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Full-Text Articles in Physical Sciences and Mathematics
Pumping Up The [N I] Nebular Lines, Gary J. Ferland, W. J. Henney, C. R. O'Dell, R. L. Porter, P. A. M. Vanhoof, R. J. R. Williams
Pumping Up The [N I] Nebular Lines, Gary J. Ferland, W. J. Henney, C. R. O'Dell, R. L. Porter, P. A. M. Vanhoof, R. J. R. Williams
Physics and Astronomy Faculty Publications
The optical [N I] doublet near 5200 Å is anomalously strong in a variety of emission-line objects. We compute a detailed photoionization model and use it to show that pumping by far-ultraviolet (FUV) stellar radiation previously posited as a general explanation applies to the Orion Nebula (M42) and its companion M43; but, it is unlikely to explain planetary nebulae and supernova remnants. Our models establish that the observed nearly constant equivalent width of [N I] with respect to the dust-scattered stellar continuum depends primarily on three factors: the FUV to visual-band flux ratio of the stellar population, the optical properties …
Herschel/Spire Observations Of The Dusty Disk Of Ngc 4244., Benne W. Holwerda, S. Bianchi, T. Boker, D. Radburn-Smith, R. S. De Jong, M. Baes, P. C. Van Der Kruit, M. Xilouris, K. D. Gordon, J. J. Dalcanton
Herschel/Spire Observations Of The Dusty Disk Of Ngc 4244., Benne W. Holwerda, S. Bianchi, T. Boker, D. Radburn-Smith, R. S. De Jong, M. Baes, P. C. Van Der Kruit, M. Xilouris, K. D. Gordon, J. J. Dalcanton
Faculty Scholarship
We present Herschel/SPIRE images at 250, 350, and 500 μm of NGC 4244, a typical low-mass, disk-only and edge-on spiral galaxy. The dust disk is clumpy and shows signs of truncation at the break radius of the stellar disk. This disk coincides with the densest part of the Hi disk. We compare the spectral energy distribution (SED), including the new SPIRE fluxes, to 3D radiative transfer models; a smooth model disk and a clumpy model with embedded heating. Each model requires a very high value for the dust scale-length (hd = 2−5 h∗), higher dust masses than previous models of …