[ OIII ] \lambda 5007 Å emission lines of 16 intracluster planetary nebulae candidates in the Coma cluster were detected with a Multi-Slit Imaging Spectroscopy ( MSIS ) technique using FOCAS on the Subaru telescope .
The identification of these faint emission sources as PNe is supported by ( i ) their point-like flux distribution in both space and wavelength , with tight limits on the continuum flux ; ( ii ) the identification of the second [ OIII ] \lambda 4959 line in the only object at high enough velocity that this line too falls into the filter bandpass ; ( iii ) emission line fluxes consistent with PNe at 100 Mpc distance , in the range 2.8 \times 10 ^ { -19 } -1.7 \times 10 ^ { -18 } { erg s } ^ { -1 } { { cm } } ^ { -2 } ; and ( iv ) a narrow velocity distribution approximately centered on the systemic velocity of the Coma cluster .
Comparing with the velocities of galaxies in our field , we conclude that the great majority of these candidates would be intracluster PNe , free floating in the Coma cluster core .
Their velocity dispersion is \sim 760 { km s ^ { -1 } } , and their mean velocity is lower than that of the galaxies .
The velocity distribution suggests that the intracluster stellar population has different dynamics from the galaxies in the Coma cluster core .