Search

Although double-peaked narrow emission-line galaxies have been studied extensively in the past years, only a few are reported with the Green pea (GP) galaxies. Here we present our discovery of five GP galaxies with double-peaked narrow [O  iii ] emission lines, referred to as DPGPs, selected from the LAMOST and SDSS spectroscopic surveys. We find that these five DPGPs have blueshifted narrow components more prominent than the redshifted components, with velocity offsets of [O  iii ]λ5007Å ranging from 306 to 518 |$\rm km\, s^{-1}$|⁠ , and full widths at half maximums of individual components ranging from 263 to 441 |$\rm km\, s^{-1}$|⁠. By analysing the spectra and the spectral energy distributions (SEDs), we find that they have larger metallicities and stellar masses compared with other GPs. The H α line width, emission-line diagnostic, mid-infrared colour, radio emission, and SED fitting provide evidence of the AGN activities in these DPGPs. They have the same spectral properties of type 2 quasars. Furthermore, we discuss the possible nature of the double-peaked narrow emission-line profiles of these DPGPs and find that they are more likely to be dual active galactic nuclei (AGNs). These DPGP galaxies are ideal laboratories for exploring the growth mode of AGNs in the extremely luminous emission-line galaxies, the co-evolution between AGNs and host galaxies, and the evolution of high-redshift galaxies in the early Universe. [ABSTRACT FROM AUTHOR]

We review the mechanisms driving the ionized gas outflows in radio-quiet (RQ) AGN. Although it constitutes ∼90% of the AGN population, what drives these outflows in these AGNs remains an open question. High-resolution imaging and integral field unit (IFU) observation is key to spatially resolving these outflows, whereas radio observations are important to comprehend the underlying radiative processes. Radio interferometric observations have detected linear, collimated structures on the hundreds of pc scale in RQ AGN, which may be very similar to the extended radio jets in powerful galaxies. Proper motions measured in some objects are sub-relativistic. Other processes, such as synchrotron radiation from shock-accelerated gas around the outflows could give rise to radio emissions as well. Near the launching region, these outflows may be driven by the thermal energy of the accretion disk and exhibit free–free emission. IFU observations on the other hand have detected evidence of both winds and jets and the outflows driven by them in radio-quiet AGN. Some examples include nearby AGN such as Mrk 1044 and HE 1353-1917. An IFU study of nearby (z  < 0.06 ) RQ AGN has found that these outflows may be related to their radio properties on <100 pc scale, rather than their accretion properties. Recent JWST observations of RQ AGN XID 2028 have revealed that radio jets and wind could inflate bubbles, create cavities, and trigger star formation. Future high-resolution multi-wavelength observations and numerical simulations taking account of both jets and winds are hence essential to understand the complex interaction between radio-quiet AGN and the host from sub-pc to kpc scales. [ABSTRACT FROM AUTHOR]