ﻻ يوجد ملخص باللغة العربية
We collect multi-wavelength measurements of the nuclear emission of 20 low luminosity FR I radio-galaxies to test the viability of the FR I - BL Lac unifying model. Although poorly sampled, the Spectral Energy Distributions (SED) of FR Is are consistent with the double peaked shape characteristic of BL Lacs. Furthermore while the distribution of the FR Is in the broad-band spectral index planes shows essentially no overlap with the regions where HBL and LBL are located, this can be simply due to the effects of relativistic beaming. More quantitatively, deriving the beaming Doppler factor of a given radio-galaxy from its X-ray luminosity ratio with respect to BL Lacs with similar extended radio luminosity, we find that i) the luminosity in all bands, ii) the value of the spectral indices, iii) the slope of the X-ray spectrum, iv) the overall SED shape, may be all simultaneously reproduced. However, the corresponding jet bulk Lorentz factors are significantly smaller than those derived for BL Lacs from other observational and theoretical considerations. This suggests to consider a simple variant of the unification scheme that allows for the presence of a velocity structure in the jet.
We consider archival ROSAT and HST observations of five FRI radio galaxies and isolate their nuclear emission from that of the host galaxy. This enable us to determine the Spectral Energy Distributions (SED) of their nuclei spanning from the radio to
Electrons are accelerated at the shock wave diffuse and advect outward, and subsequently drift away into the emitting region of the jet that is located in the downstream flow from the plane shock. The current work considers the acceleration of the el
We present results of multi-wavelength (MWL) observations of the high-frequency-peaked BL Lacertae (HBL) object 1ES 0806+524 (z=0.138). Triggered by a high optical state, very high energy (VHE; E > 100 GeV) observations were carried out with the MAGI
We report observations of a transient source fermi from radio to grs. fermi was discovered by the {it Fermi-LAT} in May 2017. Follow-up {it Swift-XRT} observations revealed three flaring episodes through March 2018, and the peak X-ray flux is about $
We present a detailed investigation of the flaring activity observed from a BL Lac object, S5 0716+714 , during its brightest ever optical state in the second half of January 2015. Observed almost simultaneously in the optical, X-rays and {gamma}-ray