Joint Discussion 9, IAU General Assembly 2003


Thursday 17 July and Monday 21 July, 2003

Proceedings -- Programme -- Rationale -- Timeliness -- Sessions -- Speakers


Instead of a classical proceedings, we will publish real papers in a dedicated volume of a refereed journal, as was done previously for the Potsdam meeting on Sunspots and Starspots in Astronomische Nachrichten, Vol. 323, pp 155 - 440. This will benefit our speakers, many of whom are are younger researchers, since all contributions count as refereed publications.

We publish the papers in a dedicated issue of Astronomische Nachrichten (AN) without page charges. Each paper will be refereed and treated as a regularly submitted paper, just that it appears in a dedicated issue. The AN Editorial Board have generously reserved 80-100 journal pages in an issue of Volume 325, to be published early in 2004. We thus have to impose page limits of 4 pages for oral contributions, and 1 page for poster papers. AN provides full electronic access including ADS/CDS cross referencing including an abstract service.

Authors should prepare their papers using the AN LaTeX templates which should be downloaded from here as a gzipped tar file. Alternatively you may request the files by email to

Once papers have been prepared they should be emailed as PDF or gzipped Postscript files to the Editors (see addresses below) for refereeing. We will probably call upon meeting participants to act as referees in some instances, so please be prepared to help us out here!

The deadline for receipt of manuscripts by the Editors is 30 September 2003.

Once your paper has been refereed and the final version accepted, the source files should be uploaded to the journal as detailed in the Instructions for Authors on the AN web page.

We hope that those of you who wish to purchase the relevant volume of the journal have already placed your orders with Axel Schwope at the meeting. If by any chance you missed out in Sydney, please contact Axel to place your order and arrange payment.

In addition, a set of extended abstracts will be published in the official record of the General Assembly, in "Highlights of Astronomy". Information on how this will be done will be posted here as soon as we can find out for ourselves!

Andrew Collier Cameron <>
Axel Schwope <>
Sonja Vrielmann <>


JD9-I:   Thursday July 17  (Harbourside Meeting Room 4)

14:00 - 14:30  Micro-arcsecond astrotomography (Keith Horne)
14:30 - 14:50  Eclipse mapping (Raymundo Baptista)
14:50 - 15:10  Doppler tomography, including modulated tomography (Danny Steeghs)
15:10 - 15:30  Stellar surface imaging, including magnetic imaging (Gaitee Hussain)

15:30 - 16:00  Posters / Coffee Break

16:00 - 16:15  Differential rotation of stars (Pascal Petit)
16:15 - 16:30  Roche tomography of CV secondaries (Chris Watson)
16:30 - 16:45  Doppler tomography of Algols (Mercedes Richards)
16:45 - 17:00  Tomographic studies of exoplanet atmospheres (Andrew Collier Cameron)
17:00 - 17:15  Echo mapping of active galactic nuclei (Brad Peterson)
17:15 - 17:30  Echo mapping of X-ray binaries (Keith Horne)

JD9-II:  Monday July 21  (Promenade Meeting Room 3)

09:00 - 09:15  Accretion  (Paula Szkody)
09:15 - 09:30  Doppler mapping of CVs (Luisa Morales Rueda)
09:30 - 09:45  Tomography of X-ray binaries (Saeqa Vrtilek)
09:45 - 10:00  Mapping the accretion disk of Her X-1 (Denis Leahy)
10:00 - 10:15  Eclipse mapping of Algols (Geraldine Peters)
10:15 - 10:30  Surface images of the short-period contact binary, AE Phe (John Barnes)

10:30 - 11:00  Posters / Coffee Break

11:00 - 11:15  Doppler mapping of magnetic CVs (Axel Schwope)
11:15 - 11:30  Stokes imaging of magnetic CVs (Stephen Potter)
11:30 - 11:45  Selected magnetic CVs (Gaghik Tovmassian)
11:45 - 12:00  Few-projections astrotomography (Michail Agafonov)
12:00 - 12:15  Tomography of stellar non-radial pulsations (Svetlana Berdyugina)
12:15 - 12:30  The atmosphere of V471 Tau (Fred Walter)

Proceedings -- Programme -- Rationale -- Timeliness -- Sessions -- Speakers

Scientific Rationale

Even in the new millenium, many astronomical objects cannot be spatially resolved with any available telescope. Most stars are too small and galaxies are too far away to be imaged directly or in detail in the forseeable future. However, advances in analysing techniques allow us now to create detailed indirect images using tomographic methods. These methods allow us to obtain for the first time micro-arcsecond resolution images of surfaces of accretion discs and stellar objects.

Astrotomography takes advantage of the fact that we can observe an object from different angles. A series of n-dimensional images of a full cycle can be fed into a computer in order to yield a (n+1)-dimensional picture of the object. These pictures can be further analysed and compared to existing theoretical models. Tomography opens a wealth of new information on the object under investigation.

In the case of Cataclysmic Variables, we have verified the presence of accretion discs and streams and of thick disc rims shielding the donor star surface from irradiation by the hot inner disc. We have revealed the existence of tidally induced spiral shock waves in accretion discs. We have measured the magnetic field strength, the angle of the magnetic poles of Polars, disc radii, disc temperatures and surface densities of Dwarf Novae and Nova-likes. We find that the disc must have a sandwich like structure, however, details are still uncertain. But the quiescent state of dwarf novae as well as the high and low states in nova-likes and polars are not fully understood. We expect a comprehensive picture to be developed in the near future to which such a discussion will contribute tremendeously.

Echo mapping, or reverberation mapping, was developed to analyze the structure and velocity field of the microarcsecond-scale emission-line regions in active galactic nuclei or quasars via time delays between continuum and emission-line variations caused by reflection and reprocessing of radiation. It is also beginning to yield information on accretion-disc structure. To date, application of this technique has yielded sizes of the emission-line regions and demonstrated radial ionization stratification, and has led to measurements of the masses of the supermassive black holes that power these sources. The next generation of reverberation mapping experiments, using dedicated facilities, will resolve finer-scale structures, such as temperature-radius profiles, and settle definitively the origin of the emission-line gas and clarify how quasars are fueled.

The analysis of cool stars has revealed not only that their surface are covered with large cool spots but also with changing magnetic field patterns, and that both are affected by surface differential rotation similar to what we see on the Sun. However, only Doppler tomography with a baseline of several years will reveal if these stars undergo solar-type cycles. We expect to hear first results at the proposed Joint discussion.

We propose to discuss these and further new results from research areas in Astrotomography, e.g. Zeeman-Doppler Mapping, Roche Tomography and Doppler tomography of Algols and W UMas, during this joint discussion.

Proceedings -- Programme -- Rationale -- Timeliness -- Sessions -- Speakers


The time of the Sydney General Assembly is an ideal time for a joint discussion on astrotomography for the following reasons: Proceedings -- Programme -- Rationale -- Timeliness -- Sessions -- Speakers

Scientific Sessions

The JD9 programme will occupy four sessions of 1.5 hours each.  These sessions will have review talks by established researchers and young scientists.  In addition, there will be discussions of new observations and techniques as well as the accretion physics that we can extract from our studies.

Thursday July 17 (JD9-I):
The official JD09 session on "Astrotomography" and will be held on July 17 from 2pm to 5:30pm in Harbourside Meeting Room 4 (capacity 200).  There will be a 30-minute  break for coffee and posters between the sessions from 3:30pm  to 4:00pm.

Monday July 21 (JD9-II):
Thanks to the generosity of Paula Szkody, President of Commission 42, we will have access to two additional sessions during the "Commission 42 Working Group on Accretion" workshop on July 21 from 9am to 12:30pm in Promenade Meeting Room 3 (capacity 65).   There will be a 30-minute  break for coffee and posters between the sessions from 10:30am  to 11:00 am.

List of Speakers

Michail Agafonov               (Few-projections astrotomography)
Raymundo Baptista            (Eclipse mapping & Spectral mapping of cataclysmic variables)
John Barnes                          (Surface images of the short-period contact binary, AE Phe)
Svetlana Berdyugina          (Tomography of stellar non-radial pulsations)
Andrew Collier Cameron  (Tomographic studies of exoplanet atmospheres)
Keith Horne                          (Micro-arcsecond Astrotomography)
Gaitee Hussain                     (Zeeman and Doppler mapping of stars)
Denis Leahy                          (Mapping the accretion disk of Her X-1)
Luisa Morales Rueda          (Doppler mapping of nonmagnetic CVs)
Geraldine Peters                  (Eclipse mapping of Algols)
Brad Peterson                       (Echo mapping of Active Galactic Nuclei)
Pascal Petit                           (Differential rotation of stars)
Stephen Potter                     (Stokes imaging of magnetic CVs)
Mercedes Richards              (Doppler tomography of Algols)
Axel Schwope                      (Doppler mapping of magnetic CVs)
Danny Steeghs                     (Spiral waves in accretion discs)
Paula Szkody                        (Accretion)
Saeqa Vrtilek                       (Tomography of X-ray binaries)
Fred Walter                          (The atmosphere of V471 Tau)
Chris Watson                       (Roche tomography of CV secondaries)

List of Poster Presentations

Conny Aerts                               (Surface mapping of B stars)
Michail Agafanov                     (Few projections astrotomography)
Raymundo Baptista                   (Eclipse mapping of IP Peg)
Supriya Chakrabarti                 (Spectral imaging for the spidr mission)
Juan Echevarria                         (Starspots on AE Aqr B)
Paul Groot                                   (Tomography of AM CVn stars)
Gaitee Hussain                            (Zeeman Doppler images of the Sun)
Stephen Marsden                       (Imaging of a G dwarf)
Takeo Minezaki                         (Optical & NIR variabilities of NGC 4151)
Luisa Morales-Rueda               (New instruments on the Liverpool Telescope)
Brad Peterson                             (KRONOS)
Encarni Romero-Colmenero (Stokes imaging of QS Tel)
Christine Thurl                           (Microlensing stellar atmospheres)
Chris Watson                              (ULTRACAM)
Atsunori Yonehara                   (Mapping flares in quasars)

CV=Cataclysmic Variable

Scientific Organizing Committee:
         R. Baptista (Brazil), A. Collier Cameron (UK, co-chair), V. Dhillon (UK), J.-F. Donati (France), E. Harlaftis (Greece), L. Morales Rueda (UK, co-chair), B. Peterson (USA), N. Piskunov (Sweden), M. Richards (USA, Chair), A. Schwope (Germany) & S. Vrielmann (South Africa)

Editors of Proceedings:
         Andrew Collier Cameron (Chief Editor), Axel Schwope, & Sonja Vrielmann

Contact Address:
         Mercedes Richards, Penn State University, Dept. of Astronomy & Astrophysics, 525 Davey Lab, University Park, PA 16802, USA; Tel: (814) 865-0150, Fax: (814) 863-2842, e-mail:

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