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We study the decay phase of solar flares in several spectral bands using a method based on that successfully applied to white light flares observed on an M4 dwarf. We selected and processed 102 events detected in the Sun-as-a-star flux…

Solar and Stellar Astrophysics · Physics 2021-02-10 Larisa K. Kashapova , Anne-Marie Broomhall , Alena I. Larionova , Elena G. Kupriyanova , Ilya D. Motyk

Efforts are underway to use high-precision timing of pulsars in order to detect low-frequency gravitational waves. A limit to this technique is the timing noise generated by dispersion in the plasma along the line of sight to the pulsar,…

High Energy Astrophysical Phenomena · Physics 2022-02-04 P. Kumar , S. M. White , K. Stovall , J. Dowell , G. B. Taylor

An analysis of DAMA data (as reconstructed from DAMA publications) confirms the presence of an annual oscillation, but with a lower significance level than that claimed by DAMA. The phase of their signal is 0.39 +/- 0.02, corresponding to a…

High Energy Physics - Phenomenology · Physics 2012-10-30 Peter A. Sturrock , Ephraim Fischbach , Jere H. Jenkins , Rafael Lang , Jonathan Nistor

The analysis of the observations of solar activity indexes SSN (NOAA Sunspot Numbers), the radio flux at a wavelength of 10.7 cm (F10.7) and the solar constant (TSI) during the cycles 22 - 24 is presented. We found a decrease of the…

Solar and Stellar Astrophysics · Physics 2015-10-08 E. A. Bruevich , G. V. Yakunina

We investigate the response of outer radiation belt electron fluxes to different solar wind and geomagnetic indices using an interpretable machine learning method. We reconstruct the electron flux variation during 19 enhancement and 7…

Space Physics · Physics 2024-01-12 Donglai Ma , Jacob Bortnik , Qianli Ma , Man Hua , Xiangning Chu

The sunspot activity is the end result of the cyclic destruction and regeneration of magnetic fields by the dynamo action. We propose a new method to analyze the daily sunspot areas data recorded since 1874. By computing the power spectral…

Solar and Stellar Astrophysics · Physics 2015-05-20 Ilidio Lopes , Hugo G. Silva

Neutrinos generated during solar flares remain elusive. However, after $50$ years of discussion and search, the potential knowledge unleashed by their discovery keeps the search crucial. Neutrinos associated with solar flares provide…

Solar and Stellar Astrophysics · Physics 2020-10-12 K. Okamoto , Y. Nakano , S. Masuda , Y. Itow , M. Miyake , T. Terasawa , S. Ito , M. Nakahata

The observed persistence of specific periodicities detected in time series associated with solar surface magnetic activity over several solar cycles has led to numerous papers supporting the existence of preferred longitudes. Recent…

Astrophysics · Physics 2007-05-23 C. J. Henney , B. R. Durney

Ice cores are known to yield information about astronomical phenomena as well as information about past climate. We report time series analyses of annually resolved nitrate variations in an ice core, drilled at the Dome Fuji station in East…

Solar and Stellar Astrophysics · Physics 2022-09-26 Yuko Motizuki , Yoichi Nakai , Kazuya Takahashi , Takashi Imamura , Hideaki Motoyama

In this paper, we analyze the impact of information freshness on supervised learning based forecasting. In these applications, a neural network is trained to predict a time-varying target (e.g., solar power), based on multiple correlated…

Machine Learning · Computer Science 2021-04-09 Md Kamran Chowdhury Shisher , Heyang Qin , Lei Yang , Feng Yan , Yin Sun

The daily sunspot numbers of the whole disk as well as the northern and southern hemispheres from January 1, 1945 to December 31, 2010 are used to investigate the temporal variation of the rotational cycle length through the continuous…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. -L. Xie , X. -J. Shi , J. -C. Xu

We provide the results from a spectral analysis of nuclear decay data displaying annually varying periodic fluctuations. The analyzed data were obtained from three distinct data sets: 32Si and 36Cl decays reported by an experiment performed…

A commonly-used paradigm to estimate changes in the frequency of past events or the size of populations is to consider the occurrence rate of archaeological/environmental samples found at a site over time. The reliability of such a…

Methodology · Statistics 2025-05-01 Timothy J Heaton , Sara Al-assam , Edouard Bard

We present a combined analysis of XMM-Newton, Chandra and Rosat observations of the isolated neutron star RX J0720.4-3125, spanning a total period of \sim 7 years. We develop a maximum likelihood periodogramme based on \Delta C statistic…

In this paper, the post-1977 photometric observations of PKS 2155-304 are compiled and used to discuss the variation periodicity. Largest amplitude variations ($\Delta U = 1^{m}.5$; $\Delta B = 1^{m}.65$; $\Delta V = 1^{m}.85 $; $\Delta R =…

Astrophysics · Physics 2007-05-23 J. H. Fan , R. G. Lin

The aim of the present study is to show the varying asymmetries during the decay of sunspot groups. The source of input data is the SoHO/MDI-Debrecen Database (SDD) sunspot catalog that contains the magnetic polarity data for time interval…

Solar and Stellar Astrophysics · Physics 2022-02-02 Judit Muraközy

In our recent investigation, we utilized a century's worth of archival optical data to search for a decade-long periodicity from the blazar PG 1553+113, finding a hint of a 22-yr period. Building on this foundation, the current study…

High Energy Astrophysical Phenomena · Physics 2025-06-03 Sagar Adhikari , Pablo Peñil , Alberto Domínguez , Marco Ajello , Sara Buson , Alba Rico

New data and results on the optical behaviour of the blazar PKS 0735+178 are presented. In addition the whole historical light curve, and a new photometric calibration of comparison stars are reported. Optical spectral indexes are…

With its relatively long observation time per pointing, the Parkes multibeam survey was effective in detecting nulling pulsars. We have made 2-hour observations of 23 pulsars which showed evidence for pulse nulling or mode changing in the…

Astrophysics · Physics 2008-11-26 N. Wang , R. N. Manchester , S. Johnston

Variability is a well known phenomenon in low-mass young stellar objects, but in recent years the monitoring of methanol masers and infrared continuum emission has permitted the detection of both burst-like episodes and periodic variations…

Solar and Stellar Astrophysics · Physics 2026-05-20 Riccardo Cesaroni