Abstract
We present new deep near-infrared images of dark clouds in the Perseus molecular complex. These images show beautiful extended emission that we model as scattered ambient starlight and name cloudshine. The brightness and color variation of cloudshine complicates the production of extinction maps, the best tracer of column density in clouds. However, since the profile of reflected light is essentially a function of mass distribution, cloudshine provides a new way to study the structure of dark clouds. Previous work has used optical scattered light to study the density profile of tenuous clouds; extending this technique into the infrared provides a high-resolution view into the interiors of very dense clouds, bypassing the complexities of using thermal dust emission, which is biased by grain temperature, or molecular tracers, which have complicated depletion patterns. As new wide-field infrared cameras are used to study star-forming regions at greater depth, cloudshine will be widely observed and should be seen as a new high-resolution tool, rather than an inconvenience.
Highlights
The mass structure of molecular clouds can be studied in a variety of ways, but none are without problems
Dust emission at submillimeter wavelengths depends on the emitting characteristics of grains, which may vary across molecular clouds
In this Letter we report on near-IR observations originally made to construct an extinction map in the outer regions of the Perseus molecular cloud at moderate column densities (AV ! 30 mag) and relatively high Galactic latitude
Summary
The mass structure of molecular clouds can be studied in a variety of ways, but none are without problems. The most direct method for determining the mass structure is extinction mapping, exemplified by NICER (Near-Infrared Color Excess method Revisited; Lombardi & Alves 2001), which uses the reddening of background stars in the near-infrared to infer the dust column density The resolution of this method is proportional to the number of background stars visible through the cloud: this is a function of Galactic position, the quantity of obscuring material, and the depth of the images used. 30 mag) and relatively high Galactic latitude In these deep images (complete to J p 20.1, H p 20, Ks p 19.3), there is pronounced emission structure associated with the clouds The cloudshine presents a new way to study the mass structure of molecular clouds at subarcsecond resolution
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
