NGC 1569 - IB(s)m

NGC 1569

De Vaucouleurs Atlas Type: IB(s)m

Filter: B

Telescope: UH 2.2-m
North up , East left
Field Dimensions: 3.1 x 2.3 arcminutes

RC3 Type: IBm
RSA Type: SmIV/Amorph
Surface Brightness Range Displayed: 18.0-26.5 mag per square arcsec
Absolute Blue Magnitude: -16.7

De Vaucouleurs Atlas Description:

This high surface brightness galaxy shows considerable central star formation and weak spiral features. The galaxy is clearly an irregular of the Magellanic type. The (s) classification is based on the weak spiral features, which are partly due to dust. There are numerous resolved individual stars across the image, and there also appears to be a nucleus. The B-I color index map shows that while the apparent nucleus is blue, there are many red objects across the image. These could be a mix of foreground stars and red supergiants in the galaxy.

NGC 1569 is a member of the IC 342 -Maffei Group, and is one of the nearest starburst dwarf irregulars ; it has been the subject of many studies. Buta and McCall (1999) showed that in deep I-band images, there is an extensive outer light distribution giving the galaxy the appearance of an elliptical. This interpretation is supported by the major and minor axis luminosity profiles, which follow an r1/4 law. Buta and McCall (1999) classified the galaxy as I(Amorphous ) because of this background light. In blue light, however, the galaxy is an Im.