XMM-NuSTAR Observation and Multiwavelength SED Modeling of Blazar 4FGL J1520.8-0348

Abstract

Active galactic nuclei (AGNs) can power relativistic jets, which are called blazars when pointed close to our line of sight. Depending on the presence or absence of emission lines in their optical spectra, blazars are categorized into flat spectrum radio quasars (FSRQs) or BL Lacertae (BL Lacs) objects. According to the 'blazar sequence', as synchrotron peak frequency (${\nu }_{pk}^{sy}$) shifts to higher energies, the synchrotron peak luminosity decreases. This means that BL Lacs as luminous as FSRQs, and with synchrotron peak frequencies ${\nu }_{pk}^{sy}>10^{15}$ Hz, should not exist. Detected as a high-synchrotron peak (HSP; ${\nu }_{pk}^{sy}>10^{15}$ Hz) BL Lac, 4FGL J1520.8-0348 shows high gamma-ray luminosity ($L_{\gamma }>10^{46}\mathrm{erg}{\mathrm{s}}^{-1}$), being at a high redshift of $z=$1.46. Since it is an outlier in the 'blazar sequence', the process of its jet acceleration and power may be different from bona fide BL Lacs. In this work, we constrain its spectral energy distribution (SED) by modeling the multi-wavelength data from infrared to $\gamma$-ray regime. Simultaneous X-ray data was obtained from X-ray Multi-Mirror Mission and Nuclear Spectroscopic Telescope Array to constrain the synchrotron emission and underlying electron distribution. On undertaking the SED modeling of the source, including the effect of extragalactic background light, we conclude that the source is more likely to be a 'blue FSRQ' or 'masquerading BL Lac' where the BL Lac is actually a FSRQ in disguise.

References in corpus (16)

• Active Galactic Nuclei: what's in a name?
• GROND - a 7-channel imager
• The blazar sequence: a new perspective
• The Imprint of The Extragalactic Background Light in the Gamma-Ray Spectra of Blazars
• MOJAVE. XVII. Jet Kinematics and Parent Population Properties of Relativistically Beamed Radio-Loud Blazars
• TXS 0506+056, the first cosmic neutrino source, is not a BL Lac
• An observational determination of the evolving extragalactic background light from the multiwavelength HST/CANDELS survey in the Fermi and CTA era
• IACHEC Cross-Calibration of Chandra, NuSTAR, Swift, Suzaku, and XMM-Newton with 3C 273 and PKS 2155-304
• The energy output of the Universe from 0.1 micron to 1000 micron
• General Physical Properties of CGRaBS Blazars
• F-GAMMA: Variability Doppler factors of blazars from multiwavelength monitoring
• Optical spectroscopic survey of a sample of Unidentified Fermi objects
• New High-z Fermi BL Lacs with the Photometric Dropout Technique
• Normalization of the extragalactic background light from high-energy gamma-ray observations
• Blazar jets launched with similar energy per baryon, independently of their power
• NuSTAR Observations and multi-wavelength modeling of the high-redshift BL Lac Object 4FGL J2146.5-1344

Cited by in corpus (2)

• Spectral Energy Distribution Modeling of BL Lacertae During a Large Submillimeter Outburst and Low X-Ray Polarization State
• The Gamma-ray Luminosity Function of Flat-Spectrum Radio Quasars