2. Observational dataset
Source names, coordinates, and redshifts of the selected sample were taken from the NASA Extragalactic Database (NED) 2, and are listed in Table 1. Infrared observations were obtained for 18 of the sources with the Imaging Photopolarimeter on ISO (ISOPHOT; Lemke et al. 1996), and 3 were observed with IRAC1 on the 2.2 m ESO/MPE telescope. Millimetre and sub-mm data were obtained for 10 objects with the IRAM interferometer at Plateau de Bure in France (Guilloteau et al. 1992), the Sub-millimetre Common User Bolometer Array (SCUBA; Holland et al. 1999) on the James Clerk Maxwell Telescope 3 and the Swedish ESO Sub-mm Telescope (SEST) of the European Southern Observatory (ESO) at La Silla. The instruments used for each object are indicated in a footnote to Table 1.
Table 1. Basic properties of the sample.
The observational details (observing date, wavelength, and measured flux density) of IRAC1, SEST, IRAM, and SCUBA observations are reported in Table 2. The data obtained with the SEST telescope were reduced to outside the atmosphere, corrected for the gain elevation characteristic of the telescope, and calibrated with Uranus. All IRAM observations were performed in compact configuration. All five antenna were used during most of the observations, with the exceptions indicated in a footnote of Table 2. The calibrators were 3C 454.3 for 3C 47, and 22040+420 and 1928+738 during the two observations of HS 1946+7658. SCUBA observations yielded good results at 850 µm only due to marginal weather. The fluxes were calibrated using the canonical gain value of 220 Jy/V, since a calibration scan at 850 µm was not done. The chosen value is relatively insensitive to the weather and should be good to within 20%. ISOPHOT observations and data reduction are described in the next section. These new observations were supplemented with literature data from radio to near-IR. We have also collected data at soft X-ray energies. For reasons of homogeneity we collected only ROSAT data, available for most of the sources. From published soft X-ray spectra we derived the flux at 1 keV corrected for absorption. The observed absorption is always compatible with the galactic absorption. The list of references from which data were retrieved, for each object, is reported in Table 3.
Table 2. IRAC1, SEST, IRAM and SCUBA results.
Table 3. List of references of selected published data.
© European Southern Observatory (ESO) 2000
Online publication: October 30, 19100