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The short period variable star MG1-688432 has been discovered to exhibit occasional extremely high energy optical outbursts as high as 10^31 joules. Outbursts are typically of several hours duration. These events are often highly…

Solar and Stellar Astrophysics · Physics 2021-08-25 Roy A. Tucker , Eric R. Craine , Brian L. Craine , Andy S. Kulessa , Christopher J. Corbally , Adam L. Kraus

We report the findings of a uGMRT observing campaign on FRB 180916.J0158+65, discovered recently to show a 16.35-day periodicity of its active cycle. We observed the source at 550-750 MHz for $\sim 2$ hours each during three successive…

High Energy Astrophysical Phenomena · Physics 2020-09-29 Visweshwar Ram Marthi , Tasha Gautam , Dongzi Li , Hsiu-Hsien Lin , Robert Main , Arun Kumar Naidu , Ue-Li Pen , Robert Wharton

In this work, archive 1.4 and 4.86 GHz radio continuum data from the VLA were re-reduced and, together with the 1.4 GHz maps from the NVSS, investigated for the presence of a detectable, non-thermal continuum radio emission that could be…

Astrophysics of Galaxies · Physics 2019-12-02 Błażej Nikiel-Wroczyński

Observations with the Australia Telescope Compact Array revealed intra-hour variations in the radio source PKS B1322-110 (Bignall et al. 2019). As part of an optical follow-up, we obtained Gemini Halpha and Halpha continuum (HalphaC) images…

We present a study of the radio environment of the gamma-ray source 3EG J1828+0142. This source presents a very high variability index in its gamma emission and a steep high-energy spectral index $\Gamma\sim-2.8$. Large-scale radio maps at…

Astrophysics · Physics 2007-05-23 Jorge A. Combi , Gustavo E. Romero , Diego F. Torres , Brian Punsly

Owing to their quiet evolutionary histories, nearby dwarf galaxies (stellar masses $M_\star \lesssim 3 \times 10^9 M_\odot$) have the potential to teach us about the mechanism(s) that 'seeded' the growth of supermassive black holes, and…

We report the discovery of variable radio emission associated with the T Tauri star, V830 Tau, which was recently shown to host a hot Jupiter companion. Very Large Array observations at a frequency of 6 GHz reveal a detection on 01 May 2011…

A detailed study of the spectrum and variability of the source HESS J1745-290 in the Galactic Center (GC) region using new data from the H.E.S.S. array of Cherenkov telescopes is presented. Flaring activity and Quasi Periodic Oscillations…

Astrophysics of Galaxies · Physics 2012-08-27 H. E. S. S. collaboration , : , F. Aharonian

Here we report on new, multi-wavelength radio observations of the unusual point source "N3" that appears to be located in the vicinity of the Galactic Center. VLA observations between 2 and 50 GHz reveal that N3 is a compact and bright…

We have found a peculiar radio source in the field of one of the hottest known clusters of galaxies 1E0657-56. It is slightly extended, highly polarised (54% at 8.8GHz) and has a very steep spectrum, with alpha ~ -1 at 1.3 GHz, steepening…

Astrophysics · Physics 2009-11-07 H. Liang , R. D. Ekers , R. W. Hunstead , E. E. Falco , P. Shaver

We report the detection of radio emission from the known X-ray flaring star EXO 040830$-$7134.7 during MeerKAT observations of the nearby cataclysmic variable VW Hydri. We have three epochs of MeerKAT observations, where the star is not…

Solar and Stellar Astrophysics · Physics 2021-12-15 L. N. Driessen , D. R. A. Williams , I. McDonald , B. W. Stappers , D. A. H. Buckley , R. P. Fender , P. A. Woudt

The close active binary HR 5110 was observed at six epochs over 26 days using a global VLBI array at 15.4~GHz. We used phase-referencing to determine the position of the radio centroid at each epoch with an uncertainty significantly smaller…

Solar and Stellar Astrophysics · Physics 2015-09-23 Evan Abbuhl , Robert Mutel , Christene Lynch , Manuel Güedel

Radio and near-infared observations towards the steep spectrum Galactic plane radio source WKB 0314+57.8 are presented, in order to clarify the nature of this source. The radio observations include archival and survey data, together with…

Astrophysics · Physics 2007-05-23 D. A. Green , M. Lacy , S. Bhatnagar , E. L. Gates , P. J. Warner

We report on a deep search for radio pulsations toward five unidentified ASCA X-ray sources coincident with EGRET gamma-ray sources. This search has led to the discovery of a young and energetic pulsar using data obtained with the new…

We report radio observations, made with the Australia Telescope Compact Array, of the X-ray transient XTE J1701-462. This system has been classified as a new `Z' source, displaying characteristic patterns of behaviour probably associated…

Astrophysics · Physics 2009-11-13 R P Fender , M Dahlem , J Homan , S Corbel , R Sault , T M Belloni

The hard X-ray source SAX J0635+0533 shows pulsations at a period of 33.8 ms and is thought to be associated with a bright Be star. We here report on radio observations towards this source with the VLA and Arecibo radiotelescopes. With the…

Astrophysics · Physics 2007-05-23 L. Nicastro , B. M. Gaensler , M. A. McLaughlin

Recently, a number of ultracool dwarfs have been found to produce periodic radio bursts with high brightness temperature and polarization degree; the emission properties are similar to the auroral radio emissions of the magnetized planets…

Solar and Stellar Astrophysics · Physics 2015-06-03 A. A. Kuznetsov , J. G. Doyle , S. Yu , G. Hallinan , A. Antonova , A. Golden

We report the discovery of an eclipsing binary -- PTF1 J072456$+$125301-- composed of a subdwarf B (sdB) star ($g'=17.2^m$) with a faint companion. Subdwarf B stars are core helium-burning stars, which can be found on the extreme horizontal…

Solar and Stellar Astrophysics · Physics 2015-08-19 M. Schindewolf , D. Levitan , U. Heber , H. Drechsel , V. Schaffenroth , T. Kuper , T. Prince

We present radio continuum light curves of the magnetar SGR J1745$-$2900 and Sgr A* obtained with multi-frequency, multi-epoch Very Large Array observations between 2012 and 2014. During this period, a powerful X-ray outburst from SGR…

High Energy Astrophysical Phenomena · Physics 2015-10-07 F. Yusef-Zadeh , R. Diesing , M. Wardle , L. O. Sjouwerman , M. Royster , W. D. Cotton , D. Roberts , C. Heinke

We have analyzed three XMM-Newton observations of the central part of the unidentified TeV \gamma-ray source HESS J1804-216. We focus on two X-ray sources 2XMMi J180442.0-214221 (Src 1) and 2XMMi J180432.5-214009 (Src 2), which were…

High Energy Astrophysical Phenomena · Physics 2019-08-15 Dacheng Lin , Natalie A. Webb , Didier Barret
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