Multi-Wavelength (ISM) Dust Signatures Karl D. Gordon Astronomer STScI, Baltimore, MD ISM*@ST Group Meeting 25 Oct 2021 [email protected] @karllark2000 karllark@github
Optical Features (origin unknown) Massa, Fitzpatrick, Gordon, et al. 2020, ApJ, 891, 67 Centers: 4370, 4870, & 6300 A Widths: ~10% Two blue correlate w/ 2175 A
Discovery 1973 Observations made with U. of MN/UCSD 60” on Mt. Lemon and KP 50” with cooled filter-wheel spectrometer (R = 67) 11.3 mm feature too broad to be a atomic emission line
Aromatic versus Aliphatic Aromatics have benzene rings 3.3 mm feature Aliphatics do not have benzene rings 3.4 mm feature Furton, D. et al. 1999, 526, 752 Lab IRS6 (Gal. Center) Cyg OB2 No. 12
Polycyclic Aromatic Hydrocarbons Hudgins, D. M. & Allamandola, L. J. Astrophysics of Dust, ASP Conference Series, Vol. 309, Eds. Adolf N. Witt, Geoffrey C. Clayton and Bruce T. Draine., 665 Lab. Data Orion (ISO)
Dorschner et al. 1995, A&A, 300, 503 Gordon et al. 2000, ApJ, 544, 859 Olivine Silicates Fe Feature @ ~1.5 micron? Emission spectrum from reflection nebula NGC 7023 NW filament