Results 81 to 90 of about 101,827 (259)

Populations of Extragalactic Radio Sources [PDF]

Australian Journal of Physics, 1994
In the late 1950s and early 1960s, radio sky surveys were the centre of an intense and public debate-Big-Bang versus Steady-State cosmology-the arguments revolving about source counts and statistical interpretations in the face of instrumental complications.
openaire   +1 more source

Isolated Neutron Stars as Science Validation for XMM2ATHENA: Ensuring Robust Data for Future X‐Ray Astronomy

Astronomische Nachrichten, Volume 346, Issue 3-4, March-May 2025.
ABSTRACT The discovery of radio‐quiet, x‐ray thermally emitting isolated neutron stars (XINSs) in the ROSAT All‐Sky Survey revealed a previously overlooked component of the neutron star population. Advancements in x‐ray instrumentation and the availability of deep, wide‐area optical surveys now enable us to explore XINSs at fainter x‐ray fluxes and ...
Adriana Mancini Pires, Christian Motch, Axel Schwope, Iris Traulsen, Jean Ballet, Sudip Chakraborty, David Homan, Jan Kurpas, Ada Nebot Gomez‐Moràn, François‐Xavier Pineau, Hugo Tranin, Natalie Webb   +11 more
wiley   +1 more source

High-frequency predictions for number counts and spectral properties of extragalactic radio sources. New evidence of a break at mm wavelengths in spectra of bright blazar sources [PDF]

, 2011
We present models to predict high-frequency counts of extragalactic radio sources using physically grounded recipes to describe the complex spectral behaviour of blazars that dominate the mm-wave counts at bright flux densities. We show that simple power-
M. Tucci, L. To, olatti, G. Zotti, E. González   +4 more
semanticscholar   +1 more source

SOURCES WITH LOW-FREQUENCY STEEPNESS SPECTRUM CONCERNING THE UNIFIED MODEL

Odessa Astronomical Publications, 2012
Based on data of the data of the Grakovo catalogue of the extragalactic sources, detected at the decametre band with the UTR-2 radio telescope , it was established, that properties of radio sources with lowfrequency steepness of spectrum are in ...
A. P. Miroshnichenko
doaj   +1 more source

Discovery of the Luminous, Decades-long, Extragalactic Radio Transient FIRST J141918.9+394036 [PDF]

Astrophysical Journal, 2018
We present the discovery of a slowly evolving, extragalactic radio transient, FIRST J141918.9+394036, identified by comparing a catalog of radio sources in nearby galaxies against new observations from the Very Large Array Sky Survey.
C. Law, B. Gaensler, B. Metzger, E. Ofek, L. Berkeley, D. Institute, Toronto, Columbia, Weizmann Institute   +8 more
semanticscholar   +1 more source

Optical positions of compact extragalactic radio sources with respect to the Hipparcos Catalogue [PDF]

, 1998
Optical positions relative to the Hipparcos Catalogue, and therefore within the International Celestial Reference System (ICRS), have been obtained for the optical counterparts of 25 compact extragalactic radio sources (CERS) south of +10 .
Costa Hechenleitner, Edgardo, Loyola, P., E. Costa, Costa, E., P. Loyola   +4 more
core   +1 more source

The Cosmic Evolution of Fast Radio Bursts Inferred from the CHIME/FRB Baseband Catalog 1

The Astrophysical Journal
Redshift and luminosity distributions are essential for understanding the cosmic evolution of extragalactic objects and phenomena, such as galaxies, gamma-ray bursts, and fast radio bursts (FRBs).
Om Gupta, Paz Beniamini, Pawan Kumar, Steven L. Finkelstein   +3 more
doaj   +1 more source

A Formation Mechanism for “Wrong Way” Radio Relics

The Astrophysical Journal Letters, 2023
Radio relics are typically found to be arc-like regions of synchrotron emission in the outskirts of merging galaxy clusters, bowing out from the cluster center.
Ludwig M. Böss, Ulrich P. Steinwandel, Klaus Dolag   +2 more
doaj   +1 more source

Probing extreme black‐hole outflows on short timescales via high spectral‐resolution x‐ray imagers

Astronomische Nachrichten, Volume 345, Issue 6-7, July-August 2024.
Abstract We investigate outflows and the physics of super‐Eddington versus sub‐Eddington regimes in black hole systems. Our focus is on prospective science using next‐generation high‐resolution soft x‐ray instruments. We highlight the properties of black hole ultraluminous x‐ray source (ULX) systems in particular. Owing to scale invariance in accreting
C. Pinto, J. F. Steiner, A. Bodaghee, P. Chakraborty, M. Sobolewska, D. R. Pasham, A. Ogorzalek, J. Zuhone, A. Bogdan, M. Vogelsberger   +9 more
wiley   +1 more source

Radio Afterglows from Tidal Disruption Events: An Unbiased Sample from ASKAP RACS

The Astrophysical Journal
Late-time (∼a year) radio follow-up of optically discovered tidal disruption events (TDEs) is increasingly resulting in detections at radio wavelengths, and there is growing evidence for this late-time radio activity to be common to the broad class of ...
Akash Anumarlapudi, Dougal Dobie, David L. Kaplan, Tara Murphy, Assaf Horesh, Emil Lenc, Laura Driessen, Stefan W. Duchesne, Hannah Dykaar, B. M. Gaensler, Timothy J. Galvin, Joe Grundy, George Heald, Aidan W. Hotan, Minh Huynh, James K. Leung, David McConnell, Vanessa A. Moss, Joshua Pritchard, Wasim Raja, Kovi Rose, Gregory Sivakoff, Yuanming Wang, Ziteng Wang, Mark H. Wieringa, Matthew T. Whiting   +25 more
doaj   +1 more source