Letter | Published:

21-cm Absorption of the Radiation from 3C273

Naturevolume 199pages990991 (1963) | Download Citation



THE radio source 3C273 has been identified1,2 with a star-like object of about thirteenth magnitude having a faint jet. However, the optical spectrum of the star contains a number of broad emission features which can be explained as hydrogen, magnesium and oxygen lines with a red-shift δλ/λ0 of 0.158 (refs. 2 and 3). Schmidt suggests that the stellar object is either a nearby ultradense star or, more probably, the abnormally luminous nuclear region of a galaxy at a distance of about 500 megaparsecs. The second possibility would make 3C273 the most luminous object known.

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  1. 1

    Hazard, C., Mackey, M. B., and Shimmins, A. J., Nature, 197, 1037 (1963).

  2. 2

    Schmidt, M., Nature, 197, 1040 (1963).

  3. 3

    Oke, J. B., Nature, 197, 1040 (1963).

  4. 4

    McGee, R. X. (private communication).

  5. 5

    Maltby, P., Matthews, T. A., and Moffet, A. T., Astrophys. J., 137, 153 (1963).

  6. 6

    Robinson, B. J., Proc. Inst. Rad. Eng. (Austral.), 24, 119 (1963).

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  1. C.S.I.R.O., Radiophysics Laboratory, University Grounds, Sydney

    • B. J. ROBINSON
    • , K. J. VAN DAMME
    •  & J. A. KOEHLER


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