Detection of Pulsed Hard X-ray Emission from 4U 0142+61 with Fermi/GBM
ATel #7300; Ersin Gogus (Sabanci Univ. Istanbul), George Younes (GWU), Chryssa Kouveliotou (GWU) report on behalf of a larger collaboration:
on 27 Mar 2015; 14:26 UT
Credential Certification: Ersin Gogus (ersing@sabanciuniv.edu)
Subjects: X-ray, Gamma Ray, Neutron Star, Soft Gamma-ray Repeater
As part of our effort to monitor pulsed hard X-ray emission from magnetars with Fermi/GBM, we searched continuously recorded daily data (CTIME, 0.256 s time resolution) of 4U 0142+61 collected on March 1, 2015, soon after the onset of its latest activation (GCN #17507). We obtained the spin frequency of the magnetar using Swift XRT observations performed on the same day (Observation ID: 00030738055, ~4 ks exposure) as 0.115083(3) Hz and used it to fold the GBM data. We find that pulsed hard X-rays from 4U 0142+61 can be detected up to about 300 keV. We also find a marginal evidence of declining RMS pulsed count rates with energy: RMS pulsed count rates are 0.0061(7), 0.0040(8), 0.0046(8), and 0.0039(8) cts/s in the 11-26.5, 26.5-50.4, 50.4-101.3, and 101.3-298.6 keV ranges, respectively. Further investigations of the pulsed hard X-ray emission of this magnetar are ongoing. Energy resolved pulse profiles of the source as seen on March 1, 2015 can be seen at: https://www.dropbox.com/s/akesqy92vzql5iu/4u0142_150301_d10_pulseprof_energy.pdf?dl=0
