DR ELIZABETH ALEXANDER: FIRST FEMALE RADIO ASTRONOMER? Wayne Orchiston Australia Telescope National Facility, and Anglo-Australian Observatory, PO Box.

DR ELIZABETH ALEXANDER: FIRST FEMALE RADIO ASTRONOMER?

Wayne Orchiston

Australia Telescope National Facility, andAnglo-Australian Observatory, PO Box 76, Epping, NSW 2121, Australia.

[email protected]

1. INTRODUCTION

Jansky & Reber

WWII radar

Solar Detections

• Hey (UK)• Reber; Southworth (US)• Alexander (NZ)• Germans (Denmark)• Slee (Australia)

2. FRANCES ELIZABETH SOMERVILLE ALEXANDER (neé CALDWELL)

1908 b. December 13 (Merton, Surrey, UK)

1909 India (Patna Science College)

1918 England

1931 Cambridge (Geology; Harkness Prize)

1934 Cambridge Ph.D. (Aymestry Limestone)

1935 Married Dr N.S. Alexander

1936 Singapore (Navy: radio direction-finding)

1942 New Zealand (+ William, Mary & Bernice)

1946 England

1947 Singapore (Raffles College > U Malaya)

1952 Nigeria (University College, Ibadan )

1958 d. October 23 (Ibadan, Nigeria)

RDL (Op. Res. Section)

• Radar developments• Whales & seagulls• ‘Canterbury Project’

3. WARTIME IN N.Z.

• ‘Norfolk Island Effect’

4. THE ‘NORFOLK ISLAND EFFECT’

RNZAF 200 MHz COL radar units N.Z. + Norfolk Is

Norfolk Island: 1945 March 27 – April 01

Large increases in ‘radio noise’ recorded near sunrise & sunset

“Rotation of the aerial showed noise fluctuations corresponding fairly closely to the radiation diagram of the aerial. At its maximum the noise reached saturation on the azimuth of the sun …” (Alexander, 1945a: 1).

Elizabeth Alexander assigned to investigate the“Norfolk Island Effect”

Monitoring: 1945 April 10 – 23 Northern NZ + Norfolk Is

1 = Norfolk Island 2 = North Cape3 = Whangaroa4 = Maunganui Bluff5 = Piha

#5

At Whangaroa microammeter inserted between

the receiver output and diode limiter = immediate

results.

Combined observations enough to convince

Alexander that

“… the Norfolk Island effect was significant

and was connected with radiation from the

sun …”

1945 July-December: Air Force, Army & NavyRadars N.Z. + Norfolk Island

Intense 200 MHz solar emission centred on October 5:

“… violent surges of noise were observed at regular intervals. These surges were of momentary duration and sent the noise meter needle hard over.” (Alexander, 1945b).

At Piha (#5) Yagi also tracked Sun; gain < radar

“Noise signals from the direction of the sun were observed. The signals fluctuated rapidly but did not completely disappear until sunset.” (ibid.).

Overall results, 1945

End 1945/early 1946 radar stations & RDL closed:E.A. to England + Singapore

Publication (new N.Z. journal): “The Sun’s radio energy.” Radio and Electronics, 1(1): 16-18 (1946).

• 1945 March 28 ‘noise’ at Norfolk Is. not previously observed• Christened ‘Norfolk Island Effect’• 1945 March-December two periods of intense sunspot activity & “… these coincided with periods of intense solar “noise”.”• Reports submitted to UK & Australia• Detections by others noted • Solar emission at 200 MHz non-thermal in origin, but “To deduce solar temperatures of millions of degrees from this radiation, as has been suggested … is absurd.”• “It is not in the least surprising that the Sun should emit radio waves.”• More observations/analysis required (role of amateurs).

5. THE SEQUEL

Canterbury Project I. Thomsen (Nature paper)A. Maxwell (M.Sc. Thesis)R.F. Joyce

6. CONCLUDING REMARKS

Fortuitous: “Right place; right time!”

Anomalies: female, family, age, education

First female ‘radio astronomer’?

NZ sequel

Acknowledgements: Mary Harris, Bernice Jones, Bill Alexander, Gordon Burns, National Archives of New Zealand, E.R. Collins, Woody Sullivan.