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Tuesday, October 30, 2012

Full color map of the Milky Way bulge

As you know, our galaxy is called the Milky Way. Although we know far more about it than about other galaxies, it has been difficult to catalogue all the stars contained within it, particularly those located in the galactic center. The stars in this region are packed tightly together into a distended bulge that is obscured by dust. Luckily, infrared telescopes can see through that dust. Enter the VISTA telescope and a team of cosmologists led by Roberto Saito of Pontificia Universidad Catolica de Chile, Universidad de Valparaiso and The Milky Way Millennium Nucleus, Chile.

Between 2010 and 2011, the VISTA telescope was used to observe the Milky Way bulge in five different passbands (ranges of wavelengths). This data was compiled to make up the Variables in the Via Lactea (VVV), a public survey of the Milky Way. Saito and his colleagues used the VVV to create the following stunning panorama:


Caption: This striking view of the central parts of the Milky Way was obtained with the VISTA survey telescope at ESO’s Paranal Observatory in Chile. This huge picture is 108,500 by 81,500 pixels and contains nearly nine billion pixels. It was created by combining thousands of individual images from VISTA, taken through three different infrared filters, into a single monumental mosaic. These data form part of the VVV public survey and have been used to study a much larger number of individual stars in the central parts of the Milky Way than ever before. Because VISTA has a camera sensitive to infrared light it can see through much of the dust blocking the view for optical telescopes, although many more opaque dust filaments still show up well in this picture.
Credit: ESO/VVV Consortium Acknowledgement: Ignacio Toledo.

Okay, so it’s not that stunning, as astronomy pictures go. But keep in mind that this is the first single diagram of the entire Milky Way bulge, and that it contains over 84 million stars. 

Saito, R., Minniti, D., Dias, B., Hempel, M., Rejkuba, M., Alonso-GarcĂ­a, J., Barbuy, B., Catelan, M., Emerson, J., Gonzalez, O., Lucas, P., & Zoccali, M. (2012). Milky Way demographics with the VVV survey Astronomy & Astrophysics, 544 DOI: 10.1051/0004-6361/201219448