Planetary nebulae populations in the haloes of nearby massive early-type galaxies
: J. Hartke, M. Arnaboldi, O. Gerhard, A. I. Ennis, C. Pulsoni, L. Coccato, A. Cortesi, K.C. Freeman, K. Kuijken, M. Merrifield, N. Napolitano
: 2023
: arXiv.org
: arXiv
: https://arxiv.org/abs/2312.02587
: https://arxiv.org/abs/2312.02587
Planetary nebulae (PNe) are excellent tracers of the metal-poor haloes of nearby early-type galaxies. They are commonly used to trace spatial distribution and kinematics of the halo and intracluster light at distances of up to 100 Mpcs. The results on the early-type galaxy M105 in the Leo I group represent a benchmark for the quantitative analysis of halo and intragroup light. Since the Leo I group lies at just a 10 Mpc distance, it is at the ideal location to compare results from resolved stellar populations with the homogeneous constraints over a much larger field of view from the PN populations. In M105, we have -- for the first time -- established a direct link between the presence of a metal-poor halo as traced by resolved red-giant branch stars and a PN population with a high specific frequency (α-parameter). This confirms our inferences that the high α-parameter PN population in the outer halo of M49 in the Virgo Cluster traces the metal-poor halo and intra-group light.