Dissecting the Local Environment of FRB 190608 in the Spiral Arm of its Host Galaxy

• Published in: The Astrophysical journal Vol. 922; no. 2; pp. 173 - 188
• Main Authors: Chittidi, Jay S., Simha, Sunil, Mannings, Alexandra, Prochaska, J. Xavier, Ryder, Stuart D., Rafelski, Marc, Neeleman, Marcel, Macquart, Jean-Pierre, Tejos, Nicolas, Jorgenson, Regina A., Day, Cherie K., Marnoch, Lachlan, Bhandari, Shivani, Deller, Adam T., Qiu, Hao, Bannister, Keith W., Shannon, Ryan M., Heintz, Kasper E.
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01.12.2021; IOP Publishing
• Subjects: Astrophysics; Emission; Field cameras; Galactic rotation; Galaxies; Galaxy kinematics; High resolution; Hubble Space Telescope; Interstellar matter; Interstellar medium; Kinematics; Localization; Radio bursts; Radio transient sources; Space telescopes; Spiral galaxies; Star & galaxy formation; Star formation; Stars & galaxies; Surface brightness
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/ac2818

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 (Σ SFR = 1.5 × 10 −2 M ⊙ yr −1 kpc −2 ) in the northwest spiral arm of HG 190608. Using H β emission present in our Keck Cosmic Web Imager integral field spectrum of the galaxy with a surface brightness of μ H β = ( 3.36 ± 0.21 ) × 10 − 17 erg s − 1 cm − 2 arcsec − 2 , we infer an extinction-corrected H α surface brightness and compute a dispersion measure (DM) from the interstellar medium of HG 190608 of DM Host,ISM = 94 ± 38 pc cm −3 . The galaxy rotates with a circular velocity v circ = 141 ± 8 km s −1 at an inclination i gas = 37° ± 3°, giving a dynamical mass M halo dyn ≈ 10 11.96 ± 0.08 M ⊙ . This implies a halo contribution to the DM of DM Host,Halo = 55 ± 25 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 Ω p = 34 ± 6 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 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.