X-ray measurements of the elemental abundances for the diffuse emission in the nuclear starburst galaxy NGC 3079
Abstract
Outflows driven by feedback leave imprints on a galaxy's diffuse X-ray emission. Elemental abundances provide key diagnostics of feedback-driven chemical enrichment. We present a spectroscopic study of the diffuse X-ray emission in NGC 3079 using XMM-Newton RGS and EPIC, focusing on the nuclear region and the extended galactic-scale superbubble (GSB). We analyzed the high-resolution RGS spectrum of the central ∼4 kpc region, encompassing the ∼1 kpc nuclear superbubble (NSB), and the EPIC spectrum of the GSB out to 5' (∼25 kpc). The nuclear spectrum is best described by a multi-temperature thermal-plasma model plus a charge-exchange (CX) component, which contributes approximately 13% of the total observed energy flux in the 0.2−2 keV band. The best-fit O/Fe and Ne/Fe ratios are $0.47$ and $0.77$ in solar units. Comparing these ratios with IMF-weighted core-collapse supernova (SNcc) yields gives an upper progenitor-mass cutoff of Mu≃13−15 M⊙ for pure SNcc enrichment. For the best-fit spectral model, including an SNIa contribution increases the inferred cutoff, but its 1σ upper limit remains below 25 M⊙ for SNIa fractions up to 10% within the adopted yield models. The characteristic ages of the NSB and GSB are 0.92+0.39−0.46 Myr and 29.6+1.6−2.9 Myr, respectively, suggesting episodic feedback in NGC 3079.
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BibTeX
@misc{liu2026xray,
title = {{X-ray measurements of the elemental abundances for the diffuse emission in the nuclear starburst galaxy NGC 3079}},
author = {Jiejia Liu and Junjie Mao and Shuinai Zhang and Guan-Fu Liu and Rui Huang and Wei Cui},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.37646},
eprint = {2609.37646},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.37646},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - X-ray measurements of the elemental abundances for the diffuse emission in the nuclear starburst galaxy NGC 3079
AU - Jiejia Liu
AU - Junjie Mao
AU - Shuinai Zhang
AU - Guan-Fu Liu
AU - Rui Huang
AU - Wei Cui
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.37646
UR - https://arxiv.org/abs/2609.37646
AB - Outflows driven by feedback leave imprints on a galaxy's diffuse X-ray emission. Elemental abundances provide key diagnostics of feedback-driven chemical enrichment. We present a spectroscopic study of the diffuse X-ray emission in NGC 3079 using XMM-Newton RGS and EPIC, focusing on the nuclear region and the extended galactic-scale superbubble (GSB). We analyzed the high-resolution RGS spectrum of the central ∼4 kpc region, encompassing the ∼1 kpc nuclear superbubble (NSB), and the EPIC spectrum of the GSB out to 5' (∼25 kpc). The nuclear spectrum is best described by a multi-temperature thermal-plasma model plus a charge-exchange (CX) component, which contributes approximately 13% of the total observed energy flux in the 0.2−2 keV band. The best-fit O/Fe and Ne/Fe ratios are $0.47$ and $0.77$ in solar units. Comparing these ratios with IMF-weighted core-collapse supernova (SNcc) yields gives an upper progenitor-mass cutoff of M_u≃13−15 M_⊙ for pure SNcc enrichment. For the best-fit spectral model, including an SNIa contribution increases the inferred cutoff, but its 1σ upper limit remains below 25 M_⊙ for SNIa fractions up to 10% within the adopted yield models. The characteristic ages of the NSB and GSB are 0.92^+0.39_−0.46 Myr and 29.6^+1.6_−2.9 Myr, respectively, suggesting episodic feedback in NGC 3079.
ER -