1,136 research outputs found
First hours of the GRB 030329 optical afterglow
We present the first results of the observations of the extremely bright
optical afterglow of gamma-ray burst (GRB) 030329 with the 1.5m Russian-Turkish
telescope RTT150 (TUBITAK National Observatory, Bakyrlytepe, Turkey). RTT150
was one of the first 1.5m-class telescopes pointed to the afterglow.
Observations were started approximately 6 hours after the burst. During the
first 5 hours of our observations the afterglow faded exactly as a power law
with index -1.19+-0.01 in each of the BVRI Bessel filters. After that, in all
BVRI filters simultaneously we observe a steepening of the power law light
curve. The power law decay index smoothly approaches the value ~= -1.9,
observed by other observatories later. This power law break occurs at t-t_0
=0.57 days and lasts for +-0.1 days. We observe no variability above the
gradual fading with the upper limits 10--1% on time scales 0.1--1000s. Spectral
flux distribution in four BVRI filters corresponds to the power law spectrum
with spectral index \alpha=0.66+-0.01. The change of the power law decay index
in the end of our observations can be interpreted as a signature of collimated
ultrarelativistic jet. The afterglow flux distribution in radio, optical and
x-rays is consistent with synchrotron spectrum. We continue our observations of
this unique object with RTT150.Comment: Astronomy Letters, Vol. 29, No. 9, p. 573; 6 pages, 5 figures;
pagination corrected; the original Russian version can be found at
http://hea.iki.rssi.ru/~br/030329/pfh030329.pd
Search for a signal on intermediate baryon systems formation in hadron-nuclear and nuclear-nuclear interactions at high energies
We have analyzed the behavior of different characteristics of hadron-nuclear
and nuclear-nuclear interactions as a function of centrality to get a signal on
the formation of intermediate baryon systems. We observed that the data
demonstrate the regime change and saturation. The angular distributions of slow
particles exhibit some structure in the above mentioned reactions at low
energy. We believe that the structure could be connected with the formation and
decay of the percolation cluster. With increasing the mass of colliding nuclei,
the structure starts to become weak and almost disappears ultimately. This
shows that the number of secondary internuclear interactions increases with
increasing the mass of the colliding nuclei. The latter could be a reason of
the disintegration of any intermediate formations as well as clusters, which
decrease their influence on the angular distribution of the emitted particles.Comment: 2 pages and one figur
Human-Altered Soils at an Archeological Site of the Bronze Age: The Tyater-Araslanovo-Ii Settlement, Southern Cis-Ural Region, Russia
This paper presents the results of studying the soils at the archeological site of the Tyater-Araslanovo-II settlement located in the Republic of Bashkortostan, eastern European Russia. The settlement functioned in the 15th–12th centuries BCE (the Late Bronze Age). We compared the soil properties at four sites in the study area: archeological (1), buried (2), affected by long pyrogenic exposure (3), and background site (4). In soil samples, the total carbon content, the fractional composition of humus and organic matter characteristics, alkaline hydrolyzable nitrogen, total phosphorus, mobile phosphorus, potassium, absorbed calcium and magnesium, pH, particle size distribution, basal soil respiration, and optical density were estimated. The study results showed the anthropogenic impact on the archeological site’s soils. The newly formed AU horizon at the archeological site (1), affected by the cattle summer camp, was richer in soil nutrients and agrochemical properties, namely, the content of exchangeable and gross forms of phosphorus, alkaline hydrolyzable nitrogen, and exchange cations of the soil absorbing complex compared to the reference soil (4). For the pyrogenic layer (AU[hh]pyr ) from the ancient furnace (fireplace) (3), the mobile and total forms of phosphorus were several times higher than those in the reference soil (4) but inferior regarding other agrochemical parameters. Thus, the activities of ancient people (especially cattle breeding) greatly influenced the properties of the soil. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This study was performed within the framework of state assignment of the Ministry of Science and Education of the Russian Federation no. 075-00326-19-00 in theme no. AAA-A18-118022190102-3. This work was also supported by a grant from the Russian Science Foundation, project no. 17-16-01030, “Soil biota dynamics in chronoseries of post-technogenic landscapes: analyses of soil-ecological effectiveness of ecosystems restoration”, and by the Kazan Federal University Strategic Academic Leadership Program
Collective behaviour of partons could be a source of energetic hadrons
We discuss the idea that collective behaviour of the quarks/partons, which
has been intensely discussed for the last 40 years in relativistic
hadron-nuclear and nuclear-nuclear interactions and confirmed by new data
coming from the ultrarelativistic heavy ion collisions, can lead to energetic
particle production. Created from hadronization of the quark/parton (or
quarks/partons), energetic particles could get the energy of grouped partons
from coherent interactions. Therefore, we think that in the centre of some
massive stars, a medium with high density, close to Quantum Chromodynamic one
could be a source of the super high-energy cosmic rays.Comment: 8 pages, 8 figure
Electrical Properties of the Layered Single Crystals TlGaSe2 and TlInS2
In the doped crystals TlGaSe2 and TlInS2, using method of temperature dependencies of DC resistance in the temperature range
of 100 – 300 K, the phase transitions at the temperatures of 240 – 245 K and 105 – 120 K were observed. The AC conductance measurements at room temperature indicated the hopping mechanism of carrier transport in the studied samples
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