VLT Image Captures a "Cosmic Hawk" Spanning its Wings.

The European Southern Observatory (ESO) just released its photo of the week. This image, acquired by the Very Large Telescope (VLT) in Chile, shows the RCW 36 nebula, located about 2,300 light-years away in the Vela Constellation. But to observers, it looks like a cosmic hawk spreading its wings: the dark clouds at the center resembling the hawk's head and body, and the filaments extending to the right and left serving as the wings. And in a nice twist, the image itself was acquired by the High Acuity Wide-field K-band Imager-1 (HAWK-1) instrument on the VLT.

This high-performance, near-infrared imager is designed to capture deep, high-resolution images that allow it to penetrate the clouds of dust and gas that obscure dimmer objects, such as newly forming stars. Several new stars are visible beneath the hawk in the image, nestled amid clouds of nebula gas and dust. The intense radiation from these massive young stars illuminates the nebula, causing it to glow blue, red, and white. However, it is the population of faint brown dwarfs that was of interest to the astronomers taking this image.

Brown dwarfs are essentially sub-stellar objects, very large gas giants that were not massive enough to undergo gravitational collapse and fuse hydrogen. The HAWK-1 is ideally suited to this task, combining high sensitivity with adaptive optics that correct for atmospheric interference. This allowed the international team, led by astronomers from the Instituto de Astrofĩsica e Ciências do Espaço (IA) in Lisbon, to identify the many fainter objects in the picture. Their efforts are described in a paper that appeared in *Astronomy & Astrophysics*: "Substellar population of the young massive cluster RCW 36 in Vela."

In addition to providing vital data that will improve our understanding of how brown dwarfs form, the study produced a striking image. Afonso do Brito do Vale, a PhD student at the IA and the lead author on the paper, described it as “massive stars ‘pushing’ away the clouds of gas and dust around them, almost like an animal breaking through its eggshell for the first time." This completes the image, giving the impression that the hawk is protecting these baby stars and brown dwarfs as if they were its eggs. Over time, new stars will "hatch" and join the nest!

Further Reading: ESO, Astronomy & Astrophysics