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FUTURE SEMINARS, 2013 September, 17 Joerg Buechner (Max
Planck Institute for Solar System Research) "Magnetic
reconnection at the Sun" September, 10 Irina Kitiashvili (Stanford
University, Kazan University) "Turbulent MHD
processes at the Sun " June, 27 Carl Gwinn (University
of California, Santa Barbara) "RadioAstron Pulsar
Early Science Results" Abstract: The early science program for the
RadioAstron mission has produced remarkable results for pulsars. Using baselines
as long as 220,00 km, we locate the material that scatters nearby pulsars,
only 2-8 pc from Earth. Observations
of more distant, highly-scattered pulsars show fringes on baselines of tens
of Earth diameters, where scattering should lead to zero average visibility.
We discuss possible interpretations of this result. June, 17 Salvatore Capozziello (University
of Napoli “Federico II”) "Scaling Relations
from Gamma Ray Bursts to constrain Cosmography" Abstract: Relations connecting gamma ray burst quantities
can be used to constrain cosmographic parameters of the Hubble law at
medium-high redshifts. We consider a sample of gamma ray bursts to construct
the luminosity distance to redshift relation and derive the values of the
parameters q_0, j_0, and s_0. The analysis is compared with other methods in
the literature. Gamma ray bursts, if calibrated by SNeIa, seem reliable as
distance indicators and give cosmographic parameters in good agreement with
some Dark Energy models. June, 13 Michael S. Briggs (The
Center for Space Plasma and Aeronomic Research, Huntsville, USA) "Observations of
Terrestrial Gamma-ray Flashes (TGFs) by the Fermi Gamma-ray Burst Monitor
(GBM)" Abstract with references: Observations of Terrestrial Gamma-ray
Flashes (TGFs) by the Fermi Gamma-ray Burst Monitor (GBM) TGFs have were discovered in the early 1990s
and since then have been observed with several astrophysical instruments,
most recently with the Gamma-ray Burst Monitor (GBM) on Fermi. With the large
effective area of GBM new properties of the pulses have been found: in
addition to the previously known muliple pulses with ms separations, very
close pulses are observed [1,4]. The GBM sample has two pulse types; also,
the rise time is aways equal to or shorter than the fall time [1]. A new GBM
datatype and TGF search method has been implemented, making GBM the
instrument with the highest TGF detection rate [7]. In addition to fainter
TGFs, GBM is detecting TGFs shorter than ever before detected, with durations
as short as 50 microseconds [7]. Some TGFs are observed at great distances
from the source when electrons follow the Earth's magnetic field in a
beam. GBM found these Terrestrial
Electron Beams (TEBs) to also contain positrons [2]. Correlation of GBM TGFs
with ground-based radio observations has revealed new features [3,5,6]. A
strong correlation between radio detection probabilty and gamma-ray duration
changed our interpretation of the VLF radio detections, showing that they are
of the current of the TGF itself [6]. preprints:
http://gammaray.nsstc.nasa.gov/publications/tgf_journal.html [1] First Results on Terrestrial Gamma-ray
Flashes from the Fermi Gamma-ray Burst Monitor, M. S. Briggs, G. J. Fishman,
V. Connaughton, et al., J. Geophys. Res. (2010). [2] Electron-Positron Beams from Terrestrial
Lightning Observed with Fermi GBM, M. S. Briggs, V. Connaughton, C. A.
Wilson-Hodge, et al., Geophys. Res. Lett (2010). [3] Associations between Fermi GBM
Terrestrial Gamma-ray Flashes and sferics from the WWLLN, V. Connaughton, M.
S. Briggs, R. H. Holzworth, et al., J. Geophys. Res. (2010). [4] Temporal properties of the terrestrial
gamma-ray flashes from the Gamma-Ray Burst Monitor on the Fermi Observatory,
G. J. Fishman,, M. S. Briggs, V. Connaughton, et al., J. Geophys. Res. (2011). [5] The lightning-TGF relationship on
microsecond timescales, S. Cummer, G. Lu, M. S. Briggs, et al., Geophys. Res.
Lett (2011). [6] Radio signals from electron beams in
Terrestrial Gamma-ray Flashes, V. Connaughton, M. S. Briggs, S. Xiong, et
al., J. Geophys. Res. (2012). [7] Terrestrial Gamma-ray Flashes in the
Fermi era: Improved Observations and Analysis Methods, M. S. Briggs, S.
Xiong, V. Connaughton, et al., J. Geophys. Res. (2013). Michael S. Briggs National Space Science & Technology
Center Principal Research Scientist University of Alabama in Huntsville Gamma-Ray Astronomy Group 320 Sparkman Drive The Center for Space Plasma and Aeronomic
Research (CSPAR) Huntsville, AL 35805 Michael.Briggs@uah.edu or
Michael.S.Briggs@nasa.gov 256-961-7667 April, 30 A.P. Itin (Institut für Laser-Physik, Hamburg, Germany; Zentrum für Optische Quantentechnologien (ZOQ), Hamburg, Germany; Space Research Institute (IKI), Moscow) "Bose-Einstein
condensates: fundamental applications on the Earth and in space. Projects QUANTUS,
PRIMUS, MAIUS, ZARM" April, 26 1.
Weiqun Gan (the Purple Mountain Observatory, Nanjing, China) 2. Li Feng (the Purple Mountain Observatory, Nanjing, China) 1.
Before the formal talk, I would like to take a few minutes to give a brief
introduction of solar community in China and PMO. Then I will focus on our
recent work on frequency distribution of solar flares: the scaled peak
distribution of GOES flares; the thermal energy distribution of flares; a
fitting study of the flare distribution. 2. On 2011 September 6, an X-class flare and a halo
coronal mass ejection (CME) were observed from Earth erupting from the same
active region AR 11283. The magnetic energy partition between them has been
investigated. SDO/HMI vector magnetograms were used to obtain the coronal
magnetic field using the nonlinear force-free field (NLFFF) extrapolation
method. The free magnetic energies before and after the flare were calculated
to estimate the released energy available to power the flare and the CME. For
the flare energetics, thermal and nonthermal energies were derived using the
RHESSI and GOES data. To obtain the radiative output, SDO/EVE data in the
0.1-37 nm waveband were utilized. We have reconstructed the three-dimensional
(3D) periphery of the CME from the coronagraph images observed by STEREO-A,
B, and SOHO. The mass calculations were then based on a more precise
Thomson-scattering geometry. The subsequent estimate of the kinetic and
potential energies of the CME took advantage of the more accurate mass, and
the height and speed in a 3D frame. The released free magnetic energy
resulting from the NLFFF model is about 6.4 × 1031 erg, which has a
possible upper limit of 1.8 × 1032 erg. The thermal and nonthermal
energies are lower than the radiative output of 2.2 × 1031 erg from SDO/EVE
for this event. The total radiation covering the whole solar spectrum is
probably a few times larger. The sum of the kinetic and potential energy of
the CME could go up to 6.5 × 1031 erg. Therefore, the free energy is
able to power the flare and the CME in AR 11283. Within the uncertainty, the
flare and the CME may consume a similar amount of free energy. April, 18 L. Rykhlova (INASAN) "Chelyabinsk
meteorite and asteroid and cometary hazard" Abstract: Chelyabinsk meteorite entered Earth' s atmosphere at
about 9-20 YEKT with estimated speed of 18 km/s. The total kinetic energy
before atmospheric impact equivalent to approximately 450-500 kilotons of
TNT. The object had not been detected before atmospheric entry. |
