Highlights - Volume 499-2 (May IV 2009)

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HIGHLIGHTS: this week in A&A

Volume 499-2 (May IV 2009)


In section 6. Interstellar and circumstellar matter

“Imaging galactic diffuse clouds: CO emission, reddening, and turbulent flow in gas around zeta Ophiuchi”, by H.S. Liszt, J. Pety, and K. Tachihara, A&A 499, p. 503

The manuscript by Liszt et al. offers an important warning to past, current, and future absorption-line studies of diffuse interstellar clouds – that is, singular, pencil-beam lines of sight may not provide accurate descriptions of diffuse cloud structure. The authors provide a careful analysis of CO emission from the diffuse cloud associated with zeta Oph. They demonstrate the strong variation of CO with reddening, the narrow individual line widths of CO that do not reflect the spatially resolved, supersonic motions due to turbulence. 


In section 8. Stellar atmospheres

“The nature of the light variability of the silicon star HR 7224”, by J. Krtička et al., A&A 499, p. 567

This paper explains the light variations of rotating CP stars for one example, based on the uneven surface distribution of chemical elements, by means of detailed stellar-model atmosphere techniques. 


In section 1. Letters to the Editor. Sub-Sect. 4: Extragalactic astronomy

“Discovery of a bright radio transient in M82: a new radio supernova?”, A. Brunthaler, K.M. Menten et al., A&A 499, p. L17

Starburst galaxies are expected to have frequent supernovae, and indeed it has been estimated that the nearby irregular galaxy M82 with an active starburst in its nuclear region should have a supernova every 10 years. In the Letter highlighted in this issue however, Brunthaler et al. announce the detection of a bright radio transient in the nucleus of M82, which decayed on a timescale of about 6 months. This could perhaps be a new radio supernova, but the lack of a counterpart at other wavelengths is disturbing. This underlines the point that M82 is worth watching!


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© Astronomy & Astrophysics 2009