IRAS F02044+0957: radio source in interacting system of galaxies

The steep spectrum of IRAS F02044+0957 was obtained with the RATAN-600 radio telescope at four frequencies. Optical spectroscopy of the system components, was carried out with the 2.1m telescope of the Guillermo Haro Observatory. Observational data allow us to conclude that this object is a pair of interacting galaxies, a LINER and a HII galaxy, at z = 0.093. Trushkin & Verkhodanov (1995) compiled a list of about 750 objects by using the CATS, as a result of cross-identifications of infrared IRAS catalogues and the source catalogue of Texas survey at 365 MHz. From the sample of steep spectra sources we selected those without classification in public databases (CATS, NED, ADS and LEDA). One of these objects is IRAS F02044+0957, identified with the NVSS radio source J020706+101147. Radio observations were carried out in April 23–25, 1999 with the North Sector of the RATAN–600 telescope. The wide-band radiometer complex at four frequencies: 2.3, 3.9, 7.7 and 11.2 GHz, was used. The nearby non-variable radio source PKS 1345+12, was used as the flux density calibration source. A linear fitting to the radio spectrum was used to estimate a spectral index by the least square method. Each point of the spectrum was weighted proportionally to the value of 1/(∆ S/Sν); where ∆ S/Sν is the relative error of the flux density. The radio spectrum is described by a power-law Sν [Jy] = 85 ν−0.94±0.02 MHz. The radio luminosity in the frequency interval from 365 to 104 MHz is L = 9.381 × 1034 erg sec−1 cm−2 (assuming H0=64 km Mpc−1 sec−1 andq0=0.8). Optical spectroscopy of objects marked by A, B, C, D, and E in Fig. 1, was obtained in August and November 1999. We used the 2.1m telescope of the Guillermo Haro Observatory (GHO) in Cananea, Sonora, Mexico, operated by the National Institute of Astrophysics, Optics and Electronics (INAOE). The Faint Object Spectrograph and Camera (LFOSC) (Zickgraf et al. 1997) was used. A setup, covering the spectral range 4200 − 9000Å with a dispersion of 8.2 Å/pix was adopted. The effective instrumental spectral resolution is about 15 Å.