NGC 5557: not detected in our survey (estimated I_HI_ < 2.6 Jy km s^-1^).
Classified as an elliptical; the upper limit to its gas content
(M_HI_/L_B_ < 0.02 M_sun_/L_sun,B_) is consistent with its classification.
April 9/10, 1937
NGC 5557 has a normal E2 morphology. It forms a wide
configuration (separation of 19') with the interacting binary pair of
NGC 5544 and 5545 (Arp 199, VV210, Karachentsev 422). The redshifts
are v_o(5544) = 3139 km/s and v_o(5545) = 3145 km/s from Karachentsev,
and v_o(5557) = 3243 km/s from the RSA2. The mean redshift distance of
64 Mpc (H = 50) gives a projected linear separation of NGC 5557 from
the interacting pair of 350 kpc.
Photometry, Dynamics, and Mass Determination:
Ap. J., 139, 284, 1964.
E1 (de Vaucouleurs)
Bright nucleus. No structure.
Lick 13 and Heidelberg Veroff. Vol. 9, 1926 dimensions are for the bright
M.N.R.A.S., 98, 620, 1938.
Round; 0.4' in diameter, with a very bright and rather large nucleus. A star
of about magn. 15 is projected on the southeastern edge of the nebulosity.