We present a high-resolution analysis of the host galaxy of fast radio burst FRB 190608 , an SBc galaxy at z = 0.11778 ( hereafter HG 190608 ) , to dissect its local environment and its contributions to the FRB properties .
Our Hubble Space Telescope WFC3/UVIS image reveals that the sub-arcsecond localization of FRB 190608 is coincident with a knot of star-formation ( \Sigma _ { SFR } = 1.2 \times 10 ^ { -2 } ~ { } { M } _ { \odot } kpc ^ { -2 } ) in one of the prominent spiral arms of HG 190608 .
This is confirmed by H \beta emission present in our Keck/KCWI integral field spectrum of the galaxy with a surface brightness of \mu _ { H \beta } = \mathrm { ( 3.35 \pm 0.18 ) \times 10 ^ { -17 } erg s ^ { -1 } cm ^ { -2 } % arcsec ^ { -2 } } .
We infer an extinction-corrected H \alpha surface brightness and compute a dispersion measure from the interstellar medium of HG 190608 of { DM } _ { Host,ISM } = 82 \pm 35 ~ { } { pc cm ^ { -3 } } .
The galaxy rotates with a circular velocity v _ { circ } = 141 \pm 8 ~ { } { km s ^ { -1 } } at an inclination i _ { gas } = 37 \pm 3 ^ { \circ } , giving a dynamical mass M _ { halo } ^ { dyn } \approx 10 ^ { 11.96 \pm 0.08 } ~ { } { M } _ { \odot } .
A surface photometric analysis of the galaxy using FORS2 imaging suggests a stellar disk inclination of i _ { stellar } = 26 \pm 3 ^ { \circ } .
The dynamical mass estimate implies a halo contribution to the dispersion measure of { DM } _ { Host,Halo } = 55 \pm 25 { pc cm ^ { -3 } } subject to assumptions on the density profile and fraction of baryons retained .
The relatively high temporal broadening ( \tau = 3.3 \pm 0.2 ms at 1.28 GHz ) and rotation measure ( RM = 353 \pm 2 ~ { } { rad m ^ { -2 } } ) \citep Day+20 of FRB 190608 may be attributable to both turbulent gas within the spiral arm and gas local to the FRB progenitor .
In contrast to previous high-resolution studies of FRB progenitor environments , we find no evidence for disturbed morphology , emission , nor kinematics for FRB 190608 .