# Nitrogen abundance in the X-ray halos of clusters and groups of galaxies

Junjie Mao, J. de Plaa, J. S. Kaastra, Ciro Pinto, Liyi Gu, F. Mernier, Hong-Liang Yan, Yu-Ying Zhang, H. Akamatsu

Research output: Contribution to journalArticle

2 Citations (Scopus)

### Abstract

Chemical abundances in the X-ray halos (also known as the intracluster medium, ICM) of clusters and groups of galaxies can be measured via prominent emission line features in their X-ray spectra. Elemental abundances are footprints of time-integrated yields of various stellar populations that have left their specific abundance patterns prior to and during the cluster and group evolution. We aim to constrain nitrogen abundances in the CHEmical Evolution RGS Sample (CHEERS), which contains 44 nearby groups and clusters of galaxies, in order to have a better understanding of their chemical enrichment. We examine the high-resolution spectra of the CHEERS sample carefully and take into account various systematic effects in the spectral modelling. We compare the observed abundance ratios with those in the Galactic stellar populations, as well as predictions from stellar yields (low- and intermediate-mass stars, massive stars and degenerate stars). The nitrogen abundance can only be well constrained ($\gtrsim3\sigma$) in one cluster of galaxies and seven groups of galaxies. The [O/Fe] -- [Fe/H] relation of the ICM is comparable to that for the Galaxy, while both [N/Fe] and [N/O] ratios of the ICM are higher than in the Galaxy. Future studies on nitrogen radial distributions are required to tell whether the obtained higher [N/Fe] and [N/O] ratios are biased due to the small extraction region ($r/r_{500}\lesssim0.05$) that we adopt here. Since abundances of odd-$Z$ elements are more sensitive to the initial metallicity of stellar populations, accurate abundance measurements of N, Na and Al are required to better constrain the chemical enrichment in the X-ray halos of clusters and groups of galaxies.
Original language English A9 15 Astronomy and Astrophysics 621 19 Dec 2018 https://doi.org/10.1051/0004-6361/201730931 Published - 1 Jan 2019

### Fingerprint

Galaxies
halos
Nitrogen
galaxies
nitrogen
X rays
x rays
Stars
chemical evolution
stars
footprints
massive stars
footprint
metallicity
chemical
high resolution
prediction
predictions

### Keywords

• astro-ph.HE
• astro-ph.GA
• cosmology
• galaxies: clusters
• intracluster medium
• X-rays: galaxies
• spectroscopy

### Cite this

Mao, J., Plaa, J. D., Kaastra, J. S., Pinto, C., Gu, L., Mernier, F., ... Akamatsu, H. (2019). Nitrogen abundance in the X-ray halos of clusters and groups of galaxies. Astronomy and Astrophysics, 621, [A9]. https://doi.org/10.1051/0004-6361/201730931
Mao, Junjie ; Plaa, J. de ; Kaastra, J. S. ; Pinto, Ciro ; Gu, Liyi ; Mernier, F. ; Yan, Hong-Liang ; Zhang, Yu-Ying ; Akamatsu, H. / Nitrogen abundance in the X-ray halos of clusters and groups of galaxies. In: Astronomy and Astrophysics. 2019 ; Vol. 621.
title = "Nitrogen abundance in the X-ray halos of clusters and groups of galaxies",
abstract = "Chemical abundances in the X-ray halos (also known as the intracluster medium, ICM) of clusters and groups of galaxies can be measured via prominent emission line features in their X-ray spectra. Elemental abundances are footprints of time-integrated yields of various stellar populations that have left their specific abundance patterns prior to and during the cluster and group evolution. We aim to constrain nitrogen abundances in the CHEmical Evolution RGS Sample (CHEERS), which contains 44 nearby groups and clusters of galaxies, in order to have a better understanding of their chemical enrichment. We examine the high-resolution spectra of the CHEERS sample carefully and take into account various systematic effects in the spectral modelling. We compare the observed abundance ratios with those in the Galactic stellar populations, as well as predictions from stellar yields (low- and intermediate-mass stars, massive stars and degenerate stars). The nitrogen abundance can only be well constrained ($\gtrsim3\sigma$) in one cluster of galaxies and seven groups of galaxies. The [O/Fe] -- [Fe/H] relation of the ICM is comparable to that for the Galaxy, while both [N/Fe] and [N/O] ratios of the ICM are higher than in the Galaxy. Future studies on nitrogen radial distributions are required to tell whether the obtained higher [N/Fe] and [N/O] ratios are biased due to the small extraction region ($r/r_{500}\lesssim0.05$) that we adopt here. Since abundances of odd-$Z$ elements are more sensitive to the initial metallicity of stellar populations, accurate abundance measurements of N, Na and Al are required to better constrain the chemical enrichment in the X-ray halos of clusters and groups of galaxies.",
keywords = "astro-ph.HE, astro-ph.GA, cosmology, galaxies: clusters, intracluster medium, X-rays: galaxies, spectroscopy",
author = "Junjie Mao and Plaa, {J. de} and Kaastra, {J. S.} and Ciro Pinto and Liyi Gu and F. Mernier and Hong-Liang Yan and Yu-Ying Zhang and H. Akamatsu",
year = "2019",
month = "1",
day = "1",
doi = "10.1051/0004-6361/201730931",
language = "English",
volume = "621",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",

}

Mao, J, Plaa, JD, Kaastra, JS, Pinto, C, Gu, L, Mernier, F, Yan, H-L, Zhang, Y-Y & Akamatsu, H 2019, 'Nitrogen abundance in the X-ray halos of clusters and groups of galaxies', Astronomy and Astrophysics, vol. 621, A9. https://doi.org/10.1051/0004-6361/201730931

Nitrogen abundance in the X-ray halos of clusters and groups of galaxies. / Mao, Junjie; Plaa, J. de; Kaastra, J. S.; Pinto, Ciro; Gu, Liyi; Mernier, F.; Yan, Hong-Liang; Zhang, Yu-Ying; Akamatsu, H.

In: Astronomy and Astrophysics, Vol. 621, A9, 01.01.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Nitrogen abundance in the X-ray halos of clusters and groups of galaxies

AU - Mao, Junjie

AU - Plaa, J. de

AU - Kaastra, J. S.

AU - Pinto, Ciro

AU - Gu, Liyi

AU - Mernier, F.

AU - Yan, Hong-Liang

AU - Zhang, Yu-Ying

AU - Akamatsu, H.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Chemical abundances in the X-ray halos (also known as the intracluster medium, ICM) of clusters and groups of galaxies can be measured via prominent emission line features in their X-ray spectra. Elemental abundances are footprints of time-integrated yields of various stellar populations that have left their specific abundance patterns prior to and during the cluster and group evolution. We aim to constrain nitrogen abundances in the CHEmical Evolution RGS Sample (CHEERS), which contains 44 nearby groups and clusters of galaxies, in order to have a better understanding of their chemical enrichment. We examine the high-resolution spectra of the CHEERS sample carefully and take into account various systematic effects in the spectral modelling. We compare the observed abundance ratios with those in the Galactic stellar populations, as well as predictions from stellar yields (low- and intermediate-mass stars, massive stars and degenerate stars). The nitrogen abundance can only be well constrained ($\gtrsim3\sigma$) in one cluster of galaxies and seven groups of galaxies. The [O/Fe] -- [Fe/H] relation of the ICM is comparable to that for the Galaxy, while both [N/Fe] and [N/O] ratios of the ICM are higher than in the Galaxy. Future studies on nitrogen radial distributions are required to tell whether the obtained higher [N/Fe] and [N/O] ratios are biased due to the small extraction region ($r/r_{500}\lesssim0.05$) that we adopt here. Since abundances of odd-$Z$ elements are more sensitive to the initial metallicity of stellar populations, accurate abundance measurements of N, Na and Al are required to better constrain the chemical enrichment in the X-ray halos of clusters and groups of galaxies.

AB - Chemical abundances in the X-ray halos (also known as the intracluster medium, ICM) of clusters and groups of galaxies can be measured via prominent emission line features in their X-ray spectra. Elemental abundances are footprints of time-integrated yields of various stellar populations that have left their specific abundance patterns prior to and during the cluster and group evolution. We aim to constrain nitrogen abundances in the CHEmical Evolution RGS Sample (CHEERS), which contains 44 nearby groups and clusters of galaxies, in order to have a better understanding of their chemical enrichment. We examine the high-resolution spectra of the CHEERS sample carefully and take into account various systematic effects in the spectral modelling. We compare the observed abundance ratios with those in the Galactic stellar populations, as well as predictions from stellar yields (low- and intermediate-mass stars, massive stars and degenerate stars). The nitrogen abundance can only be well constrained ($\gtrsim3\sigma$) in one cluster of galaxies and seven groups of galaxies. The [O/Fe] -- [Fe/H] relation of the ICM is comparable to that for the Galaxy, while both [N/Fe] and [N/O] ratios of the ICM are higher than in the Galaxy. Future studies on nitrogen radial distributions are required to tell whether the obtained higher [N/Fe] and [N/O] ratios are biased due to the small extraction region ($r/r_{500}\lesssim0.05$) that we adopt here. Since abundances of odd-$Z$ elements are more sensitive to the initial metallicity of stellar populations, accurate abundance measurements of N, Na and Al are required to better constrain the chemical enrichment in the X-ray halos of clusters and groups of galaxies.

KW - astro-ph.HE

KW - astro-ph.GA

KW - cosmology

KW - galaxies: clusters

KW - intracluster medium

KW - X-rays: galaxies

KW - spectroscopy

UR - https://arxiv.org/abs/1809.04870v1

U2 - 10.1051/0004-6361/201730931

DO - 10.1051/0004-6361/201730931

M3 - Article

VL - 621

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A9

ER -