Blue halo ata7/29/2023 Also, the recent suite of magneto-hydrodynamical numerical simulation for galaxy formation, named Auriga (Grand et al. It is also shown that the break in the stellar halo slope, which might be present in the MW halo, can be made by tidal debris from a merging satellite when it is at an apocenter position (Deason et al. ( 2014) investigated the results of numerical simulation for the merging-driven formation of a stellar halo by Bullock and Johnston ( 2005) and showed that the slope of the density profile for the outer part of a stellar halo depends on the average time of merging, in such a manner that the case of a more recent merging time reveals a shallower radial density profile over 50 < r/kpc < 100. The smooth component of a stellar halo is also affected by the past merging history. The former substructures correspond to the merging events within a few dynamical times, whereas the latter ones in phase space persist over many billion years (e.g., Helmi & White 1999 Bullock & Johnston 2005 Cooper et al. Indeed, many halo substructures have been identified in the form of stellar streams in spatial coordinates as well as separate clumps in phase space. Because of the long relaxation time in the halo, the structure of a current stellar halo, including the distribution of both smooth and non-smooth spatial features, reflects the past merging and accretion histories. This comparison suggests that the MW stellar halo may consist of the two overlapping components: the in situ inner halo as probed by RR Lyrae stars showing a relatively steep radial density profile and the ex situ outer halo with a shallow profile probed by BHBs here, which is made by accretion of small stellar systems.Ī stellar halo surrounding a disk galaxy like our Milky Way (MW) is thought to have been developed through hierarchical assembly of small stellar systems such as dwarf galaxies (Searle & Zinn 1978). ![]() The slopes of the halo density profiles are compared with those from the suite of hydrodynamical simulations for the formation of stellar halos. The latter profile with a prolate shape having an axial ratio of |$q=1.72^$| is most likely and this halo may hold a rather sharp boundary at r ≃ 160 kpc. We found from the candidate BHBs in the range of 18.5 r b. In order to select the most likely BHBs by removing blue straggler stars (BSs) and other contamination in a statistically significant manner, we have developed and applied an extensive Bayesian method, instead of the simple color cuts adopted in our previous work, where each of the template BHBs and non-BHBs obtained from the available catalogs are represented as a mixture of multiple Gaussian distributions in the color–color diagrams. These halo tracers are extracted from the ( g, r, i, z)-band multi-photometry in the internal data release of the ongoing Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) surveyed over a ∼550 deg 2 area. Blue-Delta ended the conversation by wishing him good luck.We report on the global structure of the Milky Way (MW) stellar halo up to its outer boundary based on the analysis of blue horizontal-branch stars (BHBs). ![]() Dragon X-ray inquired whether the Aegis Fate was a space-borne or an ocean-borne vessel, to which Blue-Delta answered that the Aegis Fate was a Frigate-designated "Exo-asset." Dragon X-ray then reported to be less than a kilometer away from the objective, and "ain't that desperate" for support. Requesting for support again, Blue-Delta told Dragon X-ray that the only available support in any way was the UNSC Aegis Fate. X-ray acknowledged receiving the warning and reported movement again, requesting for support to "soften them up." After being asked for the location of the enemy forces, Dragon X-ray responded and gave him the grid co-ordinates. X-ray was unable to hear Blue-Delta's response due to enemy movement, to which Blue-Delta warned him again. Blue-Delta warned X-ray that his unit was the only UNSC asset in the area, meaning that any support would take a while to arrive. Background ĭuring the Fall of Reach, Dragon X-ray, the radioman of an unidentified UNSC ground asset radioed in Blue-Delta for assistance. ![]() Blue-Delta was the codename of a member of HIGHCOM who was present during the Fall of Reach.
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