Radio polarization maps of shell-type SNRs II. Sedov models with evolution of turbulent magnetic field

Polarized radio emission has been mapped with great detail in several Galactic supernova remnants (SNRs), but has not yet been exploited to the extent it deserves. We have developed a method to model maps of the Stokes parameters for shell-like SNRs during their Sedov evolution phase. At first, 3-dimensional structure of a SNR has been computed, by modeling the distribution of the magnetohydrodynamic parameters and of the accelerated particles. The generation and dissipation of the turbulent component of magnetic field everywhere in SNR are also considered taking into account its interaction with accelerated particles. Then, in order to model the emission, we have used a generalization of the classical synchrotron theory, valid for the case in which the magnetic field has ordered and disordered components. Finally, 2-dimensional projected maps have been derived, for different orientations of SNR and of interstellar magnetic field with respect to the observer. An important effect to consider is the Faraday rotation of the polarization planes inside the SNR interior. In this paper we present details of the model, and describe general properties of the images.Comment: accepted in MNRA

Some properties of synchrotron radio and inverse-Compton gamma-ray images of supernova remnants

The synchrotron radio maps of supernova remnants (SNRs) in uniform interstellar medium and interstellar magnetic field (ISMF) are analyzed, allowing different `sensitivity' of injection efficiency to the shock obliquity. The very-high energy gamma-ray maps due to inverse Compton process are also synthesized. The properties of images in these different wavelength bands are compared, with particular emphasis on the location of the bright limbs in bilateral SNRs. Recent H.E.S.S. observations of SN 1006 show that the radio and IC gamma-ray limbs coincide, and we found that this may happen if: i) injection is isotropic but the variation of the maximum energy of electrons is rather quick to compensate for differences in magnetic field; ii) obliquity dependence of injection (either quasi-parallel or quasi-perpendicular) and the electron maximum energy is strong enough to dominate magnetic field variation. In the latter case, the obliquity dependence of the injection and the maximum energy should not be opposite. We argue that the position of the limbs alone and even their coincidence in radio, X-rays and gamma-rays, as it is discovered by H.E.S.S. in SN 1006, cannot be conclusive about the dependence of the electron injection efficiency, the compression/amplification of ISMF and the electron maximum energy on the obliquity angle.Comment: Accepted for publication in MNRA

Observational constraints on the modeling of SN1006

Experimental spectra and images of the supernova remnant SN1006 have been reported for radio, X-ray and TeV gamma-ray bands. Several comparisons between models and observations have been discussed in the literature, showing that the broad-band spectrum from the whole remnant as well as a sharpest radial profile of the X-ray brightness can be both fitted by adopting a model of SN1006 which strongly depends on the non-linear effects of the accelerated cosmic rays; these models predict post-shock magnetic field (MF) strengths of the order of 150 micro G. Here we present a new way to compare models and observations, in order to put constraints on the physical parameters and mechanisms governing the remnant. In particular, we show that a simple model based on the classic MHD and cosmic rays acceleration theories allows us to investigate the spatially distributed characteristics of SN1006 and to put observational constraints on the kinetics and MF. Our method includes modelling and comparison of the azimuthal and radial profiles of the surface brightness in radio, hard X-rays and TeV gamma-rays as well as the azimuthal variations of the electron maximum energy. In addition, this simple model also provides good fits to the radio-to-gamma-ray spectrum of SN1006. We find that our best-fit model predicts an effective MF strength inside SN1006 of 32 micro G, in good agreement with the `leptonic' model suggested by the HESS Collaboration (2010). Finally, some difficulties in both the `classic' and the non-linear models are discussed. A number of evidences about non-uniformity of MF around SN1006 are noted.Comment: 15 pages, 13 figures, accepted for publication on MNRA

Hadronic gamma-ray images of Sedov supernova remnants

A number of modern experiments in high-energy astrophysics produce images of supernova remnants (SNRs) in the TeV and GeV gamma-rays. Either relativistic electrons (due to the inverse-Compton scattering) or protons (due to the pion decays) may be responsible for this emission. In particular, the broad-band spectra of SNRs may be explained in both leptonic and hadronic scenarios. Another kind of observational data, namely, images of SNRs, is an important part of experimental information. We present a method to model gamma-ray images of Sedov SNRs in uniform media and magnetic field due to hadronic emission. These gamma-rays are assumed to appear as a consequence of meson decays produced in inelastic collisions of accelerated protons with thermal protons downstream of the shock - a model would be relevant for SNRs without firm confirmations of the shock-cloud interaction, as e.g. SN1006. Distribution of surface brightness of the shell-like SNR is synthesized numerically for a number of configurations. An approximate analytical formula for azimuthal and radial variation of hadronic gamma-ray brightness close to the shock is derived. The properties of images as well as the main factors determining the surface brightness distribution are determined. Some conclusions which would be relevant to SN1006 are discussed.Comment: 11 pages, 7 figures, to be published in MNRA

ЭССЕНЦИАЛЬНЫЕ МИКРОНУТРИЕНТЫ – КОМПОНЕНТЫ АНТИОКСИДАНТНОЙ ЗАЩИТЫ В НЕКОТОРЫХ ВИДАХ РОДА АLLIUM

One of the urgent tasks at the present time is to obtain and widely use functional foods that have antioxidant  and anticarcinogenic effects, which serve not only to meet human needs  in   proteins,  fats,  carbohydrates, micro  -   and macronutrients,  but also contribute to the immune system, improve the heart and other human organs. For food plants, rich in antioxidant protection components, include perennial onions, from the variety of wild species which are in demand by modern medicine are only very few. The Republic of Komi is classified as the most uncomfortable  territories for human habitation.  In the flora of the Komi Republic there are three types of perennial bows – Allium angulosum  L., A. schoenoprasum L. and A. strictum Schrad.   The collection of the Botanical garden of the Institute of biology, Komi scientific center includes more than 150 species. Comparison of the chemical composition of  four  types  of  onions  from  the Botanical gardens of the Komi scientific center and Moscow state University (MSU) showed that  the  total  content  of flavonoids in  onions, Komi scientific center of  the  BS  is much higher, and the content of selenium is lower than in the same types of BS, Moscow state University. In samples of onions sticking out in the Republic of Tuva, the Republic of Buryatia,  in the Altai Mountains, the Se content is also much higher than in regional species. The soils of the Komi Republic are  depleted  Se,  however, as  shown  by  our research, wild and cultivated species of the genus Allium, are batteries of this trace element. According to our calculations, the use of 100 g of fresh herbs of chives may meet up to 60% of the daily needs of the human body in ascorbic acid, up to 94% manganese, 20% copper, 12% zinc.Одной из актуальных задач в настоящее время является получение и широкое использование продуктов функционального  питания, обладающих антиоксидантным и антиканцерогенным действием, которые служат не только удовлетворению потребностей человека в белках, жирах, углеводах, микро- и макроэлементах, но и способствуют повышению иммунитета, улучшению работы сердца и других органов человека. К пищевым растениям, богатым компонентами   антиоксидантной    защиты, относят    многолетние луки. Республика Коми отнесена к наиболее дискомфортным для проживания человека территориям. Во флоре Республики Коми встречается   три  вида  многолетних  луков –  Allium angulosum L.,  A. schoenoprasum L. и A. strictum Schrad.  Коллекция Ботанического сада Института  биологии Коми НЦ УрО РАН (БС) насчитывает более 150 видов. Согласно полученным данным, содержание марганца, меди и цинка в почвах и фитомассе растений Республики Коми ниже мировых кларков. Сравнение химического состава четырех видов лука из коллекций Ботанических садов Коми НЦ и Московского государственного университета (МГУ) показало, что общее содержание флавоноидов в луках из БС Коми НЦ значительно выше, а содержание селена – ниже, чем в аналогичных видах из БС МГУ. В образцах лука торчащего,  собранного в Республике  Тува, Республике  Бурятия, на Горном Алтае, содержание Se также значительно  выше, чем в региональных видах. Почвы Республики Коми обеднены Se, однако, как показали наши исследования, дикорастущие и культивируемые виды рода Allium являются аккумуляторами  этого микроэлемента.  По нашим подсчетам, при употреблении 100 г свежей зелени шнитт-лука возможно удовлетворение до 60% суточной потребности организма  человека в аскорбиновой кислоте, до 94% – марганца, 20% – меди, 12% – цинка. Организация комплексных исследований, направленных на оценку селенового и микронутриентного статуса населения республики, изучение их зонального распределения в различных типах почв и содержание эссенциальных микронутриентов в продуктах питания, культивируемых и дикорастущих растениях, произрастающих на данной  территории, представляет большой интерес

The SST-1M project for the Cherenkov Telescope Array

The SST-1M project, run by a Consortium of institutes from Czech Republic, Poland and Switzerland, has been proposed as a solution for implementing the small-size telescope array of the southern site of the Cherenkov Telescope Array. The technology is a pathfinder for efficient production of cost-effective imaging air Cherenkov telescopes. We report on the main system features and recent upgrades, the performances validation and the operation campaign carried out in 2018