Multifrequency variability of the blazar AO 0235+164 the WEBT campaign in 2004-2005 and long-term SED analysis
<b>Aims.</b> A huge multiwavelength campaign targeting the blazar AO 0235+164 was organized by the Whole Earth Blazar Telescope (WEBT) in 2003-2005 to study the variability properties of the source. <b>Methods.</b> Monitoring observations were carried out at cm and mm wavele...
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| Formato: | Articulo |
| Lenguaje: | Inglés |
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2006
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| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/83062 |
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I19-R120-10915-83062 |
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dspace |
| institution |
Universidad Nacional de La Plata |
| institution_str |
I-19 |
| repository_str |
R-120 |
| collection |
SEDICI (UNLP) |
| language |
Inglés |
| topic |
Ciencias Astronómicas Ciencias Exactas Galaxies: active Galaxies: BL lacertae objects: general Galaxies: BL lacertae objects: individual: AO 0235+164 Galaxies: jets Galaxies: quasars: general |
| spellingShingle |
Ciencias Astronómicas Ciencias Exactas Galaxies: active Galaxies: BL lacertae objects: general Galaxies: BL lacertae objects: individual: AO 0235+164 Galaxies: jets Galaxies: quasars: general Romero, Gustavo Esteban Araudo, Anabella Teresa Cellone, Sergio Aldo Multifrequency variability of the blazar AO 0235+164 the WEBT campaign in 2004-2005 and long-term SED analysis |
| topic_facet |
Ciencias Astronómicas Ciencias Exactas Galaxies: active Galaxies: BL lacertae objects: general Galaxies: BL lacertae objects: individual: AO 0235+164 Galaxies: jets Galaxies: quasars: general |
| description |
<b>Aims.</b> A huge multiwavelength campaign targeting the blazar AO 0235+164 was organized by the Whole Earth Blazar Telescope (WEBT) in 2003-2005 to study the variability properties of the source.
<b>Methods.</b> Monitoring observations were carried out at cm and mm wavelengths, and in the near-IR and optical bands, while three pointings by the XMM-Newton satellite provided information on the X-ray and UV emission.
<b>Results.</b> We present the data acquired during the second observing season, 2004-2005, by 27 radio-to-optical telescopes. The ∼2600 data points collected allow us to trace the low-energy behaviour of the source in detail, revealing an increased near-IR and optical activity with respect to the previous season. Increased variability is also found at the higher radio frequencies, down to ∼15 GHz, but not at the lower ones. While the X-ray (and optical) light curves obtained during the XMM-Newton pointings reveal no significant short-term variability, the simultaneous intraday radio observations with the 100 m telescope at Effelsberg show flux-density changes at 10.5 GHz, which are more likely due to a combination of intrinsic and extrinsic processes.
<b>Conclusions.</b> The radio (and optical) outburst predicted to peak around February-March 2004 on the basis of the previously observed 5-6 yr quasi-periodicity did not occur. The analysis of the optical light curves reveals now a longer characteristic time scale of variability of ∼8 yr, which is also present in the radio data. The spectral energy distributions corresponding to the XMM-Newton observations performed during the WEBT campaign are compared with those pertaining to previous pointings of X-ray satellites. Bright, soft X-ray spectra can be described in terms of an extra component, which appears also when the source is faint through a hard UV spectrum and a curvature of the X-ray spectrum. Finally, there might be a correlation between the X-ray and optical bright states with a long time delay of about 5 yr, which would require a geometrical interpretation. |
| format |
Articulo Articulo |
| author |
Romero, Gustavo Esteban Araudo, Anabella Teresa Cellone, Sergio Aldo |
| author_facet |
Romero, Gustavo Esteban Araudo, Anabella Teresa Cellone, Sergio Aldo |
| author_sort |
Romero, Gustavo Esteban |
| title |
Multifrequency variability of the blazar AO 0235+164 the WEBT campaign in 2004-2005 and long-term SED analysis |
| title_short |
Multifrequency variability of the blazar AO 0235+164 the WEBT campaign in 2004-2005 and long-term SED analysis |
| title_full |
Multifrequency variability of the blazar AO 0235+164 the WEBT campaign in 2004-2005 and long-term SED analysis |
| title_fullStr |
Multifrequency variability of the blazar AO 0235+164 the WEBT campaign in 2004-2005 and long-term SED analysis |
| title_full_unstemmed |
Multifrequency variability of the blazar AO 0235+164 the WEBT campaign in 2004-2005 and long-term SED analysis |
| title_sort |
multifrequency variability of the blazar ao 0235+164 the webt campaign in 2004-2005 and long-term sed analysis |
| publishDate |
2006 |
| url |
http://sedici.unlp.edu.ar/handle/10915/83062 |
| work_keys_str_mv |
AT romerogustavoesteban multifrequencyvariabilityoftheblazarao0235164thewebtcampaignin20042005andlongtermsedanalysis AT araudoanabellateresa multifrequencyvariabilityoftheblazarao0235164thewebtcampaignin20042005andlongtermsedanalysis AT cellonesergioaldo multifrequencyvariabilityoftheblazarao0235164thewebtcampaignin20042005andlongtermsedanalysis |
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Repositorios |
| _version_ |
1764820488245215235 |