تقرير
The 230 GHz Variability of Numerical Models of Sagittarius A* II. The Physical Origins of the Variability
| العنوان: | The 230 GHz Variability of Numerical Models of Sagittarius A* II. The Physical Origins of the Variability |
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| المؤلفون: | Chan, Ho-Sang, Chan, Chi-kwan |
| سنة النشر: | 2024 |
| المجموعة: | Astrophysics General Relativity and Quantum Cosmology |
| مصطلحات موضوعية: | Astrophysics - High Energy Astrophysical Phenomena, General Relativity and Quantum Cosmology |
| الوصف: | We explored in Chan et al. 2024 how the ion-electron temperature ratio affects certain numerical models of Sagittarius A* (Sgr A*). Specifically, we studied these effects in magnetic-dominated regions in magnetic-arrested disk (MAD), focusing on the $3$-hour variability at $230$ GHz -- $M_{\Delta T}$. In this study, we investigate how variations in electron temperature prescription parameter, $R_{\rm Low}$, influence $M_{\Delta T}$ by analyzing a series of general-relativistic raytracing (GRRT) snapshots. In certain black hole models with a spin $a > 0$, we discover that increasing $R_{\rm Low}$ renders the photon ring more optically thick, obscuring the varying accretion flows that contribute to the variability. However, as $R_{\rm Low}$ increases further, MAD flux eruptions become more pronounced, compensating for the decrease in $M_{\Delta T}$. For models with a spin $a < 0$, although a higher $R_{\rm Low}$ also increases the optical thickness of the fluid, voids within the optically thick gas fail to cover the entire photon ring. Similarly, flux eruptions are more prominent as $R_{\rm Low}$ increases further, contributing to the observed rise in $M_{\Delta T}$ against $R_{\rm Low}$. For black holes with $a \approx 0$, although the effect of increasing optical depth is still present, their $230$ GHz light curves and hence $M_{\Delta T}$ are insensitive to the changes in $R_{\rm Low}$. Furthermore, we find that the variability of the $230$ GHz light curves at $R_{\rm Low} = 1$ correlates with fluctuations in the internal energy of the gas near the black hole, indicating that unusual gas heating may be the source of significant $M_{\Delta T}$ seen in simulations. Our findings highlight potential approaches for refining $M_{\Delta T}$ to better align with observations when modelling Sgr A* or other low-luminosity active galactic nuclei. Comment: 16 pages, 15 figures |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2408.04132 |
| رقم الأكسشن: | edsarx.2408.04132 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |