Browsing by Author "Greimel, R."

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    A new planetary nebula in the outer reaches of the Galaxy
    (2011) Viironen, K.; Mampaso, A.; Corradi, R. L. M.; Drew, J. E.; Frew, D. J.; Giammanco, C.; Greimel, R.; Liimets, T.; Lindberg, J. E.; Rodriguez, M.; Sabin, L.; Sale, S. E.; Wilson, P. A.; Zijlstra, A.
    Aims. A proper determination of the abundance gradient in the Milky Way requires the observation of objects at large galactiocentric distances. With this aim, we are exploring the planetary nebula population towards the Galactic anticentre. In this article, the discovery and physico-chemical study of a new planetary nebula towards the anticentre direction, IPHASX J052531.19+281945.1 (PNG 178.1-04.0), is presented.
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    First results of an H alpha based search of classical Be stars in the Perseus Arm and beyond
    (OXFORD UNIV PRESS, 2013) Raddi, R.; Drew, J. E.; Fabregat, J.; Steeghs, D.; Wright, N. J.; Sale, S. E.; Farnhill, H. J.; Barlow, M. J.; Greimel, R.; Sabin, L.; Corradi, R. M. L.; Drake, J. J.
    We investigate a region of the Galactic plane, between 120 degrees <= l <= 140 degrees and -1 degrees <= b <= +4 degrees, and uncover a population of moderately reddened (E(B - V) similar to 1) classical Be stars within and beyond the Perseus and Outer Arms. 370 candidate emission-line stars (13 less than or similar to r less than or similar to 16) selected from the Isaac Newton Telescope Photometric H alpha Survey of the Northern Galactic plane have been followed up spectroscopically. A subset of these, 67 stars with properties consistent with those of classical Be stars, have been observed at sufficient spectral resolution (Delta lambda approximate to 2-4 angstrom) at blue wavelengths to narrow down their spectral types. We determine these to a precision estimated to be +/-1 subtype and then we measure reddenings via spectral energy distribution fitting with reference to appropriate model atmospheres. Corrections for contribution to colour excess from circumstellar discs are made using an established scaling to H alpha emission equivalent width. Spectroscopic parallaxes are obtained after luminosity class has been constrained via estimates of distances to neighbouring A/F stars with similar reddenings. Overwhelmingly, the stars in the sample are confirmed as luminous classical Be stars at heliocentric distances ranging from 2 kpc up to similar to 2 kpc. However, the errors are presently too large to enable the cumulative distribution function with respect to distance to distinguish between models placing the stars exclusively in spiral arms, or in a smooth exponentially declining distribution.
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    The Gaia-ESO Survey: Stellar content and elemental abundances in the massive cluster NGC 6705
    (2014) Cantat-Gaudin, T.; Vallenari, A.; Zaggia, S.; Bragaglia, A.; Sordo, R.; Drew, J. E.; Eisloeffel, J.; Farnhill, H. J.; Gonzalez-Solares, E.; Greimel, R.; Irwin, M. J.; Kupcu-Yoldas, A.; Jordi, C.; Blomme, R.; Sampedro, L.; Costado, M. T.; Alfaro, E.; Smiljanic, R.; Magrini, L.; Donati, P.; Friel, E. D.; Jacobson, H.; Abbas, U.; Hatzidimitriou, D.; Spagna, A.; Vecchiato, A.; Balaguer-Nunez, L.; Lardo, C.; Tosi, M.; Pancino, E.; Klutsch, A.; Tautvaisiene, G.; Drazdauskas, A.; Puzeras, E.; Jimenez-Esteban, F.; Maiorca, E.; Geisler, D.; Roman, I. San; Villanova, S.; Gilmore, G.; Randich, S.; Bensby, T.; Flaccomio, E.; Lanzafame, A.; Recio-Blanco, A.; Damiani, F.; Hourihane, A.; Jofre, P.; de Laverny, P.; Masseron, T.; Morbidelli, L.; Prisinzano, L.; Sacco, G. G.; Sbordone, L.; Worley, C. C.
    Context. Chemically inhomogeneous populations are observed in most globular clusters, but not in open clusters. Cluster mass seems to play a key role in the existence of multiple populations.
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    The Necklace: equatorial and polar outflows from the binary central star of the new planetary nebula IPHASX J194359.5+170901
    (2011) Corradi, R. L. M.; Sabin, L.; Miszalski, B.; Rodriguez-Gil, P.; Santander-Garcia, M.; Jones, D.; Drew, J. E.; Mampaso, A.; Barlow, M. J.; Rubio-Diez, M. M.; Casares, J.; Viironen, K.; Frew, D. J.; Giammanco, C.; Greimel, R.; Sale, S. E.
    IPHASX J194359.5+170901 is a new high-excitation planetary nebula with remarkable characteristics. It consists of a knotty ring expanding at a speed of 28 km s-1, and a fast collimated outflow in the form of faint lobes and caps along the direction perpendicular to the ring. The expansion speed of the polar caps is similar to 100 km s-1, and their kinematical age is twice as large as the age of the ring.