In Search of the Baiji: An Adventure in China

Images of the Crab Nebula obtained by detecting the light emitted in different wavelength regions of the electromagnetic spectrum.
Images of the Crab Nebula obtained by detecting the light emitted in different wavelength regions of the electromagnetic spectrum. This object is a cloud of gases that are the remnant of a supernova – a massive star that exploded in 1054 AD. At the center of the nebula is a pulsar – a very small, rapidly spinning, strongly magnetic neutron star left over from the collapse of the supernova progenitor’s core.

All of the images show the same area of sky, except for the gamma-ray image. The resolving power of the gamma-ray telescopes was lower than that of the telescopes used for the other images, so the gamma-ray image is “fuzzy” and covers a larger area of sky. The inset box in the lower right corner of the gamma-ray panel shows the visible light image at the relative size of the other panels. The green cross at the center of the gamma-ray image marks the same position as the centers of the other panels. The Crab Nebula appears smaller in the ultraviolet and X-ray images because these very energetic wavelengths of light are emitted from physically smaller regions close to the pulsar at the center of the nebula. All of the panels show “false color” images, meaning that the colors represent either the intensity range of a single wavelength or wavelength range of light (radio, ultraviolet, X-ray, gamma ray) or the relative brightness of several different wavelengths of light (infrared, visible).

[Credits: radio – Very Large Array, 1992, NRAO/AUI and M. Bietenholz; infrared – Spitzer Space Telescope, 2005, NASA/JPL-Caltech/R. Gehrz, University of Minnesota; visible – Hubble Space Telescope, 1999-2000,  NASA/ESA/J.Hester and A. Loll, Arizona State University; ultraviolet – Ultraviolet Imaging Telescope/ASTRO-1, 1990, NASA/UIT; X-ray – Chandra X-ray Observatory, 2001 and 2004, NASA/CXC/SAO/F. Seward; gamma ray – Major Atmospheric Gamma-ray Imaging Cherenkov Telescopes, 2010-2012, S. Klepser/MAGIC Collaboration. Image mosaic by D. W. Hoard.]




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