PRESIDENCY UNIVERSITY X-ray Surface Brightness Profiles of Galaxy Groups from Cosmological Simulations RUDRANI KAR CHOWDHURY PRESIDENCY UNIVERSITY M.Sc thesis advisor Suchetana Chatterjee

Lx – T Relation in Galaxy Groups/Clusters Analytic models and numerical simulations of cluster formation predict that temperature and X-ray luminosity are related as but observation shows that

2.98 0.19 for 0.069<Z<0.2 (red circles) 2.62 0.21 for Z>0.2 (green triangles) 2.69 0.18 for cooling clusters (blue squares) Andersson et. al 2009 Some other effect seems to be responsible for changing the LX-T slope. One possibility is AGN Feedback

ACTIVE GALACTIC NUCLEI (AGN) CENTRAL SUPERMASSIVE BLACK HOLE IN A GALAXY ACCRETING MASS FROM THE SURROUNDINGS

AGN FEEDBACK IN GALAXY CLUSTERS HST image of MS0735.6 + 7421 cluster Chandra X-ray image in blue VLA radio image in red McNamara & Nulsen 2007

OTHER OBSERVATIONAL PROOF OF AGN ACTIVITY Cooling flow problem in galaxy clusters Cosmic downsizing

Aim of this Work Using two cosmological hydrodynamic simulation we now want to study the effect of feedback on the X-ray surface brightness profile of galaxy groups. Both simulation starts from the same initial conditions. One set includes a model of AGN feedback One set does not include AGN feedback.

COSMOLOGICAL SIMULATION The simulation used in this purpose has the following properties…. Box size Total no. of particles in the box Total no. of particles is the sum of cold dark matter particles gas particles, star particles and black hole particles. Mass of dark matter is Mass of gas particles is

Simulation Snapshot Density of gas color coded by temperature. DiMatteo et al. 2008 Density of gas color coded by temperature. Yellow circles represent black holes. Dark matter and stars are not shown in this plot.

BLACK HOLE FEEDBACK Seed black hole grow in size by accreting mass from the surrounding Accretion rate is given by Luminosity of the black hole is Feedback energy is

METHODOLOGY Spherical region of radius 100 kpc is considered around the black hole X-ray map is constructed by allocating spatial grids to the region of space and computing smoothed x-ray flux at a given grid point To construct the x-ray surface brightness profile , map is divided into a no. of annular regions and x-ray flux of each region is calculated and a differential profile of flux is made as a function of distance Mass of 2nd most massive BH at Z=3 is Accretion rate is Mass of the host halo of this black hole

RESULT The left panel shows the X-ray map with feedback for 2nd most massive black hole at Z=3. The right panel shows the x-ray map without feedback for the same black hole

This is the differential profile of x-ray flux for with (dotted line) feedback and without feedback (solid line) cases

Conclusion and Future Work Without AGN feedback the x-ray flux is high at the centre X-ray flux is low at the centre & high outside when AGN activity is considered Our result is in accordance with the observation by McNamara & Nulsen We have studied this AGN activity for one red shift & one black hole In future our plan is to study this effect for more than one red shift & black hole

THANK YOU