Spatially Resolved Molecular Gas Properties of Host Galaxy of Type I
  Superluminous Supernova SN 2017egm
  We present the results of CO(1-0) observations of the host galaxy of a Type I
superluminous supernova (SLSN-I), SN2017egm, one of the closest SLSNe-I at z =
0.03063, by using the Atacama Large Millimeter/submillimeter Array. The
molecular gas mass of the host galaxy is $M_{\rm gas} = (4.8 \pm 0.3) \times
10^9$ $M_{\odot}$, placing it on the sequence of normal star-forming galaxies
in an $M_{\rm gas}$-star-formation rate (SFR) plane. The molecular hydrogen
column density at the location of SN2017egm is higher than that of the Type II
SN PTF10bgl, which is also located in the same host galaxy, and those of other
Type II and Ia SNe located in different galaxies, suggesting that SLSNe-I have
a preference for a dense molecular gas environment. On the other hand, the
column density at the location of SN2017egm is comparable to those of Type Ibc
SNe. The surface densities of molecular gas and the SFR at the location of
SN2017egm are consistent with those of spatially resolved local star-forming
galaxies and follow the Schmidt-Kennicutt relation. These facts suggest that
SLSNe-I can occur in environments with the same star-formation mechanism as in
normal star-forming galaxies.
