The magnetic connectivity of coronal shocks from behind-the-limb flares to the visible solar surface during γ\gamma-ray events

Context. The observation of >100 MeV {\gamma}-rays in the minutes to hours following solar flares suggests that high-energy particles interacting in the solar atmosphere can be stored and/or accelerated for long time periods. The occasions when {\gamma}-rays are detected even when the solar eruptions occurred beyond the solar limb as viewed from Earth provide favorable viewing conditions for studying the role of coronal shocks driven by coronal mass ejections (CMEs) in the acceleration of these particles. Aims: In this paper, we investigate the spatial and temporal evolution of the coronal shocks inferred from stereoscopic observations of behind-the-limb flares to determine if they could be the source of the particles producing the {\gamma}-rays. Methods: We analyzed the CMEs and early formation of coronal shocks associated with {\gamma}-ray events measured by the Fermi-Large Area Telescope (LAT) from three eruptions behind the solar limb as viewed from Earth on 2013 Oct. 11, 2014 Jan. 06 and Sep. 01. We used a 3D triangulation technique, based on remote-sensing observations to model the expansion of the CME shocks from above the solar surface to the upper corona. Coupling the expansion model to various models of the coronal magnetic field allowed us to derive the time-dependent distribution of shock Mach numbers and the magnetic connection of particles produced by the shock to the solar surface visible from Earth. Results: The reconstructed shock fronts for the three events became magnetically connected to the visible solar surface after the start of the flare and just before the onset of the >100 MeV {\gamma}-ray emission. The shock surface at these connections also exhibited supercritical Mach numbers required for significant particle energization. [...] (Abridged)Comment: 20 pages, 15 figures, version published in A&

Global Energetics of Thirty-Eight Large Solar Eruptive Events

We have evaluated the energetics of 38 solar eruptive events observed by a variety of spacecraft instruments between February 2002 and December 2006, as accurately as the observations allow. The measured energetic components include: (1) the radiated energy in the GOES 1 - 8 A band; (2) the total energy radiated from the soft X-ray (SXR) emitting plasma; (3) the peak energy in the SXR-emitting plasma; (4) the bolometric radiated energy over the full duration of the event; (5) the energy in flare-accelerated electrons above 20 keV and in flare-accelerated ions above 1 MeV; (6) the kinetic and potential energies of the coronal mass ejection (CME); (7) the energy in solar energetic particles (SEPs) observed in interplanetary space; and (8) the amount of free (nonpotential) magnetic energy estimated to be available in the pertinent active region. Major conclusions include: (1) the energy radiated by the SXR-emitting plasma exceeds, by about half an order of magnitude, the peak energy content of the thermal plasma that produces this radiation; (2) the energy content in flare-accelerated electrons and ions is sufficient to supply the bolometric energy radiated across all wavelengths throughout the event; (3) the energy contents of flare-accelerated electrons and ions are comparable; (4) the energy in SEPs is typically a few percent of the CME kinetic energy (measured in the rest frame of the solar wind); and (5) the available magnetic energy is sufficient to power the CME, the flare-accelerated particles, and the hot thermal plasma

INTEGRAL/IBIS search for e-e+ annihilation radiation from the Galactic Center Region

Electron-positron annihilation radiation from the Galactic Center region has been detected since the seventies, but its astrophysical origin is still a topic of a scientific debate. We have analyzed data of the gamma-ray imager IBIS/ISGRI onboard of ESA's INTEGRAL platform in the e$^{-}$e$^{+}$ line. During the first year of the missions Galactic Center Deep Exposure no evidence for point sources at 511 keV has been found in the ISGRI data; the $2 \sigma$ upper limit for resolved single point sources is estimated to be $1.6\times 10^{-4} ph cm^{-2} s^{-1}$.Comment: 6 pages, 3 figures; Cospar 2004. To be published in: Advances in Space Researc

Orthographic facilitation in oral vocabulary acquisition

An experiment investigated whether exposure to orthography facilitates oral vocabulary learning. A total of 58 typically developing children aged 8-9 years were taught 12 nonwords. Children were trained to associate novel phonological forms with pictures of novel objects. Pictures were used as referents to represent novel word meanings. For half of the nonwords children were additionally exposed to orthography, although they were not alerted to its presence, nor were they instructed to use it. After this training phase a nonword-picture matching posttest was used to assess learning of nonword meaning, and a spelling posttest was used to assess learning of nonword orthography. Children showed robust learning for novel spelling patterns after incidental exposure to orthography. Further, we observed stronger learning for nonword-referent pairings trained with orthography. The degree of orthographic facilitation observed in posttests was related to children's reading levels, with more advanced readers showing more benefit from the presence of orthography

Neutron capture and 2.2 MeV emission in the atmosphere of the secondary of an X-ray binary

We consider the production of 2.22 MeV radiation resulting from the capture of neutrons in the atmosphere of the secondary in an X-ray binary system, where the neutrons are produced in the accretion disk around the compact primary star and radiated in all directions. We have considered several accretion disk models (ADAF, ADIOS, SLE, Uniform-Temperature) and a varity of parameters (accretion rate, mass of the compact object, mass, temperature and composition of the secondary star, distance between the two objects, etc.). The neutron rates are calculated by a network of nuclear reactions in the accretion disk, and this is handled by a reaction-rate formulation taking into account the structure equations given by each accretion model. The processes undergone by the neutrons in the atmosphere of the companion star are studied in great detail, including thermalization, elastic and inelastic scatterings, absorption, escape from the surface, decay, and capture by protons. The radiative transfer of the 2.22 MeV photons is treated separately, taking into consideration the composition and density of the star's atmosphere. The final flux of the 2.22 MeV radiation that can be detected from earth is calculated taking into account the distance to the source, the direction of observation with respect to the binary system frame, and the rotation of the source, as this can lead to an observable periodicity in the flux. We produce phasograms of the 2.22 MeV intensity as well as spectra of the line, where rotational Doppler shift effects can lead to changes in the spectra that are measurable by INTEGRAL's spectrometer (SPI).Comment: 13 pages, 10 figures, A&A in pres

Internal structure of the San Jacinto fault zone at Jackass Flat from data recorded by a dense linear array

The internal structure of the Clark fault in the trifurcation area of the San Jacinto fault zone is imaged using seismograms recorded by a dense linear array (Jackass Flat, JF) crossing the surface trace of the fault and an adjacent array (TR) to the SW. Delay times between phase arrivals associated with ∼3500 local earthquakes and nine teleseismic events are used to estimate velocity variations within the arrays. The teleseismic P waves travel faster beneath the TR than the JF array, in contrast to larger scale tomographic results. Statistical analysis of local P-wave delay times indicates that the entire JF array, with an aperture of ∼400 m, is inside a low-velocity damage zone. This low-velocity zone is bounded on the NE side by a shallow bimaterial interface generating fault zone head waves, and it contains an inner zone of more intense damage generating fault zone trapped waves. The P-wave velocity contrast across the local bounding bimaterial interface is 10–15 per cent. The trapping structure is associated with a width of ∼200 m, S-wave velocity reduction of ∼35 per cent with respect to the surrounding rock, Q-value of ∼20 and depth of ∼3.5 km. The imaging results suggest that the main seismogenic fault is near the SW end of the JF array, in agreement with a prominent geomorphologic feature. The existence of intense local damage on the crustal block with faster larger scale velocity at depth is consistent with common propagation of earthquake ruptures in the area to the NW

Global Energetics of Large Solar Eruptive Events

We have evaluated the energetics of the larger solar eruptive events recorded with a variety of spacecraft instruments between February 2002 and December 2006. All of the energetically important components of the flares and of the accompanying coronal mass ejections and solar energetic particles have been evaluated as accurately as the observations allow. These components include the following : (1) the total energy in the high temperature plasma determined from the RHESSI thermal X-ray observations; (2) the total energies in accelerated electrons above 20 keV and ions above 1 MeV from RHESSI hard X-ray and gamma-ray observations, respectively; (3) the potential and kinetic energies of the CME from SOHO/LASCO observations; (4) the solar energetic particle (SEP) energy estimates from in situ measurements on ACE, GOES, and SOHO; (5) the total radiated energy from the SORCEITSI measurements where available, and otherwise from the Flare Irradiance Spectral Model (FISM). The results are assimilated and discussed relative to the probable amount of non potential magnetic energy estimated to be available in the flaring active regions from MDI line-of-sight magnetograms

11. Changes in Adolescent and Young Adult (AYA) Relationship Status during COVID19: Data from a 30 Country Sexual and Reproductive Health Study

This article is made available for unrestricted research re-use and secondary analysis in any form or be any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.Purpose: Important milestones - including romantic/sexual relationship development - were impacted by COVID19 mitigation measures. We examined self-reported change in relationship status before, during and after COVID among AYA who participated in a 30-country survey. Methods: Data were drawn from the International Sexual Health And REproductive Health Survey (I-SHARE-1), a multi-country, cross-sectional, online study conducted to assess the impact of the pandemic on adult sexual health across the globe. Participants were recruited through local, regional, and national networks (e.g. listservs of professional organizations and international health organizations, social media, etc.) of each country’s research team. We drew a subsample of AYA (N=7527 18-26 years; 32.3% of the total sample; 60.1% female, 86.1% cisgender, 77.1% heterosexual). We examined 5 categories of relationship status change: 1) unpartnered pre/post; 2) unpartnered pre, new partner post; 3) same partner pre/post; 4) partnered pre, broke up, unpartnered post; 5) partnered pre, broke up, new partner post. Random intercept mixed effects multinomial regression (gllamm; Stata 17.0; all p<.05) adjusted for country-level clustering was used to understand how demographic (age, gender identity, sexual identity, employment status during COVID, mental health, distancing or isolation during COVID) and country-level predictors (income group, Oxford Stringency Index [national response to COVID], Palma Ratio [country-income inequality) and Gender Inequality Index (country-gender inequality) were associated with relationship change. Results: 15% of AYA had no partner pre/post COVID, 5% were unpartnered pre-COVID with new partner post. 63.3% had the same partner pre/post, whereas 11.3% had a partner pre-COVID, but broke up and had no new partner post-COVID. Less than 5% had a new partner post-COVID after breaking up with their pre-COVID partner. Of those who broke up with their partner, the majority ended during (44.4%) or after (26.6%) COVID-lockdowns, and one-third thought social distancing precipitated the relationship’s end. Older (RRR=0.86-0.91), female (RRR=0.32-0.63) and transgender AYA (RRR=0.10-0.37) all had a lower risk, and sexual minority AYA had a higher risk (RRR=1.35-1.51), of being in all status categories compared to being in the same relationship before-and-after COVID. Higher mental health scores were linked to lower probability of being unpartnered pre/post as compared to being partnered pre/post (RRR=0.89-0.82). Social-distancing was associated with a lower risk for pre-COVID unpartnered individuals finding new post-COVID relationships (RRR=0.76) or of partnered individuals breaking up, while ever being in isolation was associated with higher risk of being unpartnered pre/post (RRR=1.20). Higher country income was associated with being unpartered pre-COVID (RRR=0.08-0.12) and higher risk of having a pre-COVID relationship break-up (RRR=1.32). Unpartnered individuals in countries with higher lockdown stringency had a greater probability of finding a new post-COVID relationship (RRR=1.13). Conclusions: COVID measures were associated with AYA relationships both initiating and ending. Strategies for relationship development/support should be included as part of preparation for future public health emergencies