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We present spectroscopy of binary quasar candidates selected from Data Release 4 of the Sloan Digital Sky Survey (SDSS DR4) using Kernel Density Estimation (KDE). We present 27 new sets of observations, 10 of which are binary quasars,…

Stellar flares are abundant in space photometric light curves. As they are now available in large enough numbers, the statistical study of their overall temporal morphology is timely. We use light curves from the Transiting Exoplanet Survey…

Solar and Stellar Astrophysics · Physics 2025-02-12 Bálint Seli , Krisztián Vida , Katalin Oláh , Anna Görgei , Szabolcs Soós , András Pál , Levente Kriskovics , Zsolt Kővári

The low luminosity, X-ray flaring activity, of the sub-class of high mass X-ray binaries called Supergiant Fast X-ray Transients, has been investigated using XMM-Newton public observations, taking advantage of the products made publicly…

High Energy Astrophysical Phenomena · Physics 2019-05-15 L. Sidoli , K. A. Postnov , A. Belfiore , M. Marelli , D. Salvetti , R. Salvaterra , A. De Luca , P. Esposito

Modern time-domain surveys produce alert streams at a scale that makes exhaustive manual inspection infeasible, requiring automated methods to identify unusual transients for follow-up. In this work, we present an unsupervised anomaly…

Solar and Stellar Astrophysics · Physics 2026-02-16 Leyla Iskandarli , Chris J. Lintott , Steve Croft , Heloise Stevance , Joshua Weston

Sunquakes (SQs) have been routinely observed in the solar photosphere, but it is only recently that signatures of these events have been detected in the chromosphere. We investigate whether signatures of SQs are common in Ultraviolet (UV)…

Solar and Stellar Astrophysics · Physics 2021-10-20 Sean Quinn , Mihalis Mathioudakis , Christopher J. Nelson , Ryan O. Milligan , Aaron Reid , David B. Jess

The physics and demographics of type 2 quasars remain poorly understood, and new samples of such objects selected in a variety of ways can give insight into their physical properties, evolution, and relationship to their host galaxies. We…

Astrophysics of Galaxies · Physics 2017-03-17 Sihan Yuan , Michael A. Strauss , Nadia L. Zakamska

Based on a 10 years sample of gamma-ray flares of FSRQs collected with FERMI and AGILE, I report on this proceeding the advance on a statistical study of variability for a sample of more than 300 FSRQs. I will focus on waiting time between…

High Energy Astrophysical Phenomena · Physics 2025-07-08 Luigi Pacciani

We present the second catalog of flaring gamma-ray sources (2FAV) detected with the Fermi All-sky Variability Analysis (FAVA), a tool that blindly searches for transients over the entire sky observed by the Large Area Telescope (LAT) on…

High Energy Astrophysical Phenomena · Physics 2017-09-13 S. Abdollahi , M. Ackermann , M. Ajello , A. Albert , L. Baldini , J. Ballet , G. Barbiellini , D. Bastieri , J. Becerra Gonzalez , R. Bellazzini , E. Bissaldi , R. D. Blandford , E. D. Bloom , R. Bonino , E. Bottacini , J. Bregeon , P. Bruel , R. Buehler , S. Buson , R. A. Cameron , M. Caragiulo , P. A. Caraveo , E. Cavazzuti , C. Cecchi , A. Chekhtman , C. C. Cheung , G. Chiaro , S. Ciprini , J. Conrad , D. Costantin , F. Costanza , S. Cutini , F. D'Ammando , F. de Palma , A. Desai , R. Desiante , S. W. Digel , N. Di Lalla , M. Di Mauro , L. Di Venere , B. Donaggio , P. S. Drell , C. Favuzzi , S. J. Fegan , E. C. Ferrara , W. B. Focke , A. Franckowiak , Y. Fukazawa , S. Funk , P. Fusco , F. Gargano , D. Gasparrini , N. Giglietto , M. Giomi , F. Giordano , M. Giroletti , T. Glanzman , D. Green , I. A. Grenier , J. E. Grove , L. Guillemot , S. Guiriec , E. Hays , D. Horan , T. Jogler , G. Jóhannesson , A. S. Johnson , D. Kocevski , M. Kuss , G. La Mura , S. Larsson , L. Latronico , J. Li , F. Longo , F. Loparco , M. N. Lovellette , P. Lubrano , J. D. Magill , S. Maldera , A. Manfreda , M. Mayer , M. N. Mazziotta , P. F. Michelson , W. Mitthumsiri , T. Mizuno , M. E. Monzani , A. Morselli , I. V. Moskalenko , M. Negro , E. Nuss , T. Ohsugi , N. Omodei , M. Orienti , E. Orlando , V. S. Paliya , D. Paneque , J. S. Perkins , M. Persic , M. Pesce-Rollins , V. Petrosian , F. Piron , T. A. Porter , G. Principe , S. Rainò , R. Rando , M. Razzano , S. Razzaque , A. Reimer , O. Reimer , C. Sgrò , D. Simone , E. J. Siskind , F. Spada , G. Spandre , P. Spinelli , L. Stawarz , D. J. Suson , M. Takahashi , K. Tanaka , J. B. Thayer , D. J. Thompson , D. F. Torres , E. Torresi , G. Tosti , E. Troja , G. Vianello , K. S. Wood

We present a catalog of quasars selected from broad-band photometric ugri data of the Kilo-Degree Survey Data Release 3 (KiDS DR3). The QSOs are identified by the random forest (RF) supervised machine learning model, trained on SDSS DR14…

Instrumentation and Methods for Astrophysics · Physics 2019-04-10 S. Nakoneczny , M. Bilicki , A. Solarz , A. Pollo , N. Maddox , C. Spiniello , M. Brescia , N. R. Napolitano

Variations in scaling behavior in the flux and emissions of gravitational lensed quasars can provide valuable information about the dynamics within the sources and their cosmological evolution with time. Here, we study the multifractal…

We have observed 104 gravitationally-lensed quasars at $z\sim1-4$ with Herschel/SPIRE, the largest such sample ever studied. By targeting gravitational lenses, we probe intrinsic far-infrared (FIR) luminosities and star formation rates…

The 100,000 spectra from the 2 degree Field Galaxy Redshift Survey (2dFGRS) in the 100k Public Data Release represent the largest single compilation of galaxy spectra available. By virtue of its sheer size and the properties of the…

Astrophysics · Physics 2009-11-07 Darren S. Madgwick , Paul C. Hewett , Daniel J. Mortlock , Ofer Lahav

Solar flares represent one of the most intense forms of solar activity. Understanding the evolution of physical parameters in the solar atmosphere during flares is key to studying flare mechanisms and improving prediction capabilities.…

Solar and Stellar Astrophysics · Physics 2026-05-27 W. Xu , Q. Hao , Z. Zheng , J. Hong , J. Hu , Y. Qiu , C. Li , M. D. Ding , C. Fang

We present the results of a search for stellar flares in the first data release from the Next Generation Transit Survey (NGTS). We have found 610 flares from 339 stars, with spectral types between F8 and M6, the majority of which belong to…

Machine learning methods are well established in the classification of quasars (QSOs). However, the advent of light curve observations adds a great amount of complexity to the problem. Our goal is to use the Zwicky Transient Facility (ZTF)…

We present the proof-of-concept of a method to find strongly lensed quasars using their spatially-extended photometric variability through difference imaging in cadenced imaging survey data. We apply the method to Pan-STARRS, starting with…

This work investigates symbolic regression (SR) as an interpretable alternative to black-box machine learning for the classification of stars, galaxies, and quasars in the Sloan Digital Sky Survey Data Release 17 (SDSS DR17). We conduct a…

Instrumentation and Methods for Astrophysics · Physics 2026-03-02 Rachit Deshpande , Shantanu Desai

We present CLARA, a modular framework for unsupervised transit detection in TESS light curves, leveraging Unsupervised Random Forests (URFs) trained on synthetic datasets and guided by morphological similarity analysis. This work addresses…

Instrumentation and Methods for Astrophysics · Physics 2025-09-24 Mainak Dasgupta

Ultraviolet flare emission can drive photochemistry in exoplanet atmospheres and even serve as the primary source of uncertainty in atmospheric retrievals. Additionally, flare energy budgets are not well-understood due to a paucity of…