NGC 1705 - I0 pec/BCD

NGC 1705

De Vaucouleurs Atlas Type: I0 pec/BCD

Filter: B

Telescope: LCO 2.5-m
North up , East left
Field Dimensions: 3.6 x 2.7 arcminutes

RC3 Type: SA0-: pec
RSA Type: Amorphous
Surface Brightness Range Displayed: 17.5-27.0 mag per square arcsec
Absolute Blue Magnitude: -16.3

De Vaucouleurs Atlas Description:

The Atlas image shows an elliptical-shaped galaxy with a patchy center and strange surrounding filaments reminiscent of what is seen in M82 . NGC 1705 is classified as SA0-: pec in RC3 , but it has very blue colors for such a type. Sandage and Brucato (1979) placed it into their Amorphous class, while Meurer, Freeman, and Dopita (1989) recognized it as a nucleated Blue Compact Dwarf galaxy (see book section 2.17.1). In this case, the nucleus is an extremely luminous super star cluster having an abolute magnitude MB ~ -15 (Melnick, Moles, and Tervelich 1985). This object, which shows saturation spikes in the Atlas image, is also much brighter than any other cluster in the galaxy. Quillen, Ramirez, and Frogel (1995) showed that the blue colors are concentrated mainly in the central region. Meurer, Freeman, and Dopita (1989) showed that the apparent filaments are bright in H-alpha and show kinematic evidence of outflow, powered by the bright nucleus.