X-ray study of extended emission around M 86 observed with Suzaku

Abstract

We analyzed the Suzaku data of M86 and its adjacent regions to study the extended emission around it. The M86 core, the plume, and the tail extending toward the northwest were clearly detected, as well as the extended halo around them. From the position angle ∼ 45 • to ∼ 275 • , the surface brightness distribution of the core and the extended halo was represented relatively well with a single β-model of β ∼ 0.5 up to 15 ′ -20 ′ . The X-ray spectra of the core was represented with a two-temperature model of kT ∼ 0.9 keV and ∼ 0.6 keV. The temperatures of the core and the halo have a positive gradient in the center, and reach the maximum of kT ∼ 1.0 keV at r ∼ 7 ′ , indicating that the halo gas is located in a larger scale potential structure than that of the galaxy. The temperatures of the plume and the tail were 0.86 ± 0.01 keV and 1.00 ± 0.01 keV. We succeeded in determining the abundances of α-element separately, for the core, the plume, the tail, and the halo for the first time. Abundance ratios with respect to Fe were consistent with the solar ratios everywhere, except for Ne. The abundance of Fe was ∼ 0.7 in the core and in the plume, while that in the tail was ∼ 1.0, but the difference was not significant considering the uncertainties of the ICM. The abundance of the halo was almost the same up to r ∼ 10 ′ , and then it becomes significantly smaller (0.2-0.3) at r > ∼ 10 ′ , indicating the gas with low metal abundance still remains in the outer halo. From the surface brightness distribution, we estimated the gas mass (∼ 3 × 10 10 M ⊙ ) and the dynamical mass (∼ 3 × 10 12 M ⊙ ) in r < 100 kpc. The gas mass to the dynamical mass ratio was 10 −3 -10 −2 , suggesting a significant fraction of the halo gas has been stripped.

Implications of the mild gas motion found withHitomiin the core of the Perseus cluster

“…3 for their rough locations) enable us to search for possible turbulence caused by M 86, and to constrain its energy injection to the ICM. The simulation employs the temperature, abundances, and emission measures of the M 86 ISM, as well as of the surrounding Virgo ICM, as measured with Suzaku (Hishi et al 2017). Assuming that the turbulence is 165 km s −1 (Hitomi Collaboration 2016) at the upstream, and is boosted by ∆σ = 400 km s −1 at the tail and downstream, the enhancement would be detected with XRISM if we invested rather long exposures, ∼400 ks at the upstream and downstream, and 100 ks at the tail.…”

Implications of the mild gas motion found with Hitomi in the core of the Perseus cluster

“…redHigh-resolution X-ray spectra of the upstream, tail, and the downstream regions (see Figure 3 for their rough locations) will enable us to search for possible turbulence caused by M 86, and to constrain its energy injection to the ICM. The simulation employs the temperature, abundances, and emission measures of the M 86 ISM, as well as of the surrounding Virgo ICM, as measured with Suzaku (Hishi et al 2017). Assuming that the turbulence is 165 km s −1 (Hitomi Collaboration et al 2016) at the upstream, and is boosted by ∆σ = 400 km s −1 at the tail and downstream, the enhancement would be detected with XRISM, if we invest rather long exposures, ∼ 400 ks at the upstream and downstream, and 100 ks at the tail.…”