Investigation of CTA 1 with Suzaku Observation

We report on an 105 ks Suzaku observation of the supernova remnant CTA 1 (G119.5+10.2). The Suzaku soft X-ray observation was carried out with both timing mode and imaging mode. A ~ 10' extended feature, which is interpreted as a bow-shock component of the pulsar wind nebula (PWN), 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 and discuss our observations of this complex nebula with previous X-ray investigations. 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 due to the loss of the precise imaging ability to accurately determine the source contribution. The spectra of XIS and HXD can be directly connected without a significant spectral break according to our analysis. Future observations of NuSTAR and Astro-H would be able to resolve the contamination and provide an accurate hard X-ray measurement of CTA 1.

[1]  D. Thompson,et al.  PRECISE γ-RAY TIMING AND RADIO OBSERVATIONS OF 17 FERMI γ-RAY PULSARS , 2010, 1011.2468.

[2]  L. Lin,et al.  DETECTION OF AN X-RAY PULSATION FOR THE GAMMA-RAY PULSAR CENTERED IN CTA 1 , 2010, 1010.1354.

[3]  William W. Zhang,et al.  The Nuclear Spectroscopic Telescope Array (NuSTAR): optics overview and current status , 2010, Astronomical Telescopes + Instrumentation.

[4]  D. Thompson,et al.  EIGHT γ-RAY PULSARS DISCOVERED IN BLIND FREQUENCY SEARCHES OF FERMI LAT DATA , 2010, 1006.2134.

[5]  Nasa,et al.  Suzaku Discovery of a Hard X-Ray Tail in the Persistent Spectra from the Magnetar 1E 1547.0$-$5408 during its 2009 Activity , 2010, Publications of the Astronomical Society of Japan.

[6]  D. Thompson,et al.  Detection of 16 Gamma-Ray Pulsars Through Blind Frequency Searches Using the Fermi LAT , 2009, Science.

[7]  Yasushi Fukazawa,et al.  Modeling and Reproducibility of Suzaku HXD PIN/GSO Background , 2009, 0901.0419.

[8]  D. Thompson,et al.  The Fermi Gamma-Ray Space Telescope Discovers the Pulsar in the Young Galactic Supernova Remnant CTA 1 , 2008, Science.

[9]  Shunsaku Okada,et al.  The X-Ray Telescope onboard Suzaku , 2007 .

[10]  Ryuichi Fujimoto,et al.  The X-Ray Observatory Suzaku , 2007 .

[11]  J. A. Gregory,et al.  X-Ray Imaging Spectrometer (XIS) on Board Suzaku , 2007 .

[12]  Tuneyoshi Kamae,et al.  Hard X-Ray Detector (HXD) on Board Suzaku , 2006, astro-ph/0611232.

[13]  Probing the Proper Motion of the Central Compact Object in Puppis-A , 2006, astro-ph/0606750.

[14]  L. Lin,et al.  Periodicity Search in the X-ray Data of RX J0007.0+7302 , 2005 .

[15]  R. Taam,et al.  Pulsar Wind Nebulae and the X-Ray Emission of Nonaccreting Neutron Stars , 2004, astro-ph/0408460.

[16]  D. J. Helfand,et al.  X-Ray, Radio, and Optical Observations of the Putative Pulsar in the Supernova Remnant CTA 1 , 2004, astro-ph/0404312.

[17]  F. Camilo,et al.  The Mouse that Soared: High-Resolution X-Ray Imaging of the Pulsar-powered Bow Shock G359.23–0.82 , 2003, astro-ph/0312362.

[18]  J. Hughes,et al.  X-Ray Observations of the Compact Source in CTA 1 , 2003, astro-ph/0310250.

[19]  R. Romani,et al.  Fitting Pulsar Wind Tori , 2003, astro-ph/0310155.

[20]  Bonn,et al.  Systematic bias in interstellar magnetic field estimates , 2003, astro-ph/0307330.

[21]  J. Cordes,et al.  Pulsar Jets: Implications for Neutron Star Kicks and Initial Spins , 2000, astro-ph/0007272.

[22]  E. Phinney,et al.  Birth kicks as the origin of pulsar rotation , 1998, Nature.

[23]  F. Marshall,et al.  RXTE Measurement of the Diffuse X-Ray Emission from the Galactic Ridge: Implications for the Energetics of the Interstellar Medium , 1998, astro-ph/9804012.

[24]  H Germany,et al.  A candidate gamma‐ray pulsar in the supernova remnant CTA 1 , 1997, astro-ph/9710111.

[25]  K. Torii,et al.  Nonthermal X-Ray Emission from CTA 1 , 1997 .

[26]  D. Nice,et al.  A Survey of EGRET Sources for Pulsed Radio Emission , 1997 .

[27]  A. Lyne,et al.  A search for radio pulsars in globular clusters, supernova remnants and transient X-ray sources , 1996 .

[28]  D. L. Bertsch,et al.  The Second EGRET Catalog of High-Energy Gamma-Ray Sources , 1995 .

[29]  B. Schmidt,et al.  X-Ray Emission from the Supernova Remnant CTA 1 , 1995 .

[30]  T. Landecker,et al.  The Supernova Remnant CTA1 and the Surrounding Interstellar Medium , 1993 .

[31]  S. Holt,et al.  Discovery of soft X-ray pulsations from the γ-ray source Geminga , 1992, Nature.

[32]  M. Longair,et al.  Observational cosmology. , 1978, Science.