Fermi Gamma-ray Space Telescope

Simultaneous Broadband Observations of the Jet-dominated Gamma-ray Galaxies Mrk 421 and Mrk 501 with NuSTAR

Amy Furniss
on behalf of the NuSTAR Team and the Fermi, VERITAS and MAGIC Collaborations

Abstract:

The exceptionally energetic particle populations at work within powerful relativistic jets associated with active galaxies such and Mrk 421 and Mrk 501 make these sources natural targets for the NuSTAR hard X-ray instrument. This space-based satellite can observe the non-thermal emission between 3 and 70 keV with unprecedented sensitivity. The emission is likely due to the synchrotron process, and particles responsible for the X-ray emission produce gamma-rays via inverse Compton up-scattering, which can be observed by the Fermi Large Area Telescope, VERITAS and MAGIC. NuSTAR observed Mrk 421 both during quiescence and an exceptionally variable elevated state, where the source displayed sub-day flux variations hard X-ray energies. The observation campaign for Mrk 501 also sampled a low and high state, with ample simultaneous broadband data available for detailed SED modeling. We will present the results from these multiwavelength campaigns, with particular emphasis on the implications for the study of the most relativistic particle populations at work within the jets, and the details of how the Compton scattering takes pace (Thomson vs. Klein-Nishina).