Table 2: Rough sizes of the box (from rotation axis to corner) and the central stellar disc (radius in kpc) determined on the mass distribution of the young population alone. The radius of main linear resonances for A ^sf and B ^nosf. hILR is the horizontal inner Lindblad resonance, vILR the vertical one and hUHR is the horizontal ultra harmonic resonance.

	600	1000	1500	2000
	Myr	Myr	Myr	Myr
Box and disc sizes
Disc	0.27	0.43	0.50	0.50
Boxy	0.67	1.17	1.40	1.59
Boxy/disc	2.48	2.69	2.80	3.18
Resonance radii of A sf
hILR	1.27	1.61	1.89	1.80
vILR	N/A	1.34	1.68	1.81
hUHR	3.57	3.82	4.21	4.00
Resonance radii of B nosf
hILR	1.61	2.24	2.45	2.84
vILR	N/A	N/A	N/A	2.95
hUHR	4.69	5.12	5.25	5.26