Very narrow coronal mass ejections producing solar energetic particles

Aims. Our main aim is to study the relationship between low-energy solar particles (energies below 1 MeV) and very narrow coronal mass ejections (“jets” with angular width ≤20 ◦ ). Methods. For this purpose, we considered 125 very narrow coronal mass ejections (CMEs) from 1999 to 2003 that are potentially associated with low-energy solar particles (LESPs). These events were chosen on the basis of their source location. We studied only very narrow CMEs at the western limb, which are expected to have good magnetic connectivity with Earth. Results. We found 24 very narrow CMEs associated with energetic particles such as ions (protons and 3 He), electrons, or both. We show that arrival times at Earth of energetic particles are consistent with onset times of the respective CMEs, and that in the same time intervals, there are no other potential sources of energetic particles. We also demonstrate statistical di ff erences for the angular width distributions using the Kolmogorov–Smirnov test for angular widths for these 24 events. We consider a coherent sample of jets (mostly originating from boundaries of coronal holes) to identify properties of events that produce solar energetic particles (velocities, widths, and position angles). Our study presents a new approach and result: very narrow CMEs can generate low-energy particles in the vicinity of Earth without other activity on the Sun. The results could be very useful for space weather forecasting

Badanie geoefektywności koronalnych wyrzutów masy

Niniejsza rozprawa prezentuje wyniki badań nad geoefektywnością koronalnych wyrzutów masy (KWM), Badania były skoncentrowane na dwóch istotnych aspektach dotyczących prognozowania pogody kosmicznej. Jednym aspektem badań było pokazanie korelacji miedzy zjawiskami na słońcu a KWM produkującymi energetyczne cząstki. Badania pokazały, że bardzo wąskie KWM mogą generować w pobliżu Ziemi niskoenergetyczne cząstki (energie poniżej 1 MeV) bez dodatkowej aktywności na Słońcu, Pokazano także, iż obszary aktywne zlokalizowane na wschodniej części tarczy słonecznej mogą produkować energetyczne cząstki jedynie jeżeli ich struktura magnetyczna jest bardzo złożona. Natomiast obszary aktywne zlokalizowane w środkowej oraz zachodniej części tarczy słonecznej nie muszą mieć złożonej struktury magnetycznej aby produkować energetyczne cząstki. Drugi aspekt badań dotyczył zdefiniowania zjawisk wpływających na badanie KWM przy wykorzystaniu koronografów, W tych badaniach oceniono efektywność detekcji koronografów LASCO i pokazano, że te koronografy są w stanie wykryć wszystkie potencjalnie geoefektywne KWM, Jednak obserwacje przy użyciu koronografów są obarczone efektem projekcji, Z tego powodu praktycznie niemożliwe jest wyznaczenie rzeczywistych parametrów KWM przez co trudniej jest przewidzieć ich geoefektywność, W tych badaniach, wykorzystując obserwacje z satelit STEREO będących w kwadraturze względem Ziemi, oszacowany został efekt projekcji wpływający na wyznaczanie prędkość KWM, Pokazano, że ten efekt zależy w dużym stopniu od szerokości kątowych oraz lokalizacji KWM na Słońcu, Wszystkie otrzymane wyniki mogą być bardzo przydatne do prognozowania pogody kosmicznej.This dissertation is an attempt to investigate geoeffectiveness of CMEs, The study was focused on two important aspects regarding the prediction of space weather. Firstly, it was presented relationship between energetic phenomena on the Sun and CMEs producing solar energetic particles. Scientific considerations demonstrated that very narrow CMEs can generate low energy particles (energies below 1 MeV) in the Earth's vicinity without other activity on the Sun, It was also shown that SEP events associated with active regions from eastern longitudes have to be complex to produce SEP events at Earth, On the other hand, SEP particles originating from mid-longitudes (30°<latitude<70°) on the west side of solar disk can be also associated with the least complex active regions. Secondly, two phenomena affecting CMEs detection in coronagraphs have been defined. During the study the detection efficiency of LASCO coronagraphs was evaluated. It was shown that the detection efficiency of the LASCO coronagraphs with typical data availability is sufficient to record all potentially geoeffective CMEs, However, coronagraphic observations of CMEs are subject to projection effects. This makes it practically impossible to determine the true properties of CMEs and therefore makes more difficult to forecast their geoeffectiveness. In this study, using quadrature observations with the two STEREO spacecrafts, projection effects affecting velocity of CMEs included in the SOHO/LASCO catalog were estimated. It was demonstrated that this effect depends significantly on width and source location of CMEs, All these results could be very useful for forecasting of space weather

Statistical studies of giant radio sources

This work consisted of arrangement and cataloging of all previously knowngiant radio sources. The main objective of this study was to create acatalog of giants, which is homogeneous source of information for future research,and for large-scale radio surveys of the sky. The data were taken to the catalog from available publications. Task was to complement the incompleteinformation, classification and analysis of the sample of objects.I researched the sample of objects in terms of statistical analysisand drafted a correlation between optical brightness of galaxies and theirredshift, as well as other dependencies. In addition, I created spatialdistributions for all known 218 giant radio sources, which give valuableinformation about distribution of these objects in the sky.Niniejsza praca polegała na uporządkowaniu i skatalogowaniu wszystkich dotychczas znanych gigantycznych radioźródeł. Głównym celem pracy było stworzenie katalogu gigantów, który stanowiłby jednorodne źródło informacji dla przyszłych badań, a także dla wielkoskalowych radiowych przeglądów nieba. Dane do katalogu zostały zaczerpnięte z dostępnych publikacji. Praca polegała na uzupełnieniu często niekompletnych informacji, klasyfikacji i analizie próbki obiektów. Opracowałam dane pod względem statystycznym i sporządziłam korelacje jasności optycznych galaktyk macierzystych i ich przesunięcia ku czerwieni, oraz inne zależności. Ponadto stworzyłam rozkłady dla wszystkich znanych 218 gigantycznych radioźródeł, które nasuwają ciekawe wnioski na temat przestrzennego rozmieszczenia tych obiektów na niebie

Dynamics of CMEs in the LASCO field of view

A large set (16000) of coronal mass ejections (CMEs) observed during 1996-2011 was selected to study their dynamics in the LASCO field of view (LFOV). These events were selected based on the criterion that at least three height-time measurements were available for each CME. The height-time measurements included in the SOHO/LASCO catalog were used to determine velocities and accelerations of the respective CMEs at successive distances from the Sun. Next, these parameters were sorted into 30 subsamples depending on the distance from the Sun at which they were determined. The mean velocities and accelerations calculated for the successive distance-dependent subsamples of CMEs were used to study their dynamics. We demonstrate that CMEs in the LFOV manifest three distinct phases of propagation: (i) The propelling Lorentz force dominates the dynamics of CMEs in the inner (C2 LASCO) FOV, (ii) a stable propagation occurs as a result of the balance between the propelling and drag forces, (iii) the drag force dominates at the outer edge of the LFOV. When we considered different categories of CME separately, we found different acceleration distance profiles for different categories

An updated catalog of giant radio sources

We present a catalogue of 349 giant radio sources (GRSs including both galaxies and quasars). The database contains all giants known to date from the literature. These GRSs cover the redshift range of 0.016$<$z$<$3.22 and include radio sources of projected linear sizes larger than 0.7~Mpc which extend up to 4.7~Mpc. We provide the principal parameters (i.e. exact position of the host in the sky, redshift, angular and projected linear size, red optical magnitude, radio morphology type, total radio flux density and luminosity) for all the sources as well as characteristics of the sample. Based on the distribution of GRSs in the sky we identify regions where there is a paucity of giants, so that future surveys for this type of objects could concentrate primarily in these fields. From the analysis presented here, we estimate a lower limit for the expected number of GRSs as about 2000, for the resolution and sensitivity limits of FIRST, NRAO VLA Sky Survey and Sloan Digital Sky Survey surveys. Compared with earlier compilations, there is a significant increase in the number of large giants with sizes $>$ 2 Mpc as well as those at high redshifts with z$>$1. We discuss aspects of their evolution and suggest that these are consistent with evolutionary models.Comment: 20 pages, 7 figures, 1 table. Accepted to publish in ApJ