Flux density measurements of 560 radio sources in 86 megahertz frequenc

Aetyukh, V. S.

Dagkesamanskiy, R. D.

Kozhukhov, V. N.

Vitkevich, V. V.

English

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RESULTS OF OBSERVATIONS OF 560 RADIO SOURCES I N  ITE 
FREQUENCY OF 86 MEGAHERTZ 
V.  S .  ARTYUKH 
V. V. VITKEVICH 
R .  D. DAGKESMANSKIY 
V.  N .  KOZHUKHOV 
( USSR ) 
(THRU) 
N68 - 2 14 6 4  8 (ACCESSION NUMBER) 
20 APRIL 1968 
https://ntrs.nasa.gov/search.jsp?R=19680011995 2020-03-12T08:30:43+00:00Z
ST- RA- SA- 10705 
RESULTS OF OBSERVATIONS OF 560 RADIO SOURCES I N  THE 
FREQUENCY OF 86 MEGAHERTZ 
(*I 
Doklady A . N .  SSSR, 
Astronomiya, 
Tom 178, No.6, 1271-2, 
Izdatel'stvo "NAUKA", 1968. 
SUMMARY 
by V.  S. AETYUKH 
V. V. VITKEVICH 
R. D. DAGKESWSKIY 
V. N .  KOZHUKHOV 
This note is already an abstract of the results of measurements of flu 
densities of radio sources from catalogs 3C [l] and 3CR [2] using 560 radio 
sources in the frequency of 86 mc/s, and carried out from February 1965 to 
.June 1967. 
coming papers [ S ,  61. 
The full results of observations will be presented in the forth- 
* 
* *  
During the period from February 1965 to June 1967 measurements were con- 
dwted of flux densities of radiosources from catalogs 3C [l] and 3CR [ Z ]  in 
the frequencies of 86 Mc/s. In all 560 sources were observed against the 
East-West web the FIN range-cross-shaped radiotelescope (DKR-1000). The 
antenna utilized is described in detail in [4]. 
The results of observations are fully decsribed in [ 5, 61 , where the 
right ascensions aigW,o the flux densities S, the spectral indices x,  and also 
the root-mean-square errors Aa and AS for all the sources from catalogs 3C and 
3Cr are given. The values of these quantities were obtained, 
means of no less than 5 readings of each source. 
as a rule, by 
The right ascensions were determined by the sidereal time of source's pas- 
sage through the radiation pattern maximum of the radiotelescope. 
time, besides the correction for the precession, a correction was introduced, 
taking into account the inclination of the horizontal axis, the azimuth and 
the instrument's collimation error and also the receiver's time constant. These 
corrections were determined by 35 sources, identified with the optical objects 
whose coordinates were borrowed from [ 7 ] .  
amo,o for most of the sources was no worse than k 1'. 
At the same 
The precision of determination of 
The measurements of fluxes' densities were relative. 
(*I REZUL'TATY NABLYUDENIY 560 RADIOISTOCHNIKOV NA CHASTOTE 86 MGH 
. 2 
Following were the standard sources used: 3C 123, 218, 348, 353, 380, 409. 
Their fluxes' densities, upon correction for angular dimensions are: Si== 368, 
S2,* = 583, SJGB = 684, Sm = 396, 8380 = 120, 274% = 182 w/m2 ahz). 
Besides, 30 sources were utilized as secondary standards, so that from 2 to 4 
calibrated soucres were available for each registration. For most of the sour- 
ces the errors in the determination of S did not exceed 10 percent. The inte- 
gral distribution of sources by flux densities in the frequency of 86 Mc/sec 
are plotted in Fig.1, b) When plotting this distribution and with the view - 
of eliminating galactic objects, only those sources were utilized, for which 
the galactic latitude lbl z 10'. 
(all in units 
300 
t 
30 
0 
0 
X 
0 
0 
X * I  
*I I 
O 0  "., 
z 
0 0  \ 
0 
O 0  i b  
0 X 
0 n 
Omo 9 
a 
a 
0 
0 
. o  a 
x 
a ' n  
0 
I I 
/J-a Jrn/MZza t 0 - N  
s- 
Fig.1. Dependence 1gN-1gS. 
a) v = 178 Mc/s (Cat. 3CR) ; 
b) v = 86 Mc/s (our own mea- 
surements) 
t,; 
The inclination of dependence 
lg N - lg S is n = 1.78 - 0.15. This 
value practically coincides with the 
value of n in the 178 Mc frequency 
(Fig.1, a), which is evidence of the 
absence of more or less significant 
variation of the mean spectral in- 
dex of sources with flux density in 
the indicated frequency band. 
Fig.2. Histogram of spectral in- 
dices (in the 178-86 Mc frequency 
band. a) for sources of catalog 
2CR, having lb[  >loo,; 
quasars 
b) for 
Spectral indices x were obtained on the basis of the measured f lux den- 
sities in the frequency of 86 Mc/sec and of their values in the frequency of 
178 Mc/sec (catalo 3CR). The histogram of spectral indices of sources with 
galactic latitude B bl >, loo is shown i n  Fiq.2,a. The mean value 2 = 0.89-0.02 
and the dispersion is O X =  0.31. Inasmuch as the individual values were ob- 
tained with an error of. %0.20 ,  the corrected value of the dispersion will be 
0% = 0.24. 
An analogous histogram was cosstructed for quasars (Fig.2, b). For them 
we obtained 2 = 0.89-0.05, which coincides with x for the remaining sources. - 
3 
The dispersion fo r  quasars = 0 , s  exceeds somewhat u, fo r  a l l  sources. 
Although the indicated excess i n  the value of 0, fo r  quasars is  not great ,  
it seems to  us that  it actually takes plave indeed. 
With the view of investigating the dependence of the spectral index on S, 
w e  have broken down the sources with Ibl > 10' in to  5 group by f lux densit ies.  
The mean values of spectaal indices and the i r  errors  fo r  each of these groups 
a re  plotted i n  Fig.3. As may be seen from Fig.3 the mean value of the spectral  
index remains within the li- 
m i t s  of e r rors ,  invariable 
through values of flux den- 
si t ies 
S = 11. w/m2 .hz 
and increases for  weaker 
sources. More detailed ana- 
l y s i s  has shown that  the c 
cause of t h i s  increase of x 
resides i n  the systematic 
underrating of flux densi- 
ties of weak radio sources 
i n  the catalog 3CR by about 
5 percent. 
$; 1 y ~~ ,! 
Q fo /dQ . &#-- 
Fig.3. 
on the density of the flux S. 
the corrected value of R fo r  weak sources 
Dependence of the mean spectral index X 
The cross denotes 
The introductiun of the corresponding correction leads t o  the decrease 
of the mean spectral  index for  weak sources t o  the value x = 0.88, indicated 
i n  Fig.3 by the cross. A t  the same time, the mean spectral  index found by a l l  
sources entering into the histogram (Fig .2 ,  a ) ,  taking in to  account the indi-  
cated correction, decreases t o  0.86. 
In s t i t u t e  of Physics i n  the name of 
P. N.  Lebedev of the USSR Ac.of Sc. 
(F.I.A.N.) 
REFERENCES 
Manuscript received on 
18 November 1967 
[l]. D .  0. EDGE, W .  B. McADAM E T  AL. 
[ 2 ] .  A. S. BENNET. Ib id .  68, 163, 1962. 
[3] .  
[41.  
[SI. V .  S. AliTYUKH, V .  V .  VITKEVICH ET AL. 
[6] .  
[ " I .  
Mem. R . A . S . ,  68, 37, 1959. 
V. V. V I T K E V I C H ,  P. D. KALACHEV. Trudy FIAN, a, 1965. 
V.  S. ARTYUKH, V.  V. VITKEVICH,  R .  D. DAGKESAMANSKIY. A s t r o n o m . Z h .  4 4 ,  
P r e p r i n t  F I A N ,  ~ 0 . 8 2 ,  1967. 
5 ,  1%7. 
V. S. ARTYUKH, V .  V .  VITKEVICH ET AL. A s t r o n o m .  Z h .  - 45, 3, 1968. 
J. D. WYNDHAM. A s t r o p h y s .  J. &, No.2, 459, 1966. 
CONTRACT N o . N A S - 5 - 1 2 4 8 7  
VOLT TECHNICAL CORPORATION 
Translated by ANDRE L .  BRICHANT 
on 20 A p r i l  1968 


Results of Observations of 560 Radio Sources in the Frequency of 86 Megahertz

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