Controversies in radio astronomy, observational mistakes, false priority claims overinterpretation

1. Controversies in radio astronomy,observational mistakes,false priority claimsoverinterpretation Richard Wielebinski Max-Planck-Institut für Radioastronomie Bonn, Germany

2. There are numerous controveries, observational mistakes, false priority claims, or overinterpretation on record in radio astronomy. Here are some examples: • The Ryle-Mills controversy about source counts • The priority claims of detection of polarized Galactic radio waves • The problems with Zeeman effect observations • The search for the Sunyayev-Zel’dovich effect • The use of interferometer data without large scale spacings + • The real detection of recombination lines that was not accepted as real by a session chairman

3. Hay, Parsons, Phillips (1946) detected discrete radio sources (in contrast to the the diffuse Galactic emission of Jansky and Reber) Cambridge: Ryle, Smith, Elsmore (1950) publish a list of 50 sources observed with interferometry Sydney: Bolton, Stanley, Slee (1949) identifysome sources – SNR, radio galaxy, active galaxy Mills (1952) lists 77 discrete radio sources Cambridge:Shakeshaft, Ryle, et al. (1955) publish the 2C catalogue with 1936 radio sources Sydney: Mills & Slee (1957) publish 383 sources that overlap the Cambridge survey that shows SERIOUSDISAGREEMENT!!!!!

4. The controversy between Ryle and Mills based on the use of interferometer by Ryle and of a pencil beam instrument (Mills‘ cross) by Mills. The interferometer picked up confusing sources in nearby fringes.However,Ryle developed phase switching that led to aperture synthesis and ultimately to the Nobel Prize.

5. The controversy continued for a while.... • Shakeshaft (1957) still claimed 1906 sources • Edge, Shakeshaft et al. (1959) produced the 3C catalogue of sources with only 471 entries • Bennett (1962) re-examined all the source data and produced the 3CR catalogue with 470 entries – this catalogue was the basis of a great history of discovery • Mills devoted more attention to the Galaxy • Mills moved from CSIRO to Sydney University and constructed the Molonglo Cross. • Ryle developed the aperture synthesis method

6. Synchrotron radiation was expected to be linearly polarized • Kiepenheuer (1949) suggests the synchrotron process is the cause of Galactic emission • Shklovsky (1953) argues that optical Crab A emission is synchrotron emission. Soviet optical astronomers Vashikadze (1954) and Dombrovsky (1954) publish optical polarization data for Crab A. • Mayer at al. (1957) and Kuzmin & Udal‘tsev (1957) detect linear polarization in Crab A • Thomson (1957); Pawsey & Harting (1960) Pauliny- Toth et al. (1961) set upper limits to polarization only.

7. Razin V.A. (1958) claims detection of linear polarization of Galactic radio waves at 212 MHz with a 18° x 20° beam and at 90 MHz with 25° x 25° beam!! • Wielebinski et al. (1962a) real detection at 408MHz with a 7° beam • Westerhout et al. (1962) real detection at 408 MHz with a 2° beam • Wielebinski & Shakeshaft (1962b) detect ionospheric Faraday rotation • Wielebinski (1963 PhD thesis) fails to detect polarization at 178 MHz with a 2° x 20’ beam (in conrast to Razin’s claim) • Muller et al. (1963) observe at 610 MHz and detect Galactic Faraday rotation. • Mathewson and Milne (1965) make southern hemisphere polarization maps at 408 MHz In retrospect the claim of Razin (1958) was unreal. Faraday depolarization at his wavelengths and with the large beam would depolarize the emission

8. Sunyayev & Zel’dovich effect was first published in 1970, Parijski (1973) The S-Z effect is the ‘cooloing’ of the Cosmic Microwave Background by hot plasma found in clusters of galaxies Immediately Parijskii (1973) claimed detection of -1.0 mK in the direction of Coma A at ~ 5cm wavelength A long list of publications followed, usually with negative results. Other compact clusters were investigated with success X-ray observations gave information about the hot plasma and reanimated the subject in the 1980s

9. Deiss et al. (1997) mapped Coma at λ21cm, Thierbach et al. (2003) mapped the region at λ11cm and λ 6cm. An extended halo was found at all frequencies. In addition the region is full of discrete sources. λ21cm Based on our data we expect a signal of +10mK not a ‘hole’ of -1mK The result of Parijskii was obviously wrong!!!

10. The Zeeman effect The Zeeman effect is a direct method of measuring of magnetic fields. It was used by Hale (1905) to show Solar magnetic fields. The radio Zeeman effect for HI line was suggested by Bolton & Wild (1957)

11. Zeeman effect observations were started in Jodrell Bank in 1958. Several PhD thesis were completed, all with negative results. Finally Verschuur (1968) announced the discovery using the 140ft dish in NRAO This work was taken up by C.Heiles There was a long controversy about the reality of Zeeman effect detections by the above authors, in particular in HI emission clouds. The Zeeman effect was detected in OH and later in H2O maser regions.

12. Missing spacings problem The advent of the Westerbork aperture synthesis telescope led to a flood of results. Often 1.4GHz and 4.8 GHz observation were compared. λ21cm λ6cm

13. The observations of the galaxy M51 (Segalovitz et al. 1976) showed linear polarization vectors in the inner galaxy at 6cm and in the outer galaxy at 21cm. Tosa and Fujimoto (1978) publish Rotation Measure for M51 using the above data – although the vectors were from different regions Only recently missing spacings (e.g. VLA + Effelsberg) can be added in polarization (see Beck & Hoernes, 1999)

14. Recombination lines • Kardashev (1959) predicts the existence of recombination lines of hydrogen • Sorochenko & Borodzich (1964) • A. Drawskich & Z. Dravskich (1964) Announce the discovery. This is presented at the Hamburg 1964 IAU General Assembly The session chairman finds the overheads unconvincing!! Höglund & Mezger (1965) announce their discovery in Science, made in NRAO

15. There are many other similar problems in the published literature What is important is to look back and try to understand why the problems were created, not solved. Thank you!