2009) and was identified as a member of Hubble class (R)SAB(rs)ab (Hubble 1926 Buta, Corwin & Odewahn 2007), i.e. M94 has an optical radius R 25 of ∼5.6 arcmin or ∼7 kpc (Trujillo et al. In this work, we aim to do a multiwavelength study of this source, and hence we will first briefly describe this source in different wavebands. Therefore, the M94 nucleus represents a unique possibility to probe the extremely low-accretion rate physics thought to govern these types of sources. The findings in this work add to the growing body of evidence that the physics of weakly accreting black holes scales with mass in a rather straightforward fashion.Īccretion, accretion discs, black hole physics, radiation mechanisms: non-thermal, galaxies: active, galaxies: jets, radio continuum: galaxies 1 INTRODUCTIONĪt 4.8 ± 0.8 Mpc, M94 is the closest known galaxy that has a low-luminosity active galactic nucleus (LLAGN) classified as an obscured low-ionization emission-line region, LINER (L2 Ho, Filippenko & Sargent 1997 Roberts, Schurch & Warwick 2001) and is the least luminous member of the LINER class found thus far ( L bol ∼ 2.5 × 10 40 erg s −1 Constantin & Seth 2012). We find that the nuclear broad-band spectrum of M94 is consistent with a relativistic outflow of low inclination. We compare our results with previous trends found for other AGN using the same model (NGC 4051, M81*, M87 and Sgr A*), as well as hard- and quiescent-state X-ray binaries. We explore this data set, which further includes non-simultaneous data from the Very Large Array, the Gemini telescope, the Hubble Space Telescope and the Chandra X-ray observatory, in terms of an outflow-dominated model. Thanks to the e-MERLIN resolution and sensitivity, we resolve for the first time a double structure composed of two radio sources separated by ∼1 arcsec, previously observed only at higher frequency. The SED comprises mainly high-resolution (mostly sub-arcsecond, or, at the distance to M94, ≲23 pc from the nucleus) observations from the literature, archival data, as well as previously unpublished sub-millimetre data from the Plateau de Bure Interferometer (PdBI) and the Combined Array for Research in Millimeter-wave Astronomy, in conjunction with new electronic MultiElement Radio Interferometric Network (e-MERLIN) L-band (1.5 GHz) observations.
We have compiled a new multiwavelength spectral energy distribution (SED) for the closest obscured low-ionization emission-line region active galactic nucleus (AGN), NGC 4736, also known as M94.