Name: Mike Barlow

Institution: University College London

e-mail: mjb(no-spam)star.ucl.ac.uk

Partner Contry: UK

Science Meeting: Yes

User Meeting: Yes

NGO Staff Meeting: No

Presentation: Yes

Format: Poster

Title: bHROS high spectral resolution observations of PN forbidden and recombination line profiles

Co-author: M. J. Barlow (1), A. S. Hales (1,2), P. J. Storey (1), X.-W. Liu(3), Y. G. Tsamis (1), M. E. Aderin (1)

Co-authors' Institutions: 1: Dept. of Physics & Astronomy, University College London, UK 2: NRAO, Charlottesville, Virginia, USA 3: Dept. of Astronomy, Peking University, Beijing, China

Abstract:

We have acquired high spectral resolution observations (R=150,000) of the planetary nebulae NGC 7009 and NGC 6153, using bHROS on Gemini South. For NGC 7009, they reveal that the [OIII] 4363A forbidden line has a FWHM linewidth that is 1.5 times larger than that shown by OII recombination lines in the same spectrum, despite the fact that these lines are all emitted by the O2 ion. The bHROS spectra of NGC 6153 also show that its OII lines have significantly narrower linewidths than do the [OIII] 4363A and 5007A lines but, in addition, these two [OIII] lines show very different velocity profiles, implying the presence of large temperature variations in the nebula.

Comments:

I would like to submit a second poster abstract, on TReCS 10 and 20um high spatial resolution imaging and long-slit spectroscopy of post-AGB objects and young planetary nebulae, revealing grain composition changes on small scales. Please advise me how to submit the details.

Second Poster

Title: High spatial resolution mid-IR imaging and long-slit spectroscopy of dual-dust chemistry post-AGB objects and planetary nebulae

Co-authors: M. J. Barlow (1), J. E. Bowey (1), S. Lorenz-Martins (2), T. M. Gledhill (3), K. Volk (4), K. Cunha (5,6)

Co-authors' Institutions: 1: University College London, UK 2: Observatorio do Valongo, Universidade Federal do Rio de Janeiro, Brazil 3: University of Hertfordshire, U.K. 4: Gemini Observatory, Hawaii, USA 5: National Optical Astronomy Observatory, Tucson, USA 6: Observatorio Nacional, Rio de Janeiro, Brazil

Abstract:

We have obtained TReCS 10- and 20-um band images and long-slit spectra of a number of compact post-AGB objects and young planetary nebulae, several of which exhibit dual-dust chemistries as indicated by the simultaneous presence in their spectra of emission band due to silicates (O-rich chemistry) and to UIBs (the Unidentified Infrared Bands; attributed to PAHs and indicative of C-rich chemistry). The TReCS images and spectra have subarcsecond resolution and show a clear spatial separation between the locations of the different emission components. For one of our targets, the young [WC10] planetary nebula CPD-56 8032, HST STIS spectra had already shown the central star's near-ultraviolet continuum light to be split into two bright peaks separated 0.10 arcsec (De Marco et al. 2002, ApJ, 574, L83), the gap being attributed to an obscuring dust disk or torus. Our TReCS 10-um long-slit spectra of this object show strong UIB emission in the outer parts of its compact nebulosity, but these disappear at the centre of the nebula, being replaced by a continuum spectrum with an apparent silicate absorption feature. We will present these data and those for several other objects in our sample.