Poster details
Exploring the AGN-ram pressure stripping connection
Abstract
Context. A correlation between the presence of active galactic nuclei at the centre of jellyfish galaxies and the ram-pressure stripping (RPS) phenomenon has been proposed. Previous works have found, indeed, that galaxies with the most disturbed morphologies due to the interaction between the intra-cluster medium (ICM) and the inter-stellar medium (ISM) show a higher incidence of nuclear activity.
Aims. Confirm previous findings based on a relatively small sample on a more robust statistical ground and compare it with a sample of galaxies in the field selected homogeneously. Moreover, we wanted to study the incidence of AGN as a function of the galaxy stellar mass.
Methods. We use data from the GAs Stripping Phenomena in galaxies (GASP) survey to draw a sample of RPS candidates in cluster and to build up Baldwin, Phillips & Terlevich (BPT) diagrams in order to classify them as AGN or star-forming galaxies. The sample was enlarged by adding RPS candidates retrieved from a general search in the literature with available AGN information. We exploit the fifteenth data release of the MaNGA survey (DR15) to build up a control sample of galaxies, excluding those in clusters, in order to have only field members presumably affected by less intense ram-pressure stripping. We classify the AGNs in MaNGA on the basis of BPT. To compute the fAGN, we first match the stellar mass distribution of the two samples with a Monte Carlo random extraction - resulted to be independent according to a Kolmogorov-Smirnov (K-S) test. Then, we compute the fraction of the extracted and the reference samples for two different mass bins, M* > 1e9 Msun and M* > 1e10 Msun respectively.
Results. We find a correlation between the presence of the AGN and the galaxy stellar mass. Indeed, there are no AGN in galaxies with M* 1e9 Msun. The RPS sample presents an AGN fraction of 0.27 +/- 0.04, in contrast with the lower value for the field of 0.16(+0.03)(-0.04). The GASP and the literature samples are compatible within 1sigma.
Conclusions. Results are consistent with the hypothesis that RPS can trigger the AGN activity, supported also by the location of the AGN candidates in GASP in the low radii region of the phase-space.
Aims. Confirm previous findings based on a relatively small sample on a more robust statistical ground and compare it with a sample of galaxies in the field selected homogeneously. Moreover, we wanted to study the incidence of AGN as a function of the galaxy stellar mass.
Methods. We use data from the GAs Stripping Phenomena in galaxies (GASP) survey to draw a sample of RPS candidates in cluster and to build up Baldwin, Phillips & Terlevich (BPT) diagrams in order to classify them as AGN or star-forming galaxies. The sample was enlarged by adding RPS candidates retrieved from a general search in the literature with available AGN information. We exploit the fifteenth data release of the MaNGA survey (DR15) to build up a control sample of galaxies, excluding those in clusters, in order to have only field members presumably affected by less intense ram-pressure stripping. We classify the AGNs in MaNGA on the basis of BPT. To compute the fAGN, we first match the stellar mass distribution of the two samples with a Monte Carlo random extraction - resulted to be independent according to a Kolmogorov-Smirnov (K-S) test. Then, we compute the fraction of the extracted and the reference samples for two different mass bins, M* > 1e9 Msun and M* > 1e10 Msun respectively.
Results. We find a correlation between the presence of the AGN and the galaxy stellar mass. Indeed, there are no AGN in galaxies with M* 1e9 Msun. The RPS sample presents an AGN fraction of 0.27 +/- 0.04, in contrast with the lower value for the field of 0.16(+0.03)(-0.04). The GASP and the literature samples are compatible within 1sigma.
Conclusions. Results are consistent with the hypothesis that RPS can trigger the AGN activity, supported also by the location of the AGN candidates in GASP in the low radii region of the phase-space.