Radio observations of new magnetar Swift J1555.2-5402 using the NASA Deep Space Network

ATel #14678; K. Bansal (JPL), A. B. Pearlman (McGill University, McGill Space Institute, Caltech), W. A. Majid (JPL, Caltech), R. S. Wharton (JPL), T. A. Prince (Caltech, JPL), S. Horiuchi (CSIRO)
on 6 Jun 2021; 08:57 UT
Credential Certification: Walid Majid (majidw@gmail.com)

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Swift J1555.2-5402 is a newly discovered magnetar, which was first detected in X-rays by the Swift Burst Alert Telescope (BAT) (GCN #30120), and was subsequently followed by the NICER telescope (ATel #14674, GCN #30126), which reported a 3.86 second periodicity in this source. We report on our recent radio observations of Swift J1555.2-5402 using the NASA Deep Space Network (DSN).

We observed this source on June 4, 2021, 06:59:02 UTC for 1.3 hours using the DSN radio dish (DSS-36) in Canberra, Australia, at center frequencies 2.3 GHz (S-band) and 8.4 GHz (X-band) simultaneously. Data were recorded with a bandwidth of ~120 MHz at S-band and ~440 MHz at X-band, using the pulsar backend in filterbank search mode with frequency and time resolution of 0.98 MHz and 512 microseconds, respectively. These observations were targeted at R.A. (J2000) = 15:55:08.556 and Dec. (J2000) = -54:03:38.74, as found by Swift/XRT (ATel #14674).

We searched for pulsed emission using the nominal spin period reported by NICER, but also blindly using Fourier-based and FFA periodicity search algorithms, after dedispersing the data at multiple DM trials in the range of 0-5000 pc cm^-3. We do not detect any pulsed emission at either S-band or X-band. We place a 7-sigma upper limit on its flux density of 0.31(6) mJy at S-band and 0.16(3) mJy at X-band assuming a duty cycle of 10%.

We also searched for single pulses in this data and did not detect any candidates above a signal-to-noise ratio of 7. Assuming a 1 ms duration pulse, we place a 7-sigma upper limit on the fluence of single pulse candidates to be 1.8(4) Jy ms at S-band and 0.9(2) Jy ms at X-band.

We encourage additional observations at other radio frequencies to further explore the radio properties of this source.

We thank the DSN team for their rapid response in scheduling the observations.