Astronomers at Lomonosov Moscow State University in cooperation with their French colleagues and with the help of citizen scientists have released «The Reference Catalog of galaxy SEDs» (RCSED), which contains value-added information about 800,000 galaxies. The catalog is accessible on the web and its description has been published in the Astrophysical Journal Supplement (impact factor -- 11.257). Two co-authors of the research paper are undergraduate students at the Faculty of Physics, Lomonosov Moscow State University. While still working on the catalog, the team has published a few research papers based on the data from it, including a study published by the prestigious interdisciplinary journal Science.
What can one learn using RCSED and why is it unique?
RCSED describes properties of 800,000 galaxies derived from the elaborated data analysis. For every galaxy, it presents its stellar composition, brightness at ultraviolet, optical, and near-infrared wavelengths. From RCSED, one can also access galaxy spectra obtained by the Sloan Digital Sky Survey, measurements of spectral lines, and properties determined from them, such as the chemical composition of stars and gas, contained in those galaxies. This makes RCSED the first catalog of its kind, which contains results of detailed homogeneous analysis for such large number of objects. Dr. Igor Chilingarian, an astronomer at Smithsonian Astrophysical Observatory, USA and a Lead Researcher at Sternberg Astronomical Institute, Lomonosov Moscow State University says: "For every galaxy we also provide a small cutout image from three sky surveys, which show how the galaxy looks at different wavelengths. This provides us with the data for further investigations." Dr. Ivan Katkov, a Senior Researcher at Sternberg Astronomical Institute adds: "The analysis of emission line profiles presented in RCSED is substantially more detailed and accurate then the data published in other catalogs".
RCSED is really flexible and very easy to use. By simply entering the object name or its coordinates in the search field, the web site will provide in a single page all the information referring to that object contained in the catalog. One can also use the catalog through Virtual Observatory applications such as TOPCAT. The RCSED web site also provides tutorials including the one, which describes a technique that Igor Chilingarian and Ivan Zolotukhin exploited to discover new compact elliptical galaxies, which were later published in the research paper «Isolated compact elliptical galaxies: Stellar systems that ran away».
Another interesting detail about RCSED is that the team actively used the help of citizen scientists to develop the project web site. And among them there were high-level experts in software development and web design, who have daytime jobs in the largest Russian IT-companies. Dr. Ivan Zolotukhin, a Researcher at Sternberg Astronomical Institute, explains: "Programmers sometimes get burnt out by their routine work, and they would like to do something interesting and pleasant in their spare time, for instance, to help scientists. We are very grateful to them, they have become important members of our team and significantly strengthened our project. It's been always interesting for us to cooperate with IT specialists and we have a lot more projects where they can contribute. So if you use git, program in Python or know HTML/CSS, love stars, have a bit of spare time and are willing to help an international research team - please, contact us using the address published on the web page.
Dr. Ivan Katkov adds: "The RCSED catalog became possible thanks to the application of an interdisciplinary Big Data approach as we had to apply very complex scientific algorithms to a large dataset in a massively parallel way.
