Eight new MSPs in NGC 6440 and NGC 6441

TL;DR

This paper reports the discovery of eight new millisecond pulsars in the globular clusters NGC 6440 and NGC 6441, including notable binary systems with potential implications for neutron star physics.

Contribution

It presents the discovery of five new MSPs in NGC 6440 and three in NGC 6441, with detailed analysis of a unique eccentric binary system in NGC 6440.

Findings

Eight new MSPs discovered in two globular clusters.

One binary pulsar has an eccentric orbit and a high total mass estimate.

Potential constraints on neutron star equations of state from the binary system.

Abstract

We report the discovery of five new millisecond pulsars in the globular cluster NGC 6440 and three new ones in NGC 6441; each cluster has one previously known pulsar. Four of the new pulsars are found in binary systems. One of the new pulsars, PSR J1748-2021B in NGC 6440, is notable for its eccentric (e = 0.57) and wide (P_b = 20.5 days) orbit. If the rate of advance of periastron is due solely to general relativity, we can estimate of the total mass of this binary system: 2.92 +/- 0.20 solar masses. This would imply an anomalously large mass for this pulsar, which could introduce important constraints in the study of the equation of state for cold neutron matter.