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L-filters and TL-filters in IL-algebras
No full textIn this paper, we introduce the concepts of L-filter and TL-filter as two
different generalizations of the notion of fuzzy filter in IL-algebras. We investigate some
properties with respect to these concepts. We study the relationship between L-filters
and TL-filters. We give some characterizations for filters of IL-algebras by using Lfilters
and TL-filters. We present additional conditions so that the notions of L-filter
and TL-filter coincide in an IL-algebra
Observational diversity of bright long-lived Type II supernovae
No full textIn various types of supernovae (SNe), strong interaction between the SN ejecta and circumstellar material (CSM) has been reported. This raises questions about their progenitors and mass-loss processes shortly before the explosion. Recently, the bright long-lived Type II SN 2021irp was proposed to be a standard Type II SN interacting with disk-like CSM. The observational properties suggest that the progenitor was a massive star (∼8-18 M_⊙) in a binary system and underwent a mass-ejection process due to the binary interaction just before the explosion. Similar scenarios, i.e., a Type II SN interacting with a CSM disk, have also been invoked to explain some Type IIn SNe. Here, we study the diversity of the observational properties of bright long-lived Type II (21irp-like) SNe. We analyze the diversity of their CSM properties, in order to understand their progenitors and mass-loss mechanisms and their relations with the other types of interacting SNe. We performed photometry, spectroscopy, and/or polarimetry for four 21irp-like SNe. Based on these observations as well as published data of SN 2021irp itself and well-observed bright and long-lived type II SNe including SNe 2010jl, 2015da, and 2017hcc, we discuss their CSM characteristics. This sample of SNe shows luminous and long-lived photometric evolution, with some variations in the photometric evolution (from ∼-17 to ∼-20 absolute mag in the r/o band even at ∼ 200 days after the explosion). They show photospheric spectra characterized mainly by Balmer lines for several hundreds of days, with some variations in the shapes of the lines. They show high polarization with slight variations in the polarization degrees (∼1-3 % at the brightness peak) with rapid declines with time (from ∼3-6 % before the peak to ∼1 % at ∼200 days after the peak). The general observational properties are consistent with the disk-CSM-interaction scenario, i.e., typical Type II SNe interacting with disk-like CSM. At the same time, the variation in the observational properties suggest diversity in the CSM mass and the opening angle of the CSM disk. These variations in the CSM properties are likely to be be related to the binary parameters of the progenitor systems and/or the properties of the progenitor and companion stars
Scaler rates from the Pierre Auger Observatory
No full textThe modulation of low-energy galactic cosmic rays reflects interplanetary magnetic field variations and can provide useful information on solar activity. An array of ground-surface detectors can reveal the secondary particles, which originate from the interaction of cosmic rays with the atmosphere. In this work, we present an investigation of the low-threshold rate (scaler) time series recorded in 16 yr of operation by the Pierre Auger Observatory surface detectors in Malargüe, Argentina. Through an advanced spectral analysis, we detected highly statistically significant variations in the time series with periods ranging from the decadal to the daily scale. We investigate their origin, revealing a direct connection with solar variability. Thanks to their intrinsic very low noise level, the Auger scalers allow a thorough and detailed investigation of the galactic cosmic-ray flux variations in the heliosphere at different timescales and can, therefore, be considered a new proxy of solar variability