NuSTAR Perspective on High-redshift MeV Blazars

L. Marcotulli, V. Paliya, M. Ajello, A. Kaur, S. Marchesi, M. Rajagopal, D. Hartmann, D. Gasparrini, R. Ojha, G. Madejski

Research output: Contribution to journalArticle


With bolometric luminosities exceeding 1048 erg s-1, powerful jets, and supermassive black holes at their center, MeV blazars are some of the most extreme sources in the universe. Recently, the Fermi-Large Area Telescope detected five new γ-ray emitting MeV blazars beyond redshift z = 3.1. With the goal of precisely characterizing the jet properties of these extreme sources, we started a multiwavelength campaign to follow them up with joint Nuclear Spectroscopic Telescope Array, Swift, and the Southeastern Association for Research in Astronomy's optical telescopes. We observe six high-redshift quasars, four of them belonging to the new γ-ray emitting MeV blazars. Thorough X-ray analysis reveals spectral flattening at soft X-ray for three of these objects. The source NVSS J151002+570243 also shows a peculiar rehardening of the X-ray spectrum at energies E > 6 keV. Adopting a one-zone leptonic emission model, this combination of hard X-rays and γ-rays enables us to determine the location of the Inverse Compton peak and to accurately constrain the jet characteristics. In the context of the jet-accretion disk connection, we find that all six sources have jet powers exceeding accretion disk luminosity, seemingly validating this positive correlation even beyond z > 3. Our six sources are found to have black holes, further raising the space density of supermassive black holes in the redshift bin z = [3, 4].

Original languageEnglish (US)
Article number164
JournalAstrophysical Journal
Issue number2
StatePublished - Feb 1 2020

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Marcotulli, L., Paliya, V., Ajello, M., Kaur, A., Marchesi, S., Rajagopal, M., Hartmann, D., Gasparrini, D., Ojha, R., & Madejski, G. (2020). NuSTAR Perspective on High-redshift MeV Blazars. Astrophysical Journal, 889(2), [164].