Svojstva visokoenergijskoga gama-zračenja iz aktivnih galaktičkih jezgri opažanih teleskopima magic

Active galactic nuclei (AGN) are bright compact regions in the centres of galaxies, that emit radiation across the entire electromagnetic spectrum. They are believed to be powered by supermassive black holes (SMBH), which actively accrete matter. Some of that matter is ejected in the form of collimated jets of ultrarelativistic particles. Jets are sources of electromagnetic radiation of all wavelengths. A significant portion of energy radiated by AGN is emitted in the form of -rays. In addition, -rays are produced through physical processes different from the ones responsible for lower energy radiation. Therefore, in order to understand how jets are formed and how particles are accelerated to ultrarelativistic energies, it is important to understand the mechanisms and locations of -ray production within AGN. To reach closer to this goal here we study the very high energy (VHE) -radiation from three sources belonging to different classes of AGN: M87 (radio galaxy), PKS 1222+21 (flat spectrum radio quasar) and H1722+119 (BL Lac object). For these sources we obtained VHE -ray spectra and light curves using the MAGIC ground-based Cherenkov telescopes. We used long term monitoring of M87 to evaluate the level of low emission state. We propose a structured jet “spine-layer” scenario to explain the emission from M87. It places the VHE -ray emission region in the vicinity of the SMBH, and suggests that, if viewed head on, the emission from M87 would resemble that from a typical BL Lac. PKS 1222+21 was first detected by the MAGIC telescopes. Very short variability timescale and absence of a cut-off in the VHE spectrum sets constraints on VHE -ray emission region, and on emission models. We performed a multiwavelength study using contemporaneous data, concluding that the -ray emission region is most probably located outside of the broad line region, and that it is possible to explain the emission using a simple one-zone emission scenario. H1722+119 is a source with unknown redshift, first detected by the MAGIC telescopes. We performed a multiwavelength study using contemporaneous data, and estimated the redshift of the source using -rays to z = 0.4. As expected, different types of emission models are required to explain emission from different types of sources. However, we also find that the VHE -radiation originates in different locations in the sources we studied.Aktivne galaktičke jezgre (AGN) su sjajna i zbijena područja u središtima galaksija, koja zrače preko cijelog spektra elektromagnetskog zračenja. Smatra se da ih napajaju supermasivne crne rupe (SMBH) koje aktivno prikupljaju materiju. Dio te materije izbacuju u obliku kolimiranog mlaza ultrarelativističkih čestica. Mlazovi su izvori elektromagnetskog zračenja svih frekvencija. Značajan udio energije koju zrače AGN odnose -zrake. Uz to, -zrake nastaju u procesima različitima od onih u kojima nastaje zračenje nižih energija. Stoga, da bismo razumjeli mehanizam nastanka mlazova i ubrzavanja čestica do ultrarelativističkih energija, važno je da razumijemo način i područje nastanka - zraka. Da bismo se primakli tom cilju, u ovom radu smo proučili -zračenje vrlo visokih energija (VHE) iz tri izvora, od kojih svaki spada u drugi razred AGN: M87 (radio galaksija), PKS 1222+21 (radio kvazar ravnog spektra) te H1722+119 (objekt tipa BL Lac). Spektre i svjetlosne krivulje ovih izvora dobili smo promatrajući ih zemaljskim Čerenkovljevim teleskopima MAGIC. Opažanjem M87 tijekom tri godine, odredili smo osnovnu razinu zračenja. Predložili smo strukturirani “kičma-plašt” model za opis zračenja, čime smo pokazali da je moguće objasniti emisiju iz područja u blizini SMBH u M87. VHE -zračenje iz PKS 1222+21 je otkriveno teleskopima MAGIC. Opažena promjenjivost toka zračenja na kratkim vremenskim skalama postavlja granicu na veličinu područja zračenja, te na modele emisije. Koristeći istovremene podatke, napravili smo studiju zračenja na različitim valnim duljinama i zaključili da se područje zračenja - zraka najvjerojatnije nalazi izvan područja širokih linija (BLR) te da se emisija može objasniti jednostavnim modelom zračenja iz jednog područja. H1722+119 je izvor nepoznatog crvenog pomaka. VHE -zračenje otkriveno je teleskopima MAGIC. Koristeći istovremene podatke, napravili smo studiju zračenja na različitim valnim duljinama te procijenili crveni pomak izvora na z = 0, 4. Prema očekivanjima, potrebno je primijeniti različite teorijske modele da bismo opisali zračenje iz različitih vrsta izvora. Međutim, vidjeli smo i da VHE -zrake nastaju na različitim mjestima u proučavanim izvorima

Using molecular markers in the identification of different genotypes of lucerne (Medicago sativa L.)

In order to have successful breeding, it is necessary to introduce new breeding material constantly and to use it through various types of hybridisation to increase the existing variability. Ten (10) lucerne varieties of different geographic origin were used in the study. Six varieties originated from the Republic of Serbia (Kruševačka 22, Kruševačka 28, NS-Banat ZMS II, NS-Mediana ZMS V, Zaječarska 83 and Čačanka 10), three varieties originated from the Republic of Croatia (Osječka 66, Osječka 88 and Osječka 99) and one variety originated from the Republika Srpska (Banjalučanka). A total of 100 seeds per each of 10 (ten) lucerne varieties were placed in Petri dishes to germinate. The dishes were placed in the seed germination chamber with the altering temperature of 20 oС in the dark for 16 h and 30 oС in the light for 8 h for seven days. The first green leaflets of lucerne seedlings (cotyledons) were used for the DNA extraction. The first and the second axes from the principal coordinates analysis accounted for a total of 63.1% of genetic variation, contained in the original dataset. It is clearly observed that the genotype Zaječarska 83 is genetically most distant from other studied lucerne genotypes. These studies confirmed that the observed collection of lucerne varieties is variable enough for the successful breeding process. Using an appropriate breeding model it is possible to breed varieties for certain purposes