کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8142540 | 1523891 | 2017 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The mineralogy of newly formed dust in active galactic nuclei
ترجمه فارسی عنوان
کانی شناسی گرد و غبار تازه در هسته های فعال کهکشانی
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
هسته های هسته ای فعال گرد و خاک، سیلیکات،
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فیزیک زمین (ژئو فیزیک)
چکیده انگلیسی
The tori around active galactic nuclei (AGN) are potential formation sites for large amounts of dust, and they may help resolve the so-called dust budget crisis at high redshift. We investigate the dust composition in 53 of the 87 Palomar Green (PG) quasars showing the 9.7 μm silicate feature in emission. By simultaneously fitting the mid-infrared spectroscopic features and the underlying continuum, we estimate the mass fraction in various amorphous and crystalline dust species. We find that the dust consists predominantly of alumina and amorphous silicates, with a small fraction in crystalline form. The mean crystallinity is 8±6%, with more than half of the crystallinities greater than 5%, well above the upper limit determined for the Galaxy. Higher values of crystallinity are found for higher oxide fractions and for more luminous sources.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Planetary and Space Science - Volume 149, 1 December 2017, Pages 56-63
Journal: Planetary and Space Science - Volume 149, 1 December 2017, Pages 56-63
نویسندگان
Sundar Srinivasan, F. Kemper, Yeyan Zhou, Lei Hao, Sarah C. Gallagher, Jinyi Shangguan, Luis C. Ho, Yanxia Xie, Peter Scicluna, Sebastien Foucaud, Rita H.T. Peng,