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ARIES Nainital Study Uses NICER and NuSTAR to Analyse TeV Blazar X-rays
Researchers from the Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital publish a study analysing broadband X-ray emissions from four classical high-energy TeV blazars. The study combines observations from NASA’s NICER and NuSTAR to compare soft and hard X-ray spectra and reports specific spectral components in different activity states.
ARIES Study on Broadband X-ray Emissions from TeV Blazars:
| Dimension | Key Details |
|---|---|
| Target objects | The study comprises four classical TeV blazars: Mrk 421 (Markarian 421), Mrk 501 (Markarian 501), PG 1553+113, and PKS 2155-304. |
| TeV blazar | TeV blazars are active galaxies emitting very-high-energy gamma rays at tera-electronvolt scales. |
| Space telescopes used | The study uses two NASA space telescopes: NICER (Neutron star Interior Composition Explorer) and NuSTAR (Nuclear Spectroscopic Telescope Array). |
| NICER observation range | NASA’s NICER captures lower-energy (soft) X-ray spectra. |
| NuSTAR observation range | NASA’s NuSTAR captures higher-energy (hard) X-ray spectra. |
| Standard blazar model assumption | In standard blazar models, X-ray emission is completely dominated by intense, beamed non-thermal radiation from the relativistic jet pointed toward Earth. |
| Accretion-flow contribution detection | When Mrk 421 and Mrk 501 enter moderate-to-low active (quiescent) states, an additional low-energy spectral component becomes detectable. |
| Accretion disk observability condition | When jet emission dims, thermal or non-thermal radiation from the accretion disk surrounding the black hole becomes observable. |
| Study evidence claim | The detection provides the first evidence of a direct accretion disk contribution in Mrk 501, and confirms earlier hints in Mrk 421. |
| Mrk 421 spectral feature | An unresolved Gaussian feature is detected in Mrk 421’s spectrum as a minor extra emission peak. |
| Mrk 421 feature indication | The Gaussian feature indicates localized energy excess, potentially linked to instrumental artifacts or localized magnetic activity near the jet base. |
| PG 1553+113 and PKS 2155-304 spectral profile | For PG 1553+113 and PKS 2155-304, the X-ray spectra strictly follow standard synchrotron models. |
| Curved spectral shape interpretation | The curved spectral shape reflects differential rates of particle energy gain (acceleration) versus radiative loss. |
| AGN physics significance | The findings establish that AGN X-ray spectra are multi-component systems influenced by accretion state transitions. |
| Jet-only origin assumption | The findings challenge the assumption that blazar X-rays originate purely from jet dynamics. |
| Use-case enabled | The findings enable astronomers to disentangle how central accretion disks feed matter into supermassive black holes while simultaneously launching relativistic jets. |