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Recently detected coherent low-frequency radio emission from M dwarf systems shares phenomenological similarities with emission produced by magnetospheric processes from the gas giant planets of our Solar System. Such beamed…

We report on the discovery of a variable radio source, VLA J070238.0+385044, associated with the proposed x-ray counterpart, 1SAX J0702.6+3850 of GRB 980329. The source was monitored from one day after the burst to one month later at…

Astrophysics · Physics 2009-10-30 G. B. Taylor , D. A. Frail , S. R. Kulkarni , D. S. Shepherd , M. Feroci , F. Frontera

We report the time variability of the late-time radio emission in a Type-I superluminous supernova (SLSN), PTF10hgi, at z = 0.0987. The Karl G. Jansky Very Large Array 3 GHz observations at 8.6 and 10 years after the explosion both detected…

We report on the variability of 443 flat spectrum, compact radio sources monitored using the VLA for 3 days in 4 epochs at ~ 4 month intervals at 5 GHz as part of the Micro-Arcsecond Scintillation-Induced Variability (MASIV) survey. Over…

Recent atmospheric models for brown dwarfs suggest that the existence of clouds in substellar objects is not needed to reproduce their spectra, nor their rotationally-induced photometric variability, believed to be due to the heterogeneous…

Solar and Stellar Astrophysics · Physics 2023-04-05 Elena Manjavacas , Paulo A. Miles-Paez , Theodora Karalidi , Johanna M. Vos , Max L. Galloway , Julien H. Girard

The mJy variable extragalactic radio sky is known to be broadly non-changing with approximately $3\%$ of persistent radio sources exhibiting variability which is largely AGN-related. In the faint (<mJy) flux density regime, it is widely…

Over 700 bright millisecond-duration radio transients, known as Fast Radio Bursts (FRBs), have been identified to date. Nevertheless, the origin of FRBs remains unknown. The two repeating FRBs (FRB 20121102A and FRB 20190520B) have been…

J1415+1320 is a well-studied blazar that exhibits strong flux density variability at a wide range of radio frequencies (2.4 $-$ 230~GHz). In this letter, we present a variability study of this source at 327~MHz using the data obtained with…

Astrophysics of Galaxies · Physics 2022-02-28 Sravani Vaddi , P. K. Manoharan , Anish Roshi

We present a multiband study of FRB 20180916B, a repeating source with a 16.3 day periodicity. We report the detection of 4, 1 and 7 bursts from observations spanning 3 days using upgraded Giant Metrewave Radio Telescope (300-500 MHz),…

In this work, we explore the long-term variability properties of the blazar PKS 0219-164 in the radio and the $\gamma$-ray regime, utilizing the OVRO 15 GHz and the \fermi/LAT observations from the period 2008--2017. We found that…

High Energy Astrophysical Phenomena · Physics 2017-09-20 Gopal Bhatta

The Wolf-Rayet star WR 46 is known to exhibit a very complex variability pattern on relatively short time scales of a few hours. Periodic but intermittent radial velocity shifts of optical lines as well as multiple photometric periods have…

Solar and Stellar Astrophysics · Physics 2015-03-19 V. Hénault-Brunet , N. St-Louis , S. V. Marchenko , A. M. T. Pollock , S. Carpano , A. Talavera

We report results of 6.7 GHz methanol maser monitoring of 139 star-forming sites with the Torun 32 m radio telescope from June 2009 to February 2013. The targets were observed at least once a month, with higher cadences of 2-4 measurements…

Astrophysics of Galaxies · Physics 2017-12-20 Marian Szymczak , Mateusz Olech , Rafał Sarniak , Paweł Wolak , Anna Bartkiewicz

We carried out a pilot campaign of radio and optical band intra-day variability (IDV) observations of five blazars (3C66A, S5 0716+714, OJ287, B0925+504, and BL Lacertae) on December 18--21, 2015 by using the radio telescope in Effelsberg…

We aim to study the optical and near-infrared linear polarimetric properties of a sample of young M7-L7 dwarfs ($\approx$1-500 Myr) with spectroscopic signatures of low- and intermediate-gravity atmospheres. We collected optical ($RIZ$) and…

Solar and Stellar Astrophysics · Physics 2016-12-26 P. A. Miles-Páez , M. R. Zapatero Osorio , E. Pallé , K. Peña Ramírez

We present some first results on the variability, polarization and general properties of radio sources selected in a blind survey at 20 GHz, the highest frequency at which a sensitive radio survey has been carried out over a large area of…

(abridged) We perform photometric time-series analysis of a sample of ten early to mid-L dwarfs in the field over three years of $K_s$-band observations with the OMEGA 2000 infrared camera of the 3.5m telescope on Calar Alto Observatory…

Solar and Stellar Astrophysics · Physics 2015-06-22 Belén López Martí , María Rosa Zapatero Osorio

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 probe the feasibility of high-frequency radio observations of very rapid flux variations in compact active galactic nuclei (AGN). Our study assumes observations at 230 GHz with a small 6-meter class observatory, using the SNU Radio…

Astrophysics of Galaxies · Physics 2017-01-18 Jae-Young Kim , Sascha Trippe

We present the results of our study of cross-correlations between long-term multi-band observations of the radio variability of the blazar 3C 279. More than a decade (2008-2022) of radio data were collected at seven different frequencies…

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