2 The DEBCA sample

The main goal of the DEBCA project is to study the link between the nuclear kinematics of the host galaxy and the fuelled central engine. We have thus compiled a list of single- and double-barred galaxies according to a few simple criteria:

• $-70\hbox{$^\circ$ }< \delta < +20\hbox{$^\circ$ }\$ where $\delta$ is the declination of the target, for observations with the VLT;
• $30\hbox{$^\circ$ }< i < 60\hbox{$^\circ$ }$, where i is the inclination angle. This ensures that the bar is clearly visible, but with an inclination high enough to have significant velocity signatures;
• D < 40 Mpc, which constrains the minimum intrinsic physical scales ( $0\hbox{$.\!\!^{\prime\prime}$ }5 \sim 100$ pc) we can probe.

We have then selected a small sample of 12 galaxies, where both Seyfert 1 and 2 were required. Four of the targets are non-active galaxies, to be used as a "control sample''. In the following Sections, we describe the observations and analysis of the first four targets of our list, three of them being generally classified as Seyfert 2's, and the fourth being a Seyfert 1 (Table 1). However evidence for the presence of a Seyfert nucleus in NGC 1808 is weak, this galaxy being better defined as a starburst galaxy: indeed optical and near-infrared spectra and more recent HST images strongly support the latter classification (e.g. Kotilainen et al. 1996). NGC 1097 and NGC 5728 are both classified as Seyfert 1's in the Veron-Cetty & Veron (1993) catalogue. Nevertheless, and although NGC 1097 does indeed contain an obscured broad-line region, characteristic of a hidden Seyfert 1 nucleus, the apparent nuclear activity of NGC 1097 is weak. This is also the case for NGC 5728 which was mentioned by Wilson et al. (1993) as a support for the unified model of Seyfert galaxies. We are therefore keeping NGC 1097 and NGC 5728 in the Seyfert 2 class.

 

 

Table 1: Optical data for the 4 galaxies

Galaxy	D	MB	Diameter	Sey	Bar1	Type	$V^{\rm Leda}_{\rm sys}$	$V^{\rm obs}_{\rm sys}$	PA $_{\rm disc}$	i	PA $_{\rm pb}^2$	PA $_{\rm nb}^3$
	[Mpc]	[mag]	[ $\,\hbox{$^\prime$ }\times \hbox{$^\prime$ }\,$]				[km$\,$s-1]	[km$\,$s-1]	[$\circ$]	[$\circ$]	[$\circ$]	[$\circ$]
NGC1097	16.8	10.2	9.3 $\times$ 6.3	S2	DB	SBb	1273	1240	130	37	138	30
NGC1365	18.6	10.3	11.2 $\times$ 6.2	S1	DB	SBb	1653	1628	32	57	91	45
NGC1808	10.9	10.8	6.5 $\times$ 3.9	SB$^{\star}$	DB	SABb	1003	1015	133	70	143	157
NGC5728	37.0	12.4	3.1 $\times$ 1.8	S2	DB	SABa	2789	2836	30	55	33	79

                  ¹ DB means Double Bar.

                  ² PA of the Primary Bar.

                  ³ PA of the Nuclear Bar.

                  $^{\star}$ Starburst galaxy: evidence for a Seyfert nucleus in NGC 1808 is weak, see text.