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We present the results of simultaneous observations of the transitional millisecond pulsar (tMSP) candidate CXOU J110926.4-650224 with the XMM-Newton satellite and the MeerKAT telescope. The source was found at an average X-ray luminosity…

We have searched for transient and/or variable radio sources in the field of Galactic micro-quasar Cygnus X-1 in 1.4 GHz (L band) using data from the Karl G. Jansky Very Large Array (JVLA). We used twenty years of data between 1983 and…

High Energy Astrophysical Phenomena · Physics 2017-07-14 Sabyasachi Pal , Dusmanta Patra , Monique Hollick , Sandip K. Chakrabarti

We report the discovery of several new pulses from the source ASKAP J175534.9-252749.1 (J1755-2527), originally identified from a single 2-min long pulse, confirming it as a long period transient (LPT) with a period of ~1.16 hours. The…

Surveys have shown that up to one tenth of all ultracool dwarfs (UCDs) are appreciable radio emitters, with their emission attributed to a combination of gyrosynchrotron radiation and the electron cyclotron maser instability (ECMI). 2M…

Solar and Stellar Astrophysics · Physics 2020-07-03 Qicheng Zhang , Gregg Hallinan , Walter Brisken , Stephen Bourke , Aaron Golden

RX J1301.9+2747 is a unique active galaxy with supersoft X-ray spectrum that lacks significant emission at energies above 2 keV. In addition, it is one of few galaxies displaying quasi-periodic X-ray eruptions that recur on a timescale of…

Fast radio bursts (FRBs) are bright milliseconds-duration radio bursts from cosmological distances. Despite intense observational and theoretical studies, their physical origin is still mysterious. One major obstacle is the lack of…

High Energy Astrophysical Phenomena · Physics 2024-11-12 Yi Xing , Wenfei Yu , Zhen Yan , Xian Zhang , Bing Zhang

We present a multiwavelength study of the unidentified Fermi gamma-ray source 0FGL J1830.3+0617, which exhibits variability above 200 MeV on timescales of days to weeks. Within the Fermi 95% confidence error contour lies B1827+0617, a radio…

High Energy Astrophysical Phenomena · Physics 2009-08-12 N. Mirabal , J. P. Halpern

We report the detection of strong, highly circularly polarised, and rotationally modulated radio pulses from the early-mid M dwarf ASKAP J181335-604720, based on strictly simultaneous radio and optical observations with the Australian…

Solar and Stellar Astrophysics · Physics 2026-05-18 Shouzhi Wang , Biwei Jiang , Qichen Huang , Shaoteng Huang , Jundan Nie

We report the serendipitous discovery of an extremely intermittent radio pulsar, PSR J1710-3452, with a relatively long spin period of 10.4 s. The object was discovered through the detection of 97 bright radio pulses in only one out of 66…

We present a long-period radio transient (GLEAM-X J0704-37) discovered to have an optical counterpart, consistent with a cool main sequence star of spectral type M3. The radio pulsations occur at the longest period yet found, 2.9 hours, and…

We report the discovery of a 20-kpc-sized H{\alpha} emission in SDSS J083803.68+540642.0, a ringed dwarf galaxy (M$_V$ = -17.89 mag) hosting an accreting intermediate-mass black hole at z=0.02957. Analysis of the HST images indicates that…

Astrophysics of Galaxies · Physics 2017-03-15 Wen-Juan Liu , Lei Qian , Xiao-Bo Dong , Ning Jiang , Paulina Lira , Zheng Cai , Feige Wang , Jinyi Yang , Ting Xiao , Minjin Kim

Fast radio bursts (FRBs) are highly dispersed millisecond-duration radio bursts. Recent observations of a Galactic FRB suggest that at least some FRBs originate from magnetars, but the origin of cosmological FRBs is still not settled. Here…

We discovered Fe $K_{\alpha}$ complex emission and pulsation in two highly variable sources (4XMM J174917.7--283329, 4XMM J174954.6--294336). The equivalent widths of 6.4 and 6.7 keV lines of 4XMM J174917.7--283329 are $99^{+84}_{-72}$ and…

High Energy Astrophysical Phenomena · Physics 2023-03-15 Samaresh Mondal , Gabriele Ponti , Frank Haberl , Kaya Mori , Nanda Rea , Mark R. Morris , Sergio Campana , Konstantina Anastasopoulou

We report on low resolution (R~3000) spectropolarimetry of the A0 supergiant star HD 92207. This star is well-known for significant spectral variability. The source was observed on seven different nights spanning approximately 3 months in…

Astrophysics · Physics 2009-11-13 R Ignace , S Hubrig , M Scholler

We report on the extreme behaviour of the high redshift blazar GB B1428+4217 at z=4.72. A continued programme of radio measurements has revealed an exceptional flare in the lightcurve, with the 15.2 GHz flux density rising by a factor ~3…

Astrophysics · Physics 2009-09-17 M. A. Worsley , A. C. Fabian , G. G. Pooley , C. J. Chandler

The Km3NET collaboration has recently reported the detection of a neutrino event with energy in excess of 100 PeV. This detection is in 2.5-3$\sigma$ tension with the upper limit on the neutrino flux at this energy imposed by IceCube and…

High Energy Astrophysical Phenomena · Physics 2025-02-19 Andrii Neronov , Foteini Oikonomou , Dmitri Semikoz

Recently, the Galactic magnetar SGR J1935+2154 has garnered attention due to its emission of an extremely luminous radio burst, reminiscent of Fast Radio Bursts (FRBs). SGR J1935+2154 is one of the most active magnetars, displaying flaring…

We report the detection of H{$\alpha$} emission in the T dwarf (methane brown dwarf) 2MASSW J1237392+652615 over three days using the Keck Low Resolution Imaging Spectrograph. The measured line flux, log(L$_{H{\alpha}}$/L$_{bol}$) = $-$4.3,…

M17 JVLA 35 is a radio source detected in projection against the M17 HII region. In recent observations, its spectrum between 4.96 and 8.46 GHz was found to be positive and very steep, with $\alpha \geq 2.9 \pm 0.6$ ($S_\nu \propto…

Astrophysics of Galaxies · Physics 2015-06-22 L. F. Rodriguez , C. Carrasco-Gonzalez , G. Montes , M. Tapia

Two recent discoveries, namely PSR J0901-4046 and GLEAM-X J162759.5-523504.3 (hereafter GLEAM-X J1627), have corroborated an extant population of radio-loud periodic sources with long periods (76 s and 1091 s respectively) whose emission…

High Energy Astrophysical Phenomena · Physics 2023-02-17 P. Beniamini , Z. Wadiasingh , J. Hare , K. Rajwade , G. Younes , A. J. van der Horst
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