# Presentation: 333978

## Mitch Begelman
JILA, University of Colorado

**Mitch Begelman**
**JILA, University of Colorado**

** ****THE FIRST SUPERMASSIVE BLACK HOLES?  **

## Mitch Begelman
JILA, University of Colorado

**Mitch Begelman**
**JILA, University of Colorado**

** ****THE FIRST SUPERMASSIVE BLACK HOLES?****or...  **

## Mitch Begelman
JILA, University of Colorado

**Mitch Begelman**
**JILA, University of Colorado**

** ****STARS: WHO NEEDS ‘EM?  **

## COLLABORATORS

**COLLABORATORS**

**Marta Volonteri (Cambridge/Michigan)**
**Martin Rees (Cambridge)**
**Elena Rossi (JILA)**
**Phil Armitage (JILA)**

## Why BHs ubiquitous in present-day galaxies
QSOs with M>109M at z>6  
Age of Universe < 20 tSalpeter 

	 Eddington-limited accretion would have to:
Start early
Be nearly continuous
Start with MBH >10 – 100 M 

**QSOs with M>10****9****M******** ****at z>6 **
**Age of Universe < 20 t****Salpeter **
****
**	**** ****Eddington-limited accretion would have to:**
**Start early**
**Be nearly continuous**
**Start with M****BH ****>10 – 100 M******** **

**NEED TO EXPLAIN:**

## The Rees Flow Chart

***Begelman & Rees, MNRAS 1978***

**The Rees Flow Chart**

## 18 years later...with 4-color printing!

***Begelman & Rees, ***
***“******Gravity’s Fatal Attraction” 1996***

***Begelman & Rees, ***
***“******Gravity’s Fatal Attraction” ***
***2******nd****** Edition, coming 2008***

## ...without a stellar precursor?

** ****CAN THE SEEDS OF  SUPERMASSIVE BHs FORM BY DIRECT COLLAPSE? **

## STARS FIRST		DIRECT COLLAPSE

-    ~**10****-4****-10****-2 ****M******** yr****-1**
**Core contraction halted by nuclear ignition**
**High-entropy throughout**

-    **> 0.1**** ****M******** yr****-1**
**Potential too deep for nuclear ignition to halt contraction**
**Low entropy core**
**    ****High entropy envelope**

## ARE HIGH INFLOW RATES POSSIBLE? 

**“****Natural” gravitational infall rate *****v******3******/G***** **
**What *****v***** to use: *****v******vir***** of background or *****c******s*****?  **
**Rotation weak: ~ radial infall, mediated by turbulence, “angular momentum segregation” **
**Rotating: global instability, “bars within bars”**
**Does fragmentation stop collapse? **
**Multiple thermal phases **
**How efficient is star formation?**
** ****Possible sites of rapid infall**
**T****vir****>10****4**** K haloes:      ****> 0.1**** ****M******** yr****-1**
**Aftermath of mergers ****(Di Matteo, Hernquist, Springel ...)**
**Wherever quasars are fed ****(imagine the BH is missing)**

## STRUCTURES LAID DOWN BY RAPID INFALL

**Self-gravity dominates**
**Radiation-dominated, rotation crucial**
**Pre-BH:**
**Entropy small near center, increases with r **
**Very different from the supermassive stars postulated by Hoyle and Fowler**** **
**Post-BH:**
**“****Nuclear” energy source is BH accretion**
**Expands and becomes fully convective**
**Like radiation-dominated (metal-free) red giant**

## RAPID INFALL: NO BLACK HOLE

**Mass m***** ****(M********) increases with time                 ****M********  ****yr****-1**
**Core with  **
**Envelope**
**Entropy increases outward – convectively stable**
**Rotation increases binding energy **
**Outer radius                           constant**
**Core radius                  shrinks**
**Nuclear burning inadequate to unbind star**
**Core mass ~ 10 M******** ****constant**
**When                        core temp.                                               **
**               ****rapid cooling by thermal neutrinos**

## +

**CORE COLLAPSE AND FORMATION OF ~10-20 M******** SEED BH**

**SUBSEQUENT ACCRETION AT EDDINGTON LIMIT **

**+**

## 
BUT WHOSE                        LIMIT?

                      EDDINGTON

**BUT WHOSE ****                     ****  LIMIT?**
**                **
**                      ****EDDINGTON**

## WHOSE                 LIMIT?           

**WHOSE                 LIMIT?           **

**SUPPOSE A SEED BH SETTLES IN THE MIDDLE OF THE ACCUMULATED GAS**

**Max. BH accretion rate is            **_**for the mass of the ENVELOPE**_

**ACCUMULATED GAS**

**BH**

## GROWTH OF AN EMBEDDED BH

**“****QUASISTAR”**

**Could seed BH grow from ~10 to >10****5 ****M****Sol**** at                  ?**
**                                                      ***(Begelman, Volonteri & Rees 06)*** **

**ACCUMULATED GAS**

## STRUCTURE OF A QUASISTAR 

**BH accretes adiabatically from quasistar interior **
**               **
**Adjusts so energy liberated              **
**Radiation-supported convective envelope (w/rotation)**
**Central temp drops to ~ 10****6 ****K**
**Radius expands to ~ 100 AU**
**Photosphere temp. drops as BH grows**
**T****eff**** < 4000 K             opacity crisis    **

## Metal-free opacities

**Metal-free opacities**

## Metal-free opacities

**Metal-free opacities**

**Plausible range of photosphere densities**

**Analogous to Hayashi track, but match to  radiation- dominated convective envelope**

## If Tphot drops below minimum (~4000 K), flux inside quasistar exceeds Eddington limit, dispersing it.

**If T****phot**** drops below minimum (~4000 K), flux inside quasistar exceeds Eddington limit, dispersing it.**

## CONNECTION TO BH ACCRETION

**Once limiting temperature is reached,**

**... ****dispersal is inevitable (and accelerates)**

## Quasistar max. mass > 105 M

**0.1 M******** ****yr****-1**

**1 M******** yr****-1**

**Quasistar max. mass > 10****5**** M******
**BH max. mass > 10****3**** M******

- Forbidden zone, Pop III opacity

## CAN QUASISTARS BE DETECTED? 

***...******consider 10******4****** K haloes as parent population***

## DETECTING A QUASISTAR

**Most time spent as ~4000 K blackbody                          **
**Radiates at Eddington limit for 10****5****m****5**** M********  **** **
** ****                                                          **
** **
**Max flux ~**** **

** ****  **

**PEAK OF BLACKBODY**

## Better to observe @ 3.5μm, on Wien tail
Corona/mass loss/jet         hard tail, easier detection

**Corona/mass loss/jet         hard tail, easier detection**

**DETECTING A QUASISTAR**

## WIEN TAIL – 

**WIEN TAIL – **
**MASS LOSS MAY IMPROVE FURTHER**

## HOW COMMON ARE QUASISTARS?

**HOW COMMON ARE QUASISTARS?**

**100 per L* galaxy**

**1 per L* galaxy**

**...****but their lifetimes are short**

## COMOVING DENSITY OF QUASISTARS

** **

- No enrichment

- Some
- enrichment

- Heavy
- enrichment

**Metal enrichment model from Scannapieco et al. 2003**

** ****L* galaxies**

**COMOVING DENSITY OF QUASISTARS**

## COMOVING DENSITY OF QUASISTARS

**COMOVING DENSITY OF QUASISTARS**

**Lifetime = 10****6 ****yr**

**Metal enrichment model from Scannapieco et al. 2003**

**1 per L* galaxy**

** **

**All 10****4 ****K haloes**

**10****4**** K haloes with ****λ****<0.02**

**100 per L* galaxy**

## QUASISTAR DENSITY ON SKY

**1/JWST field**

**Lifetime = 10****6**** yr**

**10/JWST field**

**QUASISTAR DENSITY ON SKY**

**JWST FOV ~ 4.8 arcmin****2**

## HOW TO DISTINGUISH FROM OTHER OBJECTS?

Colors: ~pure blackbody (not dust reddened)
Observe on Wien tail 
No lines (distinguish from T dwarfs)
Unresolved (distinguish from nearby starbursts)
Clustering (like 104 K haloes) 

**Colors: ~pure blackbody (not dust reddened)**
**Observe on Wien tail **
**No lines (distinguish from T dwarfs)**
**Unresolved (distinguish from nearby starbursts)**
**Clustering (like 10****4 ****K haloes)**** **

## WHAT HAPPENS NEXT?

**If super-Edd. phase extends beyond opacity crisis, BH seeds could be as massive as 10****6 ****M******** **
**Worst case: super-Edd. phase ends at ~10****3 ****M********  **
**10 t****Salpeter ****between z=10 and z=6         growth by  (only) 20,000**
**BUT**** ****           **
**Exceeding L****Edd**** by factor 2            squares growth factor!**
**Mergers can account for factor 10-100 of growth ****           **** **

## CONCLUSIONS I

**Star formation might be bypassed if inflow rate is high enough **** **
**BH seed can form in situ from the infalling envelope itself (aided by ****ν**** ****cooling) or can be captured Pop III remnant **
**BH can grow at Eddington limit for the surrounding envelope, which can be                             ****cvcvcvc****for the BH**

## CONCLUSIONS II

**BH seeds grow inside a “quasistar” powered by BH accretion, with a radiation pressure-supported convective envelope**
**Min. T****eff**** of quasistar is ~4000 K, lifetime is > 10****6**** yr                          **
**Quasistars could be common and may be detectable by JWST **