Year: 2026
Type: article
Abstract: We present a timing study of the three known central compact object (CCO) pulsars, isolated cooling neutron stars in supernova remnants, using observations from Chandra, XMM-Newton, and NICER spanning two decades. Relative to canonical young pulsars, CCOs are spinning down at a very slow rate ∣ f ̇ ∣ < 1 0 − 15 s −2 , implying a surface dipole magnetic field strength B s < 10 11 G that is too weak to account for their X-ray-emitting hot spots. Two CCO pulsars with sufficiently long monitoring, 1E 1207.4−5209 and PSR J0821−4300, are seen to deviate from steady spin-down; their timing residuals can be modeled by one or more glitches in f and f ̇ or alternatively by extreme timing noise. For the third CCO pulsar, PSR J1852+0040, the sparse temporal coverage was insufficient to detect such effects. Glitch activity and timing noise in large samples of rotation-powered pulsars correlate best with f ̇ , while the timing irregularities of the first two CCOs are extreme compared to pulsars of the same f ̇ . Nevertheless, timing activity in CCOs may arise from properties that they share with other young but more energetic pulsars: high internal temperature, strong buried magnetic field, and superfluid behavior. Alternatively, continuing low-level accretion of supernova debris is not ruled out as a source of timing noise in CCOs.
Source: The Astrophysical Journal
Authors: K. I. Perez, E. V. Gotthelf, J. P. Halpern
Institution: Columbia University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Awards: G1390571956, G3561758408, G3815726687, G5236452758, G6396050669, THE GOAL AS OUTLINED IN THE PROPOSAL IS TO OBTAIN A PHASE CONNECTED TIMING SOLUTION FOR LE 1207.4-5209 FOLLOWING AN APPARENT GLITCH. WE WILL PIECE TOGETHER A NEW TIMING SOLUTION USING ALL THE AVAILABLE MULTI-MISSION OBSERVATIONS FOR THIS PULSAR. WE WILL EXTRACT TOA MEASUREMENTS FROM EACH OBSERVATIONS AND FIT THEM COLLECTIVELY USING THE TEMPO SOFTWARE PACKAGE. WE WILL REDUCE AND ANALYZE DATA FROM THE 5 PROPOSED XMM-NEWTON OBSERVATIONS ALONG WITH 4 CHANDRA OBSERVATIONS OBTAINED AS PART OF A ON-GOING MULTI-YEAR PROPOSAL. OUR HOPE IS TO OBTAIN A NEW TIMING EPHEMERIS FOR LE 1207.4-5209 THAT TAKES INTO ACCOUNT EVERY TURN OF THE PULSAR. WE WILL COMPARE THIS NEW EPHEMERIS WITH THE PREVIOUS ONE TO ASSESS THE MAGNITUDE OF THE CHANGE IN SPIN FREQUENCY AND/ OR ITS FREQUENCY DERIVATIVE IN ORDER TO BETTER PROBE THE PHYSICS OF THE NEUTRON STAR. AN IMPORTANT COMPONENT TO THIS ENDEAVOR IS A SIMULTANEOUS SPECTRAL STUDY. WE WILL UNDERTAKE A COMPREHENSIVE PHASE-RESOLVED SPECTRAL ANALYSIS OF THE PULSAR TO LOOK FOR CHANGES BEFORE DURING AND AFTER THE GLITCH.
OpenAlex ID: W7127599710