Browsing by Author "Wang, Q. Daniel"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    90 Winds, Some X-rays, and Sgr A* Walk Into VR...
    (2021) Russell, C. T.; Luco Korn, José Baltasar; Sepúlveda, Miguel; Cuadra, Jorge; Calderón Espinoza, Diego Nicolás; Wang, Q. Daniel
    Virtual reality (VR) provides a new tool for exploring astrophysical simulations. Our case study is hydrodynamic simulations of the central parsec of the Galactic center, which models 25 Wolf-Rayet (WR) stars that are orbiting Sgr A* while ejecting their stellar winds. The VR program we are developing allows users to fully immerse themselves in a simulation snapshot, allowing them full control over their position and viewing orientation. The highlight result so far is exquisite views of material inspiraling towards the black hole. We also present a new hydrodynamic simulation that adds 65 O and 'S' stars, which causes a reduction in thermal X-ray emission in the vicinity of Sgr A* compared to the WR-only simulations....
  • Thumbnail Image
    Item
    Colliding winds in and around the stellar group IRS 13E at the galactic centre
    (OUP, 2019) Wang, Q. Daniel; Li, J.; Russel, C. M. P.; Cuadra Stipetich, Jorge Rodrigo
    IRS 13E is an enigmatic compact group of massive stars located in projection only 3.6 arcsec away from Sgr A*. This group has been suggested to be bounded by an intermediate-mass black hole (IMBH). We present a multiwavelength study of the group and its interplay with the environment. Based on Chandra observations, we find the X-ray spectrum of IRS 13E can be well characterized by an optically thin thermal plasma. The emission peaks between two strongly mass-losing Wolf–Rayet stars of the group. These properties can be reasonably well reproduced by simulated colliding winds of these two stars. However, this scenario underpredicts the X-ray intensity in outer regions. The residual emission likely results from the ram-pressure confinement of the IRS 13E group wind by the ambient medium and is apparently associated with a shell-like warm gas structure seen in Pa α and in ALMA observations. These latter observations also show strongly peaked thermal emission with unusually large velocity spread between the two stars. These results indicate that the group is colliding with the bar of the dense cool gas mini-spiral around Sgr A*. The extended X-ray morphology of IRS 13E and its association with the bar further suggest that the group is physically much farther away than the projected distance from Sgr A*. The presence of an IMBH, while favourable to keep the stars bound together, is not necessary to explain the observed stellar and gas properties of IRS 13E
  • Thumbnail Image
    Item
    The role of feedback in accretion on Low Luminosity AGN : Sgr A* case study
    (2015) Cuadra Stipetich, Jorge Rodrigo; Nayakshin, Sergei; Wang, Q. Daniel