We present and discuss optical, near-infrared and Hi measurements of the galaxy Markarian 1460 at a distance of 19Mpc in the Ursa Major Cluster. This low-luminosity (MB=-14) galaxy is unusual because (i) it is blue (B-R=0.8) and has the spectrum of an Hii galaxy, (ii) it has a light profile that is smooth and well fitted by an r1/4 and not an exponential function at all radii larger than the seeing, and (iii) it has an observed central brightness of about µB=20mag.arcsec–2, intermediate between those of elliptical galaxies (on the bright µB side) and normal low-luminosity dwarf irregular (on the low µB side) galaxies. No other known galaxy exhibits all these properties in conjunction. On morphological grounds this galaxy looks like a normal distant luminous elliptical galaxy, since the Fundamental Plane tells us that higher luminosity normal elliptical galaxies tend to have lower surface-brightnesses. Markarian 1460 has 2x107M☉ of Hi and a ratio M(Hi)/LB of 0.2, which is low compared to the typical values for star-forming dwarf galaxies. From the high surface-brightness and r1/4 profile, we infer that the baryonic component of Markarian 1460 has become self-gravitating through dissipative processes. From the colours, radio continuum, Hi and optical emission line properties, and yet smooth texture, we infer that Markarian 1460 has had significant star formation as recently as ∼1Gyr ago but not today.
The Royal Astronomical Society