The Great Markarian 421 Flare of 2010 February: Multiwavelength Variability and Correlation Studies

We report on variability and correlation studies using multiwavelength observations of the blazar Mrk 421 during the month of 2010 February, when an extraordinary flare reaching a level of ∼27 Crab Units above 1 TeV was measured in very high energy (VHE) γ-rays with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) observatory. This is the highest flux state for Mrk 421 ever observed in VHE γ-rays. Data are analyzed from a coordinated campaign across multiple instruments, including VHE γ-ray (VERITAS, Major Atmospheric Gamma-ray Imaging Cherenkov), high-energy γ-ray (Fermi-LAT), X-ray (Swift, Rossi X-ray Timing Experiment, MAXI), optical (including the GASP-WEBT collaboration and polarization data), and radio (Metsahovi, Owens Valley Radio Observatory, University of Michigan Radio Astronomy Observatory). Light curves are produced spanning multiple days before and after the peak of the VHE flare, including over several flare "decline" epochs. The main flare statistics allow 2 minute time bins to be constructed in both the VHE and optical bands enabling a cross-correlation analysis that shows evidence for an optical lag of ∼25-55 minutes, the first time-lagged correlation between these bands reported on such short timescales. Limits on the Doppler factor (δ ⪆ 33) and the size of the emission region (δ-1RB≲ 3.8 × 1013cm) are obtained from the fast variability observed by VERITAS during the main flare. Analysis of 10 minute binned VHE and X-ray data over the decline epochs shows an extraordinary range of behavior in the flux-flux relationship, from linear to quadratic to lack of correlation to anticorrelation. Taken together, these detailed observations of an unprecedented flare seen in Mrk 421 are difficult to explain with the classic single-zone synchrotron self-Compton model.</p

Insights into the high-energy γ-ray emission of Markarian 501 from extensive multifrequency observations in the Fermi era

We report on the γ-ray activity of the blazar Mrk 501 during the first 480 days of Fermi operation. We find that the average Large Area Telescope (LAT) γ-ray spectrum of Mrk 501 can be well described by a single power-law function with a photon index of 1.78 ± 0.03. While we observe relatively mild flux variations with the Fermi-LAT (within less than a factor of two), we detect remarkable spectral variability where the hardest observed spectral index within the LAT energy range is 1.52 ± 0.14, and the softest one is 2.51 ± 0.20. These unexpected spectral changes do not correlate with the measured flux variations above 0.3 GeV. In this paper, we also present the first results from the 4.5 month long multifrequency campaign (2009 March 15-August 1) on Mrk 501, which included the Very Long Baseline Array (VLBA), Swift, RXTE, MAGIC, and VERITAS, the F-GAMMA, GASP-WEBT, and other collaborations and instruments which provided excellent temporal and energy coverage of the source throughout the entire campaign. The extensive radio to TeV data set from this campaign provides us with the most detailed spectral energy distribution yet collected for this source during its relatively low activity. The average spectral energy distribution of Mrk 501 is well described by the standard one-zone synchrotron self-Compton (SSC) model. In the framework of this model, we find that the dominant emission region is characterized by a size ≲0.1 pc (comparable within a factor of few to the size of the partially resolved VLBA core at 15-43 GHz), and that the total jet power (≃1044 erg s-1) constitutes only a small fraction (∼10-3) of the Eddington luminosity. The energy distribution of the freshly accelerated radiating electrons required to fit the time-averaged data has a broken power-law form in the energy range 0.3 GeV-10 TeV, with spectral indices 2.2 and 2.7 below and above the break energy of 20 GeV. We argue that such a form is consistent with a scenario in which the bulk of the energy dissipation within the dominant emission zone of Mrk 501 is due to relativistic, proton-mediated shocks. We find that the ultrarelativistic electrons and mildly relativistic protons within the blazar zone, if comparable in number, are in approximate energy equipartition, with their energy dominating the jet magnetic field energy by about two orders of magnitude. © 2011. The American Astronomical Society

Natural hybridization between Elymus repens and Elymus hispidus assessed by AFLP analysis

Hybrid speciation within the genus Elymus is analyzed and discussed. The supposed hybrid origin of Elymus x mucronatus between Elymus repens and Elymus hispidus was tested. In this aim, pollen viability and AFLP variation of putative progenitors and progenies from two natural populations were studied. Pollen fertility of hybrids ranging from 0 to 91.95% (average 59.50%) indicates the occurrence of F1 hybrids and backcross hybrids. Seven EcoRI/MseI AFLP primer combinations generated a total of 477 AFLP fragments (300 polymorphic) for 48 parental and hybrid individuals. UPGMA and principal coordinates analysis of the AFLP data set show that hybrids are closer to E. hispidus than to E. repens and suggest unidirectional introgression towards E. hispidus. AFLP fragments of the hybrid taxon were additively inherited from the parental species and no hybrid-specific bands were identified. AFLP analysis validates the hybrid status of E. ×mucronatus. Populations in which E. repens, E. hispidus and their hybrids co-occur still progress from early hybridization stages of F1 hybrids to an advanced hybridization stage of a well-established hybrid swarm. E. ×mucronatus is potentially self-sustaining by predominant vegetative reproduction by rhizomes and partial fertility leading to the development of mature seeds. We propose to consider Elymus ×mucronatus as a new species of hybrid origin in the Polish flora

Wykorzystanie markerow RAPD do analizy zmian genetycznych zwiazanych z dlugotrwalym przechowywaniem i regeneracja ziarniakow zyta [Secale cereale L.]

Celem pracy była analiza zmian zachodzących na poziomie DNA w wyniku procesu długiego przechowywania ziarniaków żyta i ich późniejszej regeneracji w warunkach polowych w oparciu o markery typu RAPD. W tym celu przeanalizowano trzy populacje żyta 'Dańkowskie Złote', różniące się okresem przechowywania i liczbą cykli kolejnych regeneracji. Izolację DNA z 75 żywych ziarniaków z każdej serii przeprowadzono przy użyciu techniki SDS. Reakcję PCR (Łańcuchowa reakcja polimerazy) prowadzono kolejno w obecności jednego z 5-ciu 10-nukleotydowych starterów. Mieszaninę reakcyjną rozdzielano elektroforetycznie na żelu agarozowym. Uzyskano łącznie dla wszystkich populacji 110 markerów RAPD. Zaobserwowano istotne statystycznie różnice w częstotliwości 50 z nich. Te różnice mogą świadczyć o zmianach w strukturze genetycznej populacji, będących efektem długotrwałego przechowywania i regeneracji ziarniaków.The aim of studies was to analyse the genetic changes in rye seeds induced by natural ageing during long-term storage in a seed bank and after regeneration in field conditions, by means of RAPD markers. In our experiment, the seeds of three populations of different age and two different reproduction cycles of Dańkowskie Złote rye were used. Genomic DNAs were isolated from 75 seeds of each sample. The polymerase chain reaction was accomplished by means of five primers which were ten nucleotides long each. One hundred and ten RAPD markers were shared among the series. Changes in the frequency of fifty markers were statistically significant among the populations. These changes could be attributed to genetic changes related to long-term storage and regeneration of seeds

Molecular variation of Antarctic grass Deschampsia antarctica Desv. from King George Island [Antarctica]

Deschampsia antarctica Desv. plants collected on King George Islands (Antarctica) at two localities that differ in topographic and nutrition conditions exhibited morphological variation that differentiated plants of both locations. The molecular variation characteristic to individuals of both sites was tested using AFLP approach in order to verify whether morphological variation characteristic to the plants resulted from environmental factors or possibly from differences at the DNA level. Four primer pair combinations were used to generate 339 AFLP fragments, 132 of which were polymorphic and allowed evaluation of genetic relationships among D. antarctica individuals. Chi-square test revealed that only 12 signals were discriminative for the plants from both locations. Cluster analysis conducted on these AFLP fragments demonstrated that plants from the location rich in biogenes were more polymorphic than those from poor one. Our data suggest that the phenotypic variation specific to plants of both locations seem to be the result of adaptation to the environmental conditions like soil and moisture rather than reflect genetic differences

Avena sativa L. intercultivar polymorphism assessment using silicoDArT markers

Avena sativa is an important breeding species in Poland which is due to the presence of proteins, soluble fibers, fat, minerals and vitamins. Nevertheless, the development of breeding programs of Avena is limited to low within species genetic variability. Thus, marker technologies capable of identification of many polymorphic markers is required to ensure further breeding progress. The current study was devoted to the exploitation of the silicoDArT markers, based on new generation sequencing approach, for the differentiation of a number of Avena sativa lines from Polish breeding companies. More than 8000 polymorphic markers were identified that differentiated the analyzed materials according to their origin. Cluster analysis and PCoA demonstrated distinctiveness of the materials from breeding companies, especially from Plant Breeding Strzelce. It is being suggested that crossing cultivars originated from different breeding programs should support progress in this species

A New TeV Source Confirmed in Whipple Archival Data: TeV J2032+41

A re-analysis of data near Cygnus X-3 in 1989-1990 using the Whipple Observatory atmospheric Cherenkov imaging telescope confirms the existence of the TeV J2032 + 4130 source first reported at a conference by the Crimean Astrophysical Observatory and confirmed independently by the HEGRA Collaboration in a referred publication. The significance of the Whipple observations at the a priori HEGRA position is 3.3$\sigma. The peak signal was found at RA = 20 h 32 m, Dec = +41$\degres$33'. This is 0.6$\degres$ north of Cygnus X-3. The flux level (12\% of the level of the Crab Nebula) is intermediate between that reported by the Crimean (100\%) and HEGRA (3\%) groups