[en] We present 37 μm imaging of the S140 complex of infrared sources centered on IRS1 made with the FORCAST camera on SOFIA. These observations are the longest wavelength imaging to resolve clearly the three main sources seen at shorter wavelengths, IRS 1, 2, and 3, and are nearly at the diffraction limit of the 2.5 m telescope. We also obtained a small number of images at 11 and 31 μm that are useful for flux measurement. Our images cover the area of several strong submillimeter sources seen in the area—SMM 1, 2, and 3—that are not coincident with any mid-infrared sources and are not visible in our longer wavelength imaging either. Our new observations confirm previous estimates of the relative dust optical depth and source luminosity for the components in this likely cluster of early B stars. We also investigate the use of super-resolution to go beyond the basic diffraction limit in imaging on SOFIA and find that the van Cittert algorithm, together with the 'multi-resolution' technique, provides excellent results.

[en] The Becklin-Neugebauer/Kleinmann-Low (BN/KL) region of the Orion Nebula is the nearest region of high-mass star formation in our galaxy. As such, it has been the subject of intense investigation at a variety of wavelengths, which have revealed it to be brightest in the infrared to submillimeter wavelength regime. Using the newly commissioned SOFIA airborne telescope and its 5-40 μm camera FORCAST, images of the entire BN/KL complex have been acquired. The 31.5 and 37.1 μm images represent the highest resolution observations (∼<4'') ever obtained of this region at these wavelengths. These observations reveal that the BN object is not the dominant brightness source in the complex at wavelengths ≥ 31.5 μm and that this distinction goes instead to the source IRc4. It was determined from these images and derived dust color temperature maps that IRc4 is also likely to be self-luminous. A new source of emission has also been identified at wavelengths ≥ 31.5 μm that coincides with the northeastern outflow lobe from the protostellar disk associated with radio source I.

[en] We present infrared observations of the ultracompact H II region W3(OH) made by the FORCAST instrument aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA) and by the Spitzer/Infrared Array Camera. We contribute new wavelength data to the spectral energy distribution (SED), which constrains the optical depth, grain size distribution, and temperature gradient of the dusty shell surrounding the H II region. We model the dust component as a spherical shell containing an inner cavity with radius ∼600 AU, irradiated by a central star of type O9 and temperature ∼31, 000 K. The total luminosity of this system is 7.1 × 10⁴ L_☉. An observed excess of 2.2-4.5 μm emission in the SED can be explained by our viewing a cavity opening or clumpiness in the shell structure whereby radiation from the warm interior of the shell can escape. We claim to detect the nearby water maser source W3 (H₂O) at 31.4 and 37.1 μm using beam deconvolution of the FORCAST images. We constrain the flux densities of this object at 19.7-37.1 μm. Additionally, we present in situ observations of four young stellar and protostellar objects in the SOFIA field, presumably associated with the W3 molecular cloud. Results from the model SED fitting tool of Robitaille et al. suggest that two objects (2MASS J02270352+6152357 and 2MASS J02270824+6152281) are intermediate-luminosity (∼236-432 L_☉) protostars; one object (2MASS J02270887+6152344) is either a high-mass protostar with luminosity 3 × 10³ L_☉ or a less massive young star with a substantial circumstellar disk but depleted envelope; and the other (2MASS J02270743+6152281) is an intermediate-luminosity (∼768 L_☉) protostar nearing the end of its envelope accretion phase or a young star surrounded by a circumstellar disk with no appreciable circumstellar envelope.

[en] We present new mid-infrared images of the central region of the Orion Nebula using the newly commissioned Stratospheric Observatory For Infrared Astronomy airborne telescope and its 5-40 μm camera FORCAST. The 37.1 μm images represent the highest resolution observations (∼<4'') ever obtained of this region at these wavelengths. After BN/KL (which is described in a separate paper in this issue), the dominant source at all wavelengths except 37.1 μm is the Ney-Allen Nebula, a crescent-shaped extended source associated with θ¹ D Ori. The morphology of the Ney-Allen nebula in our images is consistent with the interpretation that it is ambient dust swept up by the stellar wind from θ¹ D Ori, as suggested by Smith et al. in 2005. Our observations also reveal emission from two 'proplyds' (proto-planetary disks), and a few embedded young stellar objects (YSOs; IRc 9, and OMC1-S IRS1, 2, and 10). The spectral energy distribution for IRc 9 is presented and fitted with standard YSO models from Robitaille et al. in 2007 to constrain the total luminosity, disk size, and envelope size. The diffuse, nebular emission we observe at all FORCAST wavelengths is most likely from the background photodissociation region (PDR) and shows structure that coincides roughly with Hα and [N II] emission. We conclude that the spatial variations in the diffuse emission are likely due to undulations in the surface of the background PDR.

[en] We examine eight young stellar objects in the OMC-2 star-forming region based on observations from the SOFIA/FORCAST early science phase, the Spitzer Space Telescope, the Herschel Space Observatory, Two Micron All Sky Survey, Atacama Pathfinder Experiment, and other results in the literature. We show the spectral energy distributions (SED) of these objects from near-infrared to millimeter wavelengths, and compare the SEDs with those of sheet collapse models of protostars and circumstellar disks. Four of the objects can be modeled as protostars with infalling envelopes, two as young stars surrounded by disks, and the remaining two objects have double-peaked SEDs. We model the double-peaked sources as binaries containing a young star with a disk and a protostar. The six most luminous sources are found in a dense group within a 0.15 × 0.25 pc region; these sources have luminosities ranging from 300 L_☉ to 20 L_☉. The most embedded source (OMC-2 FIR 4) can be fit by a class 0 protostar model having a luminosity of ∼50 L_☉ and mass infall rate of ∼10^–4 M_☉ yr^–1.

[en] The Galactic Center contains some of the most extreme conditions for star formation in our Galaxy, as well as many other phenomena that are unique to this region. Given our relative proximity to the Galactic Center, we are able to study details of physical processes to a level that is simply not yet possible for more distant galaxies, yielding an otherwise inaccessible view of the nuclear region of a galaxy. We recently carried out a targeted imaging survey of mid-infrared bright portions of the Galactic Center at 25 and 37 μm using the FORCAST instrument on the Stratospheric Observatory for Infrared Astronomy (SOFIA). This survey was one of the inaugural Legacy Programs from SOFIA cycle 7, observing a total area of 403 arcmin² (2180 pc²), including the Sgr A, B, and C complexes. Here we present an overview of the survey strategy, observations, and data reduction as an accompaniment to the initial public release of the survey data. We discuss interesting regions and features within the data, including extended features near the circumnuclear disk, structures in the Arched Filaments and Sickle H ii regions, and signs of embedded star formation in Sgr B2 and Sgr C. We also feature a handful of less well studied mid-infrared sources located between Sgr A and Sgr C that could be sites of relatively isolated star formation activity. Last, we discuss plans for subsequent publications and future data releases from the survey.