De Vaucouleurs Atlas Type: SB(rs)b
Telescope: NOT 2.5-m
North up , East left
Field Dimensions: 6.4 x 5.8 arcminutes
RC3 Type: SB(rs)b
RSA Type: ------
Surface Brightness Range Displayed: 19.4-27.0 mag per square arcsec
Absolute Blue Magnitude: -21.4
Elmegreen Spiral Arm Class: AC12
De Vaucouleurs Atlas Description:
This galaxy is a good example where the true bar strength is heavily masked by internal extinction. Application of the gravitational torque method (GTM ; see book Section 2.12 of the introductory section) to a 2.2 micron Ks-band image of NGC 1530 gives bar strength Qb ~ 0.6 (Block et al. 2004a). However, in blue light, the bar is heavily masked by dust in the form of strong leading dust lanes and other dust complexes. The inner pseudoring is well-defined but somewhat unusual; it refers to the partial ring arcs around the ends of the bar. This is different from other inner pseudorings (e.g., NGC 5945 ) where arms springing from the bar ends fail to close on the opposite side. The Sb classification is based on the appearance of the bright inner spiral region, and not on the asymmmetric outer arms. In the center, dust winds into the nuclear region to form a complex nuclear spiral, rather than a nuclear ring. The color index map shows that the spiral has enhanced blue colors. Beyond the bright inner spiral, both of the main arms appear to split in an asymmetric way.
NGC 1530 has been the subject of several dynamical studies and has been observed in CO (Regan et al. 1996, 1997; Reynaud and Downes 1997; Downes et al. 1996).