Quick search Find article
Quick search
Find article

The Central X-Ray Point Source in Cassiopeia A

FREE

Deepto Chakrabarty1, Michael J. Pivovaroff1, Lars E. Hernquist2, Jeremy S. Heyl2,3 and Ramesh Narayan2

Show affiliations


The spectacular "first light" observation by the Chandra X-Ray Observatory revealed an X-ray point source near the center of the 300 yr old Cas A supernova remnant. We present an analysis of the public X-ray spectral and timing data. No coherent pulsations were detected in the Chandra/HRC data. The 3 σ upper limit on the pulsed fraction is less than 35% for P > 20 ms. The Chandra/ACIS spectrum of the point source may be fitted with an ideal blackbody (kT = 0.5 keV) or with blackbody models modified by the presence of a neutron star atmosphere (kT = 0.25-0.35 keV), but the temperature is higher and the inferred emitting area lower than expected for a 300 yr old neutron star according to standard cooling models. The spectrum may also be fitted with a power-law model (photon index Γ = 2.8-3.6). Both the spectral properties and the timing limits of the point source are inconsistent with a young Crab-like pulsar but are quite similar to the properties of the anomalous X-ray pulsars. The spectral parameters are also very similar to those of the other radio-quiet X-ray point sources in the supernova remnants Pup A, RCW 103, and PKS 1209-52. Current limits on an optical counterpart for the Cas A point source rule out models that invoke fallback accretion onto a compact object if fallback disk properties are similar to those in quiescent low-mass X-ray binaries. However, the optical limits are marginally consistent with plausible alternative assumptions for a fallback disk. In this case, accreting neutron star models can explain the X-ray data, but an accreting black hole model is not promising.


Subject headings

accretion, accretion disks; black hole physics; stars: neutron; supernovae: individual (Cassiopeia A); supernova remnants; X-rays: stars


Dates

Issue 2 (2001 February 20)

Received 1999 December 27, accepted for publication 2000 August 29



  1. The Central X-Ray Point Source in Cassiopeia A

    Deepto Chakrabarty et al. 2001 ApJ 548 800

  2. Molecular Gas in the Inner 100 Parsecs of M51

    N. Z. Scoville et al 1998 ApJ 493 L63

  3. Implications from Extreme-Ultraviolet Observations for Coronal Heating of Active Stars

    Marc Audard et al 1999 ApJ 513 L53

  4. Main results of the First International PIV Challenge

    M Stanislas et al 2003 Meas. Sci. Technol. 14 R63

  5. Supernova neutrino–nucleus astrophysics

    A B Balantekin and G M Fuller 2003 J. Phys. G: Nucl. Part. Phys. 29 2513

  6. Infrared 3-4 μm Spectroscopic Investigations of a Large Sample of Nearby Ultraluminous Infrared Galaxies

    Masatoshi Imanishi et al. 2006 ApJ 637 114

  7. Science from detection of neutrinos from supernovae

    R N Boyd et al 2003 J. Phys. G: Nucl. Part. Phys. 29 2543

  8. Coherent states for a quantum particle on a circle

    K Kowalski et al 1996 J. Phys. A: Math. Gen. 29 4149

  9. Scale-invariance in gravity and implications for the cosmological constant

    Bryan Kelleher 2004 Class. Quantum Grav. 21 2623

  10. Charge measurement and mitigation for the main test masses of the GEO 600 gravitational wave observatory

    M Hewitson et al 2007 Class. Quantum Grav. 24 6379

Users also read

What's this?
This innovative new feature generates a list of articles 'also read' by other users based on them reading the original article. Article abstracts citations and references are all considered and weighted accordingly. We hope that this will help you find relevant papers for your research.

  1. A Million Second Chandra View of Cassiopeia A
  2. Spin-Down Measurement of PSR J1852+0040 in Kesteven 79: Central Compact Objects as Anti-Magnetars
  3. The X-Ray Source at the Center of the Cassiopeia A Supernova Remnant
More

View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.