The chaotic recent past of NGC 4546 vs. the peaceful life cycle of the stars

JUAN PABLO VARELA; VICTORIA REYNALDI; FAVIO FAIFER; LUIS A. GUTIÉRREZ SOTO; TIAGO RICCI

Córdoba

Conferencia; 4th Regional Extragalactic Astronomy Meeting: 60 Years Of The Sersic Law; 2023

Instituto de Astronomía Teórica y Experimental (IATE)

NGC 4546 is an S0 galaxy, located in a low-density environment that hosts a Low-Luminosity Active Galactic Nuclei (LLAGN) of the LINER (Low-Ionization Nuclear Emission Region) class. Its very central region (200pc) was studied by means on GMOS/IFU data and it´s thought that the LINER is surrounded by an old stellar population whose embedded gas emission mimics that of the LLAGN itself. Such a scenario is known as the HOLMES (HOt Low-Mass Evolved Stars) emission.However, the galaxy shows signs of having undergone an efficient accretion process as a consequence of a rather recent minor merger with a dwarf galaxy, whose tidally disrupted core (the Ultra Compact Dwarf NGC4546-UCD1) is kinematically decoupled from the NGC 4546 disk. That is, its non-negligible gas content is clearly detected at kpc scales, and is counter-rotating with respect to the stellar population. The gas, however, rotates in almost the same direction as NGC4546-UCD1, from which the galaxy has accreted some globular clusters (in the context of the two-phase mechanism of assembly process of early-type galaxies).Since this merger took place a few Gyr ago, we are dedicated to reanalyse the circumnuclear stellar population to finally unveil if the gas emission we see is due the HOLMES phenomenon, as suspected, or it is related to a younger episode of star formation, triggered by the merger.