Anisotropic AGN Outflows Filling The Cosmological Volume Paramita Barai Collaborators: Joël Germain, Hugo Martel Université Laval Québec City, Canada 5th June, 2008 The Central Kpc (Ierapetra, Crete) MAKE ~20 SLIDES --- SINCE ONLY 15 MINS FOR TALK …

Introduction Outflows observed in a large fraction of AGNs Goal: Calculate the volume fraction of the Universe filled by AGN outflows over the Hubble time Energy density Magnetic field Outflows observed in a large fraction of AGNs, both at low and high z’s, which are argued to have impact on several galaxy and star formation and large scale structures. In order to quantify the global impact which these AGN outflows might have we ask the ques … To assess their importance in the cosmic evolution of the Universe, the key question we ask is how much volume of the Universe do these outflows fill. 31-Dec-18 P. Barai, U. Laval

Motivation Spherical Outflow Previous studies Furlanetto & Loeb 2001, ApJ, 556, 619 Scannapieco & Oh 2004, ApJ, 608, 62 Levine & Gnedin 2005, ApJ, 632, 727 Spherical Outflow Anisotropically expanding outflow Implement in cosmological simulations Our Improvement 31-Dec-18

Anisotropic Outflow Blue : density iso-surface, showing the pancake (a circular ripple results from the explosion), Red : temperature iso-surface, showing the outflow. Shows explosion inside a DG that is forming at the intersection of 2 emerging filaments inside a cosmological pancake. Using Adaptive SPH algo. The outflow is anisotropic, bipolar, and goes perpendicular to the pancake plane. As told by Hugo: Snapshots of a hydrodynamic simulation of an explosion inside a cosmological pancake. Shows intersection of 2 filaments with a cluster forming at the center / junction of filaments. Whenever density gets higher than a threshold, eject some amount of hot gas outflow (RED). Einstein De-Sitter model, so z and scale invariant. Center can represent a DG. Then the box dimension is < 1 Mpc. Cosmological outflows expand anisotropically in large scales Away from high-density regions, into low-density regions, along the path of least resistance (Martel & Shapiro 2001, RevMexAA, 10, 101)

Outflow Geometry (Pieri, Martel & Grenon 2007, ApJ, 658, 36) Bipolar spherical cone Spherical coordinates (r, , ) Radius = R Opening angle =  Direction of Outflow = ê (unit vector)

Direction of Least Resistance (DLR) In large-scale filamentary structures, outflow direction is obtained from pressure of surrounding medium Implementation Find DLR around density peaks Taylor expansion of density around a peak inside sphere of radius R Rotate Cartesian coordinates to make cross-terms vanish Largest of the coefficients A, B, C  DLR Density peak means the density of a cell is greater than 6 neighboring cells. AGN locations are in density peak. 31-Dec-18 P. Barai, U. Laval

Methodology N-body Cosmological Simulation Semi-analytical model of AGN outflows Cosmological AGN population from observed luminosity function Distribute AGN in the simulation volume (at density peaks) How? (Procedures): N-body dynamics of dark matter. Our approach. Evolve AGN and their outflows within Simulation Box Compute the volume of the cosmological box filled by the outflows 31-Dec-18

Cosmological Simulation N-body simulations of a cosmological volume Box size (comoving) = 128 h–1 Mpc Triply periodic boundary conditions Expanding with the Hubble flow 2563 dark matter particles 5123 grid Evolve from z=25 up to z=0 P3M code (particle-particle/particle-mesh) Grav. softening length = 0.3  cell size = 75 h–1 kpc Particle mass = 1.32 1010 M CDM model : In subroutine GetUnits : SOME SIMULATION VALUES AND COMPUTATIONAL UNITS: Mean MATTER density at z=0 (g/cm^3) = 2.494912E-30 Mean BARYON density at z=0 (g/cm^3) = 4.106365E-31 Total Mass inside Cosmological Box: Mbox (g) = 4.404429E+50 Mbox/Msun = 2.214394E+17 Total number of DM particles =16777216 Mass of each DMP (Msun) = 1.319882E+10 One side of cubic cosmol. box (Mpc) = 1.818000E+02 One side of cubic cosmol. box (cm) = 5.609767E+26 Grid size of P-M mesh (L_box) = 1.953125E-03 For a virial mass (Msun) = 1.000000E+12 Virial Radius, R_200 (L_box) = 1.753378E-03 Virial Radius (cell size of PM mesh) = 8.977295E-01 Computational Units : Unit of mass : 4.404429E+50 g Unit of length : 5.609767E+26 cm Unit of time : 2.450587E+18 s Unit of luminosity : 9.418218E+48 ergs/s Time unit: (s) = 2.450587E+18 (Myr) = 7.765442E+04 H0 : (cgs) = 2.281507E-18 (comp unit) = 5.591031E+00 Mean IGM pressure at z=0 (cgs) = 5.586580E-19 31-Dec-18 P. Barai, U. Laval

Ambient Medium for AGN Outflows Assume: baryonic gas distribution follows dark matter in the simulation box Ambient gas density : Pressure : Temperature (assuming a photoheated medium) Mean molecular mass : 31-Dec-18 P. Barai, U. Laval

Redshift & Luminosity Distribution Observed AGN bolometric luminosity function (Hopkins, Richards & Hernquist 2007, ApJ, 654, 731) Constant AGN lifetime, TAGN = 108 yr Fraction of AGN hosting outflows = 0.2 Number of AGN Locate AGN at local density peaks Filter density above a minimum halo mass Quoting email from Hugo: This whole issue is confusing. In our simulations, the mass per particle is 1.32e10. So we don't even resolve objects of mass 1.e10. But for locating quasars, we are not using groups of particles to identify halos. Instead, we are using the density on the grid, as in Levine & Gnedin. The mean mass in a cell is smaller by a factor of 8, so it is 1.65e09. But then when a density of 200 times the mean is reached, the mass inside a cell is 3.3e11. If we wanted to actually identify small-mass halos from particles, we would need a much larger resolution. But we are merely looking for places where to locate AGN's. Gnedin & Levine could locate AGN's at any location, with a probability given by the density (their equation 2). As far as I can tell, there is no relation between the density at a chosen grid point, and the mass of the object they will actually locate there. In our case, we have to choose density peaks, and we filtered in order to eliminate local peaks caused by noise. But again, there should be no relation between the filter mass and the mass of the object.

31-Dec-18 P. Barai, U. Laval

All Sources in Box from QLF. NAGN,total = 929805 31-Dec-18 P. Barai, U. Laval

New AGN locations in a slice of box at z = 0 New AGN locations in a slice of box at z = 0.5 Black - Particles (PM), blue - Peaks, red - AGNs Slice at time step z = 0.5. Filtering mass = 109 M. There are 872 peaks and 18 AGNs in this slice which spans x = [0,1], y = [0,1], z = [0.5, 0.5055]. Quoting Joel’s email: The x and y ranges are 0 - 1 (all the box). The z range is 0.5 - 0.5055. (This is the middle... 90 to 91 Mpc / 180 Mpc). The peaks and the AGNs on the graph is only the "new ones" in this time step, in
this slice. P. Barai, U. Laval

Active-AGN Life Jet Kinetic power Jet advance Energy Pressure Relativistic outflow with  = 4/3 Overpressured : p >> px Fraction to convert bolometric to kinetic luminosity, epsK = 0.1. To Convert bolometric luminosity to kinetic luminosity in c.g.s: bLQ(i)=epsK*bLQ(i)*Lsun

Post-AGN Evolution Anisotropic Expansion when overpressured, p > px Sedov-Taylor adiabatic expansion Total AGN energy Adiabatic loss Bipolar conical outflow When reach pressure equilibrium, p = px Passive Hubble evolution, Rcomoving = Constant

Volume Filled Count mesh cells in the simulation box occurring inside the volume of one/more outflow Total number of filled cells, NAGN = total volume of box occupied by outflows Express the total volume filled as a fraction of volumes of various overdensities in the box 31-Dec-18 P. Barai, U. Laval

Fractional Volumes of box of various overdensities filled by AGN outflows (N with C = 0, 1, 2, 3, 5, 7) 31-Dec-18

31-Dec-18 P. Barai, U. Laval

Volume Averaged Energy Density 31-Dec-18 P. Barai, U. Laval

Volume Averaged Magnetic Field 31-Dec-18 P. Barai, U. Laval

Summary Implemented a semi-analytical model of anisotropic AGN outflows in N-body simulations AGN outflows pervade 13 – 24% of the volume of the Universe by the present In some cases occupy 100% of the overdense regions by z > 0 Volume averaged quantities in the filled regions at z = 0 Energy Density = 5 10–18 erg cm–3 Magnetic field = 10–9 Gauss These energy densities are consistent with / within limits of the energy density obtained from the cosmic X-ray background background. The magnetic field is consistent with intergalactic large scale magnetic fields computed by Ryu et al (1998). 31-Dec-18 P. Barai, U. Laval

References Furlanetto, S.R. & Loeb, A. 2001, ApJ, 556, 619 (FL01) Ganguly, R. & Brotherton, M.S. 2008, ApJ, 672, 102 Hopkins, P.F., Richards, G.T. & Hernquist, L. 2007, ApJ, 654, 731 Levine, R. & Gnedin, N.Y. 2005, ApJ, 632, 727 Pieri, M. M., Martel, H. & Grenon, C. 2007, ApJ, 658, 36 (PMG07) Scannapieco, E. & Oh, S.P. 2004, ApJ, 608, 62 31-Dec-18 P. Barai, U. Laval

Backup Slides

Outline Motivation Introduction N-body simulation + semi-analytical approach Outflow expansion : Early and Late phases Anisotropic (biconical) late expansion Results: volume filling fractions Conclusions 31-Dec-18 P. Barai, U. Laval

Anisotropic Outflow 31-Dec-18 P. Barai, U. Laval

Active-AGN Life Kinetic luminosity Jet advance Energy Shock half-opening angle, s = 5 Energy Spherical outflow Pressure Relativistic outflow with  = 4/3 31-Dec-18 P. Barai, U. Laval