The Proper Motion of the High Galactic Latitude Pulsar Calvera

Calvera (1RXS J141256.0+792204) is a pulsar of characteristic age 285 kyr at a high Galactic latitude of b = +37°, detected only in soft thermal X-rays. We measure a new and precise proper motion for Calvera using Chandra High Resolution Camera observations obtained 10 yr apart. We also derive a new...

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Bibliographic Details
Main Authors: M. Rigoselli, S. Mereghetti, J. P. Halpern, E. V. Gotthelf, C. G. Bassa
Format: Article
Language:English
Published: IOP Publishing 2024-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ad8cd6
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Summary:Calvera (1RXS J141256.0+792204) is a pulsar of characteristic age 285 kyr at a high Galactic latitude of b = +37°, detected only in soft thermal X-rays. We measure a new and precise proper motion for Calvera using Chandra High Resolution Camera observations obtained 10 yr apart. We also derive a new phase-connected ephemeris using 6 yr of NICER data, including the astrometric position and proper motion as fixed parameters in the timing solution. Calvera is located near the center of a faint, circular radio ring that was recently discovered by LOFAR and confirmed as a supernova remnant (SNR) by the detection of γ -ray emission with Fermi Large Area Telescope. The proper motion of 78.5 ± 2.9 mas yr ^−1 at position angle 241.°3 ± 2.°2 (in Galactic coordinates) points away from the center of the ring, a result which differs markedly from a previous low-significance measurement, and greatly simplifies the interpretation of the SNR/pulsar association. It argues that the supernova indeed birthed Calvera <10 kyr ago, with an initial spin period close to its present value of 59 ms. The tangential velocity of the pulsar depends on its uncertain distance, v _t = (372 ± 14) d _1 kpc km s ^−1 , but is probably dominated by the supernova kick, while its progenitor could have been a runaway O or B star from the Galactic disk.
ISSN:1538-4357