A. NGC 4038-4039
One of the best known and most striking formations with very long luminous and filamentary extensions is seen in the double system NGC 4038 - 4039 a schematic drawing of which is shown in Fig. 3. NGC 4038 is located at R.A. 11h 59m 18s and Decl. -18°35' (Epoch 1950.0).
Figure 3. Schematic drawing of NGC 4038 - 4039 with features as they are discernible on plates taken with the 48-inch Schmidt telescope and the 100-inch reflector. No plates have as yet been obtained with the 200-inch telescope.
According to HUMASON the apparent symbolic velocity of recession of this system is Vs = 1673 km./sec. and its distance (on the old scale) may therefore be estimated at three megaparsecs or ten million light years. The apparent photographic magnitude is about mp = +11.0 and the absolute magnitude mp = - 16.4, if the mentioned distance is used. As expected, the spectrum of the system shows emission lines. It will be of the greatest interest to investigate both the structure of NGC 4038 and its kinematic properties with the 200-inch reflector and to obtain if possible spectra of the long extensions the total length of which from tip to tip is equal to 80000 light years, as projected on the plane normal to the line of sight. NGC 4038 is a weak radio source and therefore probably a system of two galaxies in the process of a close collision.