RADIO DETECTION OF A CANDIDATE NEUTRON STAR ASSOCIATED WITH GALACTIC CENTER SUPERNOVA REMNANT SAGITTARIUS A EAST
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 78, Cambridge, MA 02138 (United States)
- Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)
We report the Very Large Array (VLA) detection of the radio counterpart of the X-ray object referred to as the 'Cannonball', which has been proposed to be the remnant neutron star resulting from the creation of the Galactic center supernova remnant, Sagittarius A East. The radio object was detected both in our new VLA image from observations in 2012 at 5.5 GHz and in archival VLA images from observations in 1987 at 4.75 GHz and in the period from 1990 to 2002 at 8.31 GHz. The radio morphology of this object is characterized as a compact, partially resolved point source located at the northern tip of a radio 'tongue' similar to the X-ray structure observed by Chandra. Behind the Cannonball, a radio counterpart to the X-ray plume is observed. This object consists of a broad radio plume with a size of 30''×15'', followed by a linear tail having a length of 30''. The compact head and broad plume sources appear to have relatively flat spectra (∝ν{sup α}) with mean values of α = –0.44 ± 0.08 and –0.10 ± 0.02, respectively, and the linear tail shows a steep spectrum with the mean value of –1.94 ± 0.05. The total radio luminosity integrated from these components is ∼8 × 10{sup 33} erg s{sup –1}, while the emission from the head and tongue amounts for only ∼1.5 × 10{sup 31} erg s{sup –1}. Based on the images obtained from the two epochs' observations at 5 GHz, we infer the proper motion of the object: μ{sub α} = 0.001 ± 0.003 arcsec yr{sup –1} and μ{sub δ} = 0.013 ± 0.003 arcsec yr{sup –1}. With an implied velocity of 500 km s{sup –1}, a plausible model can be constructed in which a runaway neutron star surrounded by a pulsar wind nebula was created in the event that produced Sgr A East. The inferred age of this object, assuming that its origin coincides with the center of Sgr A East, is approximately 9000 yr.
- OSTI ID:
- 22270567
- Journal Information:
- Astrophysical Journal, Vol. 777, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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