Flares

unkindnesskindUrban and Civil

Nov 15, 2013 (4 years and 1 month ago)

90 views

GRB
s

CENTRAL
-
ENGINE

&

FLARes

WARSAW
-

2009

Guido
Chincarini


&

Raffaella

margutti

1

WARSAW 2009

2

From

a serene

garden

To

A violent

universe

WARSAW 2009

WE WILL SHOW


GRBs

generalities


&

Optical

follow

up

at

ESO


&

in preparation
for publication


Characteristic

time

of

the

central

engine

activity

is

about

1000

s
.


The

energy

on

flare



residuals

activity

is

about

10
51

erg
.

Rest

Frame

2
.
187



14
.
43

keV
.


We

estimate

an

activity

time

[

~

20

s

]

and

the

time

the

central

engine

is

active

compared

to

the

total

time

of

the

afterglow
.

WARSAW 2009

3

GENERALITIES

WARSAW 2009

4

What is a

Gamma

Ray Burst ? (1)

Hubble Deep Field

EXTRA


galactic

events

GRB060614

Host Galaxy

At cosmological

distances
(z=6.7)

Local

Universe

(z
<0.1
)

5

WARSAW 2009

WARSAW 2009

What is a

Gamma

Ray Burst ? (2)

EXPLOSIONS
linked to the
death of stars

E
10
53
erg

6

Here

we

will

be

dealing

with

long

GRBs

.

That

is

the

prompt

emission

lasts

generally

more

than

two

seconds
.

The

Host

Galaxy

is

a

late

type

with

rather

high

specific

star

formation

rate
.

Short GRBs occur in early and late type Galaxies

7

WARSAW 2009

What is a

Gamma

Ray Burst ? (3)

TRANSIENT

NON
-
PERIODIC

events with duration
between 0.1
-
100 s

(prompt gamma

emission)

-
ray emission

VELA

Swift

AGILE

INTEGRAL

Fermi

….. MAXI


8

WARSAW 2009

What is a

Gamma

Ray Burst ? (4)

MULTI
-
WAVELENGTH

LONG
-

LASTING

emission

(months, years)


Swift

TRIGGER!!!!

Afterglow

REM


Robotic Telescopes

9

WARSAW 2009

Swift


XRT


SERVICE
-

OPT Follow UP


UNIQUE

PI

ASI

INAF

REM

ESO

TNG

ASDC

MISTICI

CIBO

OAB

IASF_PA

IASF_MI

WARSAW 2009

10

11

WARSAW 2009

GRB080329B


See eventually Movie
-

STOP Show


VLC


Open in GRB
-

Plot

Here the real challenge for the future

Time since BAT trigger in seconds

Log(Time)


Log (Flux)


t
break1

t
break2


t
-
1


t
-
2


t
-
3

Prompt

Afterglow

A long
GRB

explosion

Black Hole

12

WARSAW 2009

Light Curve Morphology
-


Time

Flux

old intruments

t
-


1

t
-


2

t

-

3

t
break

t
break

Many afterglows have

a typical pattern

Steep



flat



steep

Prompt Emission

Tail

External shock ?


Afterglow

13

WARSAW 2009

WE ADD FLARES

A is behind the shock

front of the amount

d = R/

2

14

WARSAW 2009

Light Curve Morphology
-


Time

Flux

old intruments

t
-


1

t
-


2

t

-

3

In the Swift era


Base for the analysis

t
break

t
break

Many afterglows have

a typical pattern

Steep



flat



steep

Prompt Emission

Tail

Active Engine

Old type

Afterglow

15

WARSAW 2009

ADD FLARES







1
1
1
2
1
2
1
2
0
2
1
1
exp 0
1 4
1
( )
1
r
r
r d
r r
r
m m
t
t
d
t
dec rise
t
dec ris
r d
t
t d r t
I t A for t
F t
t
t d r d r t
Width
A e
F t
asymetry
t t e t






 

 









 
 
   

  
 
 
 
   

 
 
 
   

 

 

 
 
 


 
 
 
 

 



 

 


 
 
 

 
 

 
 

e











Norris 2005

Kocevski
,
Ryde,Liang

2003

(Norris 1996)

(Kobayashi)

Et al. 1997

WARSAW 2009

16

WARSAW 2009

17

WARSAW 2009

18

GRB050724 and Flare activity


To

keep

the

sample

very

controlled

we

disregarded

in

this

work

the

flares

observed

in

SGRBs
.

However

to

illustrate

a

classical

example

we

show

the

light

curve

of

GRB
050724

and

a

possible

empirical

interpretation

of

the

early

decay

and

of

the

late

flare
.

All

fits

have

been

applied

using

the

Norris

2005

function
.

GRB060115 We show a possible fitting of the background light
curve and the various flares fitted by a
norris

2005 function

WARSAW 2009

19

WARSAW 2009

20

GRB051117A

GRB
050904

not

used
.

Late

flare

activity

rather

unusual

and

evolutionary

effects

may

be

important
.

The

effect

on

the

mean

light

curve

is

shown

in

any

case

later

on
.

WARSAW 2009

21

Light curve from GRB050904 flares

WARSAW 2009

22

The sample


36 GRB
s

Margutti



Bernardini



et al.


Long GRBs


For instance no GRB050724.


Only GRBs with spectroscopic
redshift
.


Flares must be detectable by naked eye.


The analysis has been done on the GRB rest
frame.


The standard light curve has been subtracted.


The common energy interval to all flares is
finally from 2.187 to 14.43
keV
.

23

WARSAW 2009

GRB FLARES

CONCLUSIONS

WARSAW 2009

24


Charecteristic

time

of

the

central

engine

activity

is


about

1000

s
.


The

energy

on

flare

activity

is

about

10
51

erg
.

Full

agreement

with

previous

indipendent

analysis

[COSPAR]



However

here

proper

energy

band

rest

frame


We

estimate

an

activity

time

[

~

20

s

]

and

the

time

the

central

engine

is

active

compared

to

the

total

time

since

the

alert

of

the

GRB
.


Energy

to

power

the

flares

noy

yet

known
.

Accretion,

spinning

down

pf

msgnetar
,

……
..

TBD


.


Back up

WARSAW 2009

25

WARSAW 2009

26

Figure from Kumar & Mahon 2008

Syn. cooling & curvature

Kumar&Panaitescu

Dermer

Sari et al.

This

equation

is

quite

robust
.


It

is

valid

for

both

the

forward

and

reverse

shock

and

it

is

independent

of

whether

the

reverse

shock

is

relativistic

or

Newtonian
.

Fennimore et al. Width = k E
-
0.42


If

we

assume

the

main

factor

is

the

curvature

effect

we

have

the

following

[The

Observer

way,

however

see

later

more

formal

derivation

by

Lazzati

&

Perna
:


1
1
1
2
1
1
2
2
2
1
2
;
2
2 1
0.29
peak
peak
peak peak peak
peak
f
f
f f f
f
f t with
f
t
t f
t
f
HPFW t t t
HPFW
t







 






  
 
 
 
 
  
 
 
 
   
 
 
 

2
 
 
27

WARSAW 2009





+



t
ej
+

t
ej

t
ej




2
2 2
2
2 2 2
2 2
2
2
1
ej ej ej
Flare t t t
flare flare ej
ej ej
flare
ej
flare ej
ej
flare ej
ej
flare flare
R R R
c t c t t c
t t
t
t
t t
t
t t t
t
t
t t
   
 
     





 
  
 

    




 





1
2
1
2
1
2
2 1 4 2 2
2 1 0.25
2 1 1
FWHM
Peak
FWHM
Peak
FWHM Peak
Peak ej
t
t
t
t
t t
t t







 

   
 
 
 

  
 
 

  
 
 
 
 
 
 
External

Lazy

t
ej



t
flare


28

WARSAW 2009


1


2


p

w




r


d

50

80

63

163

.49

42

121

250

80

141

227

.35

74

153

450

80

190

259

.31

90

170

650

80

228

281

.28

101

181

850

80

261

300

.27

110

190

29

WARSAW 2009

WARSAW 2009

30

GRB060526

31

WARSAW 2009

<>= 0.29
±

0.53

32

WARSAW 2009

WARSAW 2009

33

Slope 1.79

Note I have the same type of graph with

TAU increasing with WIDTH

slope 0.78
±

0.014

34

WARSAW 2009

WARSAW 2009

35

36

WARSAW 2009

<> = 0.36
±

0.2

WARSAW 2009

37

( )
dec rise
dec rise
asymetry
 

 



Norris 2005

WARSAW 2009

38

...
d
a b
d d
t t
Norm
br br

 
   
 
 
   
   
 
 
39

WARSAW 2009

Correlation

Mean

width

Energy
.

To

this

the

BAT

data

for

Flares

in

common

are

being

added
.


40

WARSAW 2009

WARSAW 2009

41

42

WARSAW 2009

Log versus Log

GRB060512

T90 = 8.4 s


z =0.44

See GCNs

GRB070124

short

THESE ARE SOME OF THE
HYPOTHESIS & PROBLEMS

SEE A FEW EXAMPLES


Do

we

need

to

subtract

the

background

underlying

curve

always?


I
f

yes

we

should

know

where

it

is

coming

from



BAT

observations
.

Is

the

precursor

having

any

role?


I
s

it

always

the

last

flare

for

the

early

XRT

slope

or

a

combination

of

spikes

or

something

else
.


Decay

slope

and

cooling



How

to

approach

it

best
.

WARSAW 2009

43

WARSAW 2009

44

GRB 060111A

Do we need the

underlying power law light

Curve?

WARSAW 2009

45

GRB 060111A
-

S

WARSAW 2009

46

GRB
060714



See

also

Krimm

et

al
.
,

2007
,

ApJ

665

-

554


WARSAW 2009

47

Light Curve Morphology
-


Time

Flux

old intruments

t
-


1

t
-


2

t

-

3

In the Swift era


Base for the analysis

t
break

t
break

Many afterglows have

a typical pattern

Steep



flat



steep

Prompt Emission

Tail

Active Engine

Old type

Afterglow

48

WARSAW 2009

WARSAW 2009

49

Mechanism producing the jets?


The observed flares have similarities to the
variability observed during the prompt emission.
They must be related to the activity of the central
engine at time at which the flares are observed.


Conversion of internal energy into bulk motion
with hydrodynamic collimation.


Energy deposition from neutrinos.


Energy released from rapidly spinning newly born
magnetar

and magnetic collimation and
acceleration.




50

WARSAW 2009


# GRB
s

Analyzed


April 15
-

2008

247
-

GRBs

83 with z

7
-

No spectra

Not early
observ

66 OK

15 no steep
decay

7 single power
law

44 steep decay
or flare

26 with flare

11 No steep
decay

15 steep

8 1 spectrum

5 many spectra


const

2 spectral
evolution

18 no flares

10 only 1
spectrum

4 More than 1
same


4 spectral
evolution

164 no z

10 One PL

41 Flares

75 no Flares

Various Fits

31 low stat or

late
Obs


7 No
lc

51

IN 4 bands and TOT

WARSAW 2009

Flares
[UPDATE 080530]

47 GRBs

67 Flares

29
Redshift

No z

33
-

69 C07

33


77 F07

52

WARSAW 2009

NORRIS 2005


CH 1 25


50


keV


CH 2 50


100


CH 3 100


300


CH > 300

WARSAW 2009

53

WARSAW 2009

54

GRB050502B
-

Three components

55

WARSAW 2009