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Related papers: A powerful bursting radio source towards the Galac…

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A new x-ray transient, designated XTE J1739-302, was discovered with the Proportional Counter Array (PCA) on the Rossi X-ray Timing Explorer (RXTE) in data from 12 August 1997. Although it was the brightest source in the Galactic Center…

Using JVLA data obtained from high-resolution observations at 5.5 GHz at multiple epochs in 2014 and 2019, we have detected a population of radio variables and transients in the radio bright zone at the Galactic center. With observations…

High Energy Astrophysical Phenomena · Physics 2021-01-06 Jun-Hui Zhao , Mark R. Morris , W. M. Goss

We report the discovery of a remarkable gamma-ray transient source near the Galactic plane, GRO J1838-04. This source was serendipitously discovered by EGRET in June 1995 with a peak intensity of 4 E(-6) ph/cm/cm/s (for photon energies…

We present the results of a radio transient and polarisation survey towards the Galactic Centre, conducted as part of the Australian Square Kilometre Array Pathfinder Variables and Slow Transients pilot survey. The survey region consisted…

The recent discovery of a milli-second radio pulsar experiencing an accretion outburst similar to those seen in low mass X-ray binaries, has opened up a new opportunity to investigate the evolutionary link between these two different…

High Energy Astrophysical Phenomena · Physics 2015-06-22 N. Degenaar , R. Wijnands , M. T. Reynolds , J. M. Miller , D. Altamirano , J. Kennea , N. Gehrels , D. Haggard , G. Ponti

The radio bright zone (RBZ) at the Galactic center has been observed with the JVLA in the A, B and C array configurations at 5.5 and 9 GHz. With a procedure for high-dynamic range imaging developed on CASA, we constructed deep images a…

High Energy Astrophysical Phenomena · Physics 2020-10-26 Jun-Hui Zhao , Mark R. Morris , W. M. Goss

We report on the identification of the new Galactic Center (GC) transient Swift J174540.7-290015 as a likely low mass X-ray binary (LMXB) located at only 16 arcsec from Sgr A*. This transient was detected on 2016 February 6th during the…

High Energy Astrophysical Phenomena · Physics 2016-06-15 G. Ponti , C. Jin , B. De Marco , N. Rea , A. Rau , F. Haberl , F. Coti Zelati , E. Bozzo , C. Ferrigno , G. C. Bower , P. Demorest

We report the discovery of a highly-polarized, highly-variable, steep-spectrum radio source, ASKAP J173608.2-321635, located $\sim$4\,deg from the Galactic center in the Galactic plane. The source was detected six times between 2020 January…

The past decades have witnessed a lot of progress in gravitational lensing with two main targets: stars and galaxies (with active galactic nuclei). The success is partially attributed to the continuous luminescence of these sources making…

High Energy Astrophysical Phenomena · Physics 2022-11-08 Kai Liao , Marek Biesiada , Zong-Hong Zhu

The high-frequency radio sky is bursting with synchrotron transients from massive stellar explosions and accretion events, but the low-frequency radio sky has so far been quiet beyond the Galactic pulsar population and the long-term…

High Energy Astrophysical Phenomena · Physics 2025-03-12 N. Hurley-Walker , X. Zhang , A. Bahramian , S. J. McSweeney , T. N. O'Doherty , P. J. Hancock , J. S. Morgan , G. E. Anderson , G. H. Heald , T. J. Galvin

We report on the results of a four-year long X-ray monitoring campaign of the central 1.2 square degrees of our Galaxy, performed with Chandra and XMM-Newton between 2005 and 2008. Our study focuses on the properties of transient X-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-04 N. Degenaar , R. Wijnands , E. M. Cackett , J. Homan , J. J. M. in 't Zand , E. Kuulkers , T. J. Maccarone , M. van der Klis

For the first time X-ray bursts have been detected from a sky position consistent with the one of GRS 1741.9-2853, a GRANAT transient source located only ~10' from the Galactic Centre. A total of 3 bursts have been observed by the Wide…

Astrophysics · Physics 2007-05-23 M. Cocchi , A. Bazzano , L. Natalucci , P. Ubertini , J. Heise , J. M. Muller , J. J. M. in 't Zand

I discuss several scenarios to explain properties of the radio transient source GCRT J1745-3009. Namely, a highly magnetized neutron star on the propeller or georotator stage, a transient propeller, and an ejector in a binary system are…

Astrophysics · Physics 2008-12-31 S. B. Popov

The transient X-ray source SAX J1810.8-2609 was discovered on 1998, March 10 with the Wide Field Cameras on board the BeppoSAX satellite, while observing the Galactic Bulge in the 2-28 keV energy range. On March 11, a strong type-I X-ray…

The Galactic center region was observed with the XRISM X-ray observatory during the performance verification phase in 2024 and a point-like X-ray source was detected with the X-ray imager Xtend at a position of (RA, Dec)=(17h46m10.8s,…

The origin of the high-frequency radio emission detected from several magnetars is poorly understood. In this paper, we report the ~40 GHz properties of SGR J1745-29 as measured using Jansky Very Large Array (JVLA) and Robert C. Byrd Green…

We report the results of a survey of the Galactic Center region (|l| < 2deg, |b| < 0.5deg) performed with the BeppoSAX satellite. The flux from the center of our Galaxy corresponds to a luminosity of ~3 10^{35} erg/s in the 2-10 keV range.…

Astrophysics · Physics 2009-10-31 L. Sidoli , S. Mereghetti , G. L. Israel , L. Chiappetti , A. Treves , M. Orlandini

Transient and variable phenomena in astrophysical sources are of particular importance to understand the underlying gamma-ray emission processes. In the very-high energy gamma-ray domain, transient and variable sources are related to…

Instrumentation and Methods for Astrophysics · Physics 2020-02-26 F. Brun , Q. Piel , M. de Naurois , S. Bernhard

Over a decade ago it was established that the remarkable high energy transients, known as soft gamma-ray repeaters (SGRs), are a Galactic population and originate from neutron stars with intense (<~ 10^15 G) magnetic fields ("magnetars").…

Recent discoveries of highly dispersed millisecond radio bursts by Thornton et al. in a survey with the Parkes radio telescope at 1.4 GHz point towards an emerging population of sources at cosmological distances whose origin is currently…

High Energy Astrophysical Phenomena · Physics 2015-06-16 D. R. Lorimer , A. Karastergiou , M. A. McLaughlin , S. Johnston