A model based on 24 Mg(1369) was developed as the source of the lines in which refractory grains in the jets, containing Mg and 0, are bombarded, by ambient protons in the local ISM. The narrowness of the features results because the recoil Mg nucleus is stopped in the grain before the 1369 keV excited state decays. A consequence of the 24 Mg interpretation is the expected appearance of other emission lines, due to 20 Ne and 20 Na, which are produced by proton bombardment of 24 Mg at the 33 MeV/nucleon energy corresponding to the velocity of the jets. These lines appear at rest energies of 1634 keV and 1636 keV, respectively, and should have essentially the same total flux as that emited at 1369 keV. The HEAO 3 data are examined to search for the 1634 keV (rest) emission. The observation and analysis, the results, and the implications for the understanding of SS 433 are discussed

Jacobson, A. S.

Ling, J. C.

Mahoney, W. A.

Wheaton, W. A.

English

NASA Technical Reports Server

1 8 3 OG 2.4-9
HEAO 3 UPPER LIMITS TO THE EXPECTED 1634 KEV LINE
FROM SS 433
Wm. A. Wheaton, 3. C. Ling, W. A. Mahoney, and A. S. Jacobson
Jet Propulsion Laboratory 169-327
California Institute of Technology
Pasadena, CA 91109
USA
1. Introduction. We have previously reported (1, hereafter paper I)
evidence for gamma-ray llne emission at energies near 1.5 MeV and 1.2 MeV
from the peculiar optical, radio, and x-ray varlable star SS 433.
Because of the pattern of energy variability, as reported in paper I, we
interpreted the observed spectral features as originating from the 1369
keV excited state of 24Mg, Doppler-shlfted according to the ephemeris (2)
for the optical emission llnes, which is explalned by the standard
kinematic model (3, 4) in terms of opposltely-dlrected relativistic Jets.
_n alternative explanatlon (5) attributes the features to Doppler-shlfted
14N emission at a rest energy of 1380 keV arising from thermonuclear
processes, essentially the CNO cycle, occurring in the Jets. However,
this model predicts a companion 5176 keV (rest energy) llne which Is only
marginally observed (5) if it is present at all, and which does not
appear to have the required intensity.
Ramaty, Kozlovsky, and Llngenfelter (7) have developed a model based
on 24Mg(1359) as the source of the lines In which refractory gralns in
the jets, containing Mg and O, are bombarded, (as seen in the frame at
rest with respect to a the jet), by ambient protons in the local ISM.
The narrowness of the features results because the recoil Mg nucleus is
stopped in the grain before the 1369 keV excited state decays. However,
as was pointed out by Norman and Bodansky (8), a consequence of the 24Mg
interpretation is the expected appearance of other emission lines, due to
2ONe and 23Na, which are produced by proton bombardment of 24Mg at the 33
MeV/nucleon energy corresponding to the velocity (_=0.26) of the Jets.
These lines appear at rest energies of 1534 keV and 1636 keV, respective-
ly, and should, if the observed features arise purely from proton
bombardment of magnesium, have essentlally the same total flux as that
emitted at 1369 keV.
We have examined the HEAO 3 data in order to search for the 1634 keV
(rest) emission predicted by Norman and Bodansky (8). Section 2
describes the observation and analysis, section 3 the results, and
section 4 discusses the implications for our understanding of SS 433.
2. Observation and Analysis. The Jet Propulsion Laboratory High Resolu-
tion Gamma-Ray Spectrometer, flown on HEAO 3 from 1979 to 1980, has been
described by Mahoney et al. (9). The experiment obseryed the region of
SS 433 from 1979 September 25 until the HEAO scan plane moved away from
the source in early November. The most compelling spectral features
reported in paper I were observed during the October 10.5 to October 29
183 
  P  I    P     
   
 .4-9 
m. . heaton, J. . i , . . ahoney,  . . J s  
Jet ropulsion aboratory 169-327 
alif rnia stit t  f ec nol gy 
as ena,   
 
1. I tr cti n. e have re i usl  re rte  ( , ereafter paper I) 
evidence for ga ma-ray line e ission at energies near 1.5 eV and 1.2 eV 
from the peculiar optical, radio, and x-ray variable star 55433. 
Bec~use of the pattern of energy ariabilit , as reported in paper I, e 
i t r r t  t  ser e  s ctr l f t r s as ri i ati  from t   
keV excited state of 24 g , oppler-shifted according to the ephe eris (2) 
for t e ptical e ission li es, hich is explained by t e standard 
i e atic odel ( , ) i  ter s f pOSitely-directed r l ti isti  j t . 
f.n alternative explanation (5) attributes the features to oppler-shifted 
14  e ission at a rest energy of 1380 ke  arisi  from ther onuclear 
processes, essentially th~ CNO cycle, occurring in the jets. o ever, 
t is odel redicts a co panion 6176 keV (rest energy) line hich is only 
arginally observed (6) if it is present at all, and hich does not 
appear t  have the required i te sit . 
Ra aty, ozlovsky, and Lingenfelter (7) have developed a odel based 
on 24Mg (1369) as the source of the lines in hich refractory grains in 
the jets, containing Mg and 0, are bo barded, (as seen in the frame at 
rest it  res ect t  a t e j t), by a bient r t s in t e local ISM. 
 rr ness f t  f t r  lt  s  t  r il g cl s i  
stopped in t e rai  before t e 1369 keV e cite  st t  decays. o ever, 
as was pOinted out by Nor an and Bodansky (8), a consequence of the 24Mg 
interpretation is the expected appearance of other e ission lines, due to 
20 e and 23 a , hich are produced by proton bo bard ent of 24 g at the 33 
eV/nucleon energy corresponding to the velocity (P=0.26) of the jets. 
These lines appear at rest energies of 1634 keV and 1636 ke , respective-
ly, and should, if the observed features arise purely from proton 
bar ent f agnesi , a e ss ntiall  t e same t t l flux as t t 
itt  t  . 
e  i  h    t       h   V 
(rest) e ission predicted by or an and odansky (8). Section 2 
escri es t e ser ati  a  a alYSis, secti   t e r s lts, a  
section 4 discusses the i plications for our understanding of 55433. 
2. bservation and nalysis. The Jet Propulsion Laboratory igh esolu-
tion a ma-Ray Spectro eter, flown on HEAO 3 from 1979 to 1980, has been 
described by ahoney et al. (9). The experi ent obseryed the region of 
SS 433 from 1979 Septe ber 26 until the HEAO scan plane oved away from 
the source in early ove ber. The ost co pelling spectral features 
reported in paper I ere observed during the ctober 10.6 to ctober 29 
https://ntrs.nasa.gov/search.jsp?R=19850025641 2020-03-20T17:53:09+00:00Z
t ime per iod,  and on ly  these data a re  discussed here, Dur ing t h i s  per iod  
t he  r e s o l u t i o n  o f  the  Instrument ranged from about 3  t o  7  keV (FWHM) f o r  
energies between 1  and 2  MeV (10).  
Data were excluded a t . h i g h  geomagnetic l a t i t u d e  ( L  > 2 1 ,  a f t e r  
passages through t he  South A t l a n t i c  Anomaly, when contaminated by charged 
p a r t i c l e s ,  o r  when t he  instrument v iewlng a x i s  po in ted more than 100' 
from the  zen i th .  We then f i t  the data w i t h i n  2160' o f  the  source t o  a  3- 
component l i n e a r  model, Independently f o r  each detector ,  i n  each energy 
channel. The 4  keV energy channels used i n  t he  ana lys is  were chosen t o  
match t he  instrument r eso lu t i on .  The l i n e a r  model included a  constant 
background component, a  background component p ropor t iona l  t o  t h e  h i gh  
energy r a d i a t i o n  environment, and a  source a t  t he  p o s i t i o n  o f  S S  433. We 
have found t he  r a d i a t i o n  environment t o  be p ropor t iona l ,  t o  a  good 
approximation, t o  the  observed de tec to r  count ra tes  over 10 MeV. The 
func t iona l  form of  each term being known, i n  p a r t i c u l a r  t he  instrument 
point-source response as a  func t ion  o f  angles and energy (91, t h e  f i t  
r e t u rns  est imates o f  the  amplitude o f  each term and i t s  e r r o r .  I n  order  
t o  reduce the  e f f e c t s  o f  systematlc e r r o r s  i n  background sub t rac t ion ,  we 
have performed the  ana lys is  on an i nd i v i dua l  scan basis,  f i r s t  f i t t i n g  t o  
ob ta i n  a  background-subtracted f l u x  est imate f o r  each, and then combining 
f l uxes  bywe igh ted  averaging (111, I n  e f f e c t  t h i s  a l lows t he  nominal ly 
constant p a r t  o f  the  background t o  vary on a  t imescale  longer than the  
20-mln spacecraf t  sp i n  per iod.  
Because other  poss ib le  cosmic sources o f  MeV r a d i a t i o n  I n  t he  reg ion 
have been Ignored, espec ia l l y  the  Cygnus sources and t he  Ga lac t i c  Center, 
broad-band continuum f luxes obtained are sub ject  t o  poss ib le  contamina- 
t i o n .  However, I n  t he  absence o f  a  f 0 r t ~ l t 0 ~ ~  energy coincidence w l t h  an 
ac tua l  s t rong  narrow cosmic emission feature,  we expect no e f f e c t  on our 
est imates f o r  narrow l i n e  f l uxes .  
3. Resul ts.  F igure 1  shows the  s  eCtrUm around 1787 keV, where we 
expect t h e  Doppler -sh i f ted 1634 keV "Ne feature from the  approaching j e t  
t o  appear, assuming the  1497 keV fea tu re  shown i n  F igure 1  o f  paper I . 
ar i ses  from 1369 keV emission. The s o l i d  curve i s  a  f i t  t o  a  constant 
continuum and a  Gaussian l i n e  centered a t  1787 keV, w l t h  w id th  g iven by 
t he  observed 1.5 MeV emission. I t  I s  c l e a r  t h a t  no i n d i c a t i o n  o f  any 
l i n e  appears, the  f i t t e d  f l u x  being (0 .6 f2 .0 )  x p h o t ~ n s c m ' ~  s - I  *. 
4. Conclusion. As po in ted out  i n  (7),, the  1369 keV fea tu re  cou ld  a l so  
a r i s e  from spa1 l a t i o n  o f  2 8 ~ i  t o  2 4 ~ g  w i thou t  producing anyth ing a t  1634. .A 
This  however should produce an emission fea tu re  a t  a  r e s t  energy o f  1779 
keV from e x c i t a t i o n  o f  the  s i l i c o n ,  t he  b lue component o f  which, cor res-  
ponding t o  the  1497 keV fea tu re  (11, would appear i n  our data near 1944 
- keV. Thus t h i s  p o s s l b l l i t y  pushes down the  requirement f o r  the 1634 keV 
feature,  'but demands a  new one a t  1779 keV. 
I t  may a lso  be poss ib le  t o  save the  model o f  2 4 ~ g  emission exc i t ed  
by ambient protons by making use o f  t he  f a c t  t h a t  the  cross-sect ion (12)  
f o r  product ion o f  1634 keV gamma rays by protons on magneslum drops o f f  
r a p i d l y  below about 20 MeV, but  t h a t  f o r  producing the  1369 keV exc i ta -  
t l o n  remains l a rge  down t o  about 5 MeV. 
184 OG 2.4-9 
ti  ri nd nly t  t  r   r . ri g is riod 
t e r solution f t e i tr nt r ged fr  bout  to  Y ( HM) f r 
nergi s t en 1 and  e  ( . 
ta r  excl d t, i h o agnetic l titude l  ), ft r 
sages t r gh t e outh ti  n t i t d y r d 
r n t  i tr nt i  xi  O d r  t n 0 
fr  t  nit .  t n it t  t  i  ± 0 f  r  o  
t l r l i pendently r ch t t in ch er  
l.   Y nergy l  ed in  al i   n o 
tch t  i tr nt soluti .  l r el i l d  t nt 
ackground c a ackground nt r rti al to t  igh 
energy r diation envi and  our  t t  sition f 554  
ave f nd t e r diation envi t to e l  to  od 
pproxi ti  to t e served tector t t s r 0 .  
f ti al f r  f each ter  eing , in rti l r t  i tr nt 
i r p e s a f ction f n l  nd nergy ( ), t  it 
turns sti t  f t  li  f c  t r  nd ts rr r. n r 
to r ce t  f t  f y t ti rr rs in ck r und tr ti
ve rf r ed t  nalysis n n i i i l c n SiS  t ting o 
tain  c fl x sti t  r nd t n bini g 
f s y e d v raging ( ). n ff t i  ll   i al y 
t nt rt f t e ackground to ry n  ti le l r t n t  
- i spacecraft spin ri . 
e t r ssible s i  o r  f  diation in t  r gion 
ave en i , special y t e s o r s nd t  l ctic t
r continuum fl  tai ed re ubj ct to sible t i
ti .  1n t  en  f  ortuitous ergy i  ith n 
ctual trong rro  s i  i sion t o f t  r 
sti t  f r rrow li e f . 
. sult . i re 1 shows t  sp ctru  round 787 Y,  
x ct t e i 1634 eY 20Ne f t r  fr  t  ppr achi  t 
to p r, assuming t e 1497 eY f t r  shown in i re  f r I 
ri s from 1369 eY i si .  olid r  is  it to  t nt 
ontinuu  and a ssian li e nt red t 787 Y, ith i th i n y 
t e serv d . e  i si . t is l r t t o i i ation f ny 
li e r , t  fitted fl x ing . ±  10-4 hotons cm-2 -1 
. l i  O d t in (7)"  69 Y t r  uld l o 
ri e f  ll tion f 8Si to 4Mg t r ci g nythi g t . 
i  v r should r  n i sion t r  t  st ergy f 79 
eY fro  xcitation f t e S t  l e nt f  
nding to t e 1497 eY f ture ( ), ld r in r ta ar 944 
Y.  t is ssibi ity s o n t  r i t f r t  634 Y 
f t r , 'but ands a ew  t 779 Y. 
It ay lso e ssible to sav  t  del f 4Mg i sion xcited 
y i t r t  y king e f  ct t  - cti 2) 
f r r uction f 634 Y  s y t  n esiu   ff 
pidly elo  bout 0 , t t r r ci g  69 Y 
tion r i s l r e o n to bout . 
1 85 06 2.4-9
+2 I I I I I J I
I
e.-.I
x
i---I
I
v+l_I
I
I
O,J
, _ +,,-,
r-
0
"1_ O
r-
X
I.---
z-1 i i I I i I I
1752 1760 1768 1776 1784 1792 1800 1808 1816
ENERGY(keY)
Figure 1. Spectrum of.SS 433 in the region which
corresponds to 1634 keV rest energy.
Thus we conclude that the emission does not result primarily from
bombardment of Jet 24Hg with protons at an interaction energy of the 33
HeV corresponding to the Jet velocity, as originally proposed (t).
Whether 24Hg (1634) is involved at a11, either secondary to St
bombardment or at some energy lower than 33 HeV, awaits further
experimental or theoretical clarification.
Acknowledgements, We thank R. E. Ltngenfelter and R. Ramaty for discus-
sions. The research described in this paper was carried out at the Jet
Propulslon Laboratory, Callfornla Institute of Technology, under contract
with the National Aeronautics and Space Administration.
References
I. Lamb, R. C., Ling, J. C., Mahoney, W. A., Wheaton, W. A., and
Jacobson, A. S., (1983), Nature 305, 37-39.
2. Hargon, B., (1984), Ann. Rev. Astron. Astrophys. 22, 507-536.
q:-' 
I 
o 
.-I 
>< 
. I 
I 
+2 
> (l.) 
T +1 
.-I 
I 
V) 
I 
N 
I 
E 
u 
I 
V) 
C 
85 OG 2.4-9 
~ 0~~~~~=+~~-4~~~~~~--~~~~~ 
.s:::. 
c.. 
........ 
>< 
:::> 
0: 
tw 
z -1~ __ ~~ __ ~ ____ ~ ____ ~ __ ~ ____ ~ ____ ~ __ ~ 
52 60 68 76 4 92 00 08 16 
RGY V) 
Figure 1. Spectrum of 55433 in the region which 
corresponds to 1634 keV rest energy. 
  clude t at t e i sion  t sult imarily fr  
bo bard ent of jet 24Mg with protons at an interaction energy of the 33 
MeV corresponding to the jet ve10tity, as originally proposed (1). 
hether 24Mg (1634) is involved at all, either secondary to Si 
bo bard ent or at so e energy lower than 33 MeV, a aits further 
experimental or theoretical clarification. 
ckno ledgements. e thank R. E. ingenfelter and R. a aty for discus-
si ns. he research escribed i  t is paper as carried t t t e Jet 
Propulsion Laboratory, California Institute of Technology, under contract 
ith the ational eronautics and Space dministration. 
ferences 
1. La b, R. C., Ling, J. C., ahoney, W. ., heaton, W. ., and 
Jacobson, . 5., (1983), ature 305, 37-39. 
2. Margon, ., (1984), ~. Rev. stron. strophys. 22, 507-536. 
1 8 6 06 2.4-9
3. Abel1, G. 0., and Hargon, B., (1979), Nature 279, 701-703.
4. Htlgrom, H., (1979), Astro__..__nn.Astrophys. 76, L3-L6.
5. Boyd, R. N., Newsom, G. H., Co]ltns II, G. W., and Wtescher, W.,
(1984), Science 225, 508-510.
6. Wheaton, W. A., Ling, J, C., Hahoney, W. A,, and 3acobson, A. S,,
(1984), B.A.A.S. t6, 472.
7. Ramaty, R., Kozlovsky, B., and Lingenfelter, R. E., (1984),
Astrophys. J. 283, Lt3-Lt6.
8. Norman, E. B., and Bodansky, D., (1984), Nature 308, 212.
9. Mahoney, W, A., Ling, J. C., Jacobson, A. S., and Tapphorn, R.,
(1980), Nuc]. Instr. Herb., t78, 363-38t.
10. Hahoney, W. A., Ling, J. C., and Jacobson, A. 5., (1981), Nuci.
Instr. Herb. 185, 449-458,
It, Harscher, A, P., Wheaton, W. A., Ling, J. C,, Mahoney, W. A., and
Jacobson, A. S. (1984) Astrophys. 3. 281, 566-569.
12. Dyer, P., Bodansky, D., Seamaster, A. 6., Norman, E. B., and Maxson,
D. R., (19fit), Phy_ Rev. C 23, 1865-1882.
188 OG 2.4-9 
3. Abell, G. 0., and Margon, B., (1979), Nature 279, 701-703. 
4. Milgrom. M., (1979), Astron. Astrophys. 76, 3-L6. 
5. Boyd, R. N., Newsom, G. H., Collins II, G. W., and W1escher, W., 
(1984), Science 225, 508-510. 
6. Wheaton, W. A., Ling, J. C., Mahoney, W. A., and Jacobson, A. 5., 
(1984), ~.~.~.~. 16, 472. 
7. Ramaty, R., Kozlovsky, B., 
Astrophys. ~. 283, I3-LI6. 
and Lingenfelter, R. E., (1984), 
8. Norman, E. B., and Bodansky, D., (1984), Nature 308, 212. 
9. Mahoney, W. A., Ling, J. C., Jacobson, A. 5., and Tapphorn, R., 
(1980), Nucl. Instr. Meth., 178, 363-381. 
10. Mahoney, W. A., Ling, J. C., and Jac bson, A. 5., ( 981), Nucl. 
Instr. Meth. 185, 449-458. 
11. Marscher, A. P., Wheaton, W. A., Ling, J. C., Mahoney, W. A., and 
Jacobson, A. S. (1984) Astrophys. ~. 281, 566-569. 
12. Dyer, P., BOdansky, D., Seamaster, A. G., Norman, E. B., and Maxson, 
D. R., (1981), Phy~ Rev. ~ 23, 1865-1882. 


HEAO 3 upper limits to the expected 1634 KeV line from SS 483

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server