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

2. 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

3. 2.98 0.19 for 0.069<Z<0.2 (red circles)
for Z>0.2 (green triangles)
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

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

5. AGN FEEDBACK IN GALAXY CLUSTERS
HST image of MS cluster
Chandra X-ray image in blue
VLA radio image in red
McNamara & Nulsen 2007

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

7. 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.

8. 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

9. 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.

10. 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

11. 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

12. 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

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

14. 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

15. THANK YOU