VLBI DETECTION OF AN ACTIVE GALACTIC NUCLEUS PAIR IN THE BINARY BLACK HOLE CANDIDATE SDSS J1536+0441
- INAF-Istituto di Radioastronomia, Via Gobetti 101, I-40129, Bologna (Italy)
- Instituto de AstrofIsica de Andalucia, CSIC, Apartado Correos 3004, 18080 Granada (Spain)
We present the first pc-scale radio imaging of the radio-quiet candidate binary black hole system SDSS J1536+0441. The observations were carried out by the European VLBI Network at a frequency of 5 GHz, allowing the imaging of SDSS J1536+0441 with a resolution of {approx}10 mas ({approx}50 pc). Two compact radio cores are detected at the position of the kpc-scale components VLA-A and VLA-B, proving the presence of two compact active nuclei with radio luminosity L{sub R} {approx} 10{sup 40} erg s{sup -1}, thus ruling out the possibility that both radio sources are powered by a 0.1 pc binary black hole. From a comparison with published 8.5 GHz flux densities, we derived an estimate of the radio spectral index of the two pc-scale cores. Both cores have a flat or an inverted spectral index, and at least for the case of VLA-A we can rule out the possibility that synchrotron self-absorption is responsible for the inverted radio spectrum. We suggest that thermal free-free emission from an X-ray-heated disk wind may be powering the radio emission in VLA-A.
- OSTI ID:
- 21448812
- Journal Information:
- Astrophysical Journal Letters, Vol. 714, Issue 2; Other Information: DOI: 10.1088/2041-8205/714/2/L271; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
BLACK HOLES
FLUX DENSITY
GALAXIES
GHZ RANGE 01-100
LUMINOSITY
QUASARS
SELF-ABSORPTION
X RADIATION
ABSORPTION
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
FREQUENCY RANGE
GHZ RANGE
IONIZING RADIATIONS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SORPTION