COMMISSION 27 OF THE I. A. U.
            INFORMATION BULLETIN ON VARIABLE STARS
                           NUMBER 31

                                          Konkoly Observatory
                                          Budapest
                                          15 June 1963



            AN ATTEMPT TO DETECT THE POLARIZATION AND
           TO EVALUATE THE INFRARED STELLAR MAGNITUDE
              OF THE UNUSUAL VARIABLE OBJECT 3C 273


     Unusual intensity distribution in the optical spectrum of the
radio-source 3C 273 (1) suggests a possible contribution of the
synchrotron mechanism of radiation. Therefore on May 13, 1963 an
attempt has been made by the authors to detect the polarization of this
object. We used a photoelectric photometer with a polaroid analyser
attached to the 50 inch reflector at the Southern Crimean Station of the
Sternberg Astronomical Institute. The effective spectral region of the
Sb-Cs photomultiplier is 3500-5800 A when used without filter. No
polarization was detected within the limits of accuracy (1 %).

     We made also an attempt to evaluate the infrared stellar
magnitude of this object by means of a Cs-O multiplier combined with
a red filter (spectral region 6400-1100 A, effective wavelength 3850 A).
The star AGK2 + 2deg1579 was used for comparison. The infrared stellar
magnitude of the object is 12m.5 in a system in which the infrared
stellar magnitudes of the A0 stars are equal to the visual magnitudes.
This observation was made on May 26, 1963. Assuming I = 12m.5 and
V = 12m.6 the continuous spectrum of the object can be represented
very roughly (through two points only) in the form J~{nu}^{0.4}, that is in
satisfactory accordance with the spectrophotometric investigations by
Oke (1). These evaluations should be considered as tentative because
the optical radiation of the object 3C 273 is variable (2, 3).

Moscow, 6 May 1963             V. I. MOROZ, V. F. YESSIPOV
                          Sternberg State Astronomical Institute


(1) J. B. Oke, Nature (in print) [BIBCODE 1963Natur.197.1040O ]
(2) A. S. Sharov and Yu. N. Efremov, Comm. 27. Inf. Bull. Var. Stars No. 23, 1963. [BIBCODE 1963IBVS...23....1S ]
(3) Harlan J. Smith and Dorrit Hoffleit, Nature, 18 May 1963 [BIBCODE 1963Natur.198..650S ]