A redshift for the host galaxy of FRB 20240114A

ATel #16613; Mohit Bhardwaj (Carnegie Mellon University), Aida Kirichenko (Universidad Nacional Autonoma de Mexico), Armando Gil de Paz (Universidad Complutense de Madrid)
on 4 May 2024; 17:08 UT
Credential Certification: Mohit Bhardwaj (mohitb@andrew.cmu.edu)

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We report a redshift estimate for the host galaxy of the hyperactive fast radio burst (FRB) 20240114A, discovered and first reported by the CHIME/FRB collaboration on January 26, 2024 (ATel #16420). The host galaxy of the FRB, SDSS J212739.84+041945.8, was confidently identified and associated by the MeerTRAP team (ATel #16446) utilizing arcsecond localization precision with MeerKAT. This association was independently verified by the EVN-PRECISE team, who localized the FRB with a conservative precision of +/-200 milliarcseconds to the same SDSS galaxy (ATel #16542). Observations of the FRB host galaxy were conducted with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) spectrograph at the GTC telescope, situated at the Roque de los Muchachos Observatory on La Palma Island, Canary Islands, Spain, on May 1, 2024 UT. In the 1800s exposure of the host galaxy, various emission lines ([OII], H-beta, [OIII], [N II], H-alpha, and [S II]) were detected at a common redshift of z=0.1300+/-0002. This redshift is consistent (within 1-sigma) with photometric redshift reported in the DESI Legacy Imaging Survey DR8 (z = 0.269 +/- 0.139; [1]). Thus, we consider this to be the redshift of the FRB20201124A host. Based on our preliminary analysis, we classify the FRB host as a dwarf star-forming galaxy (absolute r-band magnitude = -17.46 +/- 0.01 AB). Moreover, we find that the dispersion measure (DM) contribution of the FRB host could be significant (~ 330 pc/cm^3). However, the FRB sightline intersects several candidate optical/infrared detected clusters and galaxy groups ([2,3,4,5,6,7]), which could also contribute considerably to the FRB DM. Furthermore, given the similarity between the FRB 20240114A host and the hosts of two active repeating sources also localized to star-forming dwarf galaxies (FRBs 20121102A and 20190520B [8,9]), we conducted a search for a similar potential persistent radio source (PRS) counterpart in archival radio survey data (TGSS [10], RACS[11], NVSS[12], FIRST[13], VLASS[14]) but found none. The most stringent 3-sigma upper limit on the PRS is 0.30 mJy at 1.5 GHz using FIRST survey data [13], translating to a luminosity upper limit of 6.9 x 10^37 erg/s at 1.5 GHz. This is at least 4 times fainter than the PRS detected spatially coincident with FRBs 20121102A and 20190520B [8,9]. We recommend searching for a fainter radio continuum counterpart at the location of the FRB source. Finally, we express gratitude to the GTC telescope staff for scheduling and executing these observations. [1] Duncan, K J. MNRAS 512.3 (2022): 3662-3683. [2] Rykoff, E. S., et al. ApJS 224.1 (2016): 1. [3] Gal, R. R., et al. AJ 137.2 (2009): 2981. [4] Gao, J., et al. PASP 132.1008 (2020): 024101. [5] Banerjee, P., et al. NewA 58 (2018): 61-71. [6] Wen, Z. L., et al., MNRAS 475.1 (2018): 343-352. [7] Saulder, C, et al. A&A 596 (2016): A14. [8] Chatterjee, S., et al. Nature 541.7635 (2017): 58-61. [9] Niu, C-H., et al. Nature 606.7916 (2022): 873-877. [10] Intema, H. T., et al. A&A 598 (2017): A78. [11] Hale, C. L., et al. PASA 38 (2021): 1-25. [12] Condon, J. J., et al. AJ 115.5 (1998): 1693. [13] Becker, R. H., et al. AJ 450, p. 559 450 (1995): 559. [14] Lacy, M., et al. PASP 132.1009 (2020): 035001.