54 research outputs found
Position-sensitive detector for the 6-meter optical telescope
The Position-Sensitive Detector (PSD) for photometrical and spectral
observation on the 6-meter optical telescope of the Special Astrophysical
Observatory (Russia) is described. The PSD consists of a position-sensitive
tube, amplifiers of output signals, analog-to-digital converters (ADC) and a
digital logic plate, which produces a signal for ADC start and an external
strob pulse for reading information by registration system. If necessary, the
thermoelectric cooler can be used. The position-sensitive tube has the
following main elements: a photocathode, electrodes of inverting optics, a
block of microchannel plates (MCP) and a position-sensitive collector of
quadrant type. The main parameters of the PSD are the diameter of the sensitive
surface is 25 mm, the spatial resolution is better than 100 (\mu)m in the
centre and a little worse on the periphery; the dead time is near 0.5 (\mu)s;
the detection quantum efficiency is defined by the photocathode and it is not
less than 0.1, as a rule; dark current is about hundreds of cps, or less, when
cooling. PSD spectral sensitivity depends on the type of photocathode and input
window material. We use a multialkali photocathode and a fiber or UV-glass,
which gives the short- wave cut of 360 nm or 250 nm, respectively.Comment: 4 pages, 7 figures, to be published in Nuclear Instruments & Methods
in Physics Researc
High Speed Phase-Resolved 2-d UBV Photometry of the Crab pulsar
We report a phase-resolved photometric and morphological analysis of UBV data
of the Crab pulsar obtained with the 2-d TRIFFID high speed optical photometer
mounted on the Russian 6m telescope. By being able to accurately isolate the
pulsar from the nebular background at an unprecedented temporal resolution (1
\mu s), the various light curve components were accurately fluxed via
phase-resolved photometry. Within the range, our datasets are consistent
with the existing trends reported elsewhere in the literature. In terms of flux
and phase duration, both the peak Full Width Half Maxima and Half Width Half
Maxima decrease as a function of photon energy. This is similarly the case for
the flux associated with the bridge of emission. Power-law fits to the various
light curve components are as follows; \alpha = 0.07 \pm 0.19 (peak 1), \alpha
= -0.06 \pm 0.19 (peak 2) and \alpha = -0.44 \pm 0.19 (bridge) - the
uncertainty here being dominated by the integrated CCD photometry used to
independently reference the TRIFFID data. Temporally, the main peaks are
coincident to \le 10 \mu s although an accurate phase lag with respect to the
radio main peak is compromised by radio timing uncertainties. The plateau on
the Crab's main peak was definitively determined to be \leq 55 \mu s in extent
and may decrease as a function of photon energy. There is no evidence for
non-stochastic activity over the light curves or within various phase regions,
nor is there evidence of anything akin to the giant pulses noted in the radio.
Finally, there is no evidence to support the existence of a reported 60 second
modulation suggested to be as a consequence of free precession.Comment: 13 pages, 12 figures, accepted for publication in Astronomy &
Astrophysic
The Multicolor Panoramic Photometer-Polarimeter with high time resolution based on the PSD
Multicolor Panoramic Photometer-Polarimeter (MPPP) with a time resolution of
1 microsecond has been built based on a PSD and used at the 6-meter telescope
in SAO (Russia). The device allows registration of the photon fluxes in four
photometric bands simultaneously and finding values of 3 Stokes parameters.
MPPP consists of Position-Sensitive Detector (PSD), acquisition MANIA-system,
polarization unit and a set of dichroic filters. MPPP gives a possibility of
detecting photons in 2 pupils with a size of 10 - 15 arc sec centered on the
object and comparison star positions simultaneously. The first half of the
object photon flux passes through the phase rotating plate and polarizer, and
the second one through the polarizer alone. MPPP registers in each of the 4
filters four images of the object with different orientations of polarization
plane and one image of a comparison star. It allows measuring instantaneous
Stokes parameters. The main astrophysical problems to be solved with MPPP are
as follows: investigation of optical pulsars; study of GRB phenomenon in the
optical range; searching for single black holes; study of fast variability of
X-ray binaries. As an illustration of MPPP use, the results of observations at
the 6-meter telescope of Crab pulsar and soft gamma repeater are presented.Comment: 3 pages, 7 figures, to be published in Nuclear Instruments & Methods
in Physics Researc
Physical education for young students. Typologies, gaps, challenges
In the current 21st century situation, some services priorities have changed significantly, but there are always unshakable pillars. One of these pillars is physical culture. The impact of physical education and sport in General on human health, its development (both physical and spiritual) is difficult to overestimate. No wonder there are such sayings as: "In healthy body – healthy spirit" and "Sport is life. In his article, we turn to consider the approaches to organization of physical education in schools, and also to track the challenges the modern University sport facesВ сложившейся в 21-ом веке ситуации, некоторые общественные приоритеты существенно изменились, но всегда есть незыблемые столпы. Одним из таких столпов является физическая культура. Влияние физкультуры и спорта в целом на здоровье человека, на его развитие (как физическое, так и духовное) сложно переоценить. Не зря ведь существуют такие пословицы как: «В здоровом теле – здоровый дух» и «Спорт – это жизнь. В своей статье мы беремся рассмотреть подходы к организации физического воспитания в учебных заведениях, а также проследить те вызовы, с которыми современный студенческий спорт сталкиваетс
Short time scale pulse stability of the Crab pulsar in the optical band
The fine structure and the variations of the optical pulse shape and phase of
the Crab pulsar are studied on various time scales. The observations have been
carried out on 4-m William Hershel and 6-m BTA telescopes with APD photon
counter, photomultiplier based 4-channel photometer and PSD based panoramic
spectrophotopolarimeter with 1s time resolution in 1994, 1999, 2003 and
2005-2006 years. The upper limit on the pulsar precession on Dec 2, 1999 is
placed in the 10 s - 2 hours time range. The evidence of a varying from set to
set fine structure of the main pulse is found in the 1999 and 2003 years data.
No such fine structure is detected in the integral pulse shape of 1994, 1999
and 2003 years.
The drastic change of the pulse shape in the 2005-2006 years set is detected
along with the pulse shape variability and quasi-periodic phase shifts.Comment: 4 pages, 6 figures. To appear in ApSS, in the proceedings of the
conference "Isolated Neutron Stars: from the Interior to the Surface",
London, April 2006; eds. D. Page, R. Turolla and S. Zan
Discovery of the Sub-second Linearly Polarized Spikes of Synchrotron Origin in the UV Ceti Giant Optical Flare
Copyright © Astronomical Society of Australia 2017During our optical monitoring of UV Ceti, iconic late-type flaring star, with high temporal resolution using the Russian 6-m telescope in 2008, we detected a giant flare with the amplitude of about 3 magnitudes in U band. Near flare maximum, more than a dozen of spike bursts have been discovered with triangular shapes and durations from 0.6 to 1.2 s and maximal luminosities in the range (1.5–8) × 1027 erg s−1. For the half of these events, the linear polarization exceeds 35% with significance better than 5σ. We argue that these events are synchrotron emission of electron streams with the energies of several hundred MeV moving in the magnetic field of about 1.4 kG. Emission from such ultra-relativistic (with energies far exceeding 10 MeV) particles is being routinely observed in solar flares, but has never been detected from UV Ceti-type stars. This is the first ever detection of linearly polarized optical light from the UV Ceti-type stars which indicates that at least some fraction of the flaring events on these stars is powered by a non-thermal synchrotron emission mechanism
A Search for the Optical Counterpart of PSR B1951+32 in the Supernova Remnant CTB 80
Using time-resolved two-dimensional aperture photometry we have put upper
limits on the pulsed emission from two proposed optical counterparts for PSR
B1951+32. Our pulsed upper limits of m_{vpulsed}>23.3, m_{bpulsed}>24.4, m_{bpulsed}>24.3 for the second,
make it unlikely that either of these is, in fact, the pulsar. We discuss three
further candidates, but also reject these on the basis of timing results. A
search of a 5.5arcs x 5.5arcs area centred close to these stars failed to find
any significant pulsations at the reported pulsar period.Comment: 5 pages, 4 figures, typos correcte
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