FIRE 矮星系中多样的暗物质轮廓：黑洞、宇宙射线与尖核-核芯之谜
Diverse dark matter profiles in FIRE dwarfs: black holes, cosmic rays and the cusp-core enigma
AI总结：
本研究利用 FIRE-3 模型模拟发现，活动星系核反馈与恒星反馈、宇宙射线的相互作用能产生多样的矮星系暗物质密度轮廓，从而解释了观测到的旋转曲线多样性。
摘要：
矮星系在历史上对冷暗物质（CDM）模型构成了挑战，虽然许多所谓的“矮星系问题”已通过引入重子过程得到缓解，但观测到的矮星系旋转曲线的多样性仍是一个有争议的话题。与此同时，矮星系中活动星系核（AGN）观测样本的不断增加，促使我们对矮星系演化的理解发生了范式转变，传统上认为这一演化是由恒星反馈调节的。在本研究中，我们使用基于 FIRE-3 模型的一套新的矮星系宇宙学放大模拟，探讨了 AGN 反馈在塑造暗物质分布和增加矮星系旋转曲线多样性方面的潜在作用。我们的研究结果表明，矮星系中活动黑洞（BHs）的存在可以导致多样的结果，从更尖的轮廓到更接近核芯的轮廓。这种可变性源于 BHs 的双重作用，即提供额外反馈并调节恒星反馈的范围。与先前的研究一致，我们发现当包含宇宙射线（CR）建模时，AGN 反馈的影响最为显著，来自任何来源的 CRs 都会显著影响暗物质轮廓。总体而言，我们的结果强调，恒星反馈、BHs 和 CRs 之间的相互作用产生了广泛的暗物质密度轮廓谱系，这与观测到的旋转曲线形状和重子主导地位之间的相关性相吻合。这凸显了在矮星系模拟中包含全范围重子过程的重要性，以应对 CDM 范式面临的持续“小尺度挑战”。
英文摘要：
Dwarf galaxies have historically posed challenges to the cold dark matter (CDM) model and, while many of the so-called 'dwarf galaxy problems' have been mitigated by incorporating baryonic processes, the observed diversity of dwarf galaxy rotation curves remains a contentious topic. Meanwhile, the growing observational samples of active galactic nuclei (AGN) in dwarf galaxies have prompted a paradigm shift in our understanding of dwarf galaxy evolution, traditionally thought to be regulated by stellar feedback. In this study, we explore the potential role of AGN feedback in shaping dark matter distributions and increasing the diversity of dwarf galaxy rotation curves, using a new suite of cosmological zoom-in simulations of dwarf galaxies with the FIRE-3 model. Our findings indicate that the presence of active black holes (BHs) in dwarf galaxies can lead to diverse outcomes, ranging from cuspier to more core-like profiles. This variability arises from the dual role of BHs in providing additional feedback and regulating the extent of stellar feedback. Consistent with previous research, we find that AGN feedback is most impactful when cosmic ray (CR) modelling is included, with CRs from any source significantly influencing dark matter profiles. Overall, our results highlight that the interplay between stellar feedback, BHs, and CRs produces a broad spectrum of dark matter density profiles, which align with observed correlations between rotation curve shapes and baryonic dominance. This underscores the importance of including the full range of baryonic processes in dwarf galaxy simulations to address the persistent 'small-scale challenges' to the CDM paradigm.
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