-
[show abstract]
[hide abstract]
ABSTRACT: We suggest a model to consistently describe the available experimental data on the elemental cosmic-ray energy spectra obtained
in direct measurements and to make a smooth transition to the spectrum of all particles measured with extensive air showers.
The model suggests the existence of three classes of cosmic-ray sources—shocks from supernova explosions that produce power-law
rigidity spectra with different maximum rigidities and different spectral indices. The shocks from high-mass supernovae exploding
in OB associations are assumed to be the most powerful class of sources. This class of sources accelerates cosmic rays to
a maximum rigidity of 4 × 1015 V. The shocks from nonassociated supernovae exploding into a random interstellar medium are assumed to be the next class
(in order of decreasing power). This class of sources accelerates cosmic rays to a maximum rigidity of 5 × 1013 V. The third, weakest class of sources is assumed to accelerate cosmic rays to a maximum rigidity of 2 × 1011 V. Nova explosions could be possible physical objects in this class.
Astronomy Letters 04/2012; 33(1):25-33. · 0.99 Impact Factor
-
A. D. Panov,
J. H. Adams,
H. S. Ahn,
G. L. Bashindzhagyan,
J. W. Watts,
J. P. Wefel,
J. Wu,
T. G. Guzik, V. I. Zatsepin,
J. Isbert,
K. C. Kim,
M. Christl,
E. N. Kouznetsov,
M. I. Panasyuk,
E. B. Postnikov,
E. S. Seo,
N. V. Sokolskaya,
J. Chang
[show abstract]
[hide abstract]
ABSTRACT: A strong anomaly in form of a wide peak in the energy range 300–800 GeV was discovered in the first measurements of the electron
spectrum in the energy range from 20 GeV to 3 TeV by the balloon-borne experiment ATIC [1]. The experimental data processing and analysis of the electron spectrum with different criteria for selection of electrons
completely independent of the results reported in [1] is employed in the present paper. New independent analysis generally
confirms the results of [1] but shows that the spectrum in the region of the anomaly is represented by a number of narrow
peaks. Measured spectrum is compared to the spectrum of [1] and to the spectrum of the Fermi/LAT experiment.
Bulletin of the Russian Academy of Sciences Physics 04/2012; 75(3):319-322.
-
[show abstract]
[hide abstract]
ABSTRACT: We propose a model where a supernova explodes in some vicinity of our solar
system (some tens of parsecs) in the recent past (some tens of thousands years)
with the energy release in cosmic rays of order of $ 10 ^ {51} $ erg. The flux
from this supernova is added to an isotropic flux from other sources. We
consider the case where the Sun's location is not in some typical for Our
Galaxy average environment, but in the Local Superbubble about 100 pc across,
in which the diffusion coefficient $D (E) = D_0 \times E ^ {0.6} $, with the
value of $ D_0 \sim 10 ^ {25} cm^ 2 s^ {-1} $. We describe the energy
dependence of the anisotropy of cosmic rays in the TeV region, together with
the observed features of the energy spectrum of protons found in direct
measurements. Our model provides a natural explanation to the hardening of the
proton spectrum at 200 GeV, together with the observed steepening of the
spectrum above 50 TeV.
03/2012;
-
A D Panov, V I Zatsepin,
N V Sokolskaya,
J H Adams,
H S Ahn,
G L Bashindzhagyan,
J Chang,
M Christl,
T G Guzik,
J Isbert,
K C Kim,
E N Kouznetsov,
M I Panasyuk,
E B Postnikov,
E S Seo,
J Watts,
J P Wefel,
J Wu
[show abstract]
[hide abstract]
ABSTRACT: A strong excess in a form of a wide peak in the energy range of 300–800 GeV was discovered in the first measurements of the electron spectrum in the energy range from 20 GeV to 3 TeV by the balloon-borne experiment ATIC (Chang et al., 2008b). The experimental data process-ing and analysis of the electron spectrum with different criteria for selection of electrons, completely independent of the results reported in Chang et al. (2008b) is employed in the present paper. The 5 new independent analysis generally confirms the results of Chang et al. (2008b), but shows that the spectrum in the region of the excess is represented by a number of narrow peaks. The measured spectrum is compared to the spectrum of Chang et al. (2008b) and to the spectrum of the Fermi/LAT experiment .
05/2011;
-
A. D. Panov, V. I. Zatsepin,
N. V. Sokolskaya,
Adams, Jr., J. H,
H. S. Ahn,
G. L. Bashindzhagyan,
J. Chang,
M. Christl,
T. G. Guzik,
J. Isbert,
K. C. Kim,
E. N. Kouznetsov,
M. I. Panasyuk,
E. B. Postnikov,
E. S. Seo,
J. Watts,
J. P. Wefel,
J. Wu
[show abstract]
[hide abstract]
ABSTRACT: A strong excess in a form of a wide peak in the energy range of 300-800 GeV
was discovered in the first measurements of the electron spectrum in the energy
range from 20 GeV to 3 TeV by the balloon-borne experiment ATIC (J. Chang et
al. Nature, 2008). The experimental data processing and analysis of the
electron spectrum with different criteria for selection of electrons,
completely independent of the results reported in (J. Chang et al. Nature,
2008) is employed in the present paper. The new independent analysis generally
confirms the results of (J. Chang et al. Nature, 2008), but shows that the
spectrum in the region of the excess is represented by a number of narrow
peaks. The measured spectrum is compared to the spectrum of (J. Chang et al.
Nature, 2008) and to the spectrum of the Fermi/LAT experiment.
04/2011;
-
A. D. Panov,
J. H. Adams Jr,
H S Ahn,
G. L. Bashinzhagyan,
J. W. Watts,
J. P. Wefel,
J Wu,
O Ganel,
T. G. Guzik, V. I. Zatsepin,
I. Isbert,
K C Kim,
M. Christl,
E. N. Kouznetsov,
M. I. Panasyuk,
E. S. Seo,
N. V. Sokolskaya,
J Chang,
W. K. H. Schmidt,
A. R. Fazely
[show abstract]
[hide abstract]
ABSTRACT: The final results of processing the data from the balloon-born experiment
ATIC-2 (Antarctica, 2002-2003) for the energy spectra of protons and He, C, O,
Ne, Mg, Si, and Fe nuclei, the spectrum of all particles, and the mean
logarithm of atomic weight of primary cosmic rays as a function of energy are
presented. The final results are based on improvement of the methods used
earlier, in particular, considerably increased resolution of the charge
spectrum. The preliminary conclusions on the significant difference in the
spectra of protons and helium nuclei (the proton spectrum is steeper) and the
non-power character of the spectra of protons and heavier nuclei (flattening of
carbon spectrum at energies above 10 TeV) are confirmed. A complex structure of
the energy dependence of the mean logarithm of atomic weight is found.
01/2011;
-
V. I. Zatsepin,
A. D. Panov,
N. V. Sokolskaya,
J. H. Adams,
H. S. Ahn,
G. L. Bashindzhagyan,
J. Chang,
M. Christl,
A. R. Fazely,
T. G. Guzik,
J. B. Isbert,
K. C. Kim,
E. N. Kouznetsov,
M. Panasyuk,
E. S. Seo,
J. Watts,
J. P. Wefel,
J. Wu
[show abstract]
[hide abstract]
ABSTRACT: Titanium is a rare, secondary nucleus among Galactic cosmic rays. Using the Silicon matrix in the ATIC experiment, Titanium
has been separated. The energy dependence of the Ti to Fe flux ratio in the energy region from 5 GeV per nucleon to about
500 GeV per nucleon is presented.
Astronomy Letters 04/2009; 35(5):338-342. · 0.99 Impact Factor
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J Chang,
J H Adams,
H S Ahn,
G L Bashindzhagyan,
M Christl,
O Ganel,
T G Guzik,
J Isbert,
K C Kim,
E N Kuznetsov,
M I Panasyuk,
A D Panov,
W K H Schmidt,
E S Seo,
N V Sokolskaya,
J W Watts,
J P Wefel,
J Wu, V I Zatsepin
[show abstract]
[hide abstract]
ABSTRACT: Galactic cosmic rays consist of protons, electrons and ions, most of which are believed to be accelerated to relativistic speeds in supernova remnants. All components of the cosmic rays show an intensity that decreases as a power law with increasing energy (for example as E(-2.7)). Electrons in particular lose energy rapidly through synchrotron and inverse Compton processes, resulting in a relatively short lifetime (about 10(5) years) and a rapidly falling intensity, which raises the possibility of seeing the contribution from individual nearby sources (less than one kiloparsec away). Here we report an excess of galactic cosmic-ray electrons at energies of approximately 300-800 GeV, which indicates a nearby source of energetic electrons. Such a source could be an unseen astrophysical object (such as a pulsar or micro-quasar) that accelerates electrons to those energies, or the electrons could arise from the annihilation of dark matter particles (such as a Kaluza-Klein particle with a mass of about 620 GeV).
Nature 12/2008; 456(7220):362-5. · 36.28 Impact Factor
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A. D. Panov, V. I. Zatsepin,
N. V. Sokolskaya,
J. H. Adams,
H. S. Ahn,
G. L. Bashindzhagyan,
J. W. Watts,
J. P. Wefel,
J. Wu,
O. Ganel, [......],
R. M. Gunashingha,
J. Isbert,
K. C. Kim,
M. Christl,
E. N. Kouznetsov,
M. I. Panasyuk,
E. S. Seo,
J. Chang,
W. K. H. Schmidt,
A. R. Fazely
[show abstract]
[hide abstract]
ABSTRACT: The purpose of the ATIC balloon experiment is to measure the energy spectra of primary cosmic rays with individual charge resolution from protons to iron over the energy range from ∼50 GeV to 200 TeV. The particle energy is measured by a bismuth germanate (BGO) scintillation calorimeter. The procedure of calorimeter calibration is described, in particular, calibration of the temperature dependence of the calorimeter sensitivity using the data of in-flight measurements. A technique for determining the energy deposited in the calorimeter in view of the temperature dependence of its sensitivity is presented. The maximum systematic error in determining the deposited energy by the calorimeter is 10% or less, and the probable error is estimated at 6%.
Instruments and Experimental Techniques 04/2008; 51(5):665-681. · 0.36 Impact Factor
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A. D. Panov,
N. V. Sokolskaya,
Adams, Jr., J. H,
H. S. Ahn,
G. L. Bashindzhagyan,
K. E. Batkov,
J. Chang,
M. Christl,
A. R. Fazely,
O. Ganel, [......],
J. Isbert,
K. C. Kim,
E. N. Kouznetsov,
M. I. Panasyuk,
W. K. H. Schmidt,
E. S. Seo,
J. Watts,
J. P. Wefel,
J. Wu, V. I. Zatsepin
[show abstract]
[hide abstract]
ABSTRACT: The ATIC balloon-borne experiment measures the energy spectra of elements
from H to Fe in primary cosmic rays from about 100 GeV to 100 TeV. ATIC is
comprised of a fully active bismuth germanate calorimeter, a carbon target with
embedded scintillator hodoscopes, and a silicon matrix that is used as the main
charge detector. The silicon matrix produces good charge resolution for protons
and helium but only partial resolution for heavier nuclei. In the present
paper, the charge resolution of ATIC was improved and backgrounds were reduced
in the region from Be to Si by using the upper layer of the scintillator
hodoscope as an additional charge detector. The flux ratios of nuclei B/C, C/O,
N/O in the energy region from about 10 GeV/nucleon to 300 GeV/nucleon obtained
from this high-resolution, high-quality charge spectra are presented, and
compared with existing theoretical predictions.
08/2007;
-
A. D. Panov,
J. H. Adams,
H. S. Ahn,
K. E. Batkov,
G. L. Bashindzhagyan,
John W. Watts,
J. P. Wefel,
J. Wu,
O. Ganel,
T. G. Guzik, [......],
J. Isbert,
K. C. Kim,
M. Christl,
E. N. Kouznetsov,
M. I. Panasyuk,
E. S. Seo,
N. V. Sokolskaya,
J. Chang,
W. K. H. Schmidt,
A. R. Fazely
[show abstract]
[hide abstract]
ABSTRACT: This paper reports on the results of measurements performed in the course of the ATIC-2 balloon experiment (2002–2003) for
the energy spectra of particles (such as protons; He, C, O, Ne, Mg, Si, and Fe nuclei; and some groups of nuclei) and the
all-particle energy spectrum in primary cosmic rays at energies ranging from 50 GeV to 200 TeV. The conclusion is drawn that
the energy spectra of protons and helium nuclei differ substantially (the spectrum of protons is steeper) and that the shape
of the energy spectra of protons and heavy nuclei cannot be described by a power function.
Bulletin of the Russian Academy of Sciences Physics 03/2007; 71(4):494-497.
-
A. D. Panov,
J. H. Adams,
H S Ahn,
G. L. Bashindzhagyan,
K. E. Batkov,
J Chang,
M. Christl,
A. R. Fazely,
O Ganel,
R. M. Gunashingha, [......],
K C Kim,
E. N. Kouznetsov,
M. I. Panasyuk,
W. K. H. Schmidt,
E. S. Seo,
N. V. Sokolskaya,
John W. Watts,
J. P. Wefel,
J Wu, V. I. Zatsepin
[show abstract]
[hide abstract]
ABSTRACT: The results of ATIC-2 baloon experiment (2002-2003) for energy spectra of
protons, He, C, O, Ne, Mg, Si, Fe, some groups of nuclei, and all-particle
spectrum in primary cosmic rays are presented in energy region 50GeV--200TeV.
The conclusion is that the spectra of protons and helium nuclei are essentially
different (the spectrum of protons is steeper) and the spectra of protons and
heavy nuclei have no-power form.
12/2006;
-
[show abstract]
[hide abstract]
ABSTRACT: A model to describe cosmic ray spectra in the energy region from 10 GeV to 100 PeV is suggested based on the assumption that Galactic cosmic ray flux is a mixture of fluxes accelerated by shocks from nova and supernova of different types. We analyze recent experimental data on cosmic ray spectra obtained in direct measurements above the atmosphere and data obtained with ground Extensive Air Shower arrays. The model of the three classes of cosmic ray sources is consistent with direct experimental data on cosmic ray elemental spectra and gives a smooth transition from the all particle spectrum measured in the direct experiments to the all particle spectrum measured with EAS. Comment: Revised version accepted for publication in Astronomy and Astrophysics, 5 pages, 6 figures, aa.cls
01/2006;
-
N. V. Sokolskaya,
J. H. Adams,
H. S. Ahn,
K. E. Batkov,
G. L. Bashindzhagyan,
J. Z. Wang,
J. P. Wefel,
J. Wu,
O. Ganel,
T. G. Guzik, [......],
J. Isbert,
K. C. Kim,
M. Christl,
E. N. Kouznetsov,
M. I. Panasyuk,
A. D. Panov,
E. S. Seo,
A. R. Fazely,
J. Chang,
W. K. H. Schmidt
[show abstract]
[hide abstract]
ABSTRACT: We analyze the characteristics of the albedo, or the backscatter current, which constitutes a background for charge measurements
in calorimetric experiments in high-energy cosmic rays. We compare the experimental data obtained in the flights of the ATIC
spectrometer with the simulations performed using the GEANT 3.21 code. We discuss the influence of the backscatter on the
charge resolution in the ATIC experiment.
Physics of Atomic Nuclei 06/2005; 68(7):1176-1182. · 0.57 Impact Factor
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J P Wefel,
J H Adams,
H S Ahn,
G L Bashindzhagyan,
K E Batkov,
J Chang,
M Christl,
A R Fazely,
O Ganel,
R M Gunasingha, [......],
J Isbert,
K C Kim,
E N Kouznetsov,
M I Panasyuk,
A D Panov,
W K H Schmidt,
E S Seo,
N V Sokolskaya,
J Wu, V I Zatsepin
[show abstract]
[hide abstract]
ABSTRACT: Presenter: J. P. Wefel (wefel@phunds.phys.lsu.edu), usa-wefel-J-absl-og11-oral The Advanced Thin Ionization Calorimeter (ATIC) experiment measures the energy spectra of individual elements, from H to Fe, in the energy region from about 100 GeV to tens of TeV. ATIC was flown twice on long-duration balloon flights around the South Pole, 12/00-1/01 (ATIC-1), and 12/02-1/03 (ATIC-2). En-ergy deposit spectra for H and He from both flights are presented. The data from ATIC-2 (18 days) show superior resolution and preliminary analysis indicates evolving energy spectra (i.e. becoming harder with increasing energy) consistent with changes expected from propagation models. The data also suggest a slightly steeper source spectrum for H than for He.
01/2005; 3:105-108.
-
[show abstract]
[hide abstract]
ABSTRACT: The Advanced Thin Ionization Calorimeter (ATIC) was built for series of long- duration balloon flights in Antarctica. Its main goal is to measure energy spectra of cosmic ray nuclei from protons up to iron nuclei over a wide energy range from 30 GeV up to 100 TeV. The ATIC balloon experiment had its first, test flight that lasted for 16 days from 28 Dec 2000 to 13 Jan 2OO1 around the continent. The ATIC spectrometer consists of a fully active BGO calorimeter, scintillator hodoscopes and a silicon matrix. The silicon matrix, consisting of 4480 pixels, was used as a charge detector in the experiment. About 25 million cosmic ray events were detected during the flight. In the paper, the charge spectrum obtained with the silicon matrix is analyzed.
02/2004;
-
V. I. Zatsepin,
J.H. Adams,
H.S. Ahn,
G.L. Bashindzhangyan,
K.E. Batkov,
J. Chang,
M. Christl,
A.R. Fazely,
O. Ganel,
R.M. Gunasingha, [......],
K.C. Kim,
E.N. Kouznetsov,
M.I. Panasyuk,
A.D. Panov,
W.K.H. Schmidt,
E.S. Seo,
N.V. Sokolskaya,
J.Z. Wang,
J.P. Wefel,
J. Wu
[show abstract]
[hide abstract]
ABSTRACT: ATIC (Advanced Thin Ionization Calorimeter) is a balloon borne
experiment designed to measure cosmic ray composition for elements from
hydrogen to iron and their energy spectra from 30 GeV to near 100 TeV.
It is comprised of a fully active BGO calorimeter, a carbon interaction
target, scintillator ho doscopes, and a silicon matrix that is used as a
charge detector in the experiment. ATIC had two successful balloon
flights in Antarctica: from 28 Dec 2000 to 13 Jan 2001 (ATIC-1) and from
29 Dec 2002 to 18 Jan 2003 (ATIC-2). Preliminary rigidity spectra of
protons and helium nuclei and their ratio are presented for the test
flight (ATIC-1). Particular attention is given to problems associated
with measuring energy.
06/2003; 4:1829.
-
J. P. Wefel,
J.H. Adams,
H.S. Ahn,
G.L. Bashindzhangyan,
K.E. Batkov,
J. Chang,
M. Christl,
M. Cox,
S.B. Ellison,
A.R. Fazley, [......],
B. Price,
W.K.H. Schmidt,
E.S. Seo,
D. Smith,
N.V. Sokolskaya,
M. Stewart,
J.Z. Wang,
J. Watts,
J. Wu, V.I. Zatsepin
[show abstract]
[hide abstract]
ABSTRACT: The Advanced Thin Ionization Calorimeter (ATIC) balloon experiment
completed a 19.7 day science flight, 29 Dec. 02 to 18 Jan. 03, from
McMurdo, Antarctica, yielding 67 Gbytes of science data. The instrument
was fully recovered just over the trans-Antarctic mountain range. ATIC
is designed to make new measurements of the composition and energy
spectra of cosmic rays in the region up to 100 TeV total energy. The
flight and the instrument performance are described and compared to the
ATIC-1 flight from 2000-01, and some preliminary results are discussed.
06/2003; 4:1849.
-
V. I. Zatsepin,
J. H. Adams,
H. S. Ahn,
G. L. Bashindzhagyan,
K. E. Batkov,
J. Chang,
M. Christl,
A. R. Fazely,
O. Ganel,
R. M. Gunasingha, [......],
K. C. Kim,
E. N. Kouznetsov,
M. I. Panasyuk,
A. D. Panov,
W. K. H. Schmidt,
E. S. Seo,
N. V. Sokolskaya,
J. Z. Wang,
J. P. Wefel,
J. Wu
[show abstract]
[hide abstract]
ABSTRACT: albedo, radiation backscattered from an interaction and from the
subsequent shower development, provides a `background' for calorimeter
experiments. In ATIC (Advanced Thin Ionization Calorimeter), a balloon
borne instrument to measure cosmic ray composition and energy spectra
for elements from hydrogen to iron from 30 GeV to near 100 TeV, a fully
active BGO calorimeter follows a carbon interaction target and
scintillator ho doscopes. The first detector is a silicon matrix
constructed of 4480 individual silicon pixels, each 2 cm × 1.5 cm,
that provide a measurement of the charge of the primary particle in the
presence of albedo. ATIC had two successful balloon flights in
Antarctica: from 28 Dec 2000 to 13 Jan 2001 (ATIC-1) and from 29 Dec
2002 to 18 Jan 2003 (ATIC-2). We compare the albedo signals measured in
the silicon matrix during the ATIC-1 flight with simulations performed
using the GEANT 3.21 code and the QGSM event generator for
nucleus-nucleus interactions.
06/2003; 4:1861.
-
[show abstract]
[hide abstract]
ABSTRACT: The Advanced Thin Ionization Calorimeter (ATIC) was built for series of long-duration balloon flights in Antarctica. Its main goal is to measure energy spectra of cosmic ray nuclei from protons up to iron nuclei in the wide range of their energy from 30 GeV up to 100 TeV. The ATIC balloon experiment had its first, test flight that lasted for 16 days from 28 Dec 2000 to 13 Jan 2001 around the South Pole. The ATIC spectrometer consists of a fully active BGO calorimeter, scintillator hodoscopes and a silicon matrix. The silicon matrix consisted of 4480 pixels was used as a charge detector in the experiment. About 25 million cosmic ray events were detected during the flight. In the paper, the charge spectrum obtained with the silicon matrix is analyzed.
02/2003;
