Dissecting the Local Environment of FRB 190608 in the Spiral Arm of its Host Galaxy
Abstract
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 (ΣSFR = 1.5 × 10-2 M ⊙ yr-1 kpc-2) in the northwest spiral arm of HG 190608. Using Hβ emission present in our Keck Cosmic Web Imager integral field spectrum of the galaxy with a surface brightness of ${\mu }_{{\rm{H}}\beta }=(3.36\pm 0.21)\times {10}^{-17}\,\mathrm{erg}\,{{\rm{s}}}^{-1}\,{\mathrm{cm}}^{-2}\,{\mathrm{arcsec}}^{-2}> , we infer an extinction-corrected Hα surface brightness and compute a dispersion measure (DM) from the interstellar medium of HG 190608 of DMHost,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}_{\mathrm{halo}}^{\mathrm{dyn}}\approx {10}^{11.96\pm 0.08}\,{M}_{\odot }> . This implies a halo contribution to the DM of DMHost,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}_{\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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2021
- DOI:
- arXiv:
- arXiv:2005.13158
- Bibcode:
- 2021ApJ...922..173C
- Keywords:
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- 1560;
- 2008;
- 1339;
- 1569;
- 602;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 21 pages, 11 figure files, 10 figures in paper, 3 tables. Accepted to ApJ on Sept. 16, 2021, published Nov. 29, 2021