2011MNRAS.416..567A

Arp 299 is an interacting system of two components: NGC 3690 and IC 694. Throughout the last 20 years seven supernovae have been catalogued as being discovered within the system. One of these is unclassified, leaving six core-collapse supernovae: two type II (one with IIL subtype classification); two type Ib events; a type IIb supernova; and an object of indistinct type, Ib/IIb.

We analyse the relative numbers of these supernova types, together with their relative positions with respect to host galaxy properties, to investigate the implications for both progenitor characteristics and host galaxy star formation properties.

Our main findings are as follows. (1) the ratio of `stripped envelope' supernovae (types Ib and IIb) to other `normal' type II is higher than that found in the local Universe. There is ∼ 10 per cent probability that the observed supernova type ratio is drawn from an underlying distribution such as that found in galaxies in the local Universe. (2) All `stripped envelope' supernovae are more centrally concentrated within the system than the other type II ( ∼ 7 per cent chance probability). (3) All supernova environments have similar derived metallicities and there are no significant metallicity gradients found across the system. (4) The `stripped envelope' supernovae all fall on regions of Hα emission while the other type II are found to occur away from bright H II regions (again, ∼ 7 per cent chance probability).

From this investigation we draw two different – but non-mutually exclusive – interpretations on the system and its supernovae as follows. (1) The distribution of supernovae, and the relatively high fraction of types Ib and IIb events over other type II can be explained by the young age of the most recent star formation in the system, where insufficient time has expired for the observed to match the `true' relative supernova rates. If this explanation is valid then the present study provides additional (independent) evidence that both types Ib and IIb supernovae arise from progenitors of shorter stellar lifetime and hence higher mass than other type II supernovae. (2) Given the assumption that types Ib and IIb trace higher mass progenitor stars, the relatively high frequency of types Ib and IIb to other type II, and also the centralization of the former over the latter with respect to host galaxy light implies that in the centrally peaked and enhanced star formation within this system, the initial mass function is biased towards the production of high-mass stars.

Based on observations made with the Isaac Newton Telescope and the William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias.