Sco X‐1: Hints of Periodic Variability at Radio Frequencies

Autor:	C. F. Bradshaw, B. J. Geldzahler, Ed Fomalont
Rok vydání:	1997
Předmět:	Physics X-shaped radio galaxy Space and Planetary Science Astrophysics::High Energy Astrophysical Phenomena Brightness temperature Astronomy and Astrophysics Rapidity Radio frequency Astrophysics Light curve Signal Image restoration Beam (structure)
Zdroj:	The Astrophysical Journal. 481:489-499
ISSN:	1538-4357 0004-637X
DOI:	10.1086/304029
Popis:	We present the results of the flux density variability observations of Sco X-1 obtained during six VLA observing sessions between 1981 and 1990. The light curves indicate three timescales of flux density variation: slow, intermediate, and rapid. The rapidity of the variations sets a conservative upper limit on size of ~6 mas, assuming a distance of 200 pc, from light travel arguments for the radio-emitting regions. The corresponding brightness temperature of greater than 107 K indicates a nonthermal origin for the radio emission. A detailed analysis of the light curves suggests that the radio emission may exhibit true periodicity on timescales of ~3 hr. We also provide a prescription for accurate signal recovery and image restoration of point and extended sources when an object of varying signal is present in the synthesized beam.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::14e0b7235dcf0edf262136b7cc17e0ad https://doi.org/10.1086/304029 Zobrazit plný text záznamu