2013 multi-messenger transient astrophysics …kiaa.pku.edu.cn/activities/xuefeng_wu.pdfhow...

Bright broad-band afterglows of gravitational wave bursts from mergers of binary neutron stars

Xuefeng Wu Purple Mountain Observatory

Chinese Center for Antarctic Astronomy Chinese Academy of Sciences

May 8, 2013

Collaborators: He Gao, Xuan Ding, Bing Zhang & Zi-Gao Dai

2013 Multi-Messenger Transient Astrophysics Workshop

KIAA, Beijing, China; May 6 - 10, 2013

How WUniverse Expands (I)

2001.9, Nanjing University

Xue-Feng

Wu

Yong-Feng

Huang

Xiang-Yu

Wang

Yi-Zhong

Fan

Bi-Ping

Gong

Zi-Gao

Dai

Tan

Lu

Da-Ming

Wei

Pawan

Kumar

Zhuo

Li

How WUniverse Expands (II)

2009.6, Penn State University

Xue-Feng

Wu

Kenji

Toma

Peter

Meszaros Alessandra

Corsi

Derek

Fox Nino

Cucchiara

How WUniverse Expands (III)

Xue-Feng

Wu

Bing

Zhang

Bin-Bin

Zhang Wei-Hua

Lei

Bo

Zhang

Wei

Deng

He

Gao Qiang

Yuan

2010.1.2, Las Vegas

~ 300 ( 0.1)Mpc z

Credit on David Shoemaker

Motivation

Adv VIRGO & LIGO

2015? 2020?

NS+NS

10.2 ~ 2000 yrEvent Rate

Zhang 2013 ApJL

http://physics.aps.org/articles/v3/29

NS-NS coalescence

Gravitational

Wave

Electromagnetic (EM) emission signal accompany with

a GWB is essential for GW identification.

http://physics.aps.org/articles/v3/29

NS-NS coalescence

Gravitational

Wave

Electromagnetic (EM) emission signal accompany with

a GWB is essential for GW identification.

The brand new channel of GW signals combining with

old channel of EM emission would lead us better

understand our universe.

http://physics.aps.org/articles/v3/29

NS-NS coalescence

Electromagnetic (EM) emission signal accompany with

a GWB is essential for GW identification.

The brand new channel of GW signals combining with

old channel of EM emission would lead us better

understand our universe.

Remnant?

http://physics.aps.org/articles/v3/29

NS-NS coalescence

Electromagnetic (EM) emission signal accompany with

a GWB is essential for GW identification.

The brand new channel of GW signals combining with

old channel of EM emission would lead us better

understand our universe.

Remnant? EOS

http://physics.aps.org/articles/v3/29

NS-NS coalescence

Electromagnetic (EM) emission signal accompany with

a GWB is essential for GW identification.

The brand new channel of GW signals combining with

old channel of EM emission would lead us better

understand our universe.

Remnant? EOS

BH

http://physics.aps.org/articles/v3/29

NS-NS coalescence

Electromagnetic (EM) emission signal accompany with

a GWB is essential for GW identification.

The brand new channel of GW signals combining with

old channel of EM emission would lead us better

understand our universe.

Remnant? EOS

BH

NS

Metzger & Berger, 2012

SGRB

Multi-band transient ~hours, days, weeks,

or even years

Li-Paczyński Nova

Opical flare ~ 1 day

Ejecta-ISM shock

Radio ~years

Li & Paczyński, 1998

Nakar& Piran, 2011

EM signals

for a BH post-merger product

Short GRBs

γ-ray Light curve

Short GRBs

X-ray afterglow plateaus: hints of magnetar?

Rowlinson et al. (2010) Rowlinson et al. (2013)

Li-Paczynski Nova / Kilonova

Metzger et al. (2010)

Radio Afterglows

Rosswog, Piran & Nakar (2012)

What if the central product is

magnetar rather than a black hole?

Why Magnetar ?

Theoretical reason Stiff EoS

Why Magnetar ?

Theoretical reason Stiff EoS

Lattimer (2012)

Stiff equation-of-state: maximum NS mass close to 2.5 M

Why Magnetar ?

Theoretical reason Stiff EoS

Observational reason

Zhang, 2013 (Ref therein)

Lattimer & Prakash (2010)

NS with mass > 2 Msun has been discovered

(e.g., PSR J0348+0432, M=2.01+/-0.04 Msun)

NS-NS systems: total mass can be ~ 2.6 Msun

Why Magnetar ?

Theoretical reason Stiff EoS

Observational reason

Zhang, 2013 (Ref therein) Based on the observations

of the SGRB X-ray afterglows.

Rowlinson et al. 2013 Rowlinson et al. 2010

GRB 090515

NS with mass > 2 Msun has been discovered

(e.g., PSR J0348+0432, M=2.01+/-0.04 Msun)

NS-NS systems: total mass can be ~ 2.6 Msun

Why Magnetar ?

Theoretical reason Stiff EoS

Observational reason

Zhang, 2013 (Ref therein) Based on the observations

of the SGRB X-ray afterglows.

Rowlinson et al. 2013 Rowlinson et al. 2010

GRB 090515

A postmerger magnetar would

be initially rotating near the

Keplerian velocity

P~1ms.

52 2

45 0, 32 10rotE erg I P

49 1 2 6 4

,0 ,15 6 0, 310sd pL erg s B R P

3 2 6 2

45 ,15 6 0, 3

0,

~ 10rot

sd p

sd

ET s I B R P

L

NS with mass > 2 Msun has been discovered

(e.g., PSR J0348+0432, M=2.01+/-0.04 Msun)

NS-NS systems: total mass can be ~ 2.6 Msun

Hotokezaka,et al., arXiv:1212.0905

Mass Ejection during NS-NS Merger

Initial velocity: 0.1 – 0.3 c

Ejected mass: 0.0001 – 0.01 Msun

Jet-ISM shock (Afterglow)

Shocked ISM

Ejecta

SGRB

Radio

Optical

X-ray

X-ray

X-

ray

Poynting

flux

MNS

Magnetar as the central product

SGRB

Late central engine activity ~Plateau & X-ray flare

Magnetic Dissipation

X-ray Afterglow

1000 ~10000 s

8 1 210 ergs cm

Ejecta-ISM shock with

Energy Injection (EI)

Multi-band transient ~hours, days, weeks,

or even years

Gao, Ding, Wu, Zhang & Dai, 2013

Zhang, 2013

Jet-ISM shock (Afterglow)

Shocked ISM

Ejecta

SGRB

Radio

Optical

X-ray

X-ray

X-

ray

Poynting

flux

MNS

Magnetar as the central product

SGRB

Late central engine activity ~Plateau & X-ray flare

Magnetic Dissipation

X-ray Afterglow

1000 ~10000 s

8 1 210 ergs cm

Ejecta-ISM shock with

Energy Injection (EI)

Multi-band transient ~hours, days, weeks,

or even years

Zhang, 2013

Gao, Ding, Wu, Zhang & Dai, 2013

Jet-ISM shock (Afterglow)

Shocked ISM

Ejecta

SGRB

Radio

Optical

X-ray

X-ray

X-

ray

Poynting

flux

MNS

Magnetar as the central product

SGRB

Late central engine activity ~Plateau & X-ray flare

Magnetic Dissipation

X-ray Afterglow

1000 ~10000 s

8 1 210 ergs cm

Ejecta-ISM shock with

Energy Injection (EI)

Multi-band transient ~hours, days, weeks,

or even years

Gao et al, 2013

Zhang, 2013

Rowlinson et al. 2013

Jet-ISM shock (Afterglow)

Shocked ISM

Ejecta

SGRB

Radio

Optical

X-ray

X-ray

X-

ray

Poynting

flux

MNS

Magnetar as the central product

SGRB

Late central engine activity ~Plateau & X-ray flare

Magnetic Dissipation

X-ray Afterglow

1000 ~10000 s

8 1 210 ergs cm

Ejecta-ISM shock with

Energy Injection (EI)

Multi-band transient ~hours, days, weeks,

or even years

Gao et al, 2013

Zhang, 2013

Magnetic Dissipation X-ray Afterglow

Flu

x (

erg

cm

-2s

-1)

t sdT

8 2 110 erg cm s

Zhang, B., 2013, ApJL, 763,22

1/3F With , one can

roughly estimate that the

optical flux could be as

bright as 17th magnitude

in R band.

The proto-magnetar would eject a

wide-beam wind, whose dissipation

would power an X-ray afterglow as

bright as~ (10−8–10−7) erg cm−2 s−1.

The duration is typically 103–104s.

Jet-ISM shock (Afterglow)

Shocked ISM

Ejecta

SGRB

Radio

Optical

X-ray

X-ray

X-

ray

Poynting

flux

MNS

Magnetar as the central product

SGRB

Late central engine activity ~Plateau & X-ray flare

Magnetic Dissipation

X-ray Afterglow

1000 ~10000 s

8 1 210 ergs cm

Ejecta-ISM shock with

Energy Injection (EI)

Multi-band transient ~hours, days, weeks,

or even years

Zhang, 2013

Gao, Ding, Wu, Zhang & Dai, 2013

ISM (n) 0L

Energy conservation equation

49 2 6 4

0 ,15 6 0, 310 pL B R P

34

3sw pM nm R

Ejecta-ISM shock with Energy Injection Gao, Ding, Wu, Zhang & Dai, 2013, arXiv:1301.0439

0

2 2 2: ( 1) ( 1)

rot

sd

dec ej sw

ET

L

T M c M c when

Dynamics depends on and , namely

and

0L ejM

pBejM

Ejecta-ISM shock with Energy Injection

For given different

leads to different

Dynamic cases.

Some of them could

be even relativistic

pB

ejM

, ,2ej ej crM M

3 2

, ,2 45 0, 3~ 6 10ej crM M I P

Non-relativistic

If

14 4~10 , ~10ejB G M M

sd decT T

Ejecta-ISM shock with Energy Injection

X-ray:

Opt:

Radio:

11 2 1~10peakF erg cm s

~10peakF mJy

7~10peakT s

~ 1peakF Jy

4~ ~10peak sdT T s

4~ ~10peak sdT T s

15 4~10 , ~10ejB G M M

~sd decT T

Ejecta-ISM shock with Energy Injection

X-ray:

Opt:

Radio:

3~ ~10peak sdT T s

9 2 1~10peakF erg cm s

~100peakF mJy

7~10peakT s

~100peakF mJy

3~ ~10peak sdT T s

15 3~10 , ~10ejB G M M

sd decT T

Ejecta-ISM shock with Energy Injection

X-ray:

Opt:

Radio:

3~ ~10peak sdT T s

10 2 1~10peakF erg cm s

~10peakF mJy

7~10peakT s

~ 1peakF Jy

3~ ~10peak sdT T s

SGRB

Flu

x (

erg

cm

-2s

-1)

t sdT

8 2 110 erg cm s

X-ray Emission in All Directions

Magnetic dissipation

sdT

Magnetic dissipation +

Ejecta-ISM shock w/ EI

SGRB

Flu

x (

erg

cm

-2s

-1)

t sdT

8 2 110 erg cm s

X-ray Emission in All Directions

Magnetic dissipation

Magnetic dissipation +

Ejecta-ISM shock w/ EI

sdT

3 410 ~10obsT s

Late Re-brightening in SGRB 080503

Late Re-brightening in SGRB 080503

--- Li-Paczynski Model

Perley et al. 2009, ApJ, 696, 1871

Late Re-brightening in SGRB 080503

--- Refreshing Shock Model

Hascoet et al. 2012, A&A, 541, A88

Ek,0 = 7 e 50 erg

Ek,inj = 30 Ek,0

ε_e = (ε_B )^0.5

ε_B = 5 e −2,

p = 2.5

n = 1 e -3 cm−3

z = 0.5

Late Re-brightening in SGRB 080503

--- Gao, Ding, Wu, Zhang & Dai (2013) Model

Ding, Gao, Wu, Zhang & Dai 2013,

in preparation

Relativistic PTF Transient PTF11agg

--- Another GWB magnetar candidate?

Cenko et al. (2013)

Event Rate by VLA Bright Radio Transient Survery

Bower & Sauer. 2011, ApJL, 728, 14

• Field of 3C 286

• 23-year archival observation

• 1.4 GHz

event rate (>350 mJy ) is

< 6×10−4 degree−2 yr−1,

or < 20 yr −1

Bright GWB afterglow rate

uncertainties:

(1) NS-NS merger

(2) Fraction of forming a massive

millisecond magnetar

How to differentiate BH and Magnetar

Gravitational Wave Signal EM Counterpart

Chirp + Ring down

BH:

Magnetar:

After the standard chirp signal and merger

phase, there should be an extended GW

emission episode afterward due to a

secular bar-mode instability of the newly

formed proto-magnetar.

BH:

SGRB: No X-ray Plateau

No-SGRB:

No X-ray

Li-Paczyński Nova

Weak Radio Signal

SGRB: w/ X-ray Plateau

No-SGRB:

X-ray detection

Bright Opt Signal

Strong Radio Signal

Magnetar:

No extended GW

emission after merger

How to differentiate BH and Magnetar

Gravitational Wave Signal EM Counterpart

Chirp + Ring down

BH:

Magnetar:

After the standard chirp signal and merger

phase, there should be an extended GW

emission episode afterward due to a

secular bar-mode instability of the newly

formed proto-magnetar.

BH:

SGRB: No X-ray Plateau

No-SGRB:

No X-ray

Li-Paczyński Nova

Weak Radio Signal

SGRB: w/ X-ray Plateau

No-SGRB:

X-ray detection

Bright Opt Signal

Strong Radio Signal

Magnetar:

No extended GW

emission after merger

Localization Error Box

Strategy to Detect EM Counterpart of GWB

~Tens of square degree

~Tens of seconds before merger

trigger Adv-LIGO

Localization Error Box

Strategy to Detect EM Counterpart of GWB

~Tens of square degree

Two kinds of strategy

1) Small field of view, with both

fast-slewing speed and high

sensitivity.

103–104s could go through

the whole Error Box

~Tens of seconds before merger

trigger Adv-LIGO

GW Localization Error Box

Strategy to Detect EM Counterpart of GWB

~Tens of square degree

Two kinds of strategy

1) Small field of view, with both

fast-slewing speed and high

sensitivity.

If 103–104s could go through

the whole Error Box

~Tens of seconds before merger

trigger Adv-LIGO

~ sd

dec

err

slew TP

A

~ 1decP

Telescope field of view

Strategy to Detect EM Counterpart of GWB

~Tens of square degree

Two kinds of strategy

2) Large field of view, with

fast-slewing capability and

moderate sensitivity.

GWAC

Einstein Probe

~Tens of seconds before merger

trigger Adv-LIGO

GW Localization Error Box

Telescope field of view

~ sd

dec

sky

slew TP

A

If 103–104s could go through

the whole sky ~ 1decP

Thank You