MeerKAT discovery of 13 new pulsars in Omega Centauri

Abstract

The most massive globular cluster in our Galaxy, Omega Centauri, is an interesting target for pulsar searches, because of its multiple stellar populations and the intriguing possibility that it was once the nucleus of a galaxy that was absorbed into the Milky Way. The recent discoveries of pulsars in this globular cluster and their association with known X-ray sources was a hint that, given the large number of known X-ray sources, there is a much larger undiscovered pulsar population. We used the superior sensitivity of the MeerKAT radio telescope to search for pulsars in Omega Centauri. In this paper, we present some of the first results of this survey, including the discovery of 13 new pulsars; the total number of known pulsars in this cluster currently stands at 18. At least half of them are in binary systems and preliminary orbital constraints suggest that most of the binaries have light companions. We also discuss the ratio between isolated and binaries pulsars and how they were formed in this cluster.

Discovery of Astrometric Accelerations by Dark Companions in the Globular Cluster ω Centauri

“…However, we can get some cues from other rare populations, such as millisecond pulsars (MSPs) and X-ray sources. Curiously, the first bona fide MSPs in ω Cen were discovered only in 2020 (Dai et al 2020), followed by observations with the MeerKAT radio telescope and the discovery of 13 more MSPs (Chen et al 2023). Four of them are in our field (Figure 11).…”

Message in a Bottle - An Update to the Golden Record

“…Despite the lack of eclipsing phenomena, the tight orbits, low mass companions and rapid spin periods further bolster these claims. Unlike the former, the binaries J1326-4728 K and L (having periods 4.71 and 3.53 ms respectively) were determined to be eclipsing black widows [10]. In an alternate scenario, J1326-4728I, having a spin period of 18.95 ms, points to an orbital solution that suggests an orbital period of 26.71 hours with a companion mass range of [0.020, 0.046] Mʘ.…”

“…In an alternate scenario, J1326-4728I, having a spin period of 18.95 ms, points to an orbital solution that suggests an orbital period of 26.71 hours with a companion mass range of [0.020, 0.046] Mʘ. In addition, the pulsar period indicates the fact that it might be a mildly recycled pulsar [10], although assertion of the nature of the pulsar is subject to further observations. The last sections of exploration encompass the analysis of J1326-4728 N and Q, with spin periods of 6.88 and 4.13 ms respectively.…”

“…Nevertheless, its classification as a GC has been challenged, making it a possible candidate for being a stripped off core of an accreted dwarf galaxy [9]. A unique feature of the location map, ꞷ-Cen differs from other GCs because of its intricate composition of different populations of stars [10]. Multi-beam observations from MeerKAT as part of the TRAPUM GC Survey in 2021 revealed the presence of 13 new pulsars in Omega Centauri (besides the previously discovered five pulsars), more than half of which reside in binary systems; these are worth exploring in profundity.…”

A study of the light bending phenomenon under full general relativity for a pulsar in a binary with a Schwarzschild black hole

“…The LIGO detection of gravitational waves emitted by the merger of a neutron star and a black hole in a binary supported this claim (Abbott et al 2020). As the new generation of sensitive ★ E-mail: jdebnath@imsc.res.in radio telescopes like MeerKAT (Ridolfi et al 2022;Chen et al 2023) and FAST (Han et al 2021;Pan et al 2021) are discovering many pulsars presently and more discoveries are expected by them as well as by the upcoming telescopes like SKA (Hessels et al 2015), it is possible that the discovery of a pulsar−black hole binary will happen anytime soon. Hence, it is a good time to understand how different aspects of the strong field gravity would manifest in the data of the pulsar in such a binary.…”