2,647 research outputs found

    The spectroscopic evolution of the γ\gamma-ray emitting classical nova Nova Mon 2012. I. Implications for the ONe subclass of classical novae

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    Nova Mon 2012 was the first classical nova to be detected as a high energy γ\gamma-ray transient, by Fermi-LAT, before its optical discovery. We study a time sequence of high resolution optical echelle spectra (Nordic Optical Telescope) and contemporaneous NOT, STIS UV, and CHIRON echelle spectra (Nov 20/21/22). We use [O III] and Hβ\beta line fluxs to constrain the properties of the ejecta. We derive the structure from the optical and UV line profiles and compare our measured line fluxes for with predictions using Cloudy with abundances from other ONe novae. Mon 2012 is confirmed as an ONe nova. We find E(B-V)=0.85±\pm0.05 and hydrogen column density ≈5×1021\approx 5\times 10^{21} cm−2^{-2}. The corrected continuum luminosity is nearly the same in the entire observed energy range as V1974 Cyg, V382 Mon, and Nova LMC 2000 at the same epoch after outburst. The distance, about 3.6 kpc, is quite similar to V1974 Cyg. The line profiles can be modeled using an axisymmetric bipolar geometry for the ejecta with various inclinations of the axis to the line of sight, 60 \le i \le 80 degrees, an opening angle of \approx70deg,innerradius70 deg, inner radius \Delta R/R(t)\approx 0.4forpermittedlinesandlessfilledforforbiddenlines.Thefillingfactor for permitted lines and less filled for forbidden lines. The filling factor f\approx 0.1-0.3implyingM(ejecta) implying M(ejecta) \leq 6\times 10^{-5}MM_\odot.TheONenovaeappeartocompriseasinglephysicalclasswithbipolarhighmassejecta,similarlyenhancedabundances,andacommonspectroscopicevolutionwithinanarrowrangeofluminosities.Thedetected. The ONe novae appear to comprise a single physical class with bipolar high mass ejecta, similarly enhanced abundances, and a common spectroscopic evolution within a narrow range of luminosities. The detected \gamma$-ray emission may be a generic phenomenon, common to all ONe novae, possibly to all classical novae, and connected with acceleration and emission processes within the ejecta (abstract severely truncated).Comment: Submitted to A&A 9/1/2013; Accepted 27/2/2013 (in press

    A New Satellite Image Map of King George Island (South Shetland Islands, Antarctica)

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    Sistemas agroflorestais: efeitos na dinâmica de nutrientes e na macrofauna invertebrada da serapilheira.

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    Sistemas agroflorestais: efeitos na dinâmica de nutrientes e na macrofauna invertebrada da serapilheira; Sistemas agroflorestais: objetivos e benefícios; Serapilheira como fonte de nutrientes nos SAFs; Macrofauna invertebrada como indicador de qualidade do solo.bitstream/item/95222/1/DOC1710001.pd

    Endogenous territorial development in mountain environments: the case of the territory of the Alto Camaquã, Brazil.

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    The territory of Alto Camaquã, in the southern state of Rio Grande do Sul ‐ Brazil, it has been highlighted by the strengthening of family livestock from associative process based on the construction of collective territorial mark that identifies the production with the landscape socially constructed of local mountain environments

    Influence of visual cues on host-searching and learning behaviour of the egg parasitoids Telenomus podisi and Trissolcus basalis.

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    Insect parasitoids use a variety of chemical and physical cues when foraging for hosts and food. Parasitoids can learn cues that lead themto the hosts, thus contributing to better foraging.One of the cues that in?uence host-searching behaviour could be colour. In this study, we investigated the ability of females of the parasitoid wasps Telenomus podisi Ashmead and Trissolcus basalisWollaston (both Hymenoptera: Scelionidae) to respond to colours and to associate the presence of hosts ? eggs of Euschistus heros (Fabricius) (Hemiptera: Pentatomidae) ? with coloured substrates after training (associative learning). Two sets of experiments were conducted: in one the innate preference for substrate colours was examined, in the other associative learning of substrate colour and host presence was tested in multiple-choice and dual-choice experiments. In the associative learning experiments, Te. podisi and Tr. basalis were trained to respond to differently coloured substrates containing hosts in two sessions of 2 h each, with 1-h intervals. In multiple-choice experiments, the wasps displayed innate preference for yellow substrates over green, brown, black, or white ones. Even after being trained on substrates of different colours, both parasitoids continued to show preference for yellow substrates. The response to the colours of substrates of both parasitoids was related with the orientation to the plant foliage during the search for hosts
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