Table 1: Characteristic luminosity L_* in units of $L_\odot$ at 12 ${\mu }$ m (Col. 3) and 24 ${\mu }$ m (Col. 4) of the z=0 luminosity functions used here, as a function of galaxy type (Col. 1). Column 2 gives the value of the parameter p₂, the rate defined by $\textit {SFR}_i(t)=M_{{\rm gas}}(t)/{p_2}$ . Galactic winds occur at an age of 3 Gyr in ellipticals of type E and ULIRG, and at 1 Gyr in ellipticals of type E2; there are no galactic winds in spirals. Infall time scale of ULIRGs is 100 Myr as for ellipticals of type E or E2; it regularly increases for spirals from 2.8 Gyr (Sa) to 8.0 Gyr (Im) (see text for details and references). The L_*(12 ${\mu }$ m) for the normal types (other than ULIRG) are derived from the L_*(B_J) of the observed optical luminosity functions from Heyl et al. (1997) and the $B_J-12~\mu$ m and $B_J-24~\mu$ m colours, in the AB magnitude system, are computed at $z\simeq 0$ with PÉGASE.3 (Cols. 5 and 6). The value of $L_{*}(12~\mu$ m) assigned to Sbc galaxies, the brightest emitters in this band, is that of the observed luminosity function measured with IRAS (Rush et al. 1993; Shupe et al. 1998); the same offset as for Sbc is then applied to all types. The last two columns show the adopted number density fraction by type: model 1 (normal galaxies only, Col. 7) uses the type distribution derived from the UV-optical-near IR faint counts (Fioc et al. 1999a) while model 2 (normal galaxies + ULIRGs, Col. 8) is built by replacing 1/3 of normal dust-poor ellipticals (9% of all galaxies) with ultra luminous elliptical galaxies (called ULIRGs). These last galaxies evolve as dusty ellipticals, they are $\simeq$ 2.5 to $\simeq$ 5 mag brighter than normal ellipticals (depending on wavelength), and are thus as luminous as spirals Sbc in the mid-IR at z=0. The number densities for the other galaxy types are identical in both models.
Type p₂ $\log_{10}$ $\log_{10}$ Colour Colour Model 1 Model 2

(Myr) $[L_{*}(12~\mu {\rm m})/L_{\odot}]$ $[L_{*}(24~\mu {\rm m})/L_{\odot}]$ $B_J-12~\mu$ m $B_J-24~\mu$ m normal normal

_AB _AB only + ULIRGs

ULIRG 100 9.9 9.7 - - 0% 9.0%

E 100 8.9 7.7 -1.00 -2.60 9% 0%

E2 300 9.0 7.8 -1.20 -2.82 17.5% 17.5%

Sa 1400 9.0 8.8 -0.45 +0.21 7.9% 7.9%

Sb 2500 9.4 9.2 +0.37 +1.28 7.9% 7.9%

Sbc 5714 9.8 9.6 +1.38 +2.30 7.9% 7.9%

Sc 10000 9.6 9.4 +1.57 +2.46 16.6% 16.6%

Sd 14286 9.6 9.4 +1.61 +2.48 16.6% 16.6%

Im 16000 8.8 8.5 +1.57 +2.42 16.6% 16.6%

**Table 1:** Characteristic luminosity L_* in units of $L_\odot$ at 12 ${\mu }$ m (Col. 3) and 24 ${\mu }$ m (Col. 4) of the z=0 luminosity functions used here, as a function of galaxy type (Col. 1). Column 2 gives the value of the parameter p₂, the rate defined by $\textit {SFR}_i(t)=M_{{\rm gas}}(t)/{p_2}$ . Galactic winds occur at an age of 3 Gyr in ellipticals of type E and ULIRG, and at 1 Gyr in ellipticals of type E2; there are no galactic winds in spirals. Infall time scale of ULIRGs is 100 Myr as for ellipticals of type E or E2; it regularly increases for spirals from 2.8 Gyr (Sa) to 8.0 Gyr (Im) (see text for details and references). The L_*(12 ${\mu }$ m) for the normal types (other than ULIRG) are derived from the L_*(B_J) of the observed optical luminosity functions from Heyl et al. (1997) and the $B_J-12~\mu$ m and $B_J-24~\mu$ m colours, in the AB magnitude system, are computed at $z\simeq 0$ with PÉGASE.3 (Cols. 5 and 6). The value of $L_{*}(12~\mu$ m) assigned to Sbc galaxies, the brightest emitters in this band, is that of the observed luminosity function measured with *IRAS* (Rush et al. 1993; Shupe et al. 1998); the same offset as for Sbc is then applied to all types. The last two columns show the adopted number density fraction by type: model 1 (normal galaxies only, Col. 7) uses the type distribution derived from the UV-optical-near IR faint counts (Fioc et al. 1999a) while model 2 (normal galaxies + ULIRGs, Col. 8) is built by replacing 1/3 of normal dust-poor ellipticals (9% of all galaxies) with ultra luminous elliptical galaxies (called ULIRGs). These last galaxies evolve as dusty ellipticals, they are $\simeq$ 2.5 to $\simeq$ 5 mag brighter than normal ellipticals (depending on wavelength), and are thus as luminous as spirals Sbc in the mid-IR at z=0. The number densities for the other galaxy types are identical in both models.
Type	p₂	$\log_{10}$	$\log_{10}$	Colour	Colour	Model 1	Model 2
	(Myr)	$[L_{*}(12~\mu {\rm m})/L_{\odot}]$	$[L_{*}(24~\mu {\rm m})/L_{\odot}]$	$B_J-12~\mu$ m	$B_J-24~\mu$ m	normal	normal
				_AB	_AB	only	+ ULIRGs
ULIRG	100	9.9	9.7	-	-	0%	9.0%
E	100	8.9	7.7	-1.00	-2.60	9%	0%
E2	300	9.0	7.8	-1.20	-2.82	17.5%	17.5%
Sa	1400	9.0	8.8	-0.45	+0.21	7.9%	7.9%
Sb	2500	9.4	9.2	+0.37	+1.28	7.9%	7.9%
Sbc	5714	9.8	9.6	+1.38	+2.30	7.9%	7.9%
Sc	10000	9.6	9.4	+1.57	+2.46	16.6%	16.6%
Sd	14286	9.6	9.4	+1.61	+2.48	16.6%	16.6%
Im	16000	8.8	8.5	+1.57	+2.42	16.6%	16.6%

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