We present new X-ray, radio, and optical data for the unusual galaxy/cluster system J2310-437. Our results confirm the presence of an active nucleus, and suggest an interpretation as an anomalous BL Lac object of bulk relativistic Doppler factor < 2, with an optically deficient radio-to-X-ray spectrum. The radio, optical, and soft X-ray flux densities could lie along a single power-law function, lacking the curvature typical of BL Lac objects. Compared with other known sources that may have comparable multifrequency spectra, J2310-437 is the most extreme. Its low isotropic optical/UV radiation is consistent with the intensity of external photons governing the electron spectral break through Compton cooling; in this source the external photon density would be too low to produce a spectral break below the X-ray.
@article{arxiv.astro-ph/9808027,
title = {A Multiwavelength Study of the Extreme AGN J2310-437},
author = {D. M. Worrall and M. Birkinshaw and R. A. Remillard and A. Prestwich and W. H. Tucker and H. Tananbaum},
journal= {arXiv preprint arXiv:astro-ph/9808027},
year = {2009}
}
Comments
19 pages, including 10 figures, using emulateapj.sty and apjfonts.sty. To appear in the ApJ