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Archives of long photometric surveys, like the Kepler database, are a gold mine for studying flares. However, identifying them is a complex task; while in the case of single-target observations it can be easily done manually by visual…

Solar and Stellar Astrophysics · Physics 2018-09-12 Krisztián Vida , Rachael M. Roettenbacher

Context.A new reduction of the astrometric data as produced by the Hipparcos mission has been published, claiming accuracies for nearly all stars brighter than magnitude Hp = 8 to be better, by up to a factor 4, than in the original…

Astrophysics · Physics 2010-04-06 F. van Leeuwen

We present here a re-calibration of the photometric systems used in the Pantheon+ sample of Type Ia supernovae (SNe Ia) including those used for the SH0ES distance-ladder measurement of H$_0$. We utilize the large and uniform sky coverage…

We conducted a detailed long-term spectral and temporal study of flat spectrum radio quasar 4C +01.02, by using the multi-wavelength observations from Fermi-LAT, Swift-XRT, and Swift-UVOT. The $2$-day bin $\gamma$-ray lightcurve in the…

High Energy Astrophysical Phenomena · Physics 2022-06-22 Malik Zahoor , Shah Zahir , Sunder Sahayanathan , Naseer Iqbal , Aaqib Manzoor

Aims. The blazars Mrk 421 and Mrk 501 have shown multiwavelength variability on all observed timescales, and have been well studied at high energies on short timescales. We aim to characterise the long-term temporal behaviour of these…

High Energy Astrophysical Phenomena · Physics 2026-02-25 Gabrielle L. Taylor , Stefan J. Wagner , Alicja Wierzcholska , Michael Zacharias

Quantitative evaluations of differences and/or similarities between data samples define and shape optimisation problems associated with learning data distributions. Current methods to compare data often suffer from limitations in capturing…

Machine Learning · Computer Science 2024-01-23 Deborah Pelacani Cruz , George Strong , Oscar Bates , Carlos Cueto , Jiashun Yao , Lluis Guasch

Direct observations of the Hubble rate, from cosmic chronometers and the radial baryon acoustic oscillation scale, can out-perform supernovae observations in understanding the expansion history, because supernovae observations need to be…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-26 Marina Seikel , Sahba Yahya , Roy Maartens , Chris Clarkson

We present results from daily monitoring of gamma rays in the energy range $\sim0.5$ to $\sim100$ TeV with the first 17 months of data from the High Altitude Water Cherenkov (HAWC) Observatory. Its wide field of view of 2 steradians and…

High Energy Astrophysical Phenomena · Physics 2017-06-14 A. U. Abeysekara , A. Albert , R. Alfaro , C. Alvarez , J. D. Álvarez , R. Arceo , J. C. Arteaga-Velázquez , D. Avila Rojas , H. A. Ayala Solares , A. S. Barber , N. Bautista-Elivar , J. Becerra Gonzalez , A. Becerril , E. Belmont-Moreno , S. Y. BenZvi , A. Bernal , J. Braun , C. Brisbois , K. S. Caballero-Mora , T. Capistrán , A. Carramiñana , S. Casanova , M. Castillo , U. Cotti , J. Cotzomi , S. Coutiño de León , C. De León , E. De la Fuente , R. Diaz Hernandez , B. L. Dingus , M. A. DuVernois , J. C. Díaz-Vélez , R. W. Ellsworth , K. Engel , D. W. Fiorino , N. Fraija , J. A. García-González , F. Garfias , M. Gerhardt , A. González Muñoz , M. M. González , J. A. Goodman , Z. Hampel-Arias , J. P. Harding , S. Hernandez , A. Hernandez-Almada , B. Hona , C. M. Hui , P. Hüntemeyer , A. Iriarte , A. Jardin-Blicq , V. Joshi , S. Kaufmann , D. Kieda , A. Lara , R. J. Lauer , W. H. Lee , D. Lennarz , H. León Vargas , J. T. Linnemann , A. L. Longinotti , G. Luis Raya , R. Luna-García , R. López-Coto , K. Malone , S. S. Marinelli , O. Martinez , I. Martinez-Castellanos , J. Martínez-Castro , J. A. Matthews , P. Miranda-Romagnoli , E. Moreno , M. Mostafá , L. Nellen , M. Newbold , M. U. Nisa , R. Noriega-Papaqui , J. Pretz , E. G. Pérez-Pérez , Z. Ren , C. D. Rho , C. Rivière , D. Rosa-González , M. Rosenberg , E. Ruiz-Velasco , F. Salesa Greus , A. Sandoval , M. Schneider , H. Schoorlemmer , G. Sinnis , A. J. Smith , R. W. Springer , P. Surajbali , I. Taboada , O. Tibolla , K. Tollefson , I. Torres , T. N. Ukwatta , G. Vianello , T. Weisgarber , S. Westerhoff , I. G. Wisher , J. Wood , T. Yapici , P. W. Younk , A. Zepeda , H. Zhou

Reconstructing the large scale density and velocity fields from surveys of galaxy distances, is a major challenge for cosmography. The data is very noisy and sparse. Estimated distances, and thereby peculiar velocities, are strongly…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-21 Aurélien Valade , Noam I Libeskind , Yehuda Hoffman , Simon Pfeifer

Two measurements of the energy resolution were performed at MAX-Lab in Lund, Sweden, with an array of 3$\times$3 PbWO4 crystals using a tagged photon beam with energies between 19 and 56 MeV. The crystals were cooled down to -15 and -25…

Nuclear Experiment · Physics 2008-05-08 Sophie Grape

We present results of variability study of a sample of 20 powerful blazars using Fermi/LAT (0.1--300 GeV) observations. We studied decade-long observations applying various analysis tools such as flux distribution, symmetry analysis, and…

High Energy Astrophysical Phenomena · Physics 2021-07-27 Gopal Bhatta , Niraj Dhital

Optical observations of a sample of 12 $\gamma$-ray bright blazars from four optical data archives, AAVSO, SMARTS, Catalina, and Steward Observatory, are compiled to create densely sampled light curves spanning more than a decade. As a part…

High Energy Astrophysical Phenomena · Physics 2021-12-15 Gopal Bhatta

The possibility to perform the frequency analysis of the light variation of V798 Cyg on the basis of a more accurate set of data and the Fourier decomposition of the new light curve of V831 Tau allowed us to improve the knowledge of the…

Astrophysics · Physics 2016-08-30 Federica Musazzi , Ennio Poretti , Stefano Covino , Armando Arellano Ferro

We present a catalogue of ALMA flux density measurements of 754 calibrators observed between August 2012 and September 2017, for a total of 16,263 observations in different bands and epochs. The flux densities were measured reprocessing the…

We present a comprehensive 20-year multiwavelength variability study of the blazar PKS 2155-304, one of the most luminous and extensively monitored high-frequency-peaked BL Lac objects in the southern hemisphere. Using Fermi-LAT…

High Energy Astrophysical Phenomena · Physics 2026-04-02 A. Wierzcholska , M. Zacharias

We continuously monitored the blazar S5 0716+714 in the optical $g$, $r$ and $i$ bands from Nov. 10, 2017 to Jun. 06, 2019. The total number of observations is 201 nights including 26973 data points. This is a very large quasi-simultaneous…

High Energy Astrophysical Phenomena · Physics 2020-04-01 Dingrong Xiong , Jinming Bai , Junhui Fan , Dahai Yan , Minfeng Gu , Xuliang Fan , Jirong Mao , Nan Ding , Rui Xue , Weimin Yi

A recalibration of the luminosity-linewidth technique is discussed which introduces (i) new cluster calibration data, (ii) new corrections for reddening as a function of inclination, and (iii) a new zero-point calibration using 13 galaxies…

Astrophysics · Physics 2007-05-23 R. Brent Tully

We present a detailed investigation of the temporal and spectral evolution of the emission from the blazar PKS 2155-304, a high-synchrotron-peaked (HSP) blazar. Using $\gamma$-ray, X-ray, optical/UV, and infrared data assembled from the…

High Energy Astrophysical Phenomena · Physics 2025-09-16 G. Harutyunyan , N. Sahakyan , D. Bégué , M. Khachatryan

We present a new tool for data analysis: persistence discrete homology, which is well-suited to analyze filtrations of graphs. In particular, we provide a novel way of representing high-dimensional data as a filtration of graphs using…

Algebraic Topology · Mathematics 2025-06-23 Chris Kapulkin , Nathan Kershaw

Context. The international whole earth blazar telescope (WEBT) consortium planned and carried out three days of intensive micro-variability observations of S5 0716+714 from February 22, 2009 to February 25, 2009. This object was chosen due…