Rotation, Supernovae

and Gamma-Ray Bursts

When Massive Stars Die,

How Do They Explode?

Neutron Star

+

Neutrinos

Neutron Star

+

Rotation

Black Hole

+

Rotation

Colgate and White (1966)

Arnett

Wilson

Bethe

Janka

Herant

Burrows

Fryer

Mezzacappa

etc.

Hoyle (1946)

Fowler and Hoyle (1964)

LeBlanc and Wilson (1970)

Ostriker and Gunn (1971)

Bisnovatyi-Kogan (1971)

Meier

Wheeler

Usov

Thompson

etc

Bodenheimer and Woosley (1983)

Woosley (1993)

MacFadyen and Woosley (1999)

Narayan and Piran (2004)

etc

All of the above?

a question that is at

least 65 years old

(Baade and Zwicky 1939)

Ian Strong – left Ray Klebesadel – right

September 16, 2003

Gamma-ray bursts (GRBs) discovered 1969 - 72 by Vela

satellites. Published by Klebesadel, Strong and Olson (1973)

GRBs come in at least two flavors: “SHB”s and “LSB”s

Paciesas et al (2002)

Briggs et al (2002)

Koveliotou (2002)

Shortest 6 ms

GRB 910711

Longest ~2000 s

GRB 971208

“Short Hard Bursts”

Burst duration E50 z host

(sec)

GRB 05009B 0.032 0.0275 0.225 Ellipitical

GRB 050709 0.060 0.229 0.161 Late dwarf

GRB 050724 0.20 1.0 0.258 Early galaxy

GRB 050813 0.35 1.7 0.719 Elliptical

Prochaska et al (2006)

Star formation rate in hosts < 0.3 solar masses yr-1

(fac 10 less than LSBs)

Burst energy at least one order of magnitude less

Hard to make in massive star models

People think most SHBs are

merging compact objects

LSBs ~ 20 > 5 ~ 2 SF galaxies

GRB070201

Intense short hard burst observed by

Konus-Wind, Integral, and Swift

1045 erg if in Andromedabetween March 5, 1979 (2 x 1044 erg)

and SGR 1806-20 giant flare (2 x 1046 erg)

Error box 0.325 sq deg 1.1 deg from center of Andromeda

Previous bright short burst near M81

No gravitational radiation (LIGO)

peak flux 10-3 erg cm-2 s-1

• Most bursts discovered so far (though not necessarily

per fixed volume) are LSB’s at cosmological distances.

Today’s talk focuses on these.

As of April, 2008

131 bursts

SWIFT gives

an average z

about twice as

great and the

farthest GRB,

so far, is at

z = 6.3

www.astro.ku.dk/~pallja/GRBsample.html

Most distant so far is

GRB050904 z = 6.29

Frail et al. (2001)

As a relativistic jet decelerates we see a

larger fraction of the emitting surface until

we see the edges of the jet. These leads to

a panchromatic break slope of the

the afterglow light curve.

LSBs are beamed and their total energy in relativistic

ejecta is ~1051 erg.

Fruchter et al (2006)

The green circles show

GRB locations to an

accuracy of 0.15 arc

sec.

Conclusion: GRBs trace star

formation even more than the

average core-collapse supernova.

They are thus to be associated

with the most massive stars.

They also occur in young, small,

star forming galaxies that might

be metal poor.

LSBs occur in star-forming regions

Pian et al. (2006)

In general, these 4 events:

• Are lower in overall gamma-ray and x-ray

energy than typical LSBs (except for 030329)

• Have a spectrum just as hard as ordinary LSBs

(except for 060218)

• Can be made by jets with ~ 10 - 30 (Kaneko et al. 2007)

• Have much more energy in non-relativistic ejecta than in

the burst

All SN Ic - BL

Environmental Clue

Kelly, Kirshner, & Pahre (2008, submitted)

SN Ic-bl

SN Ic

LGRB

Local SN Ic and GRB have similar locations

compared to host galaxy light

Fruchter etal (2006)

-Similar (large)

progenitor

masses

Fynbo et al (2006)

Gal-Yam et al (2006)

Della Valle et al (2006)

But not all LSBs (or at least LBs) have bright supernovae

Perhaps another mechanism

at work (WD+BH?), or

the SN did not eject any56Ni.

Observations suggest that Z is low!

Fynbo, Jakobsson, & Moeller, et al, 2003, A&ApL, 406, L63

“On the Ly-alpha emission from gamma-ray

burst host galaxies: evidence for low metallicities”

Gorosabel J., Perez-Ramirez D., Sollerman J., et al.,

2005, A&A, 444, 711

“The GRB 030329 host: a blue low metallicity subluminous

galaxy with intense star formation”

Sollerman J., Ostlin G., Fynbo J. P. U., et al.,

New Astronomy, 2005, 11, 103

“On the nature of nearby GRB/SN host galaxies”

Fruchter et al. 2006, Nature, 441, 463 “Long -ray bursts and core-collapse supernovae have

different environments”

Stanek et al., 2006, Acta Astron., 56, 333 “Protecting Life in the Milky Way: Metals Keep the GRBs Away”

Local abundances of GRB-SN and

broad-lined SN Ic

Local SDSSgalaxies(Tremonti etal 2004)

Modjaz et al (2008)

SMC

LMC

Maiolino et al (2008)

astroph0806-2410

AMAZE Survey

ESO-VLT

Z ~ 2 - 3 is an era of

intense metallicity

evolution

Metallicity in low M

galaxies rises slower

than in high M

• How common are SN Ib/c? Local rate:– ~15-20% of all SN

– ~30% of CC-SN

– Broad-lined SN Ic (SN Ic-BL): ~5-10% of all SN Ib/c(Cappellaro et al 1999, Guetta & Della Valle 2007, Leaman et al. in prep)

So SN Ic-BL are 1 - 2% of all supernovae.

GRBs are a much smaller fraction

Not all SN Ic - BL are GRBs

(though they still may be “active” at some level.

Madau, della Valle, &

Panagia, MNRAS, 1998

Supernova rate per 16

arc min squared per year

~20

This corresponds to an

all sky supernova rate

observed at the earth of

6 SN/secFor comparison the

universal GRB rate is

roughly 3 /day * 300 for

beaming or

~ 0.02 GRB/sec

The rate at which massive stars die in the universe is very

high and GRBs are a small fraction of that death rate.

GRB

SN0.3%

Kocevski and Butler (2008)Some detection bias but note

absence of nearby energetic bursts

To Summarize the Observations -

For Common “Long Soft GRBs” (LSBs)

• LSBs are the deaths of massive stars. Most of the ones

studied so far are typically at redshift z >~ 1

• The stars involved may be a rare subset of those stars that make

Type Ic-BL supernovae ~~10%. Most of those that do make

GRBs are not pointed at us

• Many if not most LSBs have bright supernovae that go

along with them but the supernovae sampled so far are

not necessarily a representative sample of (distant) LSBs

• LSBs are favored by low metallicity

• LSBs in general require the production of a relativistic jet

of matter, fields and radiation ( ~ 100; E ~ 1051 erg)

The Place of LSBs in Stellar Evolution

• The observations favor (in fact were predicted by) a

model in which LSBs occur with increasing violence

in stars of lower metallicity

• The conditions that distinguish a LSB from

and ordinary core-collapse supernova are: a) the loss of

the star’s hydrogen envelope, and b) rapid rotation

(to be demonstrated). In fact here, low Z is a surrogate

for high

Today, there are two principal models being discussed

for GRBs of the “long-soft” variety:

• The collapsar model • The millisecond magnetar

Need iron core rotation at death to correspond to a

pulsar of < 5 ms period if rotation and B-fields are to matter

to the explosion. Need a period of ~ 1 ms to make GRBs.

This is much faster than observed in common pulsars.

52 2 2

ro

12 5

t

2 2 -1

E ~ 2 10 (1 ms/P) (R/10 km) erg

j

Total rotational kinetic energy for a neutr

~ (1ms/P) (R/10 km)

on st

cm s at M 1.4 M

a

0

r

6.3 1R=

For the last stable orbit around a black hole in the collapsar

model (i.e., the minimum j to make a disk)

1 2 -1

2

6

11 -6

2 3 / / 3 cm s non-rotatin4.6 10

1

g

2 / 3 / / 3 cm s Kerr a = .5 110

LSO BH

LSO BH

j GM c M M

j GM c M M

= =

= =

It is somewhat easier to produce a magnetar model!

Heger, Langer, & Woosley (2002)

This is plenty of angular

momentum to make either a

ms neutron star or a

collapsar.

Calculations agree that without

magnetic torques it is easy to make

GRBs – too easy.

Similar results by Hirishi, Meynet, &

Maeder (2004)

Spruit (2002)

Braithwaite (2006)

Denissenkov and Pinsonneault

(2006)

Zahn, Brun, and Mathis

(2007)

Torque BrB

B from differential winding

Br from Tayler-Spruit dynamo

"Any pulely poloidal field should be unstable to instabilities

on the magnetic axis of the star" (Tayler 1973)

Approximately confirmed for

white dwarf spins (Suijs et al

2008)

15 solar mass helium core born rotating rigidly at f times break up

If include WR mass loss and magnetic

fields the answer is greatly altered....

with mass loss with mass loss and B-fields

no mass loss or

B-field

15 M rotating helium star

Heger, Woosley, & Spruit (2004)

using magnetic torques as derived in

Spruit (2002)

Stellar evolution including approximate magnetic torques gives

slow rotation for common supernova progenitors. (solar metallicity)

magnetar

progenitor?

This is consistent with what is estimated for

young pulsars

from HWS04

Implication:

Rotation and magnetic fields are a minor (though

perhaps interesting) component in the explosion of

most supernova (Type IIp and Ib)

Notes:

• Ott et al. (ApJS, 2006) - 2D simulations of collapse,

bounce and post-bounce.

“… the magnitude of the precollapse iron core angular

velocities is the single most important factor in determining

the PNS spin.”

• Recent survey of Ib progenitors by Yoon and

Woosley gives P(n*) = 10 to 30 ms.

Much of the spin down occurs as the star evolves from

H depletion to He ignition, i.e. forming a red supergiant.Heger, Woosley, &

Spruit (2004)

solar metallicity

1 2 -1

2

6

11 -6

2 3 / / 3 cm s non-rotatin4.6 10

1

g

2 / 3 / / 3 cm s Kerr a = .5 110

LSO BH

LSO BH

j GM c M M

j GM c M M

= =

= =

Aside:

If the core of a massive star collapsed to a black hole, could

it simply disappear?

Probably not. Either a faint SN if envelope comes off

or a transient ULX if it doesn’t.

Possibly relevant

ApJ, 652, 518 (2006) - McClintock et al.

(spectral analysis of x-ray continuum)

Extreme spin of black hole in a Galactic microquasar

GRS 1916+105 a > 0.98

Two others quite high

Spin natal, not acquired by later accretion,

but mass ~14 solar masses.

See also Liu et al (2008) M33-X7 a = 0.77

But must all massive stars pass through

a red or blue supergiant phase?

Consider stars with the upper 5% of rotation

on the main sequence and standard rotational

mixing parameters.

Further restrict our attention to low metallicity.

Woosley & Heger (2006)

Yoon and Langer (2005)

Yoon, Langer, and Norman (2006)

earlier work by Maeder

-1v 400 km s

eq

H He

C,Ne

O

O

Si

C,Ne

He –burning

C,O produced

never a red giantvrot = 400 km/s

R = 4.8 x 1010 cm

L = 1.9 x 1039erg s-1

0.86

-6 -1 ZM = 2.4 x 10 M yr

0.01 Z

WO-star16 M

main sequence

Vink & de Koter (A&A, 442, 587, (2005))

M(WC) 10 M

M(WN) = 20 M

=

The mass loss rate can be quite low!

A typical He-burning lifetime is 0.5 My.

0.86M Z

Z is ZFe

1/2

1% solar metallicity

M Z

Solar Metallicty

(became RSG)

= 400 km/srot

v

= 400 km/srot

v

H

He-depl

C-depl

PreSN

8 ms pulsar

GRB

1% solar metallicity

10% solar metallicity

Solar metallicity

Yoon, Langer,

and Norman (2006)

Woosley and Heger (2006) find similar results but estimate a

higher metallicity threshold (30% solar) and a higher mass

cut off for making GRBs.

i..e., 1/8 solar

NGRB / NSN << 1%

out to redshift 4

saturates at 2% at

redshift 10

Caveats:

• Magnetic torques (Spruit) uncertain. Certainly

the final angular momentum could be off by

a factor of 2 or more.

• Metallicity means iron in the vicinity of the GRB,

not CNO averaged over the galaxy

• If more mass is lost along the polar axis as

theory suggests, higher metallicities can be

tolerated

• Rotation requirements for making a GRB may

have been overestimated for the millisecond magnetar

model

But how are the GRBs made in

a rapidly rotating massive star?

Dana Berry (Skyworks) and SEW

The Collapsar Model: Basics

•Wolf-Rayet Star – no hydrogen envelope – about 1 solar radius.

• Collapse time scale tens of seconds

• Rapid rotation – j ~ few x 1016 erg s

• Black hole ~ 3 solar masses accretes about a solar mass

Woosley (1993)

MacFadyen & Woosley

(1999)

In the vicinity of the rotationalaxis of the black hole, by avariety of possible processes,energy is deposited.

7.6 s after core collapse;high viscosity case.

The star collapses and forms a disk (log j > 16.5)

Zhang (2008, in progress)

MacFadyen and Zhang, in preparation (this calculation by A. MacFadyen)

Model T16A3 with

jet and disk wind

included parametrically

Slide from N. Bucciantini

Bucciantini, Quataert, Arons, Metzger and

Thompson (MNRAS; 2007) and refs

therein

Assume a pre-existing supernova

explosion in the stripped down core

of a 35 solar mass star.

Insert a spinning down 1 ms magnetar

with B ~ 1015 gauss.

Two phase wind:

Initial magetar-like wind contributes to

explosion energy. Analog to pulsar wind.

Sub-relativistic

Later magnetically accelerated neutrino

powered wind with wound up B field

makes jet. Can achieve high field to

baryon loading.

Density Pressure

4 s

5 s

6 s

Generic Jets

The jet must

maintain its direction

(< 3o) as well as its

energy input for at least

20 s or the jet dies

and there is no GRB.

No GRBs expected from

red or blue supergiants

or from central engines

that precess.

Jets precessed on a period of 2 s with half angle 3, 5, and 10 degrees

Zhang et al (2004)

3D studies of relativistic jets

by Zhang & Woosley (2008, in prep.)

As the energy of the jet is turned

down at the origin, the jet takes an

increasingly long time to break out.

The cocoon also becomes smaller

and the jet more prone to instability.

Jets were inserted at 1010 cm in a WR star with

radius 8 x 1010 cm. Jets had initial Lorentz factor

of 5 and total energy 40 times mc2.

Going to ever lower jet

energies, eventually, one

must confront the

possibility that the jet

either “dies” before

breaking out or shortly

after break out.

Relativistic input turned

off at the base at 22 s.

all calculations by

Weiqun Zhang

Maximum Lorentz factor

here (red) is about 5

or …

The supernova explodes

before the jet breaks out.

If the jet can stay on for

100’s of seconds a bright

transient may still emerge.

SN shock

1048 erg jet introduced following

a 1051 erg isotropic explosion.

Calculations on a 2275 x 2275

cylindrical grid

Implication:

Low energy jets may fail to emerge or emerge with low

Lorentz factors. One still gets a very asymmetric explosion and

possibly intermediate Lorentz factors ( ~ 10 instead of ~ 100)

Common case in stars with less rotation - e.g., nearby

GRBs with nearly solar metallicity?

Can we distinguish the collapsar

and magnetar models?

The biggest shortcoming of the collapsar model is

the large amount of angular momentum necessary to

its operation. The physics of black hole formation

also needs clarifying.

The biggest problem for the magnetar model is the

first second of evolution of a collapsing very

massive star. The accretion rate is about a solar

mass per second. What turns it around and how is

the 56Ni made?

Diagnostics:

• Low mass progenitor (e.g., Mazzai et al 2006)

• Late time magnetar activity

Generally one expects neutron stars in low mass progenitors

and black holes in heavier ones, but can we really infer the

mass of such an asymmetric explosion and is it impossible to make

a GRB with a 20 solar mass progenitor?

If a magnetar is made, one might expect energetic soft gamma-ray

burst repeater activity for years afterwards. GRB 070201 might

(barely) have been visible at the distance of GRB 980425

pulsar collapsar

Makes 56Ni MHD blast Disk wind

neutrinos?

Bright SN Deposition of Typical accretion rates

~1052 erg in 1 sec make 56Ni and not

(hard?) other Fe isotopes

Faint SNa Slow energy Fall back or “unusual”

depositionb, accretion physics

fall back

b But then need some other mechanism to explode the star. MRI?

a possibly GRB 060505 or GRB060614

56Ni

There are two ways 56Ni might be produced.

• A quasi-spherical blast from a millisecond

magnetar, or

• A wind off a disk where temperatures greater

than 5 x 109 K are achieved.

Suppress either one and you lose the 56Ni

The disk wind: MacFadyen & Woosley (2001)

Neglecting electron capture in the disk

Also recent work by Narayan and Piran (2004), Igumenshchev et al (2003), “NDAF”

GRB 070110 - Troja et al. (2007)

z = 2.35

x-ray plateau

~ 20,000 sec

~ 1052 erg

Flares.

log t 2 3 4 5 6

GRB 050904 - SWIFT

redshift 6.29

One of the most

luminous and long

lasting GRBs ever

observed.

Complex light curve.

Explosive outbursts

continued for over two

hours.

Eiso = 3.8 x 1053 erg

T90 = 225 s

Continuing pulsar activity or fall back?

MacFadyen, Heger,

and Woosley (2001)

25 M star

8 M helium core

see also Kumar, Narayan,

and Johnson (2008, in prep)