# Two-zone emission modeling of PKS 1510-089 during the high state of 2015

## TL;DR

This study models the high activity state of blazar PKS 1510-089 in 2015 using multi-wavelength data, proposing a two-zone emission model with distinct regions near the BLR and dusty torus, to explain observed variability and emission characteristics.

## Contribution

The paper introduces a two-zone emission model for PKS 1510-089 during its 2015 high state, integrating multi-wavelength data and analyzing emission regions and variability.

## Key findings

- Gamma-ray and optical/UV emissions likely originate from the same region.
- X-ray emission appears to come from a different, separate region.
- No significant correlations found among different energy band light curves.

## Abstract

PKS 1510-089 is one of the most variable blazars in the third Fermi-LAT source catalog. During 2015, this source has shown four flares identified as flare A, B, C, and D in between three quiescent states Q1, Q2, and Q3. The multi-wavelength data from Fermi-LAT, Swift-XRT/UVOT, OVRO, and SMA observatory are used in our work to model these states. Different flux doubling times have been observed in different energy bands which indicate there could be multiple emission zones. The flux doubling time from the gamma-ray and X-ray light curves are found to be 10.6 hr, 2.5 days, and the average flux doubling time in the optical/UV band is 1 day. It is possible that the gamma-ray and optical/UV emission are produced in the same region whereas X-ray emission is coming from a different region along the jet axis. We have also estimated the discrete correlations functions (DCFs) among the light curves of different energy bands to infer about their emission regions. However, our DCF analysis does not show significant correlation in different energy bands though it shows peaks in some cases at small time lags. We perform a two-zone multi-wavelength time-dependent SED modeling with one emission zone located near the outer edge of the broad line region (BLR) and another further away in the dusty/molecular torus (DT/MT) region to study this high state.