , S. V. Salii , A. V. Meshcheryakov

Various attempts have been made in the literature at describing the origin and the physical mechanisms behind flaring events in blazars with radiative emission models, but detailed properties of multi-wavelength (MWL) light curves still…

High Energy Astrophysical Phenomena · Physics 2021-07-07 A. Dmytriiev , H. Sol , A. Zech

A method is developed for estimating the emission rates of contaminants into the atmosphere from multiple point sources using measurements of particulate material deposited at ground level. The approach is based on a Gaussian plume type…

Atmospheric and Oceanic Physics · Physics 2010-06-11 Enkeleida Lushi , John M. Stockie

We put forward a scenario where blazars are classified as flat-spectrum radio quasars, BL Lacs, low synchrotron, or high synchrotron peaked objects according to a varying combination of Doppler boosted radiation from the jet, emission from…

High Energy Astrophysical Phenomena · Physics 2012-05-04 P. Padovani , P. Giommi , G. Polenta , S. Turriziani , V. D'Elia , S. Piranomonte

Gamma-ray bursts (GRBs) are commonly attributed to the demise of massive stars or the merger of binary compact objects. However, their varied emission characteristics strongly imply the existence of multiple GRB classes based on progenitor…

High Energy Astrophysical Phenomena · Physics 2024-07-12 Nishil Mehta , Shabnam Iyyani

In the recently published 3FGL catalogue, the Fermi/LAT collaboration reports the detection of $\gamma$-ray emission from 3034 sources obtained after four years of observations. The nature of 1010 of those sources is unknown, whereas 2023…

High Energy Astrophysical Phenomena · Physics 2017-06-21 J. Lefaucheur , S. Pita

In order to obtain morphological information of unlabeled galaxies, we present an unsupervised machine-learning (UML) method for morphological classification of galaxies, which can be summarized as two aspects: (1) the methodology of…

Astrophysics of Galaxies · Physics 2022-02-02 C. C. Zhou , Y. Z. Gu , G. W. Fang , Z. S. Lin