Early Science with SOFIA, the Stratospheric Observatory for Infrared Astronomy (1205.0791v1)

Abstract: The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an airborne observatory consisting of a specially modified Boeing 747SP with a 2.7-m telescope, flying at altitudes as high as 13.7 km (45,000 ft). Designed to observe at wavelengths from 0.3 micron to 1.6 mm, SOFIA operates above 99.8 % of the water vapor that obscures much of the infrared and submillimeter. SOFIA has seven science instruments under development, including an occultation photometer, near-, mid-, and far-infrared cameras, infrared spectrometers, and heterodyne receivers. SOFIA, a joint project between NASA and the German Aerospace Center DLR, began initial science flights in 2010 December, and has conducted 30 science flights in the subsequent year. During this early science period three instruments have flown: the mid-infrared camera FORCAST, the heterodyne spectrometer GREAT, and the occultation photometer HIPO. This article provides an overview of the observatory and its early performance.

Early Science with SOFIA, the Stratospheric Observatory for Infrared Astronomy

The paper "Early Science with SOFIA, the Stratospheric Observatory for Infrared Astronomy," authored by Young et al., presents an overview of the initial scientific operations and findings of SOFIA. SOFIA, a collaborative endeavor between NASA and the German Aerospace Center (DLR), is an airborne infrared observatory equipped with a 2.7-meter telescope mounted on a modified Boeing 747SP. Operating at altitudes up to 13.7 km, SOFIA surpasses 99.8% atmospheric water vapor, thus enabling observations across the infrared spectrum, which would otherwise be impaired from terrestrial locations.

Overview of SOFIA's Observational Capabilities

SOFIA's telescope is designed as a bent Cassegrain configuration, with specialized optics allowing infrared observations with diffraction-limited performance at wavelengths beyond 15 µm. Initial measurements affirm its operational competence despite challenges like airborne vibrations affecting its pointing stability. During its early science phase, SOFIA demonstrated nearly diffraction-limited observations at wavelengths over 38 µm, revealing insights into its adaptability to dynamic atmospheric conditions.

The observatory's initial scientific efforts commenced in December 2010, featuring three pivotal instruments: FORCAST (mid-infrared camera), GREAT (heterodyne submillimeter spectrometer), and HIPO (occultation photometer). These tools facilitated comprehensive data collection during 11 months, resulting in 30 science flights and accumulating over 200 hours of research observations.

Instrumentation and Data Processing

SOFIA is equipped with seven instruments spanning 0.3–250 µm, including imagers and spectrometers, offering robust observational capabilities. These instruments are categorized as Facility, Principal Investigator, and Special Purpose classes, each supported by respective development teams. The paper describes the performance and integration of early instruments like FORCAST and GREAT, detailing their contributions to the initial scientific endeavors.

Data from SOFIA's operations are stored in the SOFIA Data Archive, with accessibility governed by proprietary periods, ensuring controlled dissemination of observational results. Both raw and processed data are made available, allowing researchers to perform subsequent analyses and contribute to the growing repository of infrared astronomical insights.

Scientific Implications and Future Prospects

SOFIA's extensive observational scope provides a unique platform for infrared astronomy, enhancing our understanding of astrophysical phenomena. The paper underscores SOFIA's potential to foster instrument development and educational outreach over its projected 20-year lifespan. Future deployments to various global locations, including the Southern Hemisphere, promise broader access to celestial targets, amplifying its scientific contributions.

The document concludes with anticipations for SOFIA's continuing evolution, projecting that its comprehensive dataset will stimulate significant scientific advancements. As instrumentation capabilities refine, and agility in airborne conditions improves, SOFIA is set to be a cornerstone observatory in infrared and submillimeter astronomy, yielding research outputs pivotal to the astronomical community.