No 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.

We have been developing a compact adiabatic demagnetization refrigerator, keeping ground application and future missions in mind. A salt pill fabricated inhouse, a superconducting magnet with a passive magnetic shield around it, and a mechanical heat switch are mounted in a dedicated helium cryostat. The detector stage temperature is regulated by PID control of the magnet current, with a dI /dt term added to compensate the temperature rise due to parasitic heat. The temperature fluctuation of the detector stage is 1-2 µKrms, and the hold time was extended by about 15 % thanks to the dI /dt term. Bundle shields of the harnesses between the cryostat and the analog electronics boxes were connected to the chassis at both ends, and the analog electronics boxes were grounded to the cryostat through the bundle shields. This reduced the readout noise to 16 pA/ √ Hz in the 10-60 kHz range. Using this system, an energy resolution of 3.8 ± 0.2 eV (FWHM) was achieved at 5.9 keV.