J1 – Inter-Division D-G-H-J Commission Galaxy Spectral Energy Distributions
In the present era of ample access to observations covering the whole spectral range – from Gamma and X-ray wavelengths to radio wavelengths – it is possible to have a panchromatic view of the SED of galaxies. The SED provides a concise “summary” of a galaxy’s content. However, underneath this brevity, a wide variety of physical processes are at play that shape a galaxy’s SED.
All the components of a galaxy (gas, stars, dust…), as well as the presence of an active galactic nucleus (AGN), contribute to this emission. Like that of any investigator, the astrophysicist’s dream is to try and determine, as best as possible, the physical characteristics of the emitter(s). To meet this goal, we have to gather data over the widest spectral range possible in order to obtain information on the many physical processes that are taking place. Interpreting these data requires understanding the likely contributors to the SED of an observed galaxy and its supermassive black hole.
The first phase of any such analysis is to model the emission of these contributors over the widest range of physical conditions possible. This is why this new commission is linked to the “Stars and Stellar Physics” division for the stellar contribution, which is usually the main one in galaxies. Moreover, it is related to the “Interstellar Matter and Local Universe” division, because of the gas and dust components. The primary division is “Galaxies and Cosmology”.
We are working on defining specific Working Groups. This needs to be thoroughly discussed by the SED Commission, but Working Groups would be very useful for studying, e.g., the “Statistical Methods Used in Fitting SEDs”, the “Role of Thermally Pulsing Asymptotic Giant Branch (TP-AGB) Stars in Population Synthesis Models“, “Modeling the Contribution of Active Galactic Nuclei to Galaxy SEDs“, “Building Models for the First Stars and Galaxies“. We would also like to launch a”Cross-comparison of population synthesis models and packages” where different groups would independently model test spectra and SEDs and compare results. This medium-range effort is highly desirable and could be coordinated by a specific working group.
The justification for a SED Commission is to provide a link, a connection, a (virtual) meeting room for astronomers around the world interested in galaxy SEDs without putting limits on time or space.
The communities that would be interested in participating and sharing their efforts is vast, because of the impact of galaxy SEDs in astrophysics. An important point to stress is that SEDs are multi-wavelength astrophysical objects. Combining data secured by ground-based and space-based telescopes that observed galaxies in the past, that are now in operation or that will be in the future (JWST, SKA, LSST, EUCLID, ATHENA, ELTs, etc.) is the essence of SEDs. We absolutely need to discuss, develop and disseminate tools, models and, of course, new ideas in advance in order to be ready for the challenges that will be brought by these instruments and others.
We list a few of them that is certainly not exhaustive and may be under-representative:
* Multi-wavelength observations of galaxies (at all scales and at all redshifts)
* Building SSPs used in population synthesis
* Modeling the emission of stars, dust, AGN, gas.
* Constraining the formation and evolution of galaxies: which parameters, what methods, what bias/degeneracies?
* SED/SLED fitting
* galaxy templates for photometric redshifts
If you wish to volunteer to help (co-)organising an activity related to the Galaxy SED Commission, please contact the President: Cristina Popescu, the Vice-President: Nick Kylafis and/or the Secretary: Daniel Schaerer or any member of the Organizing Committee.
Division D High Energy Phenomena and Fundamental Physics
Division G Stars and Stellar Physics
Division H Interstellar Matter and Local Universe
Division J Galaxies and Cosmology
Commission Working Groups
Inter-Division D-G-H-J Commission WG Reference Library of Galaxy Spectral Energy Distributions (RELIGAS)
University of Central Lancashire
Jeremiah Horrocks Institute
Phone: +44 1772893551
Organization website: http://www.star.uclan.ac.uk
NCA adherence: United Kingdom
October 18, 2018
Laboratoire d’Astrophysique de Marseille
Technopole de Chateau-Gombert
38, rue Joliot-Curie
13388 Marseille Cedex 13
Phone: +33 4 91 05 69 71
Email 1: denisburgarellalamfr
Email 2: denisburgarellauniv-amufr
Personal website: https://people.lam.fr/burgarella.denis/
Organization website: http://www.lam.fr/
NCA adherence: France
June 14, 2018