Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-01-14
Astrophys.J. 588 (2003) 452-463
Astronomy and Astrophysics
Astrophysics
16 pages, 7 figures, accepted by ApJ
Scientific paper
10.1086/374039
We report spectral and variability analysis of two quiescent low mass X-ray binaries (X5 and X7, previously detected with the ROSAT HRI) in a Chandra ACIS-I observation of the globular cluster 47 Tuc. X5 demonstrates sharp eclipses with an 8.666+-0.01 hr period, as well as dips showing an increased N_H column. The thermal spectra of X5 and X7 are well-modeled by unmagnetized hydrogen atmospheres of hot neutron stars. No hard power law component is required. A possible edge or absorption feature is identified near 0.64 keV, perhaps an OV edge from a hot wind. Spectral fits imply that X7 is significantly more massive than the canonical 1.4 \Msun neutron star mass, with M>1.8 \Msun for a radius range of 9-14 km, while X5's spectrum is consistent with a neutron star of mass 1.4 \Msun for the same radius range. Alternatively, if much of the X-ray luminosity is due to continuing accretion onto the neutron star surface, the feature may be the 0.87 keV rest-frame absorption complex (O VIII & other metal lines) intrinsic to the neutron star atmosphere, and a mass of 1.4 \Msun for X7 may be allowed.
Edmonds Peter D.
Grindlay Jonathon E.
Heinke Craig O.
Lloyd Don Anthony
No associations
LandOfFree
X-ray Studies of Two Neutron Stars in 47 Tucanae: Toward Constraints on the Equation of State does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with X-ray Studies of Two Neutron Stars in 47 Tucanae: Toward Constraints on the Equation of State, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and X-ray Studies of Two Neutron Stars in 47 Tucanae: Toward Constraints on the Equation of State will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-219588