Abstract:
Possibilities to detect hostless supernova remnants (hl-SNR) in intergalactic medium using the
1 GHz band of the Square Kilometre Array (SKA) are discussed. The optical detection rate of the hl-SN
constrained from the Sloan Digital Sky Survey is used to predict a number of detectable hl-SNRs in the
radio band. With an anticipated detection sensitivity (∼ 1 µJy) and angular resolution (<1 ) with the SKA, a
significant number of hl-SNR are expected to get detected in the nearby galaxy groups, such as local group,
Virgo, Fornax and Eridanus. A few very luminous hl-SNR may also be detected in the Coma cluster and
other rich galaxy clusters up to about 100 Mpc distance. The identification of individual SNRs against other
background radio sources will require sub-arcsec angular resolution at 1 GHz to resolve the characteristic
circular morphology of the radio SNRs in nearby groups. At larger distances, where individual SNR cannot be
resolved, a population of hl-SNR may also be constrained statistically in a small region, by estimating excess
unresolved radio sources without a known optical host in a group or cluster, compared to the number density
of the background radio sources at µJy flux level.
