@Article{LaganáLoMaLaCaSc:2015:MeElSt,
author = "Lagan{\'a}, T. F. and Lovisari, L. and Martins, L. and
Lanfranchi, G. A. and Capelato, Hugo Vicente and Schellenberger,
G.",
affiliation = "{Universidade Cruzeiro do Sul} and {Universit{\"a}t Bonn} and
{Universidade Cruzeiro do Sul} and {Universidade Cruzeiro do Sul}
and {Instituto Nacional de Pesquisas Espaciais (INPE)} and
{Universit{\"a}t Bonn}",
title = "A metal-rich elongated structure in the core of the group NGC
4325",
journal = "Astronomy \& Astrophysics",
year = "2015",
volume = "573",
keywords = "galaxies, NGC 4325, intergalactic medium, halos.",
abstract = "Aims. Based on XMM-Newton, Chandra, and optical DR10-SDSS data, we
investigate the metal enrichment history of the group NGC 4325 (z
= 0.026). To complete the analysis we used chemical evolution
models and studied the optical spectrum of the central dominant
galaxy through its stellar population analysis and emission line
diagnostics to analyse its role in the metal enrichment of the
intra-group medium. Methods. We used X-ray 2D spectrally resolved
maps to resolve structure in temperature and metallicity. We also
derived gas and total masses within r2500 and r500 assuming
hydrostatic equilibrium and spherical symmetry. To perform stellar
population analysis we applied the spectral fitting technique with
STARLIGHT to the optical spectrum of the central galaxy. We
simulated the chemical evolution of the central galaxy. Results.
While the temperature, pseudo-pressure, and pseudo-entropy maps
showed no inhomogeneities, the spatial distribution of the
metallicity shows a filamentary structure in the core of this
group, which is spatially correlated with the central galaxy,
suggesting a connection between the two. The analysis of the
optical spectrum of the central galaxy showed no contribution by
any recent AGN activity. Using the star formation history as input
to chemical evolution models, we predicted the iron and oxygen
mass released by supernovae (SNe) winds in the central galaxy up
to the present time. Conclusions. Comparing the predicted amount
of mass released by the NGC 4325 galaxy to the ones derived
through X-ray analysis we conclude that the winds from the central
galaxy alone play a minor role in the IGM metal enrichment of this
group inside r2500. The SNe winds are responsible for no more than
3% of it and of the iron mass and 21% of the oxygen mass enclosed
within r2500. Our results suggest that oxygen has been produced in
the early stages of the group formation, becoming well mixed and
leading to an almost flat profile. Instead, the iron distribution
is centrally peaked, indicating that this element is still being
added to the IGM specifically in the core by the SNIa. A possible
scenario to explain the elongated metal-rich structure in the core
of the NGC 4325 is a past AGN activity, in which our results
suggest an episode older than ~107\−108 yrs and younger
than 5 × 108. Through the overall distribution of the galaxies, we
found no signs of recent merger in the group centre that could
explain the metal-rich structure.",
doi = "10.1051/0004-6361/201424821",
url = "http://dx.doi.org/10.1051/0004-6361/201424821",
issn = "0004-6361 and 1432-0746",
language = "en",
targetfile = "metal rich.pdf",
urlaccessdate = "27 abr. 2024"
}