VLBI Images of 49 Radio Supernovae in Arp 220

By C. Lonsdale, P. Diamond, H. Thrall, H. Smith, Carol J. Lonsdale. 2006

136 citations recorded by the source corpus.

We have used a very long baseline interferometry (VLBI) array at 18 cm wavelength to image the nucleus of the luminous IR galaxy Arp 220 at ~1 pc linear resolution, with very high sensitivity. The resulting map has an rms of 5.5 μJy beam-1, and careful image analysis results in 49 confirmed point sources ranging in flux density from 1.2 mJy down to ~60 μJy. Comparison with high-sensitivity data from 12 months earlier reveals at least four new sources. The favored interpretation of these sources is that they are radio supernovae, and if all new supernovae are detectable at this sensitivity, a resulting estimate of the supernova rate in the Arp 220 system is 4 ± 2 per year. The implied star formation rate is sufficient to power the entire observed far-infrared luminosity of the galaxy. The two nuclei of Arp 220 exhibit striking similarities in their radio properties, although the western nucleus is more compact, and appears to be ~3 times more luminous than the eastern nucleus. There are also some puzzling differences, and differential free-free absorption, synchrotron aging, and expansion losses may all be playing a role. Comparison with the nearby starburst galaxy M82 supports the hypothesis that the activity in Arp 220 is essentially a scaled-up version of that in M82.

Subfields: Astronomy and Astrophysics, Instrumentation, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/47a1785dbad2c417f85180cccb9deed4a0573fa5

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Citations in the corpus

The Nine Lives of Cosmic Rays in Galaxies (2015, background): “…to identify individual supernovae and young supernova remnants in highly obscured regions of starburst galaxies like Arp 220 (Batejat et al. 2011, Lonsdale et al. 2006, Parra et al. 2007) and M 82 (Fenech et al. 2008, Gendre et al. 2013), and to infer a SN event rate as high as 4±2 yr−1 in the…”
The stellar and sub-stellar IMF of simple and composite populations (2011, background): “The central region of Arp 220 has a star-formation rate of 100M⊙/yr and the large number of observed type II supernovae requires a top-heavy IMF (Lonsdale et al. 2006; Parra et al. 2007, see also Sec.”
OBSERVATIONS OF Arp 220 USING HERSCHEL-SPIRE: AN UNPRECEDENTED VIEW OF THE MOLECULAR GAS IN AN EXTREME STAR FORMATION ENVIRONMENT (2011, unknown): “Using the observed supernova rate of νSN = 4 ± 2 per year (Lonsdale et al. 2006) and (ESN = 10 51 erg) in the following expression from Maloney (1999) LSN ∼ 3 × 10 43( νSN 1yr−1 )( ESN 1051 ergs ) erg s−1, (5) we obtain total mechanical energy of ∼ 100L⊙/M⊙ (using MH2 ∼ 3 × 10 8M⊙) from supernovae…”