Filling the Infrared Gap: ISO Observations of 1 Jy BL Lacertae Objects

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dc.creatorPadovani, P.
dc.creatorGiommi, P.
dc.creatorAbraham, P.
dc.creatorCsizmadia, S.
dc.creatorMoor, A.
dc.date2006-06-09
dc.date.accessioned2026-07-07T07:12:10Z
dc.date.available2026-07-07T07:12:10Z
dc.descriptionThe large majority of BL Lacertae objects belonging to the 1 Jy sample, the class prototype for radio-selected sources, are thought to emit most of their synchrotron power in the far IR band. Ironically, this spectral region is very sparsely sampled, with only a minority of the objects having IRAS data (most of them being upper limits or low-quality detections). We aim at filling this IR gap by presenting new, simultaneous ISOCAM and ISOPHOT observations over the 7 - 200 micron range for half the sample. A measurement of the position of the synchrotron peak frequency, nu_peak, can provide information about particle acceleration mechanisms and constrain the inverse Compton radiation that will be detected by up-coming new gamma-ray missions. We have observed 17 1 Jy BL Lacertae objects with the camera and the photometer on board the Infrared Space Observatory (ISO) satellite. The ISOPHOT data reduction was done employing a novel correction, which mitigates the effect of chopping for faint sources. Using our new ISO data, complemented by nearly-simultaneous radio and optical observations for 10 and 4 objects respectively, and other multi-frequency data, we have built the spectral energy distributions of our sources (plus a previously published one) and derived the rest-frame nu_peak. Its distribution is centered at 10^13 Hz (30 micron) and is very narrow, with 60% of the BL Lacs in the 1 - 3 10^13 Hz range. Given our set of simultaneous infrared data, these represent the best determinations available of the synchrotron peak frequencies for low-energy peaked BL Lacs. A comparison with previous such estimates, based on non-simultaneous optical and near IR data, may indicate strong nu_peak variations in a number of sources, possibly associated with large flares as observed in the high-energy peaked BL Lac MKN 501. (abridged)
dc.description13 pages, 1 figure, accepted for publication in Astronomy & Astrophysics
dc.identifierhttps://arxiv.org/abs/astro-ph/0606219
dc.identifierhttp://arxiv.org/abs/astro-ph/0606219
dc.identifierAstron.Astrophys. 456 (2006) 131-139
dc.identifierdoi:10.1051/0004-6361:20065382
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/111989
dc.subjectAstrophysics
dc.titleFilling the Infrared Gap: ISO Observations of 1 Jy BL Lacertae Objects
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