We present a high-resolution analysis of the host galaxy of fast radio burst (FRB)~190608, an SB(r)c galaxy at $z=0.11778$ (hereafter HG 190608), to dissect its local environment and its contributions to the FRB properties. Our Hubble Space Telescope Wide Field Camera 3 ultraviolet and visible light image reveals that the subarcsecond localization of FRB~190608 is coincident with a knot of star-formation ($\Sigma_{ \rm SFR} = 1.5 \times 10^{ -2}~ M_{ \odot} \, \rm \, yr^{ -1} \, kpc^{ -2}$) in the northwest spiral arm of HG~190608. Using H$\beta$ emission present in our Keck Cosmic Web Imager integral field spectrum of the galaxy with a surface brightness of $\mu_{ \rm H\beta}= \mathrm{ (3.36\pm0.21)\times10^{ -17}\;erg\;s^{ -1}\;cm^{ -2}\;arcsec^{ -2}}$, we infer an extinction-corrected H$\alpha$ surface brightness and compute a dispersion measure (DM) from the interstellar medium of HG 190608 of $\rm DM_{ \rm Host,ISM} = 94 \pm 38~ \;pc\;cm^{ -3}$. The galaxy rotates with a circular velocity $v_{ \rm circ} = \rm 141 \pm 8~ km\;s^{ -1}$ at an inclination $i_{ \mathrm{ gas}} = 37 \pm 3^\circ$, giving a dynamical mass $M_{ \rm halo}^{ \rm dyn} \approx 10^{ 11.96 \pm 0.08}~M_{ \odot}$. This implies a halo contribution to the DM of $\rm DM_{ \rm Host,Halo}= \rm 55\pm25 \;pc\;cm^{ -3}$ subject to assumptions on the density profile and fraction of baryons retained. From the galaxy rotation curve, we infer a bar-induced pattern speed of $\Omega_p=34\pm 6\;\mathrm{ km\;s^{ -1}\;kpc^{ -1}}$ using linear resonance theory. We then calculate the maximum time since star-formation for a progenitor using the furthest distance to the arm's leading edge within the localization, and find $t_{ \mathrm{ enc}} = 21_{ -6}^{ +25}$ Myr. Unlike previous high-resolution studies of FRB environments, we find no evidence of disturbed morphology, emission, or kinematics for FRB 190608.
Categories: astro-ph.GA