1E 1547.0–5408: A Radio-emitting Magnetar with a Rotation Period of 2 Seconds

By F. Camilo, S. Ransom, J. Halpern, J. Reynolds. 2007

226 citations recorded by the source corpus.

The variable X-ray source 1E 1547.0-5408 was identified by Gelfand & Gaensler as a likely magnetar in G327.24-0.13, an apparent supernova remnant. No X-ray pulsations have been detected from it. Using the Parkes radio telescope, we discovered pulsations with period P = 2.069 s. Using the Australia Telescope Compact Array, we localized these to 1E 1547.0-5408. We measure = (2.318 ± 0.005) × 10-11, which for a magnetic dipole rotating in vacuo gives a surface field strength of 2.2 × 1014 G, a characteristic age of 1.4 kyr, and a spin-down luminosity of 1.0 × 1035 ergs s-1. Together with its X-ray characteristics, these rotational parameters of 1E 1547.0-5408 prove that it is a magnetar, only the second known to emit radio waves. The distance is ≈9 kpc, derived from the dispersion measure of 830 cm-3 pc. The pulse profile at a frequency of 1.4 GHz is extremely broad and asymmetric due to multipath propagation in the ISM, as a result of which only ≈75% of the total flux at 1.4 GHz is pulsed. At higher frequencies the profile is more symmetric and has FWHM = 0.12P. Unlike in normal radio pulsars, but in common with the other known radio-emitting magnetar, XTE J1810-197, the spectrum over 1.4-6.6 GHz is flat or rising, and we observe large, sudden changes in the pulse shape. In a contemporaneous Swift X-ray observation, 1E 1547.0-5408 was detected with record high flux, fX(1-8 keV) ≈ 5 × 10-12 ergs cm-2 s-1, 16 times the historic minimum. The pulsar was undetected in archival radio observations from 1998, implying a flux <0.2 times the present level. Together with the transient behavior of XTE J1810-197, these results suggest that radio emission is triggered by X-ray outbursts of usually quiescent magnetars.

Subfields: Astronomy and Astrophysics

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Citations in the corpus

Frequency-dependent effects of gravitational lensing within plasma (2015, background): “…500 MHz (Istomin & Sobyanin 2007; Lazarus et al. 2012) and the transient, highlyvariable radio emission observed from a subset of these objects (Camilo et al. 2007; Malov 2014) suggests that the density of plasma in the magnetospheres of magnetars is lower than in normal radio pulsars (Istomin…”
NuSTAR DISCOVERY OF A 3.76 s TRANSIENT MAGNETAR NEAR SAGITTARIUS A* (2013, background): “With its detection at radio wavelengths (Eatough et al. 2013b, 2013c), SGR J1745−29 is similar to the transient magnetars 1E 1547−5408 (Camilo et al. 2007), J1622−4950 (Levin et al. 2010), and XTE J1810−197 (Camilo et al. 2006), the only three radio-detected magnetars.”
A RADIO-LOUD MAGNETAR IN X-RAY QUIESCENCE (2010, background): “To date only two AXPs have confirmed radio pulsations, namely XTE J1810–197 (Camilo et al. 2006) and 1E 1547–5408 (Camilo et al. 2007a).”
Science with the Murchison Widefield Array (2012, background): “At least two magnetars have been seen as transient radio pulsars (Camilo et al. 2006, 2007), while radio searches for the INS have so far been to detect individual pulses from the sequences for assessing primary parameters of these fluctuations, since the detection of relatively stable fluctuation…”
The glitch-induced identity changes of PSR J1119−6127 (2010, methodology): “Three of the magnetars are detected as radio pulsars (Camilo et al. 2006, 2007; Levin et al. 2010) and they show characteristics similar to PSRs J1119–6127 and B0656+14.”
Observing pulsars and fast transients with LOFAR (2011, background): “Recently, however, two such sources have been shown to emit in the radio, albeit in a highly variable way (Camilo et al. 2006, 2007).”