The X-ray Source at the Center of the Cassiopeia A Supernova Remnant

Abstract

We present the first results of an XMM-Newton observation of the central X-ray source in the Cas A supernova remnant. The spectrum can be fit equally well with an absorbed steep power law (alpha~3, N_H~1.5x10^22 cm^-2) or with a bremsstrahlung with temperature kT~2.4 keV and N_H~10^22 cm^-2. A blackbody model (kT~0.7 keV) gives a slightly worse fit and requires a column density N_H~5x10^21 cm^-2 and an emitting area with radius ~0.3 km (for d=3.4 kpc). A search for pulsations for periods longer than 150 ms gave negative results. The 3 sigma upper limits on the pulsed fraction are ~13% for P>0.3 s and ~7% for P>3 s. The overall properties of the central X-ray source in Cas A are difficult to explain in terms of a rapidly spinning neutron star with a canonical magnetic field of ~10^12 G, and are more similar to those of slowly rotating neutron stars such as the Anomalous X-ray Pulsars.

15 pages, latex, 3 figures, to appear in The Astrophysical Journal; Revised version with more details on spectral analysis, fig. 1 and 2 slightly changed, revised flux values

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Cited by in corpus (30)

• The Expansion Asymmetry and Age of the Cassiopeia A Supernova Remnant
• Direct Observation of the Cooling of the Cassiopeia A Neutron Star
• Grand Unification in Neutron Stars
• Spin-down Measurement of PSR J1852+0040 in Kesteven 79: Central Compact Objects as Anti-Magnetars
• Constraints on the Progenitor of Cassiopeia A
• The Spin-down of PSR J0821-4300 and PSR J1210-5226: Confirmation of Central Compact Objects as Anti-Magnetars
• First search for gravitational waves from the youngest known neutron star
• Evolution of a buried magnetic field in the central compact object neutron stars
• The distribution of radioactive ${}^{44}$Ti in Cassiopeia A
• Cooling rates of neutron stars and the young neutron star in the Cassiopeia A supernova remnant
• Imaging X-ray, Optical, and Infrared Observations of the Transient Anomalous X-ray Pulsar XTE J1810-197
• Limit on the Axion Decay Constant from the Cooling Neutron Star in Cassiopeia A
• Measuring the Cooling of the Neutron Star in Cassiopeia A with all Chandra X-ray Observatory Detectors
• New constraints on the cooling of the Central Compact Object in Cas A
• Pulse phase variations of the X-ray spectral features in the radio-quiet neutron star 1E 1207-5209
• An X-ray Search for Compact Central Sources in Supernova Remnants I: SNRs G093.3+6.9, G315.4-2.3, G084.2+0.8, & G127.1+0.5
• Precise Timing of the X-ray Pulsar 1E 1207.4-5209: A Steady Neutron Star Weakly Magnetized at Birth
• Fading of the Transient Anomalous X-ray Pulsar XTE J1810-197
• A dedicated Chandra ACIS observation of the central compact object in the Cassiopeia A supernova remnant
• Upper limits on the rapid cooling of the Central Compact Object in Cas A
• Near-Infrared and Optical Limits for the Central X-ray Point Source in the Cassiopeia A Supernova Remnant
• Models of magnetized neutron star atmospheres: thin atmospheres and partially ionized hydrogen atmospheres with vacuum polarization
• Importance of Compton scattering for radiation spectra of isolated neutron stars with weak magnetic fields
• Comparing supernova remnants around strongly magnetized and canonical pulsars
• X-ray emission from isolated neutron stars
• Supernova progenitor stars in the initial range of 23 to 33 solar masses and their relation with the SNR Cas A
• Limits to the Cas A ${}^{44}$Ti Line Flux and Constraints on the Ejecta Energy and the Compact Source
• Discovery of a Compact X-ray Source in the LMC Supernova Remnant N23 with Chandra
• Hints of a second explosion (a quark nova) in Cassiopeia A Supernova
• Thermal Evolution of Neutron Stars as a Probe of Physics beyond the Standard Model