The analysis of Abell 1835 using a deprojection technique

Abstract

Abstract. We present the results from a detailed deprojection analysis of Abell 1835 as observed by XMM-Newton. If we fit the spectra with an isothermal plasma model, the deprojected temperature profile is flat in the outer region around 7.6 keV and decreases to ∼5.6 keV in the center, which may be connected with the gas cooling. In the central part, a two-component thermal plasma model can fit the spectrum significantly better. Moreover, the cool component (T ∼ 1.8 keV) has a much lower metal abundance than the hot component (T ∼ 8 keV), which may be due to the longer cooling time for the cool gas with lower abundance. In addition, it was found that without a main isothermal component, the standard cooling flow model cannot fit the spectrum satisfactorily. From the isothermal model fitting results we also derived the electron density n e , and fitted its radial distribution with a double-β model. The n e profile inferred with the double-β model and the deprojected X-ray gas temperature profile were then combined to derive the total mass and the total projected mass of the cluster. The projected mass is lower than that derived from the weak lensing method. However, assuming that the cluster extends to a larger radius ∼15 as found by Clowe & Schneider (2002), the two results are consistent within the error bars. Furthermore, we calculated the projected mass within the radius of ∼153 kpc implied by the presence of a gravitational lensing arc, which is about half of the mass determined from the optical lensing.

Deprojected analysis of Abell 1835 observed withChandraand compared withXMM-Newton

“…After deprojection, the temperatures do not differ much from the projected temperatures. But they are still much higher than our new result of XMM-Newton, ∼7.33 keV, which is consistent with that of Majerowicz et al (2002) and Jia et al (2004). Therefore, even when the same method of data analysis is used, the temperature differences derived from Chandra and XMM-Newton data still exist.…”

“…The deprojected spectrum of each shell is calculated by subtracting the contributions from all the outer shells (e.g., Nulsen & Böringer 1995;Matsushita et al 2002). The detailed calculation procedures were described in Chen et al (2003) and Jia et al (2004Jia et al ( , 2006.…”

“…For the purpose of comparing, we also reprocessed the XMM-Newton data of Abell 1835 (observation ID: 0551830201) in ΛCDM cosmology as done in Jia et al (2004) using SAS 11.0.0.…”

“…In addition, the masses of Abell 1835 derived from XMM-Newton and Chandra are different (Jia et al 2004;Schmidt et al 2001). Fortunately, the masses have been measured with the strong lensing method (Richard et al 2010) as well as with the weak lensing method (Zhang et al 2008).…”

XMM-Newton studies of a massive cluster of galaxies: RXC J2228.6+2036

“…Matsushita et al 2002;Nulsen & Böhringer 1995). The detailed calculation procedures were described in Jia et al (2004Jia et al ( , 2006:…”