The arrival directions of the gamma-quanta with energies of about 10 to 15th power eV which were registrated by Tien Shan experiment were compared with COS-B observations. On the basis of the Monte Carlo simulations it was shown with low probability that arrival directions of Tien Shan gamma-quanta initiated showers are not uniformly distributed. It is shown that in the region not seen by COS-B mission, the high energy gamma-ray sources should be located at position of 90 deg. 1 sup 11  130 deg and b sup 11  or = 50 deg. The integral intensity of these sources should be I ( 10 to the 15th power eV) = 4.8 + or - 1.7).10 to the 13th power/sq cm/s/str. There is no coincidence between the gamma-quanta registrated by Tien Shan experiment with Geminga intense COS-B gamma source. So it is shown that the integral photon spectrum of Geminga (I(e) approx E sup-Beta, where Beta = 0.8 for E 1 GeV) becomes steeper (Beta 1.2) in high energy region with probability 99.9.%

Karakula, S.

Stamenov, J. N.

Tkaczyk, W.

English

NASA Technical Reports Server

OG 2.7-5
268
SOME EVIDENCE FOR HIGH ENERGY GAMMA-RAY
SOURCES AT LARGE GALACTIC LATITUDES
S. Karakuia. J.N. Stamenov + and W. Tkaczyk
Institute of Physics, University of L6d_, Poland
+Instiiute for Nuclear Research and Nuclear Energy,
Sofia, Bulgaria
ABSTRACT
"Yhe arrival directions of the gamma-quanta with energies of
about 1015 eV which were registrated by q'ien Shah experiment
were compared with COS B observations.
On %he basis of the Monte Carlo simulations i% was shown with
low probability that arrival directions of Tien Shah gamma-quanta
initiated showers are not uniformly dlsiribuledi,
We show %hat in %he region not seen by COS B mission, the
high epergy _amma-ray sources should be localed at position of
90o< I_< 130 V ._r_d blf>/ 50 °. Th@ iniegral intensity of the_e sources
should be I(>i0" eV) = (4.8 + 1.V)'10 -13. cm -2. s-I. str-_, "
_l_her.e are no coincidence beiween %he gamma-quania registra-
ted by Tien Shah experiment wiih Gemir_ga iniense COS B gamma
source. So it is shown thal the integral photon specirum of Geminga
I(>E)_ E-_ , where # : 0.8 for E < i GeV) becomes steeper> 1.2) in high energy region with probability 99.90/0."
1. INTR ODUCTION
The cross-section for photonuclear interactions is much smal-
ler %hen %he cross-section for nuclear interactions of hadrons, so the
exiensive air showers (EAS) iniliated by high energy photons
should be of muon poor showers (Maze and Zawadzki. 1960). The
numerical estimations show that this type of EAS should content
about 10-15% muons of %hat in the normal showers of the same size.
The succesfull obsevations of flux from discrete sources made
by %he ground base Cerenkov detectors and extensive air showers
techniques have provided many speculations on %he origin of ultra-
high energy photons (1015-1016 ) eV from the Galactic point sources:
Cyg X-3 (Samorski e% al.. 1983 : Lloyd-Evans st al., 1983), Crab
(Dzikowski et ai.,1981,1983: Kirov et aI.,_985), Vela (pro%heroe el al.,
198zi). The observations of some excess of muons from the_ direction
OG 2.7-5 
288 
SOME EVIDENCE FOR HIGH NERGY GAMMA-RAY 
SOURCES AT LARGE G LACTIC LATITUDES 
+ ' S. Karakula, J N. Stamenov and W. Tkaczyk 
Insti ute of Physics, University of L6di, Poland 
+Institute for Nuclear Research and Nuclear Energy, 
Sofia, Bulgaria 
ABSTRACT 
The arrival directions of the gamma-quanta with nergies of 
about 015 eV w ich were regis rated by Tien Shan experiment 
were compared with COS B observations. 
On the basis of the Monte Carlo simulations it was shown with 
low probability hat arrival directions of Tien Shan gamm -quanta 
nitiated showers are not uniformly distributed.,,' 
We show that in the region not seen by COS B m ssion, the 
high energy %amma-rw sources should be located at position of 
90 0 < 11< 130 ~1fP b ~ 500 • The, integral intensity of these, sources 
should be 1(>10 eV) = (4.8 ± 1.7)' 10-13, cm-~' s-1, str-1 • 
Ther~ are no co ncidence between the gamma-quanta registra-
ted by Tien Shan experiment with Geminga ntense COS B gamma 
source. So it is shown tha  the integral photon spectrum of Geminga 
(I(>E) '" E-~ ,where ~ = 0.8 for E < 1 GeV) becomes steeper 
~ > 1.2) in high energy region with probability 99.9%. 
1. INTRODUCTION 
The cro s-section for photonuclear interactions is much smal-
ler than the cro s-section for nuclear interactions of hadrons, so the 
extensive air showers (EAS) n tiated by high nergy photons 
should be of muon poor showers (Maze and Z wadzki~ 1960). The 
numerical estimations show tha  this type of EAS should co tent 
about 10-150/0 muons of that in the normal showers of the same size. 
The succesfull obsevations of flux from discrete sources made 
by the ground base Cerenkov d tectors and extensive air showers 
techniques have provided many speculations on the origin of ultra-
high nergy photons ( 015_1016 ) eV from the Galactic point sources: 
Cyg X-3 (Samorski et al., 1983 : Lloyd-Evans et al., 1983), Crab 
(Dzikowski et al.,:1. 981,,1983: Kirov et al.,1:985) ~ Vela (Protheroe et al., 
1984). The observations of some excess of muons from thEt direction 
https://ntrs.nasa.gov/search.jsp?R=19850025665 2020-03-20T17:52:55+00:00Z
2119 OG 2.7-5
Cyg x-3 by Mont Blanc Saboratory (Rubbia, 1985) oan be of the
fundamental importance for the problems of origin of cosmic rays
and also for the problem of acceleration of particles in the astro -
physical objects.
The Tien Shan experimental data shows that there exist EAS
with anomalously small number of muons and hadrons (Stamenov, et
al., 1983). The analysis of selected characteristics of muons and
hadrons in EAS, aspecially the lateral energy structure in the sho-
wer core and the averaged cascades in the ionization calorimiter
(Nikolsky et al., 19.84) confirms the assumtion that there are EAS,
generated by primary gamma-quanta in the energy range E>4 1014eV.
In the low energy interval (50MeV - 5 GeV) the gamma emission
from point sources has been observed by two satellite missions :
SAS-2 (Fichtel et al., 1975) and COS B (Bignami et al., 1975 :
Scarsi et al., 1977). The multiwire spark chamber spectrometer tech
nique used in both experiments survived 3° of angular resolution.
The second COS B catalog (Swanenburg et al., 1981) contain 25
gamma point sources, but only four of them were identified with
known astrophysical objects (Crab, Vela, 3C 273, @ Oph molecular
cloud). "l_he most intense source 2CG 195+04: (C'Jeminga) is proba-
bly corelated wlth the nearest neutron star (Bignami et al., 1984).
In this paper we discuss the spatial distribution of eight of
high energy photons registrated by Tien Shan experiment (Stamenov
et al., 1983) and theirs coincidence with COS B gamma sources.
2. METHOD AND RESULTS
From the experimental conditions for Tien Shah array (zenith
angleS..<30 °) we have evaluated the daily exposition time for the
source located at declination 6 from the following expression:
cost--(cos8 - sin6 sln_)/cos6 cos_ ,whereS=30°, _-
43.25 °. The daily exposition time has a maximum at (_ = 52.3 ° .
We have analyzed the anisotropy of Tien Shah events in the galactic
and celestial coordinates and calculated the following parameters:
i) the sky area seen by Tien Shah EAS array for zenith angle
8 _<30°, it) the parallel (_=43.25 ° i'I'ien Shah zenith) in the ga-
lactic coordinates, iil) the parallel (_=52.3 ° (for maximum time of
exposition) in the galactic coordinates. Figure 1 shows also above
.. 
289 G .7-5 
 X-3  nt l  L r t r  ( i , ) c   f t  
fundamental i portance for the problems of origin of cosmic rays 
nd lso f r t  roblem f cceleration f articles i  t  stro -
hysical objects. 
he ien han perimental ata ows t t t re ist S 
it  omalously s all umber f uons d adrons ( tamenov, t 
al., 1983). he analysis of selected characteristics of uons and 
adrons i  AS, specially t  l t ral ergy str cture i  t  s o-
er re d t  eraged ascades i  t  i ization lorimiter 
( ikolsky et al., 19.84) c nfirms t e assumtion t at t ere re S, 
enerated by pri ary ga ma-quanta in the e ergy ra ge >4· 1014eV. 
In the lo  e ergy interval (50 MeV - 5 eV) the ga ma e ission 
fro  oint s urces as en bserved y t o satellite issions : 
AS-2 ( 'ichtel t l., 75) d OS  ( ignami t l., 75 
carsi .et al., 7). he ultiwire s ark c amber s ectrometer tech 
i ue sed in th e periments s rvived 3 0 of a gular res lution. 
he second OS  catalog ( a enburg et al.~ 81) c ntain 25 
ga ma mint s urces, but only four of the  ere identified ith 
known astrophysical objects ( rab, ela, 3C 273, Q ph olecular 
cloud). The ost intense source 2 G 195+04 (Geminga) is proba-
bly c related ith the earest neutron star ( ignami et al., 984). 
In t is aper e iscuss t  s atial istri tion f i ht f 
i h ergy hotons r gistrated y ien han periment ( tamenov 
t l., 983) d t eirs incidence ith OS  a ma urces. 
. ETHOD ND ESULTS 
'rom t  perimental nditions f r ien han rray ( nith 
angle 8 ~ 300 ) e have evaluated the daily expo sition ti e for the 
urce l ated t clination <5 fr  t  f ll ing pression: 
cos t = (cose - sin <5 sing> ')/cosd cosg> ,where 8=30 0 , fJJ-
3.25 0 • he il  position ti e as a aximum t d  .30 • 
e ave alyzed t e isotropy f li  ha n ents i  t  lactic 
nd elestial ordinates d lculated t  f ll ing arameters: 
i) the sky area seen by ien han AS array for zenith angle 
 ~ 00 , ii) t  arallel <5 43.250 (Tien 'han nith) i  t  a-
lactic coordinates, iii) the parallel d =52.3 0 (for maximum time of 
position) i  t  alactic ordinates. 'igure  ows l o ove 
2 7 0 ©G 2.7-5
parameters. Moreover I,_ig.I shows: the arrival directions of eight
high energy photons events, points sources and area seen by COZ ]9.
bIt=+90
i _@ W'"
180 '" ®
b II =-90
Fig. i. The map of the sky area in the galactic coordinates:
1-region not seen by "9ien 5ban, 2,region not seen by .COS B,
+ - Tien Shah experimental data, o,e - COS B sources,
"l_ien Shah zenith trajectory, .... - the trajectorqT of
maximum time exposition.
The high energy gamma-ray events have some tendency to be loca-
ted in the region not seen by COS B, 90o< iii< 130 °, bll> 50 °. From
the experimental conditions for the 'I'ien Shah array we have evalua-
ted the probability distribution of registration of EAS, as the function
of declination (in rectascention this distribution is uniform ).Assuming
that high energy gamma-rays sources are isotropically distributed on
the sky we randomly simulate eight positions of the arrival directions
of the EAS. From the large number (1000) of simulations we have
evaluated: ql-the mean angular radius of eight events, Q2 - the
mean angular radius of four most collimated events. Table I shows
above parameters for the Tien Shan eight events and from Monte
"Z'able i.
Carlo calculations. We can no-
o o
rice that for both parameters QI Q2
the experimental data is lower Tien 5ban 42.4 15.9
than one standard deviation .
+10 _ _+15
It can be some indication that Monte Carlo 56.1 li. 2 4.J.l 2 l
_l'ien Shan events are more
270 O  .7-5 
arameters. oreover F'ig. 1 s ows: t e arrival irections of ei ht 
high energy photons events, points sources and area seen by COS B. 
ll :+  
 
~~ ..... 
., 
~::::-"';~o 
• ~ // .. - -·-'-7· ., 
J  g-- ;~ --~ 1\ '),.r\ ~~ 
.0/.- :a ~ i~: ~~_~:; f.-/. 
- \ ~"i\ ~iiIi 30 [j!! ~"'I> /@ , .. . -. \ '-'-7 \ ~~ ~ 
-,-' n q n ~ • '. J . 2:0 \",~~.~.\ .- f • 
'" 
'/ I ~ J V-... ~- ... \ ..... ~-. -' - . : 1'-_ , .. f: ' .. -~ 
__ ~'- ~~=!!jt:: \ .. 
\ r[ ' .. 
. . l- .. ,I 
. 7'~ -30 ........ ~---. '" .\. 
. 7: ., -,I-
-......t. .--. 1-. 
.'1;' 
~~ ~ - --17' "- io" '1.-1 ..... 
I 2~ ....... 1'1;:::' ...., 60 
180 
1 ITillll 
Fig. 1. he ap of the sky area in the galactic coordinates: 
l-region not seen by Tien Shan, 2-region not seen by COS B, 
+ - Tien Shan experimental data, 0,_ - COS B sources, 
- - - Tien han nith tr j ctory, . - t e tr j ctory f 
aximum ti e exposition. 
The high energy ga ma-ray events have so e tendency to be loca-
ted in the region not seen by COS B, 90 0 < III < 1300 , b l1:;> 500 • From 
the experimental conditions for the Tien Shan array e have evalua-
ted the probability distribution of registration of EAS, as the function 
of declination (in rectascention this distribution is uniform ). ssuming 
that high energy ga ma-rays sources are isotropically distributed on 
the sky e randomly si ulate eight positions of the arrival directions 
of the AS. From the large number (1000) of si Ulations e have 
evaluated: Ql-the. mean angular radius of eight events, Q 2 - the 
ean angular radius of four ost colli ated events. able 1 shows 
above parameters for the Tien Shan eight events and from onte 
arlo lculations. e n o-
tice that for both parameters 
the experimental data is lower 
n e ndard eviation • 
It can be some indication that 
Tien han vents re ore 
Tab  1. 
ien Shan 
Monte Carlo 
Q 1 
0 Q 2 
0 
.4 .9 
10 
56.1_11•  4j.7~~ 
,. 
2 7 1 OG 2.7-5
concentrated than we expect from isotropic distribution, aspecially I
four events are concentrated in the region 90o< IIi< 130 ° and bl>
50 ° . "l_he integlaal intensity of this sources at energies E > 4. 1014eV
should be greater than (4.8 + 1.7). I0-13cm -2 s-1 sir-1 (Nikolsky
et at., 1985). Now another question: what is the reason that there
is no coincidence of 'l_ien Shah events with Crab (2CG 184-05)?
If we take the energy spectrum of Crab (Hermsen, 1980 : Masnou1.67" i0 (E/10) cm s -1,et al., 1981), F(>E) = -7 9 -2.2 -2 (E in eV)
and e_t_apolate it up to e_ergie2s of 1015 eV, the expected flux is
F(>10 eV) = 1 06. 10 -1 cm- s -1 So the expected number of
" " "-2 °
showers from the Crab is n = 3.6 10 for the effechve area Seff=
36 m 2 and corection for the exposition time (teXp =Xteff, where
_= t/24). We should notice that as it was shown by l<irov et al.,
(1985) for_ much weaker criterions the "l_ien Shah data shows the
detectable excess from the direction of the Crab. On the other hand
the COS B source 2CO 195+04 (Oeminga) has much harder energy
spect_um0._erm_en, _980 : Masnou et al., 1981), F(>E) = 6.25" 10 -7(s/10)- era- s-, (E ineV). extrapolationofthisspectrum
to the high energy (E > 103-o eV) provides that we should expect
23 gamma events on the "I_ien Shan array. Because there is no coin
cidence with this source we can conclude that th integral photon
spectrum in high energy range of Geminga I.._5"(>E) E-_ , where _ =
0.8 for E< 1 GeV becomes steeper _> 1.2 with probability 99.9°/0.
3. DISCUSSION AND CONCLUSIONS
"I'here is no coincidence between arrival directions of eight
'l_ien Shah photons events and COS B gamma sources. Monte Carlo
simulations indicated that this events are more concentrated than one
could expect from the isotropic distribution_ asp ecially four events
a concentrated in the region 900< iii< 130 °, bn> 50o: not seen by
COS B. "I'he spectrum of Geminga in high energy range should be
much steeper than expected from COS B experiment.
REFERENCES
Bignami, G.P., et al., 1975, Space Sat. Instr, !, 245.
Bignami, O.F., Caraveo, P.A. and Paul, J.A., 1984, Nature, 31___9_0,464.
Dzikowski, q'., et al., 1981, 17th Int. Cosmic Ray Conf., !, 8.
Dzikowski, "i_.,et al., 1983, J. Phys. G., 9, 459.
Fichtel, C.E., et al., 1975, fstrophys. J. 198, 163.
Hermsen, W., 1980, Ph. D. Thesis Univ. of Leiden, "I'he Netherlands.
I<irov, I.N., et al., 1985, Proc. of this Conf., OG 2.3-2.
Lloyd-Evans, J., e% al., 1983, Nature, .30___5,784.
Masnou, J.L., e% al., 1981, 17th Int. Cosmic Ray Conf., i, 177.
Maze, 19., and Zawadzki, A., 1960, Nuovo Cim., 1___?,625.
Nikolsky, S.I., et al., 1984, Adv. Space 19es., 3, No 10-12, 131.
Protheroe, R.J., e% al., 1984, Astrophys. J. (Letters), 28___0_0, L47.
lqubbia, C., 1985, ist Symposium on Underground Physics, 25-28
April, Saint-Vincent, Aosta Valley (Italy).
Samorski,M.,and Stamm,W.,1983,Astrophys.J.(Le ers), L17.
Scarsi, L., et al., 1977, Proc. 12th ESLAB Syrup. ESA SP-124,. p.3.
Stamenov, J,N., et al., 1983, 18%h Int. Cosmic Ray Conf., 6, 54.
Swanenburg,B.N.,etal.,1981,Astrophys.J. (LeUers),24__!,L69.
.. 
271 G 2.7-5 
concentrated than we expect from isotropic distribution, aspecially 
four events are concentrated in the region 90 0 < 111< 1300 and b ll> 
500 • Th  i tegr J i tensity f t is sources t nergies  · 014eV 
should be greater than (4.8 ± 1.7)· 10-13cm-2 s-l str-l (Nikolsky 
et al., 1985). ow another question: hat is the reason that there 
is no coincidence of 'I'ien han vents ith rab (2CG 84-05)? 
If we take the energy spectrum of Crab (Hermse~, 1980 : Masnou 
et al., 1981), F(>E) = 1.67· 10-7 (E/l09)-~.2 cm-':" s-l, (E in eV) 
and extEapolate it up to e,rergies of 1015 eV, the expected flux is 
(>10 1 eV) = 1.06· 10-1 cm-2 s-l. o the expected number of 
howers from the rab is n  .6 0-2 or the ffective rea eff= 
36 m2 and corection for the exposition time (texp =Xteff' whe re 
X = t/ 4). e s ould notice t at s it as shown y Kir v et al., 
(1985) for' uch eaker criterions the Tien Shan data shows the 
etectable xcess f  t e irection f t e rab. n e ther and 
t e OS  s urce CG 95+04 (Geminga) as uch arder nergy 
spectrum <J-Ierm~en, 1980 : Masnou et al., 1981), F(>E) = 6.25.10-7 
(E/l0 9 )-0. cm- s-1, (E in eV). The extrapolation of this spectrum 
to the high energy (  > 1015 e ) provides that e should expect 
23 ga ma events on the Tien Shan array. ecause there is no coi,!2 
i ence ith t is urce e an onclude t at t e i t l"al hoton 
spectrum in high energy range of eminga F (>E) '" E-~ , where ~ 
0.8 for E < 1 GeV becomes steeper ~ > 1.2 with probability 99.90/0. 
. ISCUSSION ND ONCLUSIONS 
The   o incidence etween rri al irections f i ht 
Tien han photons events and OS B ga ma s urces. onte arlo 
si ulations i icated t t t is vents re ore oncentrated t an ne 
could expect fro  the isotropic distributionb aSRecial&, four events 
a concentrated in the region 90 0 < III  130 , b 1> 50 : not seen by 
OS B. The spectrum of eminga in high energy range should be 
much steeper than expected from COS B experiment. 
EF R NCES 
Bignami, G.F., et al., 1975, Space Sci. Instr., 1, 245. 
Bignami, G.F., Caraveo, P.A. and Paul, J.A., 1984, Nature, 310, 464. 
Dzikowski, '1'., et al., 1981, 17th Int. Cosmic Ray Conf., 1, 8. 
Dzikowski~ '1'., et al., 1983, J. Phys. ., .2, 459 • 
ichtel, . ., et al., 1975, Astrophys. J. 198, 163. 
ermsen, ., 1980, Ph. D. hesis niv. of Leiden, The etherlands. 
Kirov, I.N., et al., 1985, roc. of this onf., G 2.3-2. 
Lloyd-Evans, J., et al., 1.983, Nature, 305, 784. 
asnou, J.L., et al., 1981, 17th Int. osmic ay onf., 1, 1.77. 
aze, R., and Zawadzki, A., 1960, uovo Ci ., 17, 625. 
Nikolsky, S.I., et al., 1984, Adv. Space Res., 3, No 10-12, 131. 
Protheroe, R.J., et al., 1984, strophys. J. (Letters), 280,· L47. 
Rubbia, ., 1985, 1st Symposium on nderground Physics, 25-28 
pril, aint- incent, osta alley (Italy). 
Samorski, M., and Stamm, W., 1983, Astrophys. J. (Letters), 268, L17. 
Scarsi, L., et al., 1977, Proc. 12th ESLAB Symp. ESA SP-124, p.3. 
Stamenov, J.N., et al., 1983, 18th Int. Cosmic Ray Conf., £,. 54. 
S anenburg, B.N., et al., 1981, strophys. J. (Letters), 243, L69. 


Some evidence for high energy gamma-ray sources at large galactic latitudes

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