Dependence of optical continuous spectrum of quasi-stellar sources on red shif

Kardashev, N. S.

Komberg, B. V.

English

NASA Technical Reports Server

National Aeronautics and Space Administration 
Goddard Space Flight Center 
Contract No. NAS-5-9299 
DEPENDENCE OF THE OPTICAL CONTINUOUS SPECTRUM 
OF QUASARS ON THEIR RED SHIFT 
N. S. Kardashev 
B. V. Komberg 
(USSR) 
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1 N66 35782 
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0 
(ACCESSION NUMBER) “““7 
14 A P R I L 1966 
https://ntrs.nasa.gov/search.jsp?R=19660026492 2020-03-16T20:35:48+00:00Z
ST - QSS - m- 10 475 
DEPENDENCE OF TKE OPTICAL CONTIMUOUS SPECTRUM 
OF QUASARS ON THEIR RED-SHIFT * 
Astrononicheskiy Ts i rkulyar  
BAS AN SSSR, l o .  357 
25 February 1966 
S U M M A R Y  
by I?. S. Kardashev 
& B.V. Komberg 
The determination of the  dependence of the o p t i c a l  continuous spec- 
t r u r  c f  QSS on t h e i r  r ed - sh i f t  i s  based on data of the three-color photo- 
metry (UBV). It is  f i r s t  e s t ab l i shed  f o r  QSS with known red - sh i f t s ,  reveal-  
ing an absorption "step1' i n  QSS spectra .  Prelimintlry e s t i n a t e s  of r e d - s h i f t s  
a r e  then made f o r  sone of the unident i f ied  QSS. Bowever, it is not y e t  clear 
wlrat mat ter  is responsible  €or absorption i n  i n t e r g a l e c t i c  medium, 
new i d e n t i f i c a t i o n s  of quasars  and $he i r  m-c-photometry, concentrat ing the  
r e sea rch  i n  the reg ion  (2250 2150)A f o r  d i r e c t  de tec t ion  of  the absorpt ion 
r 'step".  
Tor  f w t h e r  corroborat ion of the conclusions the authow recomnend 
* *  
W e  u t i l i z e d  f o r  t he  c h a r a c t e r i s t i c  of the  o p t i c a l  spectrum's form 
t h e  d a t a  of t h e  three-color  photometry ( U B V  system) of q u a s i s t e l l a r  sources  
(QSS) 
t tcurvaturel t  &-al - t X 2 ,  where al is t he  s p e c t r a l  index i n  W and a2 ie 
t h e  s p e c t r a l  index i n  BV C33. 
[1,2]. For the  q u a l i t a t i v e  es t imate  we introduced the  value of t h e  
The spectrum is represented i n  the  form Fy-Q-=. For the  i n t e r v a l  
from 0 t o  2,  we have : 
If t h e r e  is no break i n  the spectrum of t h e  sourcei  w e  have 
dl= a and A = O .  2 
For QSS with known r ed - sh i f t s  e and UBV we p l o t t e d  the  dependence 
of A on 1; (Fig. 1, 6o l id  curve).  
* ZAVISI i JXT '  O P T I C ~ S I ~ O G O  NEpRcR~?oGo SpEKfllRA KVAZAROV OT IKH I(RASN0GO 
SIESHCHENIYA . 
2. 
Taking i n t o  account that, as s i nc reases ,  various p o r t i o n s  of 
the  spectrum pass through t h e  UBV f i l t e r s ,  i t  may be expected t h a t  t h e  
dependence A ( z )  r e f l e c t s  some general  property of &sS spec t r a ,  Since 
the  geometr ical  sense of t he  s p e c t r a l  index 
is the  first der iva t ive ,whi le  t h e  curvature  (e) 
2 3 log F, A -  
( 3  log 512 
is t h e  second de r iva t ive ,  i t  apparently follows from Fig. 1 t h a t  t he re  is 
an "absorption s tep" i n  QSS spectra. Indeed, we have f o r  a s tepped spectrum 
where 
the  f i rs t  and the  second de r iva t ives  have a form represented  i n  Fig. 2. 
Fig, 2 
I Fig. 3 Fig. 1 
As t o  t h e  method of f ind ing  
such a el that 
For a source with such t = s2, t h a t  h2 = A, (1 + e) 
A ,  
1, = Xo (1 + 2,) w 3860 
i t  is c l e a r  from Fig. 3. For a source with 
we s h a l l  have A z A, = max A. 
4380 i, we have A = 0. 
3. 
I n  order  t o  determine the  depth of t h e  ffsteplr we s h a l l  make use of 
t he  formulas of [3]. A f t e r  t ransformations we s h a l l  ob ta in  the  r e l a t i o n  between 
t h e  q u a n t i t i e s  A and Q ( i  = 1.3)9 
i 
For A, & 1.8 we ob ta in  % 0.68. 
One may wonder where the  absorption "s tepf8 in the  spectrum of a l l  QSS 
may appear from?.- ' there are two p o s s i b i l i t i e s  : 
b m d ,  beginning a t  zbout 2250 1; 
1) the re  is near the  emission source a s u b s t m e  with a wide absorpt ion 
2 )  The substance (mat te r ) ,  respons ib le  for absorpt ion is dispersed  in 
the  i n t e r g a l a c t i c  space. 
What mat ter  i n  the  i n t e r g a l a c t i c  medium ar in the  medium surrounding 
t h e  QSS, is respons ib le  for the absorp t ion?  No u n i l a t e r a l  response t o  t h i s  
ques t ion  can y e t  be given. Le t  
t i o n  of t he  ex is tence  of anomalous absorpt ion by i n t e r s t e l l a r  dus t  with maximum 
near 2300 1. 
t i c l e  model [5] .  
us note  only, t h a t  in C43there is an indica-  
The observed absorption agrees  w e l l  wi th  the  g raph i t i c  d u s t  par- 
In t h e  model of an evolving Universe and on t h e  condi t ion of c u r t a i l i n g  
the  number of absorbing p a r t i c l e s  i n  a u n i t  of a t t end ing  volume, t h e  o p t i c a l  
t h i ckness  is 
where ro = no k ( A )  1 
k ( h )  i s  the absorpt ion coe f f i c i en t ,  qo is  the  time-lag parameter. 
no is the  dens i ty  of p a r t i c l e s  at the  present  time, 
4. 
Q SS A 
According t o  the  experimental  p o i n t s  in t h e  graph of F i g . 1  ( s o l i d  
curve)no amplitude dependence of h on 
of the matter is t h a t  t h e  amplitude of negative L\ ( A3 i n  Fig. 1) must be 
a t t a i n e d  f o r  sources  wi th  s = L l  1t1.4, while In t h i s  i n t e r v a l  of - t 
no sources  have yet been 8etected.  It i~ true, however, that among t h e  
un iden t i f i ed  QSS (and the rea re  more than 30 of them) wi th  known Et 
is t he  source 3 C - 204, f o r  which bg = - 2.25. I f  t h e  observat ions give 
for it va lues  of t with in  the  range 1.1- 1.4, t h i s  w i l l  se rve  as a con- 
f i rma t ion  of the  dependence of the amplitude of A on 
p l o t t e d  by dashee). 
is seen. Apparently, t h e  fact  
there 
(in Fig. 1 it i . ~  
The t fo recae t  
Evident ly ,  f o r  f i n a l  conclusions a broader m a t e r i a l  is requi red  
i n  regard  t o  the  i d e n t i f i c a t i o n  and photometryof q u a s i s t e l l a r  ob jec ts .  
Th i s  w i l l  al low t o  emphasice more r e l i a b l y  the  dependence of h on - s, on 
t h e  bas i s  of which estimates afg could be made even for un iden t i f i ed  
sources ,  i f  UBV are measured f o r  them. The p o s s i b i l i t y  of estinatlng - 2; M -  
ambiguously inc reases  for sources w i t h  U - B  and B-V, corresponding t o  
A c lose  t o  A, o r  t o  4,. ( I n  t5is case the  e r r o r 8  for t w i l l  not exceed 
0.1). Even according t o  the  graph A(=)  
by t he  ava i l ab le  experimental  mater ia l ,p re l iminary  estimates of e can be made 
f o r  some of the  un iden t i f i ed  quasars (see Table 1). 
brought out, which w a s  p l o t t e d  
T A B L E  1 
3 C -  138 
3 C - 275.1 
3c -2RO.l 
3 C - 268.2 
9 C - 277.1 
3C-181 
3C-284  
t L83 
+ 1.63 
+ 1.83 
t 1.8 
+ 138 - 1.m 
- 2 3 5  
For f u t u r e  es t imates  of t he  time-lag parameter, more p rec i se  values  
of t he  deyendence A ( t )  may be used. Indeed 
5. 
For sources  with c 7 2 there  must be observed a dependence A(e) 
on account of absorpt ion by i n t e r g a l a c t i c  hydrogen C6, 73. Q u a l i t a t i v e l y  i t  
must repea t  the  dependence A ( t )  for nearer  sources. 
I n  conclusion we s h a l l  s t r e s s  once more the  necess i ty  of f u r t h e r  
checking t&s csnel.aicna e h h i a e d .  Required t o  t h a t  effect  are:  
1) new i d e n t i f i c a t i o n s  of quasars and t h e i r  multi-color photometry; 
2) conducting careful  photometric i nves t iga t ions  of quasar e p s c t r a  
i n  the region Xo =( 2250 2 1 5 0 ) i  for d i r e c t  d i r e c t  de tec t ion  of t he  absorp- 
t i o n  "stepll. 
G A  ISH 
Applied Mathematics 2ep. 
I n s t i t u t e  of Mathematics i n  the  
name of Steklov of t he  
U S  S R  Academy of Sciences. 
Contract No.NAS-5-9299 Translated by ANDRE LeBRICHANT 
Consultants & Designers, Inc. 
Arl ington,  V i rg in i a  
on 14 A p r i l  1966 
R E F E  R E  N C  ES 
C13.- A. SANDAGE.- Ap. J. 9 141 (4), 1560, 1965. 
C23.- A .  SANDAGEI P o  VEXON, J. De WYNDHAM. 9 I b  142 (319 1307, 1965. 
c31.- A. SANDAGE.- I b i d .  1 3 8 ( l ) ,  30, 1963. 
C41.- T,P.STECHER,- Ib id . ,  142(4) ,  1683, 1965. 
[SI.- T. P. STECHER, B. DO".- Ib. 142 ( 4 ) .  1681, 1965. 
C61.- E. E;. SALPETER, J. W e  BAHCALL, Ib. 142 (419 1677, 1965. 
C71.- E. J. GUNM, R. A .  PETERSON.- Ib. 142 ( 4 ) ,  1633, 1965. 


Dependence of the optical continuous spectrum of quasars on their red-shift

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