%0 Generic %1 anderson2015xmmnewton %A Anderson, Michael E. %A Churazov, Eugene %A Bregman, Joel N. %D 2015 %K galaxy halos hot spiral x-ray %T A Deep XMM-Newton Study of the Hot Gaseous Halo Around NGC 1961 %U http://arxiv.org/abs/1508.01514 %X We examine 11 XMM-Newton observations of the giant spiral galaxy NGC 1961, with a total integration time of 289 ks ($100$ ks after flaring corrections). These deep X-ray data allow us to study the hot gaseous halo of a spiral galaxy in unprecedented detail. We perform both a spatial and a spectral analysis; with the former, the hot halo is detected to at least 80 kpc and with the latter the halo properties can be measured in detail up to 42 kpc. In the region of overlap, there is good agreement between the two methods. We measure the temperature profile of the hot halo, finding a negative gradient as is common for elliptical galaxies. We also measure a rough metallicity profile, which is consistent with being flat at a sub-Solar value ($Z 0.2 Z_ødot$). Converting to this metallicity, our deprojected density profile is consistent with previous parametric fits, with no evidence for a break or flattening within the inner 42 kpc (about 10% of the virial radius). We infer pressure and entropy profiles for the hot halo, and use the former to estimate the mass profile of the galaxy assuming hydrostatic equilibrium. Extrapolating these profiles to the virial radius, we infer a hot gaseous halo mass comparable to the stellar mass of the galaxy, and a total baryon fraction from the stars and hot gas of around 30%. We show that the cooling time of the hot gas is orders of magnitude longer than the dynamical time, making the hot halo stable against cooling instabilities, and argue that an extended stream of neutral Hydrogen seen to the NW of this galaxy is likely due to accretion from the intergalactic medium. The low metallicity of the hot halo suggests it too was likely accreted. We compare the hot halo of NGC 1961 to hot halos around isolated elliptical galaxies, and show that the total mass better determines the hot halo properties than the stellar mass.

@misc{anderson2015xmmnewton, abstract = {We examine 11 XMM-Newton observations of the giant spiral galaxy NGC 1961, with a total integration time of 289 ks ($\sim 100$ ks after flaring corrections). These deep X-ray data allow us to study the hot gaseous halo of a spiral galaxy in unprecedented detail. We perform both a spatial and a spectral analysis; with the former, the hot halo is detected to at least 80 kpc and with the latter the halo properties can be measured in detail up to 42 kpc. In the region of overlap, there is good agreement between the two methods. We measure the temperature profile of the hot halo, finding a negative gradient as is common for elliptical galaxies. We also measure a rough metallicity profile, which is consistent with being flat at a sub-Solar value ($Z \sim 0.2 Z_{\odot}$). Converting to this metallicity, our deprojected density profile is consistent with previous parametric fits, with no evidence for a break or flattening within the inner 42 kpc (about 10% of the virial radius). We infer pressure and entropy profiles for the hot halo, and use the former to estimate the mass profile of the galaxy assuming hydrostatic equilibrium. Extrapolating these profiles to the virial radius, we infer a hot gaseous halo mass comparable to the stellar mass of the galaxy, and a total baryon fraction from the stars and hot gas of around 30%. We show that the cooling time of the hot gas is orders of magnitude longer than the dynamical time, making the hot halo stable against cooling instabilities, and argue that an extended stream of neutral Hydrogen seen to the NW of this galaxy is likely due to accretion from the intergalactic medium. The low metallicity of the hot halo suggests it too was likely accreted. We compare the hot halo of NGC 1961 to hot halos around isolated elliptical galaxies, and show that the total mass better determines the hot halo properties than the stellar mass.}, added-at = {2015-08-10T09:40:12.000+0200}, author = {Anderson, Michael E. and Churazov, Eugene and Bregman, Joel N.}, biburl = {https://www.bibsonomy.org/bibtex/2a142840b518cd60b824e2efb075ed044/miki}, description = {[1508.01514] A Deep XMM-Newton Study of the Hot Gaseous Halo Around NGC 1961}, interhash = {9cef31efe5d03145d2ccfd3d4944cb10}, intrahash = {a142840b518cd60b824e2efb075ed044}, keywords = {galaxy halos hot spiral x-ray}, note = {cite arxiv:1508.01514Comment: 19 pages, 15 figures, submitted to MNRAS}, timestamp = {2015-08-10T09:40:12.000+0200}, title = {A Deep XMM-Newton Study of the Hot Gaseous Halo Around NGC 1961}, url = {http://arxiv.org/abs/1508.01514}, year = 2015 }