Search

ABSTRACT We report on a 105-ks Suzaku observation (obsid 404011010 with J. Takata as PI) of the supernova remnant CTA 1 (G119.5+10.2). The Suzaku soft X-ray observation was carried out using both the timing and imaging modes. A ∼10-arcmin extended feature, which is interpreted as a bow-shock component of the pulsar wind nebula, is revealed in this deep observation for the first time. The nebular spectrum can be modelled by a power law with a photon index of ∼1.8, which suggests a slow synchrotron cooling scenario. The photon index is approximately constant across this extended feature. We compare our observations of this complex nebula with previous X-ray investigations, and we discuss our findings. We do not obtain any significant pulsation from the central pulsar in the soft (0.2-12 keV) and hard (10-60 keV) X-ray data. The non-detection is mainly a result of the loss of the precise imaging ability to accurately determine the source contribution. The spectra from the X-ray imaging spectrometer and the hard X-ray detector can be directly connected without a significant spectral break, according to our analysis. Future observations by the Nuclear Spectroscopic Telescope Array ( NuSTAR) and Astro-H might be able to resolve the contamination and provide an accurate hard X-ray measurement of CTA 1. [ABSTRACT FROM AUTHOR]

Some unidentified EGRET sources have been reported to have probable X-ray counterparts. Periodicities in the X-ray data of those sources, if found, may help to strengthen the identification and to reveal their nature. We performed a detailed search of periodicities with a photon-counting method, theH-test, in the XMM and ASCA data of RX J0007.0+7302, which is the most probable X-ray counterpart to the EGRET source 3EG J0010+7309. Although no periods with enough significance were found, a possible one, at 0.1275433± 0.0000001 s (MJD 52327.03399), is quite intriguing based on results of cross-checking the two data sets. We suggest future analysis with other data to search the vicinity of this period. [ABSTRACT FROM AUTHOR]

The region around SGR 1806-20 and its host stellar cluster Cl* 1806-20 is a potentially important site of particle acceleration. The soft γ-ray repeater and Cl* 1806-20, which also contains several very massive stars including a luminous blue variable hypergiant LBV 1806-20, are capable of depositing a large amount of energy to the surroundings. Using the data taken with the Fermi Large Area Telescope (LAT), we identified an extended LAT source to the southwest of Cl* 1806-20. The centroid of the 1–50 GeV emission is consistent with that of HESS J1808-204 (until now unidentified). The LAT spectrum is best-fit by a broken power law with the break energy . The index above Eb is 2.60 ± 0.04 and is consistent with the flux and spectral index above 100 GeV for HESS J1808-204, suggesting an association between the two sources. Meanwhile, the interacting supernova remnant SNR G9.7-0.0 is also a potential contributor to the LAT flux. A tentative flux enhancement at the MeV band during a 45 day interval (2011 January 21–March 7) is also reported. We discuss possible origins of the extended LAT source in the context of both leptonic and hadronic scenarios. [ABSTRACT FROM AUTHOR]