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To investigate the impact of radio jets during the formation epoch of their massive host galaxies, we present an analysis of two massive, log(M_stel/ M_sun)~10.6 and 11.3, compact radio galaxies at z=3.5, TNJ0205+2242 and TNJ0121+1320.…

Astrophysics · Physics 2009-11-13 N. P. H. Nesvadba , M. D. Lehnert , C. De Breuck , A. Gilbert , W. van Breugel

Quasi-periodic X-ray eruptions (QPEs) are a new class of repeating nuclear transient in which repeating X-ray flares are observed coming from the nuclei of generally low mass galaxies. Here we present a comprehensive summary of the radio…

High Energy Astrophysical Phenomena · Physics 2025-09-10 A. J. Goodwin , R. Arcodia , G. Miniutti , J. C. A Miller-Jones , S. van Velzen

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 present radio very long baseline interferometry (VLBI) and X-ray studies of the starburst galaxy NGC 3628. The VLBI observation at 1.5 GHz reveals seven compact (0.7$-$7 parsec) radio sources in the central $\sim$250 parsec region of NGC…

Astrophysics of Galaxies · Physics 2023-07-26 Xiaolong Yang , Ziwei Ou

We characterize the local (2-kpc sized) environments of Type Ia, II, and Ib/c supernovae (SNe) that have recently occurred in nearby ($d\lesssim50$ Mpc) galaxies. Using ultraviolet (UV, from GALEX) and infrared (IR, from WISE) maps of 359…

Using a sample of 2922 z<0.2, spectroscopically-identified Active Galactic Nuclei (AGN) we explore the relationship between radio size and the prevalence of extreme ionised outflows, as traced using broad [O III] emission-line profiles in…

Astrophysics of Galaxies · Physics 2019-11-06 S. J. Molyneux , C. M. Harrison , M. E. Jarvis

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…

We report the discovery of high-energy $\gamma$-ray emission in the vicinity of G213.0-0.6, which is debated as a supernova remnant (SNR) or an ionized hydrogen (H$_{\rm{II}}$) region. Using 16-yr Pass 8 data from Fermi Large Area Telescope…

High Energy Astrophysical Phenomena · Physics 2025-08-22 Yuan Li , Gwenael Giacinti , Siming Liu

We present the detection of compact radio structures of fourteen radio-loud narrow line Seyfert 1 (NLS1) galaxies from Very Long Baseline Array observations at 5 GHz, which were performed in 2013. While 50\% of the sources of our sample…

Astrophysics of Galaxies · Physics 2015-10-14 Minfeng Gu , Yongjun Chen , S. Komossa , Weimin Yuan , Zhi-Qiang Shen , Kiyoaki Wajima , Hongyan Zhou , J. A. Zensus

Less than $200$ radio-loud active galactic nuclei (AGN) are known above redshift $4$. Around $40$ of them have been observed at milliarcsecond (mas) scale resolution with very long baseline interferometry (VLBI) technique. Some of them are…

We have formed a new sample which consists of extended extragalactic radio sources without obvious active galactic nuclei (AGN) in them. Most of these sources appear to be dead double radio sources. These sources with steep spectra ($\alpha…

Astrophysics of Galaxies · Physics 2011-02-11 K. S. Dwarakanath , Ruta Kale

The nature of X-shaped sources is a matter of considerable debate: it has even been proposed that they provide evidence for black hole mergers$ / $spin reorientation, and therefore constrain the rate of strong gravitational wave events…

Cosmology and Nongalactic Astrophysics · Physics 2009-04-20 D. V. Lal , M. J. Hardcastle , R. P. Kraft , C. C. Cheung , A. P. Lobanov , J. A. Zensus , S. Bhatnagar , A. P. Rao

We present the second in a series of results in which we have searched for undiscovered neutron stars in supernova remnants (SNRs). This paper deals with the largest six SNRs in our sample, too large for Chandra or XMM-Newton to cover in a…

Astrophysics · Physics 2009-11-11 D. L. Kaplan , B. M. Gaensler , S. R. Kulkarni , P. O. Slane

We report the detection of high-energy $\gamma$-ray emission in the vicinity of G172.8+1.5, which is debated as a Supernova remnant (SNR) or an ionized hydrogen (H$_{\rm{II}}$) region. Using 16-yr Pass 8 data from Fermi Large Area Telescope…

High Energy Astrophysical Phenomena · Physics 2025-10-03 Yuan Li , Gwenael Giacinti , Siming Liu

We present new radio observations of 9 members of a sample of 29 nearby (z < 0.2) BL Lac objects. The new data have been obtained with the European VLBI Network and/or the MERLIN at 1.6 and 5 GHz and complement previous observations. For…

Astrophysics · Physics 2008-11-26 M. Giroletti , G. Giovannini , G. B. Taylor , R. Falomo

(abridged) We present multiwavelength observations for a large sample of microjansky radio sources detected in ultradeep 1.4GHz maps centered on the Hubble Deep Field-North (HDF-N) and the Hawaii Survey Fields SSA13 and SSA22. Our…

A sample of 123 radio sources that exhibit significant variations at 1.4 GHz on a seven year base-line has been created using FIRST VLA B-array data from 1995 and 2002 on a strip at dec=0 near the south Galactic cap. This sample spans the…

Astrophysics · Physics 2009-11-10 W. H. de Vries , R. H. Becker , R. L. White , D. J. Helfand

Aims. The X-ray luminous and radio-loud AGN SRGE J170245.3+130104 discovered at z $\sim$ 5.5 provides unique chances to probe the SMBH growth and evolution with powerful jets in the early Universe. Methods. We present 1.35 - 5.1 GHz Very…

The supernova remnant (SNR) G315.4$-$2.3 (MSH 14$-$63 or RCW 86) exhibits strong emission across the electromagnetic spectrum. Radio polarization observations probe magnetic fields and will help to understand the evolution of the SNR. We…

Astrophysics of Galaxies · Physics 2026-04-22 X. Chen , X. Sun , J. F. Kaczmarek , B. M. Gaensler , P. Slane , J. L. West

Evidence has been mounting recently that activity in some radio-loud AGNs (RLAGNs) can cease shortly after ignition and that perhaps even a majority of very compact sources may be short-lived phenomena because of a lack of stable fuelling…

Astrophysics · Physics 2009-11-11 Magdalena Kunert-Bajraszewska , Andrzej Marecki , Peter Thomasson