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Upper limit on the radio emission from the soft gamma-ray repeater SGR 1833-0832

ATEL # 2515; M. Burgay (INAF-O.A.Cagliari), A. Possenti (INAF-O.A.Cagliari), P.Esposito (INAF-IASF Mi), G. L. Israel (INAF-0.A.Roma), N. Rea (CSIC-ICE Barcelona), J. Sarkissian (ATNF-Parkes), A. Tiengo (INAF-IASF Mi), R. Turolla (U. Padua), S. Zane (MSSL/UCL), D. Gotz (Irfu/SAp/CEA Saclay), L. Stella (INAF-0.A.Roma), S. Mereghetti (INAF-IASF Mi) on behalf of a larger collaboration
on 26 Mar 2010; 16:08 UT
Password Certification: Paolo Esposito (paoloesp@iasf-milano.inaf.it)

Subjects: Radio, Pulsars, Supernova Remnants
Referred to by ATEL #: 2521

The soft gamma-ray repeater J1833-0832 has been discovered on 2010 March 19 thanks to the detection of a short burst by Swift (GCN #10526). Prompted by the detection of a radio outburst following the X-ray transient activity of two other magnetars, the anomalous X-ray pulsars XTE J1810-197 and 1E 1547.0-5408 (Camilo et al. 2006, Nature, 442, 892; 2007, ApJ, 666, L93), we observed the source with the 64-m Parkes radio telescope.

The source was observed on March 25 2010 (MJD 55279.954) for 1.5 hrs at a frequency of 1400 MHz. The total 288 MHz bandwidth was split into 96 channels, each 3 MHz wide, and the time series was 1 bit sampled every 1 ms. Data have been searched for periodicity around the value obtained from the X-ray observations (7.564 s) over a wide range of dispersion measure values (DM < 6000 pc/cm^3, given the very high NH value derived from X-ray observations). A search for single de-dispersed pulses was also carried out.

No radio pulsation with a period matching (within +/-2.5 ms) the X-ray period (ATEL #2493, #2494), nor half of it, has been found. The single pulse search only revealed the presence of a bright known pulsar in the beam (J1833-0827, at DM 411 pc/cm^3). The upper limit on the radio pulsations flux density at 1400 MHz is 0.09 mJy, calculated for the maximum DM investigated and assuming a minimum signal-to-noise ratio of 9. The latter relatively high value for the adopted minimum signal-to-noise ratio is due to the presence of strong radio interferences at ~7.5 s, that affect the signal folded at the soft gamma-ray repeater period.

We thank Philip Edwards of ATNF for allocating us the time for this observation.


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