The Universe in the Infrared: Spitzer’s Final Voyage

The Universe in the Infrared: Spitzer's Final Voyage

Dr. Luisa Rebull, Research Scientist, Caltech/IPAC

This swirling landscape of stars is known as the North American nebula. In visible light, the region resembles North America, but in this new infrared view from NASA's Spitzer Space Telescope, the continent disappears. Where did the continent go? The reason you don't see it in Spitzer's view has to do, in part, with the fact that infrared light can penetrate dust whereas visible light cannot. Dusty, dark clouds in the visible image become transparent in Spitzer's view. In addition, Spitzer's infrared detectors pick up the glow of dusty cocoons enveloping baby stars. Clusters of young stars (about one million years old) can be found throughout the image. Slightly older but still very young stars (about 3 to 5 million years) are also liberally scattered across the complex, with concentrations near the "head" region of the Pelican nebula, which is located to the right of the North American nebula (upper right portion of this picture). Some areas of this nebula are still very thick with dust and appear dark even in Spitzer's view. For example, the dark "river" in the lower left-center of the image -- in the Gulf of Mexico region -- are likely to be the youngest stars in the complex (less than a million years old). The Spitzer image contains data from both its infrared array camera and multiband imaging photometer. Light with a wavelength of 3.6 microns has been color-coded blue; 4.5-micron light is blue-green; 5.8-micron and 8.0-micron light are green; and 24-micron light is red.

The infrared lies beyond the red end of the visible spectrum of light, and this talk starts with an exploration of infrared light. Cool and dusty things throughout the Universe appear bright in infrared. The Spitzer Space Telescope was one of NASA's Great Observatories, designed to observe the universe in infrared light. It was launched in 2003 with an expected lifetime of 5 years. Spitzer has succeeded beyond our wildest expectations, observing things from dust in our Solar System out to dusty galaxies at the edge of the Universe. On January 30, 2020, Spitzer completed its mission. In this talk, I will summarize some of the interesting engineering that made this mission so successful, and cover several scientific highlights from 16 years of Spitzer operations, with an eye towards what the James Webb Space Telescope will be studying.

Dr. Luisa Rebull, Research Scientist, Caltech/IPAC

Dr. Luisa Rebull is a research astronomer at the NASA/IPAC Infrared Science Archive (IRSA) at Caltech-IPAC. She has always wanted to be an astronomer, ever since she was very little. She got her undergraduate degree in physics from the College of William and Mary in Virginia, and her graduate degrees in astronomy and astrophysics from the University of Chicago. She has been on the science staff at IPAC since 2002. Her research focuses on the formation of young, low-mass stars all over our Galaxy (stars ~1 to 50 million years old) and in understanding how stellar rotation changes over the first billion years of a star's life.