21 research outputs found
The dust origin of the Broad Line Region and the model consequences for AGN unification scheme
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
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
We present the monitoring of the AGN continuum and MgII broad line emission
for the quasar HE 0413-4031 () based on the six-year monitoring by the
South African Large Telescope (SALT). We managed to estimate a time-delay of
days in the rest frame of the source using seven
different methods: interpolated cross-correlation function (ICCF), discrete
correlation function (DCF), -transformed DCF, JAVELIN, two estimators of
data regularity (Von Neumann, Bartels), and 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 .
The MgII line luminosity of HE 0413-4031 responds to the continuum variability
as , which is consistent with
the light-travel distance of the location of MgII emission at . Using the data of 10 other quasars, we confirm the
radius-luminosity relation for broad MgII line, which was previously determined
for broad H line for lower-redshift sources. In addition, we detect a
general departure of higher-accreting quasars from this relation in analogy to
H sample. After the accretion-rate correction of the light-travel
distance, the MgII-based radius-luminosity relation has a small scatter of only
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
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 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
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 H line.Comment: submitted to ApJ; comments welcom
Draft spaceflight bill : institution of licence described in Draft spaceflight bill
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