DIY Friday: Find a New Galaxy
You don’t necessarily have to go to Kitt Peak (pictured above) to spot galaxies these days, though it helps; according to Science Daily, we’ve entered a new era in galaxy hunting:
Astronomers using ESO’s Very Large Telescope have discovered in a single pass about a dozen otherwise invisible galaxies halfway across the Universe. The discovery, based on a technique that exploits a first-class instrument, represents a major breakthrough in the field of galaxy ‘hunting’.
The team of astronomers led by Nicolas Bouché have used quasars to find these galaxies. Quasars are very distant objects of extreme brilliance, which are used as cosmic beacons that reveal galaxies lying between the quasar and us. The galaxy’s presence is revealed by a ‘dip’ in the spectrum of the quasar – caused by the absorption of light at a specific wavelength.
The team used huge catalogues of quasars, the so-called SDSS and 2QZ catalogues, to select quasars with dips. The next step was then to observe the patches of the sky around these quasars in search for the foreground galaxies from the time the Universe was about 6 billion years old, almost half of its current age….
This is where observations taken with SINFONI on ESO’s VLT made the difference. SINFONI is an infrared ‘integral field spectrometer’ that simultaneously delivers very sharp images and highly resolved colour information (spectra) of an object on the sky.
With this special technique, which untangles the light of the galaxy from the quasar light, the team detected 14 galaxies out of the 20 pre-selected quasar patches of sky, a hefty 70% success rate.
Ok, so you don’t have access to a Very Large Telescope? Here’s a great introduction on how to observe galaxies, including a table summary of galaxies for the amateur astronomer. Also be sure to check out this great interactive sky map to peruse the night sky from your desktop, and take a moment to watch this video on how to observe galaxies from Astronomy magazine.
