Is Calvera a Gamma-ray Pulsar?

Abstract

Originally selected as a neutron star (NS) candidate in the ROSAT All-Sky Survey, 1RXS J141256.0+792204 ("Calvera") was discovered to be a 59 ms X-ray pulsar in a pair of XMM-Newton observations (Zane et al. 2011). Surprisingly, their claimed detection of this pulsar in Fermi gamma-ray data requires no period derivative, severely restricting its dipole magnetic field strength, spin-down luminosity, and distance to small values. This implies that the cooling age of Calvera is much younger than its characteristic spin-down age. If so, it could be a mildly recycled pulsar, or the first "orphaned" central compact object (CCO). Here we show that the published Fermi ephemeris fails to align the pulse phases of the two X-ray observations with each other, which indicates that the Fermi detection is almost certainly spurious. Analysis of additional Fermi data also does not confirm the gamma-ray detection. This leaves the spin-down rate of Calvera less constrained, and its place among the families of NSs uncertain. It could still be either a normal pulsar, a mildly recycled pulsar, or an orphaned CCO.

5 pages, 4 figures, to appear in The Astrophysical Journal Letters

References in corpus (8)

• A study of 315 glitches in the rotation of 102 pulsars
• The Magnificent Seven: Magnetic fields and surface temperature distributions
• Constraining the Spin-down of the Nearby Isolated Neutron Star RX J2143.0+0654
• Fermi LAT observations of the Geminga pulsar
• Discovery of an Isolated Compact Object at High Galactic Latitude
• Modeling the Surface X-ray Emission and Viewing Geometry of PSR J0821-4300 in Puppis A
• Discovery of 59ms Pulsations from 1RXS J141256.0+792204 (Calvera)
• A Strong Upper Limit on the Pulsed Radio Luminosity of the Compact Object 1RXS J141256.0+792204

Cited by in corpus (11)

• The Spin-down of PSR J0821-4300 and PSR J1210-5226: Confirmation of Central Compact Objects as Anti-Magnetars
• X-ray Measurement of the Spin-Down of Calvera: a Radio- and Gamma-ray-Quiet Pulsar
• Proper Motion and Timing of Two Unusual Pulsars: Calvera and 1E 1207.4-5209
• Neutron Star Interior Composition Explorer X-ray Timing of the Radio and Gamma-ray Quiet Pulsars PSR J1412+7922 AND PSR J1849-0001
• NICER study of pulsed thermal X-rays from Calvera: a neutron star born in the Galactic halo?
• The peculiar isolated neutron star in the Carina Nebula - Deep XMM-Newton and ESO-VLT observations of 2XMM J104608.7-594306
• Deep optical observations of unusual neutron star Calvera with the GTC
• The First Glitch in a Central Compact Object Pulsar: 1E 1207.4-5209
• Statistical ages and the cooling rate of X-ray dim isolated neutron stars
• Detection of the extended $\gamma$-ray emission from the high Galactic latitude Calvera's SNR candidate
• Calvera: A low-mass strangeon star torqued by debris disk?