With the 1000-foot radiotelescope of the Arecibo Ionospheric Observatory we have observed the positions of 69 peculiar galaxies classified by Arp (1966). Several radio sources were detected, but they could be chance coincidences. Radio maps of the radio sources are given.Asociación Argentina de Astronomí

Colombo, F.R.

Varsavsky, Carlos M.

English

El Servicio de Difusión de la Creación Intelectual

RADIOASTRONOMIA
Radio observations of peculiar galaxies 
by
Fernando R. Colombo #
Instituto Argentino de Radioastronomía 
Villa Elisa, Argentina
and
Carlos M. Varsavsky 
ALUAR, Buenos Aires, Argentina
Abstract: With the 1000-foot radiotelescope of 
the Arecibo Ionospheric Observatory we have 
observed the positions of 69 peculiar galaxies 
elassified by Arp (1966). Several radio sources 
were detected, but they could be chance coinci- 
dences. Radio maps of the radio sources are given.
I. Introduction
Arp (1963) has compiled a catalogue 
eontaining 333 peculiar galaxies that he 
classifies into four groups according to 
their sil ape, or to the nature of the pecu- 
Iiarity, taking into account gradual changes 
in peculiarity from object to object. These 
four groups are, in turn, divided into a 
number of subgroups.
Less than ten per cent of the galaxies in 
Arp’s catalogue have been identified with 
radio sources. The aim of the present work 
was to see if more of these galaxies could 
be detected at radio frequencies.
For this purpose we have used the 1000- 
foot radio telescope of the Arecibo Ionos­
pheric Observatory. Because of the limited 
motion that can be achieved with this ins- 
trument the survey was limited to declina- 
tions 3° ^ S 35°. A total of 69 galaxies 
were observed.
* Nlember of the Carrera del Investigador Cien­
tífico del Consejo Nacional de Investigaciones 
Científicas y Técnicas.
II. Equipment and observations
The survey was initiated in February, 
1968 at a frequeney of 430 Mhz using the 
C6-foot line feeder whose half-power beam- 
width is 10'. These observations continued 
throughout 1968 and 1969.
Another survey of sonto selected objeets 
was then carried out at a frequeney of 318 
Mhz with the line feeder described by La- 
londe and Harris (1970) whose HPBW is 16'.
For each galaxy we made sweeps in 
right ascensión about 3m to either side of 
íhe position of the object, at two or more 
declinations. In sorne cases we also made 
sweeps in declination at constant right as­
censión. All galaxies were observed at least 
twice at each declination on different days. 
The observations were recorded on magne- 
tic tape and the reductions were done on 
the A10 Computer. A typical observation is 
shown on Figure 1. On the basis of cali- 
brations using well known sources we arri- 
ved at 4.5°K/flux unit at 430 Mhz and 
6.8°K/flux unit at 318 Mhz.
ni. Results
For each galaxy observed at three or 
more declinations we drew the radio maps 
shown in Figure 2, where the position of 
the galaxy is indicated by a cross. Table I 
summarizes the observations, where the 
first column indicates the number given to 
the object in Arp’s catalogue, the second 
column gives the measured fluxes at 318 
Mhz and 430 Mhz. In this column a paren- 
thesis indicates a lowed limit, since the má­
ximum of the radiation is beyond the ob­
served región. In the fourth column we in- 
dicate the ñame of radio sources in Dixon’s 
(1970) catalogue which may be indentified 
with those observed by us. The fifth column 
contains some comments on the radio sour­
ces detected.
6 Asociación Argentina de Astronomía
Figura 1
Shapes and sizes of the radio sources are 
very difficult to ascertain due to the large 
side lobes of the instrument used.
Etastically we can verify whether the 
radio sources detected are really associated 
with the peculiar galaxies.
According to von Horner (1961), the 
number N (S . A.) of radio sources per 
square degree, at a given frequency, with 
flux greater or equal to S, given by:
where:
x = spectral índex of the radio source, 
X =■ wavelength in centimeters, 
n slope of the log N-log S relation 
if we take:
x = —0.8 ; n = 1.8
we get:
at 318 Mhz and S 0.15 f.u. (1°K) ;
N = 10 sources/sq. deg.
at 430 Mhz and S ^ 0.22 f.u. (1°K) ;
N = 3.7 sources/sq. deg.
From the radio maps we obtain a count 
of 5 sources/sq, deg. at 318 Mez and 3.7 
sources/sq. deg. at 430 Mhz. Therefore, we 
cannot claim that the radio sources detec­
ted can be associated with Arp’s peculiar 
galaxies.
Acknowledgements:
The authors wishes to thank J. M. Co­
mella and T. R. Hawkins for help in the 
reduction and observation procedure.
REFERENCES
Arp, H. 1966, Ap. J. Suppl. 14,1.
Dixon, R. S. 1970, Ap. J. Suppl. 20,1.
Horner, S. von 1961, Publ. N.R.A.O. 1,19. 
Lalonde, L. M. and Harris, D. E. 1970. I.E.E.E. 
Trans. Antennas and Propagation, AP-18, 41.
Boletín N<? 19 7
Figura 2 a
8 Asociación Argentina de Astronomía
Figura 2 b
Fi
gu
ra
 2 
c
10 Asociación Argentina de Astronomía
Figura 2 d
Bolktín N? 19 11
Figura 2 e
12 Asociación Argentina de Astronomía
Figura 2 f
Boletín N<? 19 13
Figura 2 g
14 Asociación Argentina de Astronomía
Figura 2 h
Boletín N<? 19 15
Figura 2 i
TABLE I
Arp Radiosource Position Fl! IX Other
Number R.A (1950.0) Dec. identifieations Notes
h m s 0 / 318 430
A 5 11 22 24 03 24.0 (.60)
11 24 10 03 29.6 .56
A 12 08 32 16 28 38.0 .76 .82
A 13 3C-454.3 ver y near
A 28 no source in
región ebserved
A
A
42
49 14 28 30 08 36.8 1.28 1.16 OQ+048,4C+08.42
id. A 28
14 29 54 08 16.8 .51 .24 overlapping at
14 30 42 08 10.8 .51 .44 318 Mhz.
14 31 36 08 35.0 (.62) Not observed at 
430 Mhz
A 56 id. A 28
A 63 09 34 00 32 40.0 (.5) (-4) B2 0934+32B (?) Extended source
09 38 19 32 34.9 1.1
L4
4C+32.31,OK+363 
B2 0938+32A,
A 68 23 45 04 03 56.0 1.2 4C+04.82
A 72. 15 40 00 18 09.4 1.4 ■1C+18.43, H 1540+18 
OR+167
15 44 00 18 10 4C+18.44
A 82 Extended source 
4m W oí A 82
A 83 11 37 40 15 41 (.56) .67
11 38 22 15 16.7 1.35 4C+15.37
A 86 23 42 30 29 23 1.7 B2 2342+29 Ohservations at
4C+29.20 430 Mhz
23 45 29 23 (.5) B2 2344+29 B at 2 deelinat.
23 49 40 29 03.3 (•85) B2 2349+29 confirm results 
oí 318 Mhz
A 87 3C-263.1 29' 
North o! A 87
A 89 id. A 28
A 9] 15 30 52 15 25 2.76 4CP 15.49, OR+151 
4C+15.49
A 94 10 17 06 20 09 .43 .64
10 19 21 20 01 .90 .89 4C+19.33,OL 233 
II 1019+19
10 22 40 20 20 4.1 3C 242,NRAO 354
A 95 14 34 21 26 45 .59 .60 OQ+256 (?)
14 31 17 26 53 .49 .29
A 99,170 23 09 30 18 31 5.4 3C 457,4C+18.70
23 16 00 18 25 1.1 VRO 18.23.04, 
OZ+127, H 2316+18
A 105 11 08 00 28 57 .45 .29
11 11 28 28 57 .88 .76
A 112 23 53 38 31 03.3 .7 B2 2353 +31A, 
4C+31.67
23 55 44 31 12.0 1.7 1.0
23 59 51 31 23.3 1.3
A 113 00 15 18 29 48 .6 .4
A 117 14 07 50 17 47.1 5.0 PKS 1407+17.OQ+112
4C+17.57, 
VRO 17.14.01
Arp Radiosouree Position Flux Other
Number R.A (1950.0) Dec. identifications Notes
h m s o / 318 430
A 119 Several sources 
with maxima 
outside observed 
región
A 128 id. A 119
A 130 00 00 35 16 13.3 (.6)
A 134 Virgo A 5o to 
the N.
A 138 11 55 40 25 11.7 1.1 Scintillate (see
11 58 10 25 16.7 2.8 OM+297,40+25.37 
PKS 1158+25.2
Fig. 1)
A 159 12 49 36 25 58.3 (-7) (.3) ON+282
A 162 10 47 06 28 07.4 (.5) OL+278
A 163 id. A 28
A 164 01 11 45 04 55.6 .6 OC+020
01 12 33 04 55.6 .4
01 15 57 04 44.7 (■4)
A 167 See map
A 169 22 12 13 13 36 8.1 3C 442,PKS2212+13 
NRA0681 
OA+576.........
A 171 14 34 18 03 40.6 6.7 PKS 1434+03; 
4C+03.30
A 190 y 02 47 06 13 30.1 (.6) (•2) CD+178
200 02 49 36 12 40.1 .6 .3
A 192 10 34 25 18 36.2 .4 OL+157
10 37 01 18 21.2 .2
A 197 11 26 33 20 41.6 .96 .48
11 28 21 20 41.6 .47 .26
11 30 09 20 41.6 .85 .48 VR+020.11.02
A 203 11 27 40 28 45.9 (.5) OM+248 (?)
A 200 16 03 12 20 39.9 .58 H 1603+20
A 212 id. A 28
A 216 23 26 11 03 15.4 .17 OZ+043 (?)
A 220 15 32 44 23 39 .34 OR+253 (?)
A 227 y 01 17 42 03 04 (.8)
157 01 18 21 03 28 3.5 4C+03,02, PKS 1118+03 
NRAO 68, 00+031
01 19 36 03 15 1.8 30 039, PKS 1109+03 
NRAO 69, 00+032.9
01 21 48 03 30 .4
A 228 01 45 50 10 12,6 1.0 00+176
A 235 id. A 28
A 242 id. A 2S
A 243 08 35 31 25 56 .6
08 35 55 25 38.1 2.4 OJ+260, PKS 0835+15 
4C 25.22
A 247 08 19 36 21 36 1.4 In map appears as
08 23 24 21 28 .3 extended
08 14 28 21 50 (-7) OJ+224 (?)
08 18 12 21 16 (.8) VR 021.08.02,OJ+230
08 18 50 21 44 (.6)
08 20 57 21 16 (.3) OJ-j-237 (?)
A 263 id. A 28
A 272 15 59 47 17 52 .27
18 Asociación Argentina de Astronomía
Arp Radiosource Position Flux Other
Number R.A (1950.0) Dec. identifications Notes
h m s o / 318 430
16 02 53 17 50.3 1.8 OJ+106,4C 17.66 
VRO 17.16.01
A 276 02 23 48 19 31.1 .42
02 27 30 19 25.1 .13
A 278 22 17 22 29 08.6 .87 B2 2217+19
A 282 00 32 39 23 34 (•2)
00 35 21 23 52.6 1.7 CTD 5
A 286 14 19 14 04 11 .51
A 288 13 28 48 14 09.5 1.9 4C+14.48, OP+148
A 290 02 01 38 14 45.8 1.4
02 02 38 14 54.4 1.6 PKS 0202+14,DA067, seen only in
NRAO 91 declination sean
02 02 38 15 07.6 .9 4C+15.05
A 294 id. A 28
A 303 id. A 28
A 305 id. A 28
A 307 09 26 00 11 46.2 2.0 4C 11.32
A 316 10 19 09 22 14.0 6.3 OL+226,NRAO 352,DAQ286
PKS 1019+22,3C 241
10 08 09 22 48.6 .91 4C 22.27, OL+214
A 327 05 15 04 06 44 .60
05 15 20 06 25 .62 4C+06.22,OG+025
A 331 01 04 44 32 09 9.2 NRAO 53, B2 010+32 
3C 31, 4C+32.35,DA035
A 333 02 35 32 10 45.3 .8 4C+10.07
02 39 42 10 45.3 (1.0) OD+166,4CP 10.08
02 42 25 10 32.4 .8 4C+10.08
A 335 10 57 25 05 02 2.3 4C+0 5.47
Observaciones en la línea de 21 can. del 
hidrógeno neutro en la región del polo 
sur celeste (8 + — 85°)
F.R.Colomb * - M.A.Gil ** - R.Morras **
* Miembro de la Carrera del Investigador Cien­
tífico del Consejo Nacional de Investigaciones 
Científicas y Técnicas.
#í> Becarios de la Comisión de Investigaciones 
Científicas de la Provincia de Buenos Aires.
Instituto Argentino de Radioastronomía 
Villa Elisa, Argentina.
Abstract: Data from the observation of the 21-cm 
neutral hydrogen line are presented for the re­
gión 297° < l < 309, —22°.<b< —32°, and 
—90 ^ v ^ 90 Km/s. Shown are 143 profiles of 
the zone and isophotes at constant l, constant b, 
and constant velocity from —36 to + 12 Km/s, 
every 4 Km/s.
En este trabajo se presentan los resul­
tados observacionales en la línea de 21 
cm del hidrógeno neutro, de la región com­
prendida entre 297° + l + 309°, —22° b 
+ - 32°, y en el rango de velocidades - 90 
< v + 90 Km/s.
Esta región galáctica corresponde a la 
zona del polo sur celeste, aproximadamen­
te al sur de — 85°. Estudios anteriores de 
Bajaja, Colomb (1973), con una más baja re­
solución angular indicaron la presencia de 
hidrógeno neutro a velocidades interme­
dias. En algunas regiones cercanas a las 
del presente estudio, las concentraciones 
de hidrógeno se presentan alineadas al 
campo magnético galáctico (Bajaja et al, 
1973). Dado este peculiar comportamien­
to del gas se decidió realizar un estudio 
más detallado de la región.


Radio observations of peculiar galaxies

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Radio observations of peculiar galaxies

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