کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1771746 | 1020895 | 2013 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Analyses of the Light Variations of OJ 287, 0716+714 and BL Lacertae
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
نجوم و فیزیک نجومی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
OJ 287 is a BL Lac object which exhibits intense activities of low peak-frequencies. Its energy spectrum in low frequency band is quite similar with those of two other TeV BL Lac objects (i.e., 0716+714 and BL Lacertae). However, the Cerenkov telescope did not detect its TeV rays. By using the observational data of these three heavenly bodies and comparing the discrepan- cies of their minimal periods of light variations and delays at 22Â GHz, 37Â GHz and B-waveband, we have further investigated the possible reason why the TeV gamma-rays of OJ 287 have not been observed. The results of analyses are as fol- lows. (1) For the minimal periods of light variations, the periods of OJ 287 at 37 GHZ and B-waveband are short. At 22Â GHz the results of OJ 287 and 0716+714 are comparable, but the period of OJ 287 is much shorter in comparison with that of BL Lacertae, and this shows that its activity is more intense. However, the TeV gamma-rays of OJ 287 have not been detected, which implies that the radiation of OJ 287 in TeV waveband may have no connection with the minimal periods of light variations in these three low-energy wavebands. (2) In respect of delays, the delay of OJ 287 in the B waveband with respect to 37Â GHz is longer than that of 0716+714, but shorter than that of BL Lacertae. Its delay at 37Â GHz in respect to 22Â GHz is shorter than that of 0716+714. Meanwhile, the delay of BL Lacertae at 37Â GHz in respect to 22Â GHz is negative, which implies that 22Â GHz precedes 37Â GHz. Via the comparison and analysis of delays, no obvious differences between OJ 287 and 0716+714 as well as BL Lacertae have been found. On the side of energy spectra, it is quite possible that due to the steep energy spectrum of OJ 287 in TeV waveband, the Cerenkov telescope has not detected the gamma radiation of OJ 287. However, nowadays it is still not clear whether the steep energy spectrum in TeV energy range has some influence on the light variations in low energy realm.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chinese Astronomy and Astrophysics - Volume 37, Issue 1, JanuaryâMarch 2013, Pages 8-16
Journal: Chinese Astronomy and Astrophysics - Volume 37, Issue 1, JanuaryâMarch 2013, Pages 8-16
نویسندگان
Wang Hong-tao, Pan Yan-ping,