2 Sample selection

 

 

Table 1: Sample completeness.

	$m_{\rm p} < 14$		$m_{\rm p} < 15$		$m_{\rm p} < 16$		$m_{\rm p} < 18$
	$N_{\rm obs}$	%	$N_{\rm obs}$	%	$N_{\rm obs}$	%	$N_{\rm obs}$	%
Coma S.C.	21	(96)	176	(99)	503	(98)	-	-
Virgo (ISO)	96	(98)	143	(83)	170	(67)	188	(42)
Virgo	195	(94)	260	(72)	295	(55)	315	(34)

We report H-band (1.65 $\mu$m ) observations of 52 faint Virgo galaxies (39 early and 13 late) selected from the VCC catalogue (Binggeli et al. 1985) (restricted to  16.0). With the aim of achieving the highest completeness level, the highest priority was given to objects lying in the region either within 2 degrees of projected radial distance from M 87 or in the corona between 4 and 6 degrees selected by the ISO consortium for complete MIR and FIR observations with ISO (see B97 for a detailed description of this selection criterium). During periods when Virgo was at airmass exceeding 2.2, we observed 20 (17 early and 3 late) galaxies in the Centaurus cluster selected from the CCC as fillers. We also observed two Pec galaxies (CGCG 97-073, 97-087) and the BCD galaxy IZw018.

Adding the present observations to those available from our previous Papers I-IV and B97 of this series, and limiting our sample to the Coma supercluster region ( $\rm0.0^o \le \delta \le 20.0^o$; $\rm 11^h30^m \le \alpha \le 13^h30^m$) and to the Virgo cluster, the complete subsample with NIR observations is as given in Table 1 in 4 bins of $m_{\rm p}$. The Coma region is completed at the limit of the Zwicky Catalogue. Assuming a distance modulus of Coma of 34.9 ( $H_{\rm0}=75~{\rm km\,s}^{-1}\,{\rm Mpc}^{-1}$) this corresponds to $M_{\rm p}=-19.2$, i.e. the observations cover a complete sample of giant galaxies. At the distance to the Virgo cluster A of 17 Mpc (Gavazzi et al. 1999), the limiting magnitude $m_{\rm p}=16$ reached by the present observations corresponds to $M_{\rm p}=-15.2$, i.e. 4 mag deeper than in Coma. However the observations of Virgo can be considered complete down to $M_{\rm p}=-17$, while they are still $\sim$50% complete at $M_{\rm p}=-15$ (slightly better in the ISO subsample). The analysis carried out in Sect. 6 comprises all objects in Table 1.