Wednesday, June 11, 2014
First-light observations by the GREAT H-channel on SOFIA: map of planetary nebula NGC 7027 in the neutral oxygen emission line at 63 microns. The effective angular resolution is indicated by the gray circle at lower left. © GREAT Consortium
With successful commissioning of its high-frequency channel, the GREAT (German Receiver for Astronomy at Terahertz Frequencies) far-infrared spectrometer onboard SOFIA is ready to explore new realms.
The new so-called H-channel was first tested during SOFIA flights on May 14, 16, and 17, and confirmed to be working perfectly. It is based upon an extremely sensitive superconductive detector and a novel "quantum cascade" terahertz laser. With that receiver added, the GREAT instrument is now capable of high-resolution spectroscopy of astrophysically important lines of atomic neutral oxygen [OI] at a wavelength of 63 μm (frequency of 4.74 TeraHertz).
First-light spectra were obtained towards planetary nebula NGC 7027 (Figure 1). That nebula is an expanding bubble of gas expelled by a dying star with approximately twice the mass of our Sun, 3,000 light-years away in the constellation of Cygnus. The nebula has been extensively studied at other wavelengths, but only GREAT can resolve the velocities of the expanding envelope in the [OI] line. The spectrum (Figure 2) represents only 2 minutes of integration, illustrating the superb sensitivity of the GREAT instrument carried into the stratosphere by SOFIA.
Dr. Dana BackmanSOFIA Outreach / SOFIA Science Center,
Phone:+1 650 604-2128
Email: firstname.lastname@example.org, Moffett Field, CA, USA