The redshift evolution of major merger triggering of luminous AGNs: a slight enhancement at z ˜ 2

Rowlands, Kate; Pawlik, Milena; Mendez-Abreu, Jairo; Wild, Vivienne; Villforth, Carolin; Hewlett, Timothy
Referencia bibliográfica

Monthly Notices of the Royal Astronomical Society, Volume 470, Issue 1, p.755-770

Fecha de publicación:
9
2017
Número de autores
6
Número de autores del IAC
1
Número de citas
41
Número de citas referidas
39
Descripción
Active galactic nuclei (AGNs), particularly the most luminous AGNs, are commonly assumed to be triggered through major mergers; however, observational evidence for this scenario is mixed. To investigate any influence of galaxy mergers on AGN triggering and luminosities through cosmic time, we present a sample of 106 luminous X-ray-selected type 1 AGNs from the COSMOS survey. These AGNs occupy a large redshift range (0.5 < z < 2.2) and two orders of magnitude in X-ray luminosity (˜1043-1045 erg s-1). AGN hosts are carefully mass and redshift matched to 486 control galaxies. A novel technique for identifying and quantifying merger features in galaxies is developed, subtracting galfit galaxy models and quantifying the residuals. Comparison to visual classification confirms this measure reliably picks out disturbance features in galaxies. No enhancement of merger features with increasing AGN luminosity is found with this metric, or by visual inspection. We analyse the redshift evolution of AGNs associated with galaxy mergers and find no merger enhancement in lower redshift bins. Contrarily, in the highest redshift bin (z ˜ 2) AGNs are ˜4 times more likely to be in galaxies exhibiting evidence of morphological disturbance compared to control galaxies, at 99 per cent confidence level (˜2.4σ) from visual inspection. Since only ˜15 per cent of these AGNs are found to be in morphologically disturbed galaxies, it is implied that major mergers at high redshift make a noticeable but subdominant contribution to AGN fuelling. At low redshifts, other processes dominate and mergers become a less significant triggering mechanism.
Proyectos relacionados
Abell 370 se encuentra a aproximadamente 4 mil millones de años luz de distancia en la constelación de Cetus, el monstruo marino
Evolución de Galaxias en Cúmulos
Las estructuras en el Universo, a todas las escalas de masa, se han formado de una forma jerárquica y principalmente producidas por fusiones de galaxias. Sin embargo, esta formación jerárquica de las galaxias está modulada por el entorno en el cual se crean y evolucionan. Mientras que las galaxias de campo presentan una evolución pasiva, los
Jairo
Méndez Abreu