A velocity resolved map of the iconic Horsehead Nebula in the [C II] 158 μm line was obtained by the upGREAT Low Frequency Array (LFA). The [CII] line is one of the strongest cooling lines in the interstellar medium, and here it traces the photodissociation region illuminated by the O9.5V star Sigma Orionis. The integrated intensity image is shown in the figure to the right. The 12’x17’ map, encompassing the nebula and the underlying cloud ridge, was obtained in just over 4 hours of observation on a single flight. The angular resolution of the map is 15.1” and the velocity resolution is 0.19 km/s (R > 106). These remarkably efficient observations were made possible by an increase in the sensitivity of the upGREAT detectors with the use of fourteen independent detectors of the LFA, and the increased mapping speed facilitated by SOFIA’s inertially stable platform.
Additional Information
Horsehead Nebula: Velocity Resolved [C II] Map
United States
