| | |
| | |
Stat |
Members: 3643 Articles: 2'487'895 Articles rated: 2609
28 March 2024 |
|
| | | |
|
Article overview
| |
|
The ROSAT X-ray Spectra of BL Lacertae Objects | Paolo Padovani
; Paolo Giommi
; | Date: |
17 Dec 1995 | Journal: | Mon.Not.Roy.Astron.Soc. 279 (1996) 526 | Subject: | astro-ph | Abstract: | We study the X-ray spectra of 85 BL Lacertae objects using the hardness ratios as given in the WGA catalogue of {it ROSAT} sources. This sample includes all WGA BL Lacs with high-quality data and comprises about 50 per cent of presently known BL Lacs. We find that BL Lacs have energy power-law spectral indices between 0 and 3 with a mean value $alpha_{
m x}sim 1.4$. Significant differences, however, are present between high-energy cutoff BL Lacs (HBLs), normally selected in the X-ray band, and low-energy cutoff BL Lacs (LBLs), generally found in radio surveys. HBLs have steeper X-ray spectral slopes ($alpha_{
m x}sim 1.5$) well correlated with $alpha_{
m ox}$, and anti-correlated with the X-ray-to-radio flux ratio and cutoff frequency, with convex overall broad-band spectra. LBLs, on the other hand, have flatter X-ray spectra ($alpha_{
m x}sim 1.1$) and concave optical-X-ray continuum. We interpret these results in terms of different mechanisms being responsible for the X-ray emission in the two classes, namely synchrotron and inverse Compton for HBLs and LBLs respectively. The observed differences are consistent with the hypothesis that HBLs and LBLs are powered by essentially the same non-thermal engines differing mainly in their synchrotron cutoff energy. | Source: | arXiv, astro-ph/9601089 | Services: | Forum | Review | PDF | Favorites |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser claudebot
|
| |
|
|
|
| News, job offers and information for researchers and scientists:
| |