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A comprehensive analysis of Fermi Blazar
  • Deep Bhattacharjee ,
  • Shounak Bhattacharya
Deep Bhattacharjee

Corresponding Author:[email protected]

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Shounak Bhattacharya


A detailed analysis of the blazars detected by the Fermi/LAT (3LAC) and (4LAC) along with the 𝛾 βˆ’ray Narrow line – Seyfert 1 Galaxies (𝛾-NLSy1s) has been provided here with emphasize to the weak anti-correlation between synchrotron peak frequency and peak luminiosity, jet kinetic power and synchrotron peak frequency along with the properties of FSRQs, BL Lacs (Chen et al, 2020) with the central engine properties that is, the accretion luminosity (πΏπ‘‘π‘–π‘ π‘˜ ) and black hole mass (𝑀𝐡𝐻 ) where study has been done regarding the broad emission spectral line systems along with the association of more massive black holes with absorption line systems where computations has been made in Eddington units (𝐿𝑑𝑖𝑠𝑐 /𝐿𝐸𝑑𝑑 ) having the broad line objects to have a higher accretion rate (𝐿𝑑𝑖𝑠𝑐 /𝐿𝐸𝑑𝑑 > 0.01) with the sources being identified in recurrence with the HighCompton Dominated (HCD-CD > 1) and Low-Compton Dominated (LCD- CD ≲ 1) objects where according to (Paliya et al, 2021) the physical properties of the Fermi Blazars are to be controlled by the accretion rate in Eddington units. From the known redshifts of the Fermi satellite data, the spectral energy distributions (SEDs) have been computed where the proton dominated jet powers and the luminosity has been computed which is of the same order of (or slightly larger than) the disc luminosity (Ghisellini et al, 2010). In case of Flat Spectrum Radio quasars (FSRQs), the high energy peak of the SED increases with the luminosity where the X-ray spectra becomes harder and harder for larger luminosities, however in case of BL Lacs, they become redder with a softer 𝛾-ray slope and high energy for peak luminosities. For all the blazars (FRSQs + BL Lacs), the higher luminosity bin is vastly populated by FRSQs while the lower luminosity bin is populated by BL Lacs (Ghisellini et al, 2017). In the Fermi LAT – Bright AGN Sample (LBAS) by combining the Fermi 𝛾-ray spectra with Swift, optical, infra-red, radio, hard X-ray, 𝛾-ray data it has been observed with accuracy that in case of 50% of the radio bright high energy peaked BL Lacs (HBL) detected in the LABS Sample, only less than 13% of the known FSRQs and LBL BL Lacs are included. The synchrotron peak frequency (π‘£π‘π‘’π‘Žπ‘˜ 𝑠 ) has been positioned between 1012.5 and 1014.5 Hz in FSRQs and between 1013 and 1017 Hz in featureless BL Lac objects. The LAC detector being more sensitive to flat spectrum 𝛾-ray sources, the exact correlation between π‘£π‘π‘’π‘Žπ‘˜ 𝑠 and 𝛾-ray spectral index highly favors the detection of the high energy peaked blazars having the Fermi overabundance compared to radio and Energetic Gamma Ray Experiment Telescope (EGRET) samples. This in turn makes a selection effect where in the soft X-ray band, HBL BL Lacs are the most dominant types of blazars (Abdo et al, 2010).