Context. Relativistic jets are a common feature of radio loud active galactic nuclei. Multifrequency observations are a unique tool to constrain their physics. Aims: We report on a detailed study of the properties of the jet of the nearby BL Lac object PKS 2201+044, one of the rare cases where the jet is detected from radio to X-rays. Methods: We use new adaptive optics near-IR observations of the source, obtained with the ESO multi-conjugated adaptive optics demonstrator (MAD) at the Very Large Telescope. These observations acquired in Ground-Layer Adaptive Optics mode are combined with images previously achieved by HST, VLA and Chandra to perform a morphological and photometric study of the jet. Results: We find a noticeable similarity in the morphology of the jet at radio, near-IR and optical wavelengths. We construct the spectral shape of the main knot of jet that appears dominated by synchrotron radiation. Conclusions: On the basis of the jet morphology and the weak lines spectrum we suggest that PKS 2201+044 belongs to the class of radio sources intermediate between FRIs and FRIIs.
The jet of the BL Lacertae object PKS 2201+044: MAD near-IR adaptive optics observations and comparison with optical, radio and X-ray data / Liuzzo E.; Falomo R.; Treves A.; Donato D.; Sambruna M.; Arcidiacono C.; Giovannini G.; and 10 more. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - STAMPA. - 528:(2011), pp. 34-45. [10.1051/0004-6361/201015570]
The jet of the BL Lacertae object PKS 2201+044: MAD near-IR adaptive optics observations and comparison with optical, radio and X-ray data
GIOVANNINI, GABRIELE;
2011
Abstract
Context. Relativistic jets are a common feature of radio loud active galactic nuclei. Multifrequency observations are a unique tool to constrain their physics. Aims: We report on a detailed study of the properties of the jet of the nearby BL Lac object PKS 2201+044, one of the rare cases where the jet is detected from radio to X-rays. Methods: We use new adaptive optics near-IR observations of the source, obtained with the ESO multi-conjugated adaptive optics demonstrator (MAD) at the Very Large Telescope. These observations acquired in Ground-Layer Adaptive Optics mode are combined with images previously achieved by HST, VLA and Chandra to perform a morphological and photometric study of the jet. Results: We find a noticeable similarity in the morphology of the jet at radio, near-IR and optical wavelengths. We construct the spectral shape of the main knot of jet that appears dominated by synchrotron radiation. Conclusions: On the basis of the jet morphology and the weak lines spectrum we suggest that PKS 2201+044 belongs to the class of radio sources intermediate between FRIs and FRIIs.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.