14 research outputs found

    New Black Hole Spin Values for Sagittarius A* Obtained with the Outflow Method

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    Six archival Chandra observations are matched with eight sets of radio data and studied in the context of the outflow method to measure and study the spin properties of Sgr A∗\rm{Sgr ~A^*}. Three radio and X-ray data sets obtained simultaneously, or partially simultaneously, are identified as preferred for the purpose of measuring the spin properties of Sgr A∗\rm{Sgr ~A^*}. Similar results are obtained with other data sets. Results obtained with the preferred data sets are combined and indicate a weighted mean value of the spin function of F=0.62±0.10\rm{F} = 0.62 \pm 0.10 and dimensionless spin angular momentum of a∗=0.90±0.06\rm{a_*} = 0.90 \pm 0.06. The spin function translates into measurements of the black hole rotational mass, Mrot\rm{M_{rot}}, irreducible mass, Mirr\rm{M_{irr}}, and spin mass-energy available for extraction, Mspin\rm{M_{spin}}, relative to the total black hole dynamical mass, Mdyn\rm{M_{dyn}}. Weighted mean values of (Mrot/Mdyn)=(0.53±0.06)\rm{(M_{rot}/M_{dyn}) = (0.53 \pm 0.06)}, (Mirr/Mdyn)=(0.85±0.04)\rm{({M_{irr}/M_{dyn})} = (0.85 \pm 0.04)}, (Mspin/Mdyn)=(0.15±0.04)\rm{({M_{spin}/M_{dyn})} = (0.15 \pm 0.04)}, Mrot=(2.2±0.3)×106 M⊙\rm{{M_{rot}} = (2.2 \pm 0.3) \times 10^6 ~M_{\odot}}, Mirr=(3.5±0.2)×106 M⊙\rm{{M_{irr}} = (3.5 \pm 0.2) \times 10^6 ~M_{\odot}}, and Mspin=(6.2±1.6)×105 M⊙\rm{{M_{spin}} = (6.2 \pm 1.6) \times 10^5 ~M_{\odot}} are obtained; of course (Mrot/Mirr)=(0.62±0.10)\rm{{(M_{rot}/M_{irr})} = (0.62 \pm 0.10)} since (Mrot/Mirr)=F\rm{{(M_{rot}/M_{irr})} = F}. Values obtained for Sgr A∗\rm{Sgr ~A^*} are compared with those obtained for M87 based on the published spin function which indicate that M87 carries substantially more rotational energy and spin mass-energy relative to the total (i.e., dynamical) black hole mass, the irreducible black hole mass, and in absolute terms.Comment: Accepted for publication in MNRAS on October 16, 202
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