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Related papers: Local Group dSph radio survey with ATCA (II): Non-…

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We present new Very Large Array observations at five frequencies, from 1.4 to 22GHz, of the extremely low-metallicity blue compact dwarf SBS0335-052. The radio spectrum shows considerable absorption at 1.49GHz, and a composite…

Astrophysics · Physics 2009-11-10 Leslie K. Hunt , Kristy K. Dyer , Trinh X. Thuan , James S. Ulvestad

Weakly Interacting Massive Particles (WIMPs) are considered to be one of the favoured dark matter candidates. Searching for any detectable signal due to the annihilation and decay of WIMPs over the entire electromagnetic spectrum has become…

High Energy Astrophysical Phenomena · Physics 2021-01-27 Arghyadeep Basu , Nirupam Roy , Samir Choudhuri , Kanan K. Datta , Debajyoti Sarkar

Dark matter annihilation in dwarf spheroidal (dSph) galaxies near the Milky Way has the potential to produce a detectable signature in gamma-rays. The amplitude of this signal depends on the dark matter density in a dSph, the dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-09 Eric J. Baxter , Jason Kumar , Andrew B. Pace , Jack Runburg

The presence of large-scale magnetic fields and ultra-relativistic electrons in the intra-cluster medium (ICM) is confirmed through the detection of diffuse radio synchrotron sources, so-called radio halos and relics. Due to their…

The BeppoSAX satellite performed a survey of the Galactic Center Region in the 1-10 keV energy band with its Narrow Field Instruments. Several bright X-ray sources containing neutron stars and black holes have been observed and studied,…

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

Dwarf satellite galaxies are a key probe of dark matter and of galaxy formation on small scales and of the dark matter halo masses of their central galaxies. They have very low surface brightness, which makes it difficult to identify and…

Astrophysics of Galaxies · Physics 2014-06-11 Allison Merritt , Pieter van Dokkum , Roberto Abraham

We present a search for FRI radio galaxies between 1 < z < 2 in the COSMOS field. In absence of spectroscopic redshift measurements, the selection method is based on multiple steps which make use of both radio and optical constraints. The…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-12 Marco Chiaberge , Grant Tremblay , Alessandro Capetti , F. Duccio Macchetto , Paolo Tozzi , William B. Sparks

Recent advances in cosmic-ray detectors have provided exceptional sensitivities of dark matter with high angular resolution. Motivated by this, we present a comprehensive study of cosmic-ray flux from dark matter decay in dwarf spheroidal…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-24 Wen Yin , Kohei Hayashi

Coherent low-frequency ($\lesssim 200$ MHz) radio emission from stars encodes the conditions of the outer corona, mass-ejection events, and space weather. Previous low-frequency searches for radio emitting stellar systems have lacked the…

We construct axisymmetric mass models for dwarf spheroidal (dSph) galaxies in the Milky Way to obtain plausible limits on the non-spherical structure of their dark halos. This is motivated by the fact that the observed luminous parts of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Kohei Hayashi , Masashi Chiba

This paper presents an alternative scenario to explain the observed properties of the Milky Way dwarf Spheroidals (MW dSphs). We show that instead of resulting from large amounts of dark matter (DM), the large velocity dispersions observed…

Astrophysics of Galaxies · Physics 2019-10-09 Francois Hammer , Yanbin Yang , Jianling Wang , Frederic Arenou , Mathieu Puech , Hector Flores

A weakly interacting dark matter candidate is difficult to detect at high-energy colliders like the LHC, if its mass is close to, or higher than a TeV. On the other hand, pair-annihilation of such particles may give rise to $e^+ e^-$ pairs…

High Energy Physics - Phenomenology · Physics 2020-02-05 Arpan Kar , Sourav Mitra , Biswarup Mukhopadhyaya , Tirthankar Roy Choudhury

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

The detection of gamma-rays from dark matter (DM) annihilation is among the scientific goals of the Fermi Large Area Telescope (formerly known as GLAST) and Cherenkov telescopes. In this paper we investigate the existence of realistic…

Astrophysics · Physics 2009-11-13 L. Pieri , A. Pizzella , E. M. Corsini , E. Dalla Bonta' , F. Bertola

We present Halpha narrow-band imaging of 17 dwarf irregular galaxies (dIs) in the nearby Centaurus A Group. Although all large galaxies of the group have a current or recent enhanced star formation episode, the dIs have normal star…

Astrophysics of Galaxies · Physics 2010-11-02 Stephanie Cote , Adam Draginda , Evan D. Skillman , Bryan W. Miller

With the improvements in radio interferometry sensitivity, the quest for coherent radio emission from exoplanets and ultra-cool dwarfs, which is indicative of their magnetic fields, has gained significant momentum in recent years. We…

An X-ray study was made to examine whether some part of the soft X-ray background is coming from hot gas in the Local Group. For this purpose, four consecutive pointings were made with ASCA toward a sky region between M 31 and M 33, which…

We present a detailed study of radio-detected dwarf galaxies (with stellar masses less than 3 billion solar masses) to characterize extreme star formation and search for (variable) radio AGNs. Our sample comes from Reines et al. (2020)…

Astrophysics of Galaxies · Physics 2026-05-01 John-Michael Eberhard , Amy E. Reines

We report the detection of diffuse radio emission which might be connected to a large-scale filament of the cosmic web covering a 8deg x 8deg area in the sky, likely associated with a z~0.1 over-density traced by nine massive galaxy…

Brown dwarf disks are excellent laboratories to test our understanding of disk physics in an extreme parameter regime. In this paper we investigate a sample of 29 well-characterized brown dwarfs and very low mass stars, for which Herschel…

Solar and Stellar Astrophysics · Physics 2016-10-19 Sebastian Daemgen , Antonella Natta , Alexander Scholz , Leonardo Testi , Ray Jayawardhana , Jane Greaves , Daniel Eastwood