DESHIMA: On-chip Spectrometer for Probing the Cosmic History of Star Formation

Advanced instruments have turned cosmology into an experimental science. The emergence of sensitive submillimeter wave sensors has lead to the discovery of an unexpectedly large amount of hidden star formation in the early universe. This could force the current understanding of cosmology to be revised.

Submillimeter Galaxies:Dusty, Massive Star Forming Galaxies in the Early Universe

Is there more that we have been overlooking? We can answer this only by further observations with submillimeter wave cameras that have higher sensitivity and more pixels. One of the goals of such instruments is to discover many of these hidden submillimeter wave galaxies, so-called SMGs.

However, ordinary submillimeter wave cameras produce only a 2D projection of the sky (as in the spectacular image above), in the same way the night sky appears to a human’s eye. The lost 3rd dimension is the direction along the line of sight, i.e., time. The farther away a galaxy is, the longer time ago that it existed, because it takes time for light to travel. In order to determine the time at which the galaxy was shining, by forming new stars and/or feeding its central super massive black hole, we need a spectrometer to measure the redshift.

DESHIMA

At our Lab, we are developing a novel submillimeter wave imaging spectrograph DESHIMA. We contribute also to the development of large-format submillimeter wave cameras with >10,000 pixels. Both the developments are being done in close collaboration with SRON and Leiden Observatory. The goal is to discover tens of thousands of SMGs over the sky with the camera, measure their distance with DESHIMA, and thereby construct a large, unbiased 3D map of SMGs. This map will give us important insight about the formation and evolution of stars and galaxies. Not only that, we might be able to see giant strings and webs made of SMGs, which trace the cosmic distribution of dark matter.

Made in Delft, together with SRON, Leiden Observatory and the University of Tokyo

DESHIMA will be the first full submillimeter wave astronomical instrument that will be developed and tested at TU Delft, in close collaboration with SRON and Leiden Observatory. The development of DESHIMA relies heavily on the enthusiasm of students and postdocs. If you are a student who would like to join our team, please contact us anytime.

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Acknowledgments

The DESHIMA project is financed by the Netherlands Organization for Scientific Research (NWO)and the Japan Society for the Promotion of Science (JSPS).