Manisha Pranati Caleb is an Indian and Australian astrophysicist whose research has used interferometry to detect fast radio bursts, [1] studied the local context of fast radio bursts, used their signals as probes into the distribution of matter in the universe, [2] and discovered repeating signals from what may be very slowly-rotating neutron stars. [3] [4] [5] She is a lecturer at the University of Sydney, in the Sydney Institute for Astronomy. [2]
Caleb was a student at Stella Maris College, Chennai in India from 2007 to 2010. She went to University College London in England for a master's degree involving spacecraft and satellite communications. Next, she became a doctoral student at the Australian National University, where she began her work on fast radio bursts. [1] [5] Her 2017 doctoral dissertation, A pursuit of fast radio transients with the UTMOST and Parkes radio telescopes, was jointly supervised by Frank Briggs, Brian Schmidt, Matthew Bailes, and Chris Flynn. [6]
She became a postdoctoral researcher at the University of Manchester in England [1] before returning to Australia for her present position as a lecturer in the Sydney Institute for Astronomy of the University of Sydney. [2]
Some of Caleb's major results include the first use of interferometry to detect fast radio bursts, in 2017, [1] [B] confirmation of the extra-galactic origin of these bursts, [7] [A] and the discoveries of ultra-long-period pulsars PSR J0901–4046 in 2020, the former slowest known pulsar at roughly 76 seconds per pulse, [3] [C] and ASKAP J1935+2148 in 2024, with roughly 54 minutes per pulse. [4] [5] [D]
A. | Caleb, M.; Flynn, C.; Bailes, M.; Barr, E. D.; Hunstead, R. W.; Keane, E. F.; Ravi, V.; van Straten, W. (March 2016), "Are the distributions of fast radio burst properties consistent with a cosmological population?", Monthly Notices of the Royal Astronomical Society, 458 (1): 708–717, arXiv: 1512.02738 , doi: 10.1093/mnras/stw175 |
B. | Caleb, M.; Flynn, C.; Bailes, M.; Barr, E. D.; Bateman, T.; Bhandari, S.; Campbell-Wilson, D.; Farah, W.; Green, A. J.; Hunstead, R. W.; Jameson, A.; Jankowski, F.; Keane, E. F.; Parthasarathy, A.; Ravi, V.; Rosado, P. A.; van Straten, W.; Venkatraman Krishnan, V. (March 2017), "The first interferometric detections of fast radio bursts", Monthly Notices of the Royal Astronomical Society, 468 (3): 3746–3756, arXiv: 1703.10173 , doi: 10.1093/mnras/stx638 |
C. | Caleb, Manisha; Heywood, Ian; Rajwade, Kaustubh; Malenta, Mateusz; Willem Stappers, Benjamin; Barr, Ewan; Chen, Weiwei; Morello, Vincent; Sanidas, Sotiris; van den Eijnden, Jakob; Kramer, Michael; Buckley, David; Brink, Jaco; Motta, Sara Elisa; Woudt, Patrick; Weltevrede, Patrick; Jankowski, Fabian; Surnis, Mayuresh; Buchner, Sarah; Bezuidenhout, Mechiel Christiaan; Driessen, Laura Nicole; Fender, Rob (May 2022), "Discovery of a radio-emitting neutron star with an ultra-long spin period of 76 s", Nature Astronomy, 6 (7): 828–836, arXiv: 2206.01346 , Bibcode:2022NatAs...6..828C, doi:10.1038/s41550-022-01688-x, PMC 7613111 , PMID 35880202 |
D. | Caleb, M.; Lenc, E.; Kaplan, D. L.; Murphy, T.; Men, Y. P.; Shannon, R. M.; Ferrario, L.; Rajwade, K. M.; Clarke, T. E.; Giacintucci, S.; Hurley-Walker, N.; Hyman, S. D.; Lower, M. E.; McSweeney, Sam; Ravi, V.; Barr, E. D.; Buchner, S.; Flynn, C. M. L.; Hessels, J. W. T.; Kramer, M.; Pritchard, J.; Stappers, B. W. (June 2024), "An emission-state-switching radio transient with a 54-minute period", Nature Astronomy, 8 (9): 1159–1168, arXiv: 2407.12266 , Bibcode:2024NatAs...8.1159C, doi: 10.1038/s41550-024-02277-w |
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Vulpecula is a faint constellation in the northern sky. Its name is Latin for "little fox", although it is commonly known simply as the fox. It was identified in the seventeenth century, and is located in the middle of the Summer Triangle.
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PSR B1919+21 is a pulsar with a period of 1.3373 seconds and a pulse width of 0.04 seconds. Discovered by Jocelyn Bell Burnell on 28 November 1967, it is the first discovered radio pulsar. The power and regularity of the signals were briefly thought to resemble an extraterrestrial beacon, leading the source to be nicknamed LGM, later LGM-1.
An astronomical radio source is an object in outer space that emits strong radio waves. Radio emission comes from a wide variety of sources. Such objects are among the most extreme and energetic physical processes in the universe.
A pulsar is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Earth, and is responsible for the pulsed appearance of emission. Neutron stars are very dense and have short, regular rotational periods. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays.
The Crab Pulsar is a relatively young neutron star. The star is the central star in the Crab Nebula, a remnant of the supernova SN 1054, which was widely observed on Earth in the year 1054. Discovered in 1968, the pulsar was the first to be connected with a supernova remnant.
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Rotating radio transients (RRATs) are sources of short, moderately bright, radio pulses, which were first discovered in 2006. RRATs are thought to be pulsars, i.e. rotating magnetised neutron stars which emit more sporadically and/or with higher pulse-to-pulse variability than the bulk of the known pulsars. The working definition of what a RRAT is, is a pulsar which is more easily discoverable in a search for bright single pulses, as opposed to in Fourier domain searches so that 'RRAT' is little more than a label and does not represent a distinct class of objects from pulsars. As of March 2015 over 100 have been reported.
PSR B1937+21 is a pulsar located in the constellation Vulpecula a few degrees in the sky away from the first discovered pulsar, PSR B1919+21. The name PSR B1937+21 is derived from the word "pulsar" and the declination and right ascension at which it is located, with the "B" indicating that the coordinates are for the 1950.0 epoch. PSR B1937+21 was discovered in 1982 by Don Backer, Shri Kulkarni, Carl Heiles, Michael Davis, and Miller Goss.
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In radio astronomy, a fast radio burst (FRB) is a transient radio pulse of length ranging from a fraction of a millisecond, for an ultra-fast radio burst, to 3 seconds, caused by some high-energy astrophysical process not yet understood. Astronomers estimate the average FRB releases as much energy in a millisecond as the Sun puts out in three days. While extremely energetic at their source, the strength of the signal reaching Earth has been described as 1,000 times less than from a mobile phone on the Moon.
Matthew Bailes is an astrophysicist and Professor at the Centre for Astrophysics and Supercomputing, Swinburne University of Technology and the Director of OzGrav, the ARC Centre of Excellence for Gravitational Wave Discovery. In 2015 he won an ARC Laureate Fellowship to work on Fast Radio Bursts. He is one of the most active researchers in pulsars and Fast Radio Bursts in the world. His research interests includes the birth, evolution of binary and millisecond pulsars, gravitational waves detection using an array of millisecond pulsars and radio astronomy data processing system design for Fast Radio Burst discovery. He is now leading his team to re-engineer the Molonglo Observatory Synthesis Telescope with a newly designed correlation system for observation of pulsars and Fast Radio Bursts (FRBs).
IGR J11014−6103, also called the Lighthouse Nebula, is a pulsar wind nebula trailing the neutron star which has the longest relativistic jet observed in the Milky Way galaxy.
Duncan Ross Lorimer is a British-born American astrophysicist. He is a professor of physics and astronomy at West Virginia University, known for the discovery of the first fast radio burst in 2007.
PSR J0901–4046 is an ultra-long period pulsar. Its period, 75.9 seconds, is the longest for any known neutron star pulsar. Its period is more than three times longer than that of PSR J0250+5854, the previous long period record-holder. The pulses are narrow; radio emission is seen from PSR J0901–4046 for only 0.5% of its rotation period.
ASKAP J1935+2148 is a neutron star/magnetar candidate located in the constellation Vulpecula, approximately 15,800 light-years away. With a rotation period of 53.8 minutes, it would be the slowest spinning neutron star ever discovered.