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Deep narrow band imagery of the diffuse ISM in M33Very deep narrow band images were obtained for several fields in the local group spiral galaxy M33 using a wide field reimaging Charge Coupled Device (CCD) camera on the 1.5 m telescope at Palomar Observatory. The reimaging system uses a 306 mm collimator and a 58 mm camera lens to put a 16 minute by 16 minute field onto a Texas Instruments 800 x 800 pixel CCD at a resolution of 1.2 arcseconds pixel (-1). The overall system is f/1.65. Images were obtained in the light of H alpha (S II) lambda lambda 6717, 6731, (O III) lambda 5007, and line-free continuum bands 100A wide, centered at 6450A and 5100A. Assuming a distance of 600 kpc to M33 (Humphreys 1980, Ap. J., 241, 587), this corresponds to a linear scale of 3.5 pc pixel (-1), and a field size of 2.8 kpc x 2.8 kpc. Researchers discuss the H alpha imagery of a field centered approx. equal to 8 minutes NE of the nucleus, including the supergiant HII region complex NGC 604. Two 2000 second H alpha images and two 300 second red continuum images were obtained of two slightly offset fields. The fields were offset to allow for discrimination between real emission and possible artifacts in the images. All images were resampled to align them with one of the H alpha frames. The continuum images were normalized to the line images using the results of aperture photometry on a grid of stars in the field, then the rescaled continuum data were directly subtracted from the line data.
Document ID
19910004889
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Hester, J. Jeff
(California Inst. of Tech. Pasadena, CA, United States)
Kulkarni, Shrinivas R.
(California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
September 6, 2013
Publication Date
July 1, 1990
Publication Information
Publication: NASA, Ames Research Center, The Interstellar Medium in External Galaxies: Summaries of Contributed Papers
Subject Category
Astrophysics
Accession Number
91N14202
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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