NGC 4013 - Sb sp

NGC 4013

De Vaucouleurs Atlas Type: Sb sp

Filter: B

Telescope: WIYN 3.5-m
North up , East left
Field Dimensions: 5.1 x 3.9 arcminutes

RC3 Type: Sb sp
RSA Type: Sbc:
Surface Brightness Range Displayed: 19.0-26.0 mag per square arcsec
Absolute Blue Magnitude: -20.1

De Vaucouleurs Atlas Description:

NGC 4013 has an extended boxy bulge and is probably barred. The bar in this case may be viewed nearly broadside-on. We base the Sb classification on the significance of this bulge and the general patchiness of the disk structure.

Most interesting is the strong planar dust lane. In blue light, this feature shows a complicated structure, with numerous filaments extending out of the plane (Howk and Savage 1999). The B-V color index map shows that, contrary to what might be expected, the planar dust is actually bluer than the stellar disk in its midsection, as in NGC 4565. Only near the top and bottom edges is the dust lane redder than the stellar disk light. The thin blue section either partly or mostly represents outer star-forming regions suffering little extinction compared to similar regions deeper in the dust layer. The redder rims of the dust layer may be too far out of the plane to show the bluing.