1 Introduction

The recent detections of optical afterglows of Gamma Ray Bursts (GRBs) confirm the low energy emission of these events. There has been optical afterglows observed for 7 GRBs so far, hence limited information is available now for their light curves, magnitudes as well as other parameters.

The common properties of optical afterglows (further OA) can be summarized as follows.

1.

The OA peak at roughly mag 14-23.

2.

They exhibit power law declines with mean power of -1.2.

3.

They seem to be related to faint host galaxies (but not in all cases).

4.

Not all of the GRBs have an associated OA.

5.

Spectra of OAs remain poorly investigated.

These general properties and behavior of OA resemble to some extent those of supernovae especially by peak magnitudes, transient behavior, and also by mean decline rates. Further, the rate of OA may be much larger than the GRBs rate due to different beaming, this factor is unknown but may reach 10 or even 100. It is therefore obvious that some of the recently detected and poorly in investigated supernovae may, in fact, represent unrevealed OA.

There are however also indications that there may be even direct physical relations between (some) GRBs and (some) SN, as illustrated by the positional and temporal coincidence of SN 1998bw with GRB 980425. This is why we have decided to study the possible correlations of GRBs and SN in more detail. In this search, we have taken all SNe detected into account including faint and poorly investigated events as they may represent unrevealed OA. Our approach is to study in detail the coincidences found and SN in question rather than make pure statistical conclusions (which are difficult due to large positional inaccuracies of GRBs and other influences such as incompleteness of SN databases). We note that the incompleteness of the SNe catalogues is large and that only 10^-3 ... 10^-4 of all SNe down to mag 23 are included.