2008ApJ...672.1137R -
Astrophys. J., 672, 1137-1143 (2008/January-2)
Discovery of an isolated compact object at high galactic latitude.
RUTLEDGE R.E., FOX D.B. and SHEVCHUK A.H.
Abstract (from CDS):
We report the discovery of a compact object at high Galactic latitude. The object was initially identified as a ROSAT All-Sky Survey Bright Source Catalog X-ray source, 1RXS J141256.0+792204, statistically likely to possess a high X-ray to optical flux ratio. Further observations using Swift, Gemini-North, and the Chandra X-Ray Observatory refined the source position and confirmed the absence of any optical counterpart to an X-ray to optical flux ratio of FX(0.1-2.4 keV)/FV>8700 (3 σ). Interpretation of 1RXS J141256.0+792204–which we have dubbed Calvera–as a typical X-ray-dim isolated neutron star would place it at z~5.1 kpc above the Galactic disk–in the Galactic halo–implying that it either has an extreme space velocity (vz≳5100 km/s) or has failed to cool according to theoretical predictions. Interpretations as a persistent anomalous X-ray pulsar or a ``compact central object'' present conflicts with these classes' typical properties. We conclude that the properties of Calvera are most consistent with those of a nearby (80-260 pc) radio pulsar, similar to the radio millisecond pulsars of 47 Tucanae, with further observations required to confirm this classification. If it is a millisecond pulsar, it is has an X-ray flux equal to the X-ray brightest millisecond pulsar (and so is tied for highest flux); the closest northern hemisphere millisecond pulsar; and potentially the closest known millisecond pulsar in the sky, making it an interesting target for X-ray study, a radio pulsar timing array, and LIGO.
Abstract Copyright:
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Journal keyword(s):
Stars: Neutron - X-Rays: General
Nomenclature:
NAME Calvera N=1. Fig.1: [RFS2008] A (Nos A-C).
Simbad objects:
33
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