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Related papers: Radio-flaring Ultracool Dwarf Population Synthesis

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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

Ultracool dwarfs, the least-massive contributors to the stellar mass function, exhibit striking magnetic properties that are inconsistent with trends for more massive stars. Here, we present the widest-band radio observations to date of an…

Solar and Stellar Astrophysics · Physics 2015-05-28 V. Ravi , G. Hallinan , G. Hobbs , D. J. Champion

The emission of intense radio pulses by flaring magnetars is investigated. Small-scale current gradients can be imprinted into a strongly magnetized outflow by the same processes that source fireball radiation in the closed magnetosphere.…

High Energy Astrophysical Phenomena · Physics 2022-12-14 Christopher Thompson

We used broad-band imaging data for 10 cool-core brightest cluster galaxies (BCGs) and conducted a Bayesian analysis using stellar population synthesis to determine the likely properties of the constituent stellar populations. Determination…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Rupal Mittal , John T. Whelan , Francoise Combes

Ultracool dwarfs encompass a wide variety of compact stellar-like objects with spectra classified as late-M, L, T and Y. Most of them have been discovered using wide-field imaging surveys. The Virtual Observatory has proven to be of great…

We study the radio - far-infrared (FIR) correlation in a sample of faint dwarf irregular galaxies using NVSS data for 1.4 GHz radio flux, Spitzer MIPS 70 um data for FIR flux, and GALEX FUV data to estimate the star formation rates (SFR).…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-04 Sambit Roychowdhury , Jayaram N. Chengalur

Recent studies of the stellar population in the solar neighborhood (<20 pc) suggest that there are undetected white dwarfs (WDs) in multiple systems with main sequence companions. Detecting these hidden stars and obtaining a more complete…

Solar and Stellar Astrophysics · Physics 2017-11-29 Ira Bar , Paul Vreeswijk , Avishay Gal-Yam , Eran O. Ofek , Gijs Nelemans

The study of diffuse radio sources is essential to our knowledge of the physical conditions in clusters of galaxies and of the role that large scale magnetic fields play in the propagation of the relativistic particles in the intracluster…

High Energy Astrophysical Phenomena · Physics 2013-09-30 Nonis , Stavros , Gizani , Nectaria A. B

Observations made using TESS revealed a sample of low mass stars which show a periodic modulation on a period $<0.2$~d. Surprisingly many of these Ultra Fast Rotating (UFR) stars showed no evidence of flare activity which would be expected…

Solar and Stellar Astrophysics · Physics 2022-02-23 Gavin Ramsay , Pasi Hakala , J. Gerry Doyle , Lauren Doyle , Stefano Bagnulo

We present detailed spectral energy distribution (SED) modeling of 14 local ultraluminous infrared galaxies (ULIRGs) with outstanding photometric data from the literature covering the ultraviolet--infrared (FIR) and radio bands ($\sim$50…

Astrophysics of Galaxies · Physics 2024-05-08 Subhrata Dey , Arti Goyal , Katarzyna Małek , Tanio Díaz-Santos

The Gaia data release 2 (DR2) contains $>$6000 objects with parallaxes $(Plx+3\times{e\_Plx})>50$mas placing them within 20pc from the Sun. Since the expected numbers extrapolating the well-known 10pc census are much lower, nearby Gaia…

Solar and Stellar Astrophysics · Physics 2020-05-13 Ralf-Dieter Scholz

The nature of two recently discovered radio emitters with unusually long periods of 18min (GLEAM-X J1627-52) and 21min (GPM J1839-10) is highly debated. Their bright radio emission resembles that of radio magnetars, but their long…

Radio detections of ultracool dwarfs provide insight into their magnetic fields and the dynamos that maintain them, especially at the very bottom of the main sequence, where other activity indicators dramatically weaken. Until recently,…

Solar and Stellar Astrophysics · Physics 2013-04-08 Peter K. G. Williams , Edo Berger , B. Ashley Zauderer

We report new spectroscopic results, obtained with UKIRT/CGS4, of a sample of 14 candidate ultracool dwarfs selected from the DENIS (Deep Near-Infrared Survey of the Southern Sky) database. A further object, selected from the 2MASS Second…

Astrophysics · Physics 2009-11-10 T. R. Kendall , X. Delfosse , E. L. Martin , T. Forveille

Radiation belts are present in all large-scale Solar System planetary magnetospheres: Earth, Jupiter, Saturn, Uranus, and Neptune. These persistent equatorial zones of trapped high energy particles up to tens of MeV can produce bright radio…

Earth and Planetary Astrophysics · Physics 2024-03-15 Melodie M. Kao , Amy J. Mioduszewski , Jackie Villadsen , Evgenya L. Shkolnik

A strong case has been made that radio waves from sources within about half a degree of the Galactic Center undergo extreme diffractive scattering. However, problems arise when standard (``Kolmogorov'') models of electron density…

Astrophysics · Physics 2009-11-11 Peter Goldreich , S. Sridhar

Radio relics are Mpc-sized synchrotron sources located in the peripheral regions of galaxy clusters. Models based on the diffuse shock acceleration (DSA) scenario have been widely accepted to explain the formation of radio relics. However,…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-05 Yihao Zhou , Haiguang Xu , Zhenghao Zhu , Yuanyuan Zhao , Shida Fan , Chenxi Shan , Yongkai Zhu , Lei Hao , Li Ji , Zhongli Zhang , Xianzhong Zheng

Context. Radio halos are megaparsec-scale diffuse radio sources{ mostly} located at the centres of merging galaxy clusters. The common mechanism invoked to explain their origin is the re-acceleration of relativistic particles caused by…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-27 G. Di Gennaro , R. J. van Weeren , R. Cassano , G. Brunetti , M. Brüggen , M. Hoeft , E. Osinga , A. Botteon , V. Cuciti , F. de Gasperin , H. J. A. Röttgering , C. Tasse

We report the results of an infrared Doppler survey designed to detect brown dwarf and giant planetary companions to a magnitude-limited sample of ultracool dwarfs. Using the NIRSPEC spectrograph on the Keck II telescope, we obtained…

Solar and Stellar Astrophysics · Physics 2015-05-19 Cullen H. Blake , David Charbonneau , Russel J. White

It has been proposed that the cool cores of galaxy clusters are stably heated by cosmic rays (CRs). If this is the case, radio mini-halos, which are often found in the central regions of cool core clusters, may be attributed to the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Yutaka Fujita , Yutaka Ohira
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