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Hritwik Bora

Publications and source records attributed to Hritwik Bora.

3 recordsLinked to original sources

Jet Power Estimates of FSRQs PKS 1441+25 and Ton 599 from Broadband SED Modeling

Flat-Spectrum Radio Quasars (FSRQs) are among the most energetic and powerful active galactic nuclei, often exhibiting jet powers comparable to or exceeding the Eddington luminosity. In this work, we performed broadband spectral energy distribution (SED) modeling of two FSRQs PKS 1441+25 and Ton 599, using Swift-XRT/UVOT, NuSTAR, Fermi-LAT and VERITAS observations during 2015 and 2021, respectively. We considered four particle distribution models: a broken power law, a log-parabola, and two energy-dependent models in which either the diffusion or acceleration timescale depends on energy. Our results show that the jet power estimates derived from models with intrinsic curvature, such as the log-parabola and energy-dependent models, are of the same order as those obtained with a broken power-law distribution. This contrasts with the case of High Synchrotron Peaked Blazars (HBLs), where the power estimates can differ by nearly two orders of magnitude between models. We attribute this difference to the lower electron break energies typically observed in FSRQs. Consequently, our findings suggest that, unlike in HBLs, the estimated jet powers in FSRQs are relatively insensitive to the assumed particle energy distribution, reflecting the dominance of external Compton processes and weaker dependence on spectral curvature.

astro-ph.HE

The dependence of Polarization Degree of Blazars on particle energy distributions

We present a formalism to predict the Polarization Degree (PD) for synchrotron emission from particles having a specified energy distribution in the presence of an ordered and random magnetic field configuration. The broad band spectral energy distribution as well as the X-ray and optical PD data for Mrk 501 have been fitted using the formalism. As reported earlier, we find that for a broken power law particle energy distribution, the PD cannot be explained, unless it is assumed that the higher energy particles experience a higher ordered magnetic field compared to the lower energy ones. On the other hand, a log parabola particle energy distribution can explain the observed higher X-ray PD compared to the optical, even when all the particles experience the same magnetic configuration. We discuss the possibility of distinguishing the two scenarios using future observations.

astro-ph.HE

Estimating the Jet Power from Broadband SED modeling of Mkn 501 for different particle distributions

We consider the broadband spectral energy distribution of the high energy peaked (HBL) blazar Mkn 501 using $\textit{Swift}$-XRT/UVOT, NuSTAR and $\textit{Fermi}$-LAT observations taken between 2013 and 2022. The spectra were fitted with a one-zone leptonic model using synchrotron and synchrotron self-Compton emission from different particle energy distributions such as a broken power-law, log-parabola, as well as distributions expected when the diffusion or the acceleration time scale are energy dependent. The jet power estimated for a broken power-law distribution was $ \sim 10^{47} (10^{44})$ erg s$^{-1}$ for a minimum electron energy $\gamma_\text{min} \sim 10 (10^3)$. However, for electron energy distributions with intrinsic curvature (such as the log-parabola form), the jet power is significantly lower at a few times $ 10^{42}$ erg s$^{-1}$ which is a few percent of the Eddington luminosity of a $10^7$ M$_\odot$ black hole, suggesting that the jet may be powered by accretion processes. We discuss the implications of these results.

astro-ph.HE