MIGHTEE-HI: Mass Models and Dark Matter properties
University of Hertfordshire（赫特福德大学）；University of Oxford（牛津大学）；Leiden University（莱顿大学）；University of Edinburgh（爱丁堡大学）；University of Cape Town（开普敦大学）；University of Portsmouth（朴茨茅斯大学）；University of the Western Cape（西开普大学）
Anastasia A. Ponomareva, P. E. Mancera Piña, A. A. Vărăşteanu, M. Glowacki, H. Desmond, M. J. Jarvis, T. Yasin, I. Heywood, N. Maddox, E. A. K. Adams, M. Baes, … 展开作者
Anastasia A. Ponomareva, P. E. Mancera Piña, A. A. Vărăşteanu, M. Glowacki, H. Desmond, M. J. Jarvis, T. Yasin, I. Heywood, N. Maddox, E. A. K. Adams, M. Baes, A. Gebek, S. Kurapati, M. Maksymowicz-Maciata, K. A. Oman, H. Pan, I. Prandoni, S. H. A. Rajohnson, I. Ruffa, K. Spekkens
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19 pages, 10 figures, accepted for publication in MNRAS
Measuring galaxy rotation curves is critical for inferring the properties of dark-matter haloes in the Lambda Cold Dark Matter ($Λ$CDM) paradigm. We present HI rotation curves and mass models for 20 galaxies from the MIGHTEE survey. Using extended HI kinematics, we construct resolved mass models that include stellar, gaseous, and dark-matter components. Stellar masses are derived using 3.6 $μ$m imaging under fixed mass-to-light ratio ($Υ_{*} = M/L$) assumptions and are complemented, for the first time for a HI-selected sample, by spatially resolved $M/L$, obtained from multi-wavelength SED fitting. We examine the ratio of baryonic to observed rotation velocity ($V_{\rm bar}/V_{\rm obs}$) at the characteristic radius $R_{2.2}$. Adopting a fixed $Υ_\star = 0.5\,M_\odot/L_\odot$ yields a clear dependence of $V_{2.2}/V_{\rm obs}$ on galaxy luminosity, while adopting $Υ_\star = 0.2\,M_\odot/L_\odot$ substantially weakens this trend. In contrast, the resolved $M/L$ analysis preserves the luminosity dependence while modifying the stellar contribution on a galaxy-by-galaxy basis, providing a more accurate representation of the underlying relation. We model the dark-matter haloes using Navarro-Frenk-White profiles and find that the different assumptions for a fixed a $M/L$ systematically shift galaxies relative to the theoretical stellar-to-halo mass and baryonic-to-halo mass relations, while the spatially varying $M/L$ yields the closest agreement with theoretical benchmarks within $Λ$CDM. We therefore demonstrate that future investigations of the dark matter properties of galaxies using rotation curves need to account for varying $M/L$ across individual galaxy profiles and between galaxies in order to obtain accurate measurements of the dark matter, and therefore test $Λ$CDM.
MIGHTEE: The dark matter haloes, duty cycle and mechanical feedback from radio-AGN up to $z \sim 2.5$
University of Oxford（牛津大学）；School of Physics and Astronomy, Institute for Astronomy, University of Edinburgh（爱丁堡大学天体物理与天文学院天体物理研究所）；Department of Physics and Astronomy, University of the Western Cape（西开普大学物理与天文系）
MIGHTEE-HI: Environmental effects of cosmic filaments on extragalactic HI detections in the COSMOS and XMM-LSS fields
University of Oxford（牛津大学）；University of Cambridge（剑桥大学）；University of the Western Cape（西开普敦大学）；University of Bristol（布里斯托大学）；Universiteit Gent（根特大学）；University of Edinburgh（爱丁堡大学）；Inter-University Institute for Data Intensive Astronomy, Department of Astronomy, University of Cape Town（开普敦大学天文学系数据密集型天文跨大学研究所）；Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, University（大学物理、天文与数学学院天体物理学研究中心）
Measurements of the HI intensity mapping power spectrum at low redshifts with MIGHTEE data: comparison with detected HI galaxies
University of the Western Cape（西开普敦大学）；South African Radio Astronomy Observatory (SARAO)（南非射电天文观测台）；The University of Edinburgh（爱丁堡大学）；The University of Manchester（曼彻斯特大学）
MIGHTEE-HI / LADUMA: Investigating the link between baryons and dynamics with 130 resolved HI-selected galaxies
University of Oxford（牛津大学）；University of the Western Cape（西开普大学）；University of Portsmouth（朴茨茅斯大学）；University of Hertfordshire（赫特福德大学）；University of Bristol（布里斯托大学）
当暗物质粒子是自相互作用玻色子但不自湮灭时，我们计算了中子星在其一生中围绕星系中心旋转时积累的暗物质粒子的数量。我们考虑到暗物质与重子物质的相互作用和暗物质球在中子星内坍缩时的时间演化。我们发现，暗物质的自相互作用在中子星核心的暗物质的快速积累中起着重要的作用。我们认为，根据对具有强暗物质自相互作用的老中子星的观测，确定暗物质质量和暗物质相互作用截面的参数空间的排斥区域的可能性。我们发现，对于暗物质密度$~10^3$ GeV/cm $^3$和暗物质质量$m_χ$小于约10 GeV，有一个潜在的排斥区域的暗物质与核子的相互作用是三个数量级更严格的比没有自相互作用。暗物质自相互作用截面的潜在排斥区比目前的子弹星系团极限强许多个数量级。例如，对于高暗物质密度区域，我们发现，对于$m_χ\sim 10$ GeV，当暗物质与核子的相互作用截面范围从$σ_{χn}\sim 10^{-52}$ cm $^2$到$10^{-57}$ cm $^2$时，暗物质自相互作用截面极限为$σ_{χχ}< 10^{-33}$ cm $^2$，这比子弹团极限强约10个数量级。
