# Presentation: 703069

## Savvas M. Koushiappas

- T6 & ISR-1, Los Alamos National Laboratory

- LA-UR/05-8246

*Figure courtesty of  Kip Thorne*

- Based on Koushiappas & Zentner, ApJ, 639, 7, 2005

## What do we know? 

*There is a **plethora of local Universe data**, such as masses, local black hole mass density, M-sigma relation, their AGN connection, etc.  *

## What do we know? 

*There is a **plethora of local Universe data**, such as masses, local black hole mass density, M-sigma relation, their AGN connection, etc.  *
*They are formed ****EARLY***

- Figures courtesy of Andrey Kravtsov

## They are formed EARLY, and that’s a big problem in trying to find out HOW

*There is a **plethora of local Universe data**, such as masses, local black hole mass density, M-sigma relation, their AGN connection, etc.  *
*They are formed **EARLY**, **and that’s a ****big**** problem in trying to find out **HOW*

## How, when and where do supermassive black hole seeds form?

- Madau & Rees, ApJ, 551, L27 (2001)

- Remnants of *the first epoch of star formation*.
**Growth**: *Accretion*

- *

- Remnants of *the evolution of a dense, angular momentum supported protogalactic disk*.
**Growth**: *Mergers*

- Koushiappas, Bullock &Dekel, MNRAS, 354, 292 (2004); Lodato & Natarajan astro-ph/0606159; Begelman, Volonteri & Rees, astro-ph/0602363

- Low mass seeds

- High mass seeds

## Slide 6

## Slide 7

## How, when and where do supermassive black hole seeds form?

- Madau & Rees, ApJ, 551, L27 (2001)

- Remnants of *the first epoch of star formation*.
**Growth**: *Accretion*

- Remnants of *the evolution of a dense, angular momentum supported protogalactic disk*.
**Growth**: *Mergers*

- Koushiappas, Bullock &Dekel, MNRAS, 354, 292 (2004); Lodato & Natarajan astro-ph/0606159; Begelman, Volonteri & Rees, astro-ph/0602363

- High mass seeds

- Low mass seeds

- *

## How can we distinguish between models like these?

## How can we distinguish between models like these?

*Theorist*

*Experimentalist*

## How can we distinguish between models like these?

***LISA***

- Wave amplitude

## Calculating the gravitational wave background

_***Method***__**:**_
- Use a *merger tree* and the *orbital evolution* of subhalos

_**Consider:**_
- “*Migration**”* timescale
* **Radiation recoil*
-  *Three body* interactions

_***Important ingredients: ***_
- - *Distribution* of black hole masses
-  Black hole *merger rate*
- - *Spectrum* of emitted radiation

- Analytical & numerical relativity, see talk by Emanuele Berti

- Koushiappas & Zentner, ApJ 639, 7 (2005)

- Koushiappas & Zentner, ApJ 639, 7 (2005)

- Volonteri, Haardt & Madau, ApJ, 582, 559 (2004)

- Low mass seeds

- High mass seeds

## The gravitational wave background in the LISA data stream

- The gravitational wave background in the *LISA* data stream

_**Testable prediction**_**:**This much _*smaller*_ than this

*A detection of a large gravity wave background = **Evidence for a high merger rate of massive black holes*

*LISA * as a galaxy formation probe:
*It can distinguish between formation mechanisms of  supermassive black hole formation*

- Sesana et al. ApJ 611, 623 (2004)

- Koushiappas & Zentner ApJ 639, 7 (2005)

- 55 *Inspiral*
- 35 *Merger*

- 250 *Inspiral*
- 700 *Merger*