This paper reports an upper limit at 10 GHz of 4 x 10^(43) erg in a 40 MHz bandwidth for the microwave pulse emission at the onset of an optically observed supernova

Baird, G. A.

Delaney, T.

Drever, R. W. P.

Fruin, J. H.

Jelley, J. V.

Meikle, W. P. S.

Morigi, G.

Palumbo, G. G. C.

Partridge, R. B.

Caltech Authors - Main

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Astron. & Astrophys. 46, 477-478 (1976) 
Letter to the Editor 
An Upper Limit to Microwave Pulse Emission 
at the Onset of a Supernova 
W. P. S. Meikle* and R. W. P. Drever 
. Department of Natural Philosophy, University of Glasgow 
G. A. Baird and T. Delaney 
Physics Department, University College, Dublin 
J. V. Jelley and J. H. Fruin 
Nuclear Physics Division, Atomic Energy Research Establishment, Harwell 
G. G. C. Palumbo and G. Morigi 
Laboratorio TESRE, Consigli_o Nazionale delle Richerche, Bologna 
R. B. Partridge 
Department of Astronomy, Haverford College 
Received October 29, 1975 
Summary. This paper reports an upper limit at 10 GHz 
of 4 x 1043 erg in a 40 MHz bandwidth for the microwave 
pulse emission at the onset of an optically observed 
supernova. 
A supernova has recently been discovered by Lovas 
(1975) in the Perseus Cluster of Galaxies at the location 
a=03h 16'!'4, ~= +41° 27' (1950.0). The network of 
tracking 10 GHz radiometers in use to search for 
prompt emission from supernovae (Delaney . et al., 
1974) has been directed towards tx=03h 16'!'1, ~= 
+41° 18' since July 1974. This position had been 
chosen on the basis of supernova statistics together 
with other factors (Palumbo, 1975) as being the most 
favourable for our experiment. The supernova therefore 
occurred almost at the maxima of our ""2?5 beams 
(-3dB). 
This supernova was first observed on 1975 March 1, 
and subsequent observations (Kirshner, 1975) suggest 
that it was discovered near its optical maximum. It 
occurred in a member of the cluster and is of Type I. 
From the work of Pskovskii (1971) and Barbon et al. 
(1974) it appears that the onset of a Type I supernova 
may occur up to 40 days before the maximum optical 
brightness. In order to allow for large uncertainties in 
this estimate we searched our data for pulses during the 
75 days prior to the time of the initial optical observation. 
During this period of interest, 1974 December 15_:.1975 
* Present address: Astronomy Group, Department of Physics, Im-
perial College of Science and Technology, London, SW7. 
Keywords: supernova - perseus cluster of galaxies -
radio pulse search 
March 1, some observing time was fost, but the overall 
2-station coverage amounted to 94.5 %, while the 3-fold 
coverage was 63.4 %. The chart records for the period 
were carefully scanned for pulses occurring within 10 rriin 
of each other at different stations above a threshold of 
twice the "peak-to-peak" noise level, i.e. approximately 
10a. The events selected by this procedure were then 
examined for coincidence with a resolving time of 20 s. 
Taking account of the absence of pulses at other 
stations, as well as the effects of local interference, the 
search failed to reveal any coincident pulse exceeding a 
threshold of 7x 10-22 Jm- 2 Hz- 1 for events shorter 
than the 0.5 s integration time. For a pulse longer than 
our integration time the corresponding threshold is 
more correctly expressed as 14 x 10-22 W m - 2 Hz- 1• 
Thus the microwave radiation emitted by the supernova 
on a timescale less than our integration time, and 
within a 40MHz band around 10 GHz, must be <4x 
1043 erg. We assume the supernova was in the cluster 
(Kirshner, 1975), i.e. at a distance of 110 Mpc (taking 
H 0 = 50 km s- 1 Mpc- 1 ). This limit also assumes iso-
tropic emission. 
The theories of the onset phase of supernovae are far 
from complete but timescales of the order of seconds or 
less are expected in various models (cf. Shklovsky, 1968). 
It should be noted that our limit at 10 GHz is greater 
© European Southern Observatory • Provided by the NASA Astrophysics Data System 
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than the maximum energy predicted by Colgate (1975). 
The spectrum of the pulse which he described is such 
that the energy per unit bandwidth is less by a factor of 
"'350 at 10 GHz than at 200 MHz, the frequency 
· around which maximum emission occurs. However, our 
previous VHF experiments (Charman et al., 1970; 
Lawless, 1971; Meikle, 1973; Drever et al., 1973) set 
limits three orders of magnitude below the maximum 
energy given by Colgate (1975) in the VHF region. 
Acknowledgements. We would like to express our gratitude to Dr. 
W. L. W. Sargent for particular scrutiny of our search area during 
the routine supernova survey programme on the 48-in. Schmidt 
Telescope at the Hale Observatories. We also wish to thank Mrs. 
Helen Brogan for valuable assistance in analysing the data. This 
work was partly supported by AERE Extra Mural Research Grants 
(Dublin and Glasgow) and NATO Grant No. 653 (Harwell and 
Bologna). 
Note Added in Proof. Recently, the explosion of another supernova 
in the Perseus Cluster has been reported (IAU Circular 2825). A 
preliminary search of our data failed to find a coincident microwave 
pulse during the 90 days preceding 1975 August 11, the date on 
which the event was first reported. Further details of this event will 
be published elsewhere. · 
References 
Barbon,R., Ciatti,F., Rosino,L. 1974, Supernovae and Supernovae 
Remnants, Ed. C. B. Cosmovici, 1973, Proceedings of the Inter-
national Conference on Supernovae, Lecce, Italy, May 7-11, 
D.Reidel Publishing Company, Dordrecht, Holland, p. 99 
Channan,W.N., Jelley,J.V., Fruin,J.H., Hodgson,E.R., Scott,P.F., 
Shakeshaft,J.R., Baird,G.A., Delaney,T., Lawless,B.G., Drever, 
R.W.P., Meikle,W.P.S., Porter,R.A., Spencer,R.E. 1970, Nature 
228,346 
Colgate,S.A. 1975, Astrophys. J. 198, 439 
Delaney, T., Baird,G.A., Smith,H., Jelley,J. V., Fruin,J.H., Meikle, 
W.P.S., Drever,R.W.P., Morigi,G., Palumbo,G.G.C., Partridge, 
R. B. 1974, Astron. & Astrophys. 36, 83 
Drever,R.W.P., Meikle,W.P.S., Hough,J., Bland,R., Lessnoff,G.W., 
Jelley,J. V., Delaney, T., Palumbo,G.G.C. 1973, Proceedings of 
the Conference on Transient Cosmic Gamma- and X-ray Sources, 
Ed. I.B.Strong, Los Alamos, USA, September 20--21, Los Alamos 
Report LA-5505-C, p. 133 
Kirshner,R. P. 1975(private communication) 
Lawless,B.G. 1971, Ph.D. Thesis, University College, Dublin, Re-
public of Ireland · 
Lovas, M. 1975, I.A. U. Circular No. 2755 
Meikle, W. P. S. 1973, Ph.D. Thesis, University of Glasgow, Glasgpw, 
U.K. 
Palumbo,G.G.C. 1975, Harwell Report (to be published) 
Pskovskii, Yu. P. 1971, Soviet. Astron. 14, 798 
Shklovsky, I. S. 1968, Supernovae, John Wiley & Sons Ltd., London, 
U. K., p. 395-396 
W. P. S. Meikle 
Astronomy Group 
Department of Physics 
Imperial College of Science and Technology 
London,SW7, U.K. 
R. W. P. Drever 
Department of Natural Philosophy 
University of Glasgow 
Glasgow, G12 SQQ, U.K. 
G. A. Baird 
T. Delaney 
Physics Department 
University College 
Belfield 
Dublin 4, Republic of Ireland 
J. V. Jelley 
J. H. Fruin 
Nuclear Physics Division 
Atomic Energy Research Establishment 
Harwell 
Oxfordshire OX11 ORA, U.K. 
G. G. C. Palumbo 
G. Morigi 
Laboratorio TESRE 
Consiglio Nazionale delle Richerche 
Via de'Castagnoli 1 
1-40126 Bologna, Italy 
R. B. Partridge 
Department of Astronomy 
Haverford College 
Haverford 
Pennsylvania 19041, USA 
© European Southern Observatory • Provided by the NASA Astrophysics Data System 


An Upper Limit to Microwave Pulse Emission at the Onset of a Supernova

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An Upper Limit to Microwave Pulse Emission at the Onset of a Supernova

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