Using the MeerKAT radio telescope array, an international team of astronomers has detected eight new millisecond pulsars. The newly found objects are in six globular clusters. The findings are reported in a paper published on March 8th at the arXiv Preprint Repository.
A pulsar is a highly magnetized rotating neutron star that emits a beam of electromagnetic radiation. The fastest rotating pulsar with a rotation cycle of less than 30 milliseconds is known as the millisecond pulsar (MSP). Astronomers assume that when the heavier components initially turn into neutron stars and then spin up for the accretion of matter from secondary stars, they form in a star system.
A class of extreme binary pulsars with a semi-degenerate companion star is called a “spider pulsar”. These objects are further classified as “black widow” when the companion mass is very small (solar mass less than 0.1), and are called “Latrodectus mactans” when the secondary star is heavy.
Currently, a group of astronomers led by Alessandro Ridolfi of the Cagliari Observatory in Italy is reporting the detection of eight new MSPs. Five of them were found to be star systems and three were faintly isolated pulsars. This discovery was made using a 64-dish MeerKAT telescope array in South Africa.
“We used the MeerKAT radio telescope to conduct the first survey of pulsars in nine globular clusters of choice. As part of this program, we used the 1km core of an L-band array for a detailed search for new pulsars. Performed., And several follow-up observations in different configurations, two of which took advantage of the full array and tying capabilities of the TRAPUM backend. Discovered eight new MSPs in six different clusters. The astronomer wrote in his dissertation.
Five new MSPs called 47 Tuc ac, 47 Tuc ad, NGC 6624G, M62G, and Ter 5 have been found in the binary system, but the objects NGC 6522D, NGC 6624H, and NGC 6752F are slightly isolated MSPs. The newly discovered pulsar has a spin period in the range of 2.74 to 8.48 ms.
According to the paper, 47 Tuc ac (2.74 ms rotation period) and 47 Tuc ad (3.74 ms rotation period) cover the “spider pulser” with low-mass companions and regular occultation of their pulse emissions. 47 Tuc ac was found to be a “black widow” with an orbital period of approximately 0.18 days and a minimum companion mass of 0.0075 solar mass. With an orbital period of about 0.32 days and a minimum companion mass of about 0.2 solar mass, we know that 47 Tucad is a “redback”. Both MSPs are located in the globular cluster 47Tuc, about 15,300 light-years away from Earth.
The NGC 6624G with a rotation period of 6.09 ms is a binary MSP with a highly eccentric orbit within the cluster NGC 6624. The orbital period is 1.54 days, the pulsar mass is about 2.1 solar mass, and its companion is estimated as follows. It is about half the size of the sun. Astronomers assume that a companion star can be either a giant white dwarf or a neutron star. Another MSP, called NGC6624H, found in this cluster has been isolated and has a rotation period of approximately 5.13 ms.
The M62G is a binary MSP with a circular orbit in a large cluster M62 about 22,000 light-years away. The rotation period is about 4.61 ms, the orbital period is about 0.77 days, and the mass of its companion is estimated to be at least 0.1 solar mass.
The remaining binary MSP, called Ter 5 an (4.8 ms rotation period), is a slightly eccentric orbit with the longest orbital period (approximately 9.62 days) of the five newly detected binary pulsars. I have. The secondary object of this system is assumed to be a white dwarf with a minimum mass of 0.43 solar mass. This object is part of the Ter5 globular cluster in the galactic bulge.
The isolated pulsars NGC6522D and NGC6752F have spin periods of 5.53 ms and 8.48 ms, respectively. NGC 6522D is located in cluster NGC 6522, about 25,000 light-years away, near the center of the galaxy. As for the slowest rotating object reported in the treatise, it is located in a core collapse cluster known as NGC 6752, about 13,000 light-years away.
Eight binary millisecond pulsars examined by researchers
Eight new millisecond pulsars from the first Meerkat globular cluster census, arXiv: 2103.04800 [astro-ph.HE] arxiv.org/abs/2103.04800
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Eight new millisecond pulsars discovered by MeerKAT
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