First Swift Observations of the Repeating FRB20240114A
ATel #16645; F. Verrecchia, M. Perri (INAF/OAR & ASI/SSDC), M. Tavani (INAF/IAPS & Univ. Roma Tor Vergata), M. Pilia (INAF/OA-Cagliari), C. Casentini (INAF/IAPS), D. Pelliciari (Univ. of Bologna, INAF/IRA), C. Pittori (INAF/OAR & ASI/SSDC), G. Bernardi, G. Bianchi, G. Naldi, G. Pupillo (INAF/IRA), A. Geminardi (IUSS), P. Esposito (IUSS), P. Limaye (MPIfR/AIfA), L. Spitler (MPIfR), on behalf of a large Collaboration
on 8 Jun 2024; 15:13 UT
Credential Certification: Francesco Verrecchia (francesco.verrecchia@ssdc.asi.it)
Subjects: Radio, X-ray, Gamma Ray, Request for Observations, Transient, Fast Radio Burst
Referred to by ATel #: 16695
We report of the observations campaign with Swift XRT and UVOT instruments of the repeating Fast Radio Burst source FRB20240114A (J2000 R.A., Dec.= 321.9160, 4.3293 deg) during a time interval when the source was reported to be in a radio activity phase (ATels #16597, #16599), with some radio bursts detected just before Swift observations (on May 5th, private communication) and some further bursts reported just after the start of our observations by Effelsberg (ATel #16620).
Our Swift X-ray observations are part of a coordinated multiwavelength campaign of this FRB including optical observations (SiFAP2) and simultaneous radio observations by a network of european small dishes radiotelescopes (ATel #16565), the italian Northern Cross radio telescope in Medicina (ATels #16434, #16547) and the dishes in Medicina and Noto.
We observed the location of FRB20240114A daily from May 7th to May 14th, 2024 in the following time intervals:
May 7th, within 05:00 - 05:15 UT, for 864 s of effective exposure;
May 8th, within 04:52 - 05:11 UT, for 1132 s of effective exposure;
May 9th, within 04:36 - 04:52 UT, for 956 s of effective exposure;
May 10th, within 04:20 - 04:38 UT, for 1052 s of effective exposure;
May 11th, within 03:53 - 04:08 UT, for 875 s of effective exposure;
May 12th, within 03:36 - 05:33 UT, for 1053 s of effective exposure;
May 13rd, within 05:03 - 05:17 UT, for 830 s of effective exposure;
May 14th, within 03:08 - 04:54 UT, for 1166 s of effective exposure;
We obtained XRT data in Windowed Timing (WT) mode: a preliminary analysis indicates that no uncatalogued X-ray source compatible with the FRB position was detected in all observations. For the Galactic HI column density value in the source direction (n_H = 4.98 x 1020 cm-2, Kalberla et al. 2005, A&A, 440, 775) and assuming a single power-law spectrum of photon index 2, we obtain the following 3-sigma flux upper limits (ULs) in the range 0.3-10 keV:
4.8 x 10-13 erg/cm2/s for the first observation on May 7th;
6.5 x 10-13 erg/cm2/s for the observations on May 8th;
7.6 x 10-13 erg/cm2/s for the observations on May 9th;
1.1 x 10-12 erg/cm2/s for the observations on May 10th;
6.6 x 10-13 erg/cm2/s for the observations on May 11th;
5.3 x 10-13 erg/cm2/s for the observations on May 12th;
7.0 x 10-13 erg/cm2/s for the observations on May 13rd;
6.6 x 10-13 erg/cm2/s for the observations on May 14th.
UVOT data where acquired in imaging, "filter of the day" mode, with exposures similar to the XRT ones. No detection on the full exposure images were obtained, and the following flux UL all for M2 filter were estimated:
6.5 x 10-14 erg/cm^2/s for May 7th;
5.7 x 10-14 erg/cm^2/s for May 8th;
6.5 x 10-14 erg/cm^2/s for May 9th;
6.5 x 10-14 erg/cm^2/s for May 10th;
9.3 x 10-14 erg/cm^2/s for May 11th;
6.5 x 10-14 erg/cm^2/s for May 12th;
7.7 x 10-14 erg/cm^2/s for May 13th;
6.0 x 10-14 erg/cm^2/s for May 14th;
Moreover, we checked carefully XRT data at the times of 7 of the 32 bursts reported by Effelsberg (private communication), detected on May 9th and covered by the XRT exposure. No X-ray emission was detected within 10 ms around each trigger time. Further observations with Swift will follow.
We encourage multifrequency observations of FRB20240114A. The Swift mission is part of NASA's medium explorer (MIDEX) program, led by NASA with participation of Italy and the UK. We thank the Swift Team for making these observations possible, in particular B. Cenko and J. DeLaunay (Swift Observatory Duty Scientist).
