21 research outputs found

    The dust origin of the Broad Line Region and the model consequences for AGN unification scheme

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    We propose a very simple physical mechanism responsible for the formation of the Low Ionization Line part of the Broad Line Region in Active Galactic Nuclei. It explains the scaling of the Broad Line Region size with the monochromatic luminosity, including the exact slope and the proportionality constant, seen in the reverberation studies of nearby sources. The scaling is independent from the mass and accretion rate of an active nucleus. The mechanism predicts the formation of a dust-driven wind in the disk region where the local effective temperature of a non-illuminated accretion disk drops below 1000 K and allows for dust formation. We explore now the predictive power of the model with the aim to differentiate between this model and the previously proposed mechanisms of the formation of the Broad Line Region. We discuss the expected departures from the universal scaling at long wavelength, and the role of the inclination angle of the accretion disk in the source. We compare the expected line profiles with Mg II line profiles in the quasars observed by us with the SALT telescope. We also discuss the tests based on the presence or absence of the broad emission lines in low luminosity active galaxies. Finally, we discuss the future tests of the model to be done with expected ground-based observations and satellite missions.Comment: Based the talk presented during the COSPAR 2014 meeting, Advances in Space Research (in press

    Effect of initial pH of medium with potato wastewater and glycerol on protein, lipid and carotenoid biosynthesis by Rhodotorula glutinis

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    Background: Rhodotorula glutinis is capable of synthesizing numerous valuable metabolites with extensive potential industrial usage. This paper reports the effect of initial culture medium pH on growth and protein, lipid, and carotenoid biosynthesis by R. glutinis. Results: The highest biomass yield was obtained in media with pH 4.0\u20137.0, and the value after 72 h was 17.2\u201319.4 gd.w./L. An initial pH of the medium in the range of 4.0\u20137.0 has no significant effect on the protein (38.5\u201341.3 g/100 gd.w.), lipid (10.2\u201312.7 g/100 gd.w.), or carotenoid (191.7\u2013202.9 \u3bcg/gd.w.) content in the biomass or on the profile of synthesized fatty acids and carotenoids. The whole pool of fatty acids was dominated by oleic (48.1\u201353.4%), linoleic (21.4\u201325.1%), and palmitic acids (13.0\u201315.8%). In these conditions, the yeast mainly synthesized torulene (43.5\u201347.7%) and \u3b2-carotene (34.7\u201338.6%), whereas the contribution of torularhodin was only 12.1\u201316.8%. Cultivation in medium with initial pH 3.0 resulted in a reduction in growth (13.0 gd.w./L) and total carotenoid (115.8 \u3bcg/gd.w.), linoleic acid (11.5%), and torularhodin (4.5%) biosynthesis. Conclusion: The different values of initial pH of the culture medium with glycerol and deproteinized potato wastewater had a significant effect on the growth and protein, lipid, and carotenoid biosynthesis by R. glutinis

    Time-delay measurement of MgII broad line response for the highly-accreting quasar HE 0413-4031: Implications for the MgII-based radius-luminosity relation

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    We present the monitoring of the AGN continuum and MgII broad line emission for the quasar HE 0413-4031 (z=1.38z=1.38) based on the six-year monitoring by the South African Large Telescope (SALT). We managed to estimate a time-delay of 302.633.1+28.7302.6^{+28.7}_{-33.1} days in the rest frame of the source using seven different methods: interpolated cross-correlation function (ICCF), discrete correlation function (DCF), zz-transformed DCF, JAVELIN, two estimators of data regularity (Von Neumann, Bartels), and χ2\chi^2 method. This time-delay is below the value expected from the standard radius-luminosity relation. However, based on the monochromatic luminosity of the source and the SED modelling, we interpret this departure as the shortening of the time-delay due to the higher accretion rate of the source, with the inferred Eddington ratio of 0.4\sim 0.4. The MgII line luminosity of HE 0413-4031 responds to the continuum variability as LlineLcont0.43±0.10L_{\rm line}\propto L_{\rm cont}^{0.43\pm 0.10}, which is consistent with the light-travel distance of the location of MgII emission at Rout1018cmR_{\rm out} \sim 10^{18}\,{\rm cm}. Using the data of 10 other quasars, we confirm the radius-luminosity relation for broad MgII line, which was previously determined for broad Hβ\beta line for lower-redshift sources. In addition, we detect a general departure of higher-accreting quasars from this relation in analogy to Hβ\beta sample. After the accretion-rate correction of the light-travel distance, the MgII-based radius-luminosity relation has a small scatter of only 0.100.10 dex.Comment: 39 pages (23 pages - Main text, 16 pages - Appendix), 21 figures, 14 tables; accepted for publication in the Astrophysical Journa

    Time delay measurement of Mg II line in CTS C30.10 with SALT

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    We report 6 yr monitoring of a distant bright quasar CTS C30.10 (z = 0.90052) with the Southern African Large Telescope (SALT). We measured the rest-frame time-lag of 562±2562\pm 2 days between the continuum variations and the response of the Mg II emission line, using the Javelin approach. More conservative approach, based on five different methods, imply the time delay of 56471+109564^{+109}_{-71} days. This time delay, combined with other available measurements of Mg II line delay, mostly for lower redshift sources, shows that the Mg II line reverberation implies a radius-luminosity relation very similar to the one based on a more frequently studied Hβ\beta line.Comment: submitted to ApJ; comments welcom

    Draft spaceflight bill : institution of licence described in Draft spaceflight bill

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    The United Kingdom is well-placed to become the first country to provide a hub for low cost launch of small satellites in Europe. British government wants to see in the country spaceports enabling the launch of small satellites as well as sub-orbital spaceflights and scientific experiments. Draft Spaceflight Bill was prepared so as to create a safe, competitive and sustainable commercial spaceflight market in the UK. Three kinds of licence were described in the Draft: operator licence, spaceport licence and range control licence. Carrying out spaceflight activities is the main duty of a holder of the operator licence and operating a spaceport is the main duty of a holder of the spaceport licence. A holder of the spaceport licence may make byelaws regulating the use and operation of the spaceport and conduct of persons within it. Any kind of the licence can be revoked, varied or suspended
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