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Optical study of NGC 7538

Journal Article · · Astrophys. J.; (United States)
DOI:https://doi.org/10.1086/164362· OSTI ID:6931824
Optical observations of NGC 7538 using CCD frames and interference filters isolating the nebular lines and continuum have been used to derive emission-line fluxes of the optical nebula and to discuss the nature of the infrared sources. The forbidden S II ratio demonstrates that the electron density increases from 500 to greater than 10,000/cu cm from the northeast to the southwest, in a manner similar to the change in extinction derived from the ratio of H-alpha/5 GHz fluxes. It is argued that IRS 1 and 2 may have an extinction component that is wavelength independent in the optical (8000-4000 A) region. 26 references.
Research Organization:
Kitt Peak National Observatory, Tucson, AZ
OSTI ID:
6931824
Journal Information:
Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 306; ISSN ASJOA
Country of Publication:
United States
Language:
English

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