ROXA J081009.9+384757.0: A 1047 erg s-1 blazar with hard X-ray synchrotron peak or a new type of radio loud AGN?

P. Giommi, E. Massaro, P. Padovani, M. Perri, E. Cavazzuti, S. Turriziani, G. Tosti, S. Colafrancesco, G. Tagliaferri, G. Chincarini, D. N. Burrows, M. Mc Math Chester, N. Gehrels

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


We report the discovery of ROXA J081009.9+384757.0 = SDSS J081009.9+384757.0, a z = 3.95 blazar with a highly unusual Spectral Energy Distribution. This object was first noticed as a probable high f x/fr high-luminosity blazar within the error region of a ≈ 10-12 erg cm-2 s-1 ROSAT source which, however, also included a much brighter late-type star. We describe the results of a recent Swift observation that establishes beyond doubt that the correct counterpart of the X-ray source is the flat spectrum radio quasar. With a luminosity well in excess of 1047 erg s-1 ROXA J081009.9+384757.0 is therefore one of the most luminous blazars known. We consider various possibilities for the nature of the electromagnetic emission from this source. In particular, we show that the SED is consistent with that of a blazar with synchrotron power peaking in the hard X-ray band. If this is indeed the case, the combination of high-luminosity and synchrotron peak in the hard-X-ray band contradicts the claimed anti-correlation between luminosity and position of the synchrotron peak usually referred to as the "blazar sequence". An alternative possibility is that the X-rays are not due to synchrotron emission, in this case the very peculiar SED of ROXA J081009.9+384757.0 would make it the first example of a new class of radio loud AGN.

Original languageEnglish (US)
Pages (from-to)97-101
Number of pages5
JournalAstronomy and Astrophysics
Issue number1
StatePublished - Jun 2007

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'ROXA J081009.9+384757.0: A 1047 erg s-1 blazar with hard X-ray synchrotron peak or a new type of radio loud AGN?'. Together they form a unique fingerprint.

Cite this