3. Remarks

   

Table 5: Distribution of supernovae according to the morphological types of their parent galaxies

	E	S0	S0/a	Sa	Sab	Sb	Sbc	Sc	Scd	Sd	Sdm	Sm	S	I0	Im	I	Pec	nc	Total
I	10	2	5	9	3	8	6	13		2			1					18	77
Ia	24	31	6	20	13	28	32	35	10	5		1	18					187	410
Iapec	3	4			2	1	3	2		1			1				1	1	19
Ib			1		1	1	1	9	1						1	1		1	17
Ib/c							2	2		1		1	1					2	9
Ic			1	1	1	2	3	9	2				4					4	27
Iac						2													2
II			2	7	5	32	23	73	12	8	3	1	11	1	2	6		56	242
IIb					1			2	1			1							5
IIn			1	1		5	4	10	1				1			2		9	34
IIpec				1		1		4					1					2	9
Pec				1	1	1		1	1									2	7
nc	38	14	15	32	16	62	42	91	7	8	1	6	58		2	19	1	177	589
Total	75	51	31	72	43	143	116	251	35	25	4	10	96	1	5	28	2	459	1447

Notes: nc means not classified supernovae and/or galaxies.

Figure 4: Histogram of the difference between the SN and galaxy magnitudes

Figure 5: Distributions of SN types (top) and of the parent galaxy morphological types (bottom)

A major effort has been devoted in searching the literature for accurate magnitudes, epochs of maximum and for assigning supernova types. For this latter task we are indebted to D. Branch (private communication) who provided us with a list of revised supernova types for many SNe. For the supernovae discovered in the periods from 1989 to 1992 and from 1992 to 1998 we have cross checked our data with those of van den Bergh (1994) and the electronic list supplied by the CBAT, respectively. Discrepancies, in both cases, have been solved by looking at the original literature, mostly consisting of IAU circulars.

The galaxy coordinates are given with various degrees of accuracy depending on the accuracy of the original Catalogue. For many anonymous galaxies, in particular for the parent galaxies of high-zSNe, the approximate galaxy position is derived from the supernova coordinates. In some cases, discrepancies may arise between the quoted off-sets of the supernova from the galaxy nucleus and the same data derived from the SN-parent relative coordinates (see e.g. SN 1965C). This happens especially for parent galaxies with ill-defined nuclei. Finally, a few supernovae have been discovered and observed only spectroscopically (e.g. SN 1995bb) and therefore they lack a photometric magnitude.

Figure 6: The Hubble diagram for all the SNe with redshift discovered up to Dec. 31, 1998. The magnitudes are those reported in the Catalogue, i.e. those at maximum when available, or those at discovery. The line is the expected position for "standard'' SNIa having $M({\rm max})=-19.50$, H0=65 km s-1 Mpc, q0=0

In Table 3 we list the 37 SNe (excluding SN 1998ab, added in the proofs) which, though announced after the publication of ASC89, were discovered on old plates obtained before December 31, 1988. Instead, Table 4 lists the 20 objects which, from the beginning of the searches up to the present time, turned out not to be supernovae. Among these latter objects, SN 1950E and 1956C were still included in ASC89. SN 1987G has been deleted because it turned out to be the same object as SN 1987D.