The Proper Motion of the Central Compact Object RX J0822-4300 in the Supernova Remnant Puppis A, Revisited

TL;DR

This study refines the proper motion measurement of the central compact object RX J0822-4300 in Puppis A using new Chandra data, providing improved velocity estimates and insights into the remnant's age.

Contribution

It presents the most accurate proper motion measurement of RX J0822-4300 to date, utilizing an extended temporal baseline and improved astrometric calibration.

Findings

Proper motion of 80.4 mas/yr with 7.7 mas/yr uncertainty.

Projected kick velocity of approximately 763 km/s.

Kinematic age discussion of Puppis A based on new measurements.

Abstract

We present an improved proper motion measurement of the central compact object RX J0822-4300, located in the supernova remnant Puppis A. By employing a new data set taken in February 2019 by the High Resolution Camera aboard the Chandra X-ray Observatory, we approximately double the available temporal baseline for our analysis to slightly more than 19 years (7000 days). We correct for the astrometric inaccuracy of Chandra using calibrator stars with known optical positions that are detected in all observations. Thereby, we obtain absolute positions of RX J0822-4300 accurate to around $0.1^{\prime\prime}$ and from these a new best estimate for its total proper motion of $\mu_{\rm tot}= (80.4 \pm 7.7)\,\rm{mas\,yr}^{-1}$. For a remnant distance of 2 kpc, this corresponds to a projected kick velocity of $(763 \pm 73)\, \rm{km\,s}^{-1}$ at a position angle of $\phi_0 = (247.8 \pm 4.4)^{\circ}$. The proper motion measurement of RX J0822-4300 is used for discussing the kinematic age of Puppis A.