The Evolution and Outflows of Hyper-Accreting Disks

The Evolution and Outflows of Hyper-Accreting Disks

with Tony Piro, Eliot Quataert & Todd Thompson

Brian Metzger, UC Berkeley

Metzger, Thompson & Quataert (2007), ApJ, 659, 561

Metzger, Quataert & Thompson (2008), MNRAS, 385, 1455

Metzger, Thompson & Quataert (2008), ApJ, 676, 1130

Metzger, Piro & Quataert (2008a), MNRAS in press

Metzger, Piro & Quataert (2008b), In preparation

Outline Introduction

Compact Object Mergers and White Dwarf AIC Short GRBs: Recent Advances and New

Puzzles

Hyper-Accreting Disk Models One-Zone “Ring” Model 1D Height-Integrated Model

Disk Outflows and Nucleosynthesis Neutrino-Driven Winds (Early Times) Viscously-Driven Winds (Late Times)

Conclusions

Compact Object Mergers (NS-NS or BH-NS) Lattimer & Schramm 1974, 1976; Paczynski 1986; Eichler et al. 1989

• Inspiral + NS Tidal Disruption– Primary Target for Advanced LIGO / VIRGO

• Disk Forms w/ Mass ~ 10-3 - 0.3 M and Radius ~10-100 km

• Hot ( kT > MeV) and Dense ( ~ 108-1012 g cm-3) Midplane

• Cooling via Neutrinos: ( >>1, ~ 0.01-100 )

• Accretion Rate GRB Progenitor?

€

˙ M ~ 10−2 −10M• s-1

Sh

iba

ta &

Ta

nig

uc

hi 2

00

6

t = 0.7 ms

t = 3 ms

“Chirp”

Accretion-Induced Collapse Nomoto & Kondo 1991; Canal

1997• Electron Capture (24Mg 20Ne 20O)

Faster than Nuclear Burning O-Ne-Mg White Dwarf Core Destabilized

776 ms post bounce

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

Des

sart

+06

Md ~ 0.1 M Disk Forms Around NS

BATSE GRBs

• High Redshift: <z> ~ 2

• Large Energies (Eiso~1052-54 ergs)

• Star Forming Hosts

• Type Ibc Broad-Line Supernovae

Long

Short

Nakar 07

€

tvisc =1

ΩKα

H

R

⎛

⎝ ⎜

⎞

⎠ ⎟−2

≈ 0.4 s MBH

3M•

⎛

⎝ ⎜

⎞

⎠ ⎟

−1/ 20.1

α

⎛

⎝ ⎜

⎞

⎠ ⎟

R

100 km

⎛

⎝ ⎜

⎞

⎠ ⎟3 / 2

H /R

0.2

⎛

⎝ ⎜

⎞

⎠ ⎟−2

Gamma-Ray Bursts: Long & Short Duration

KECK Bloom+06

GRB050509b

GRB050724

Berger+05

HUBBLE Fox+05

GRB050709

z = 0.225 SFR < 0.1 M yr-

1

z = 0.16 SFR = 0.2 M yr-1

z = 0.258 SFR < 0.03 M yr-1

Berger +05

Blo

om

+ 06

Short GRB Host Galaxies

KECK Bloom+06

GRB050509b

GRB050724

Berger+05

HUBBLE Fox+05

GRB050709

z = 0.225 SFR < 0.1 M yr-

1

z = 0.16 SFR = 0.2 M yr-1

z = 0.258 SFR < 0.03 M yr-1

Berger +05

Blo

om

+06

Short GRB Host Galaxies

GRB050724

No SN!(But Some Radioactive

Ejecta Expected…)

• Lower z

• Eiso~ 1049-51 ergs

• Older Progenitor Population

Short GRBs with Extended Emission

(Nor

ris &

Bon

nell

2006

)

GRB050709

XRT, Campana+06GRB050724

Late-Time Flaring

Who Ordered That?!

- Regular ~ 30-100 s Duration - Energy Often Exceeds GRB’s - ~25% of Swift Short Bursts

BATSE Examples

• Mass at large radii ~ rd controls disk evolution and sets

• Model enforces mass & angular momentum conservation

• Thermal Balance:

• Calculates {, T, H} @ rd(t) GIVEN rd,0, Md,0, MBH, and

A “Ring” Model of Hyper-Accreting DisksMetzger, Piro & Quataert 2008a

€

TdS

dt= ˙ q visc − ˙ q ν

€

˙ M Vr < 0

Vr > 0rdBH

Simple model allows wide exploration of parameter space: Initial disk mass/radius, viscosity , outflows, etc.

€

˙ M ≈Md

tvisc (rd )

€

˙ q visc =9

4Ω2ν , ν = α cs H

1) High Thick Disk: H ~ R- Optically Thick Matter Accretes Before Cooling

2) Neutrino-Cooled Thin Disk: H ~ 0.2 R- Optically Thin, Neutrino Luminosity L ~ 0.1 c2

- Ion Pressure Dominated / Mildly Degenerate- Neutron-Rich Composition (n/p ~ 10)

3) Low Thick Disk: H ~ R- Neutrino Cooling << Viscous Heating- Radiation Pressure-Dominated / Non-Degenerate

Three Phases of Hyper-

Accreting Disks

€

˙ M

€

˙ M

€

˙ M

1

2

3

€

e− + p → ν e + n

€

e+ + n → ν e + p

Example Ring Model Solution

MBH = 3 M Md,0 = 0.1 M rd,0 = 30 km = 0.1 tvisc,0 ~ 3 ms

r d (

km)

T (

MeV

)

0.1

Mdc

2 (1

051

erg

s)

€

M (

M s-1

)

.

Mdt-1/3

ttthickthick

Late-Time Thick Disk OutflowsAdvective disks are only marginally bound. When the disk cannot cool, a powerful viscously-driven outflow blows it apart (Blandford & Begelman 1999).

QuickTime™ and aYUV420 codec decompressor


BH

Only a small fraction of ingoing matter actually accretes onto black hole

Haw

ley

& B

alb

us

2002 Nuclear energy from

-particle formation also sufficient to

unbind disk

• XRBs Make Radio Jets Upon Thermal (Thin Disk) Power-Law (Thick Disk) Transition (e.g. Fender +99; Corbel + 00; Fender, Belloni, & Gallo 04; Gallo +04)

• Extended Emission = Thick Disk Transition?• Problem: Requires Very Low Viscosity ~ 10-3

Effect of the Thick Disk WindEffect of the Thick Disk Wind

€

tTHICK ~ 0.1 s α

0.1

⎛

⎝ ⎜

⎞

⎠ ⎟−23 /17

Md ,0

0.1M8

⎛

⎝ ⎜

⎞

⎠ ⎟

9 /17rd ,0

100 km

⎛

⎝ ⎜

⎞

⎠ ⎟9 / 34

MBH

3M8

⎛

⎝ ⎜

⎞

⎠ ⎟

1/ 2

Late-Time Short GRB Activity

tthick?

Other Sources of Extended Emission

Tidal Tail Fallback

Magnetar Spin-Down Following AIC

Rosswog 06, Lee & Ramirez-Ruiz 07

Metzger, Quataert & Thompson 08

1015 G

1016 G

3 1015 G

P0= 1 msGRB060614 Overlaid

NS

High Low

Lee &

Ram

irez-Ruiz 07

€

=˙ E

˙ M c 2

Disk Outflows & Heavy Element Synthesis• GRB Jets Require Low Density, but High Density Outflows

Probably More Common Heavy Element Formation

EBIND ~ 8 MeV nucleon-1 vOUT ~ 0.1-0.2 c• Which Heavy Isotopes are Produced Depends on:

Electron Fraction Ye = np/(nn+np)

Ye Product Nuclei

0.48 - 0.6 Mostly Ni56 - Ideal 9 Day Decay Time

0.4 - 0.48 Rare Neutron-Rich Isotopes (58Fe, 54Cr, 50Ti, 60Zn)

0.3 - 0.4 Very Rare Neutron-Rich Isotopes (78,80,82Se, 79Br)

< 0.3 r-Process Elements (e.g. Ag, Pt, Eu)

€

{n, p} ⇒ α 's ⇒ 12C ⇒ Fe - group ⇒ r - process?

Atomic Number (A)

(Ye = 0.88)

(Ye ~ 0.5)

Rare Neutron-Rich Isotopes (Ye ~ 0.3 - 0.4)

2nd/3rd Peak r-Process (Ye < 0.3) (Ye < 0.2)

• Neutrinos Heat & Unbind Matter from NS:

• Electron Fraction at set by Neutrinos– EBIND = 150 MeV, E ~ 15 MeV

~ 10 Neutrino Absorptions per Nucleon

t = 0.5 s

Bu

rro

ws,

Ha

yes,

& F

ryxe

ll 1

99

5

Neutrino Heated WindsOriginal Application: Core-Collapse

Supernovae (Duncan+ 84; Qian & Woosley 96; Thompson+ 01)

€

n

p⇒

˙ N ν eσ ν e n

˙ N ν eσ ν e p

≈Lν e

E ν e

Lν eE ν e

Ye ⇒ Yeν = 1+

Lν eE ν e

Lν eE ν e

⎛

⎝ ⎜

⎞

⎠ ⎟

−1

Emergence of the Proto-Neutron Star Wind

€

e + n → e− + p

ν e + p → e+ + n

n p n p n

Neutrino-Driven Accretion Disk WindsLevinson 06; Metzger, Thompson & Quataert 08

€

IF GMmn

2R>> E ν THEN Ye

∞ ≈ Yeν

IF GMmn

2R<< E ν THEN Ye

∞ ≈ Yedisk

BH

€

˙ M Wind (R), Ye∞

Yedisk ~ 0.1

€

Neutrino Luminosities Lν e/Lν e

and Mean Energies E ν e/E ν e

Calculated Using a Steady - State Disk Model Given ˙ M disk

L ~ 0.1 c2

€

˙ M

56Ni Production in Neutrino-Driven WindsA

ccre

tio

n R

ate

(M s-1

)

Wind Launching Radius (RISCO)

Thick DiskThin Disk

Optically Thin @ RISCO

Optically Thick @ RISCO

56Ni

Neutron-Rich Isotopes

Neutron-Rich Isotopes

GM

mp/2

R >

E

GM

mp/2

R <

E

1

10-2

10-1

1 10

rd

Metzg

er, Piro

& Q

uatert 2008

Metzg

er, Piro

& Q

uatert 2008

Mini-Supernovae Following Short GRBs

Optical / IR Follow-Up Initial Disk Properties

Li & Paczynski 1998; Kulkarni 2005; Metzger, Piro & Quataert 2008a

Mini-SN Light Curve (MNi ~ 10-3 M and Mtot ~ 10-2 M)

Total 56Ni Mass Integrated Over Disk Evolution: M

etzger, P

iro &

Qu

ataert 2008a

VJ

GRB050509b (Hjorth +05)

Metzg

er, Piro

& Q

uataert 2008a

BH spin a = 0.9

Summary So Far

Neutrino-Cooled Thin Disk PhaseNeutrino-Cooled Thin Disk Phase

- Neutron-Rich Midplane (YNeutron-Rich Midplane (Yee ~ 0.1) ~ 0.1)

- Neutrino-Driven Wind Neutrino-Driven Wind Up To ~ 10 Up To ~ 10-3 -3 MM in in 5656Ni Ni

Mini-SN Mini-SN (+ even more neutron-rich matter (+ even more neutron-rich matter

from larger radii) from larger radii)

Late-Time Thick Disk PhaseLate-Time Thick Disk Phase

- Viscously-Driven Wind Disrupts DiskViscously-Driven Wind Disrupts Disk

- Disk Composition?? Wind Composition??Disk Composition?? Wind Composition??

Late-Time Disk Composition: Disk Thickening Weak Freeze-Out

Pair Captures:

€

e− + p →ν e + n

€

e+ + n →ν e + p

Both Cool Disk AND Change Ye

Weak Freeze Out Non-Degenerate Transition Moderately Neutron-Rich Freeze-Out (Ye ~ 0.25 - 0.45)

Met

zger

, P

iro

& Q

uat

aert

200

8b

H/RH/R

DegeneracyDegeneracy

YYee

YYeeeqeq

The Thick Disk TransitionThe Thick Disk Transition

Md,0 = 0.1 M, rd,0 = 30 km, = 0.3

1D Height-Integrated Disk Calculations



Local Disk Mass r2 (M)EquationsEquationsAngular Momentum / Angular Momentum /

ContinuityContinuity

EntropyEntropy

Nuclear CompositionNuclear Composition

HeatingHeating CoolingCooling

Thickening / Freeze-Out Begins at the Outer Disk and Moves Inwards

Electron Fraction

YeeqYe



Weak Interactions Weak Interactions Drive YDrive Yee Y Yee

eqeq

Until Freeze-OutUntil Freeze-Out

Weak Freeze-Out (A

“Little Bang”)

Neutron-Rich Freeze-Out Is RobustM

pe

r bi

n

M0 = 0.1 M, = 0.3 M0 = 0.1 M, = 0.03

M0 = 0.01 M, = 0.3

Mtot = 0.02 M Mtot = 0.02 M

M pe

r bi

n

Mtot= 2 10-3 M

~10 - 30% of Initial Disk Ejected Into ISM

with Ye ~ 0.2-0.4

Production of Rare Neutron-Rich Isotopes

Hartmann +85

40 Million Times 40 Million Times Solar Abundance!!!Solar Abundance!!!

0.35 < Ye < 0.4

78,80,82Se, 79Br

YYee = 0.5 = 0.5=1-2Ye

YYee = 0.35 = 0.35YYee = 0.4 = 0.4

Merger Rates and the Short GRB Beaming Fraction

Milky Way Short GRB Rate ~ 10-6 yr-1 (Nakar 07)

Jet Opening Angle > 300

Short GRBs Less Collimated than Long GRBs (LGRB~2-100)

From known merging NS systems, Kim+06 estimate:

€

˙ N NS−NS = 3 ×10−5 − 2 ×10−4 yr -1

€

˙ N max ~ 10−5 η

0.2

⎛

⎝ ⎜

⎞

⎠ ⎟−1 Md ,0

0.1M8

⎛

⎝ ⎜

⎞

⎠ ⎟

−1

yr−1galaxy−1

Metzger, Piro & Quataert 2008bMetzger, Piro & Quataert 2008b

€

fb =˙ N SGRB

˙ N max

> 0.13 η

0.2

⎛

⎝ ⎜

⎞

⎠ ⎟

Md ,0

0.1M8

⎛

⎝ ⎜

⎞

⎠ ⎟

(Grupe +06; Soderberg +06)(Grupe +06; Soderberg +06)

Timeline of Compact Object Mergers

1) Inspiral, Tidal Disruption & Disk Formation (t ~ ms)

2) Optically-Thick, Geometrically-Thick Disk (t ~ ms)

3) Geometrically-Thin Neutrino-Cooled Disk (t ~0.1-1 s)

- Up to ~ 10-3 M in 56Ni from neutrino-driven winds (mini-SN)

4) Radiatively Inefficient Thick Disk (t > 0.1-1 s)- Degenerate Non-Degenerate

- PGAS-Dominated PRAD-Dominated

- Neutron-Rich Freeze-Out

Disk Blown Apart by Viscously-Driven Outflow- Creation of Rare Neutron-Rich Elements (“Little Bang”)

Neutrino absorptions don’t affect Ye

strongly in compact merger disks

BUT In AIC, e “flash” from shock

break-out can drive Ye > 0.5

56Ni From AIC Disk Winds

€

e + n → e− + p

Winds synthesize ~10-2 M in 56Ni

Optical Transient Surveys: ~ few yr-1 Pan-STARRs & PTF

~ 100’s yr-1 LSST

Neutron-rich material also synthesized? unusual spectral lines? (e.g, Zn, Ge, Cu?)

Freeze-Out Ye in AIC Disk Neu

trin

o L

um

ino

sity

(er

gs

s-1)

Time After Core Bounce (s)

Dessart+ 06

€

Lν e

€

Lν e

““Flash”Flash”

No No ee Flash Flash

With With ee Flash Flash

Conclusions

Isolated Disk Evolution Cannot Explain Late-Time X-Ray Emission (unless ~ 10-3) Promising alternatives: Tidal tail fall-back and

magnetar spin-down

Neutrino-driven winds create up to ~10-3M in 56Ni Mini-SN at t ~ 1 day

Neutron-Rich Nucleosynthesis CO merger rate: < 10-5 yr-1

(Md,0/0.1 M)-1

Short GRB jet opening angle: > 30(Md,0/0.1 M)1/2

~10-2 M in 56Ni from White Dwarf AIC Target for upcoming optical transient surveys

Short GRB Optical / IR Follow-Up

MHD Disk Simulations: Freeze-Out and Late-

Time Winds

Compact Object Merger Simulations

Neutron-Rich Nucleosynthesis

Observations

Theory

Spectroscopy of Metal-Poor Halo Stars

Gravitational Waves (LIGO; VIRGO)

Future Progress

Optical Transient Optical Transient SurveysSurveys

Spectra of Neutron-Rich Explosions

GRB060614; Mangano+07

Late-Time Optical Rebrightening: Mini-Supernova?

Merger Rates and the GRB Beaming Fraction

• If a fraction ~ 0.1 of initial disk mass is ejected with Ye < 0.4 per event:

€

X• =˙ N ×η Md,0 X × tgalaxy

M ISM

For tgalaxy = 10 Gyr and MISM = 109 M:

Milky Way Short GRB Rate ~ 10-6 yr-1 (Nakar 07)

Jet Opening Angle > 100

Short GRBs Less Collimated than Long GRBs (LGRB~2-100)

From known merging NS systems, Kim+06 estimate:

€

˙ N NS−NS = 3×10−5 − 2 ×10−4 yr -1

Documents

The Evolution and Outflows of Hyper-Accreting Disks