The Andrzej Sołtan Institute for Nuclear Studies - Pi of the Sky ...

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The Andrzej Sołtan Institute for Nuclear Studies - Pi of the Sky ...

SPIE International Congress On Optics and Optoelectronics 28 August – 2 September 2005, Warsaw

Marcin Sokołowski

PHD student at

Andrzej Sołtan Institute for Nuclear Studies

,,Pi of the Sky'' - search for optical

flashes of extragalactic origin

http://grb.fuw.edu.pl/


Agenda

Pi of the Sky ” collaboration

s cientific motiv ation

detector

flas h recognition algorithms

conclus ions

SPIE , 2 September 2005

http://grb.fuw.edu.pl/


The Andrzej Sołtan Institute for Nuclear Studies

G.Wrochna, K.Nawrocki, M. Sokołowski, J.Mrowca-Ciułacz , M.Górski

Center for Theoretical Physics, Polish Academy of Science

L.Mankiewicz

Pi of the Sky” Collaboration

Warsaw University

Institute of Experimental Physics

M.Ćwiok, H.Czyrkowski, R.Dąbrowski,W.Dominik, L.W.Piotrowski

Astronomical Observatory

B.Pilecki, D.Szczygieł

Warsaw University of Technology

Faculty of Electronics

A.Burd, M.Grajda, K.Poźniak, R.Romaniuk, G.Kasprowicz,S.Stankiewicz

Faculty of Physics

J.Użycki,

M.Molak

Cardinal Wyszyński University

K.Kwiecińska, K.Krupska

In cooperation with :

professor B.Paczyński PRINCETON and G.Pojmański Warsaw University (ASAS)


Scientific m otiv ation

optical counterparts of Gam m a Ray Burs ts - a fterg low s

all kind of short tim escale phenom ena 1sec – 1 year

supernovae exp losions

novae explosions

variable stars

flare stars

SPIE , 2 September 2005

http://grb.fuw.edu.pl/


Gamma Ray Bursts (GRB)

short pulses ( 0.1 – 100 s ) of gamma radiation coming from point

sources on the sky

gamma obsevation only from outside atmosphere – satellites,

information is passed through GCN

about 3 daily occure, over a dozen per month are detected by satellites

extragalactic origin and huge energies : 10 erg / s

33

Sun emits 10 erg / s , it means bilion years of Sun shine !

genesis still remains unknown, many hypothesis – death of massive

star or collision of two neutron stars in binary system

they may be accompanied by optical flash - afterglow

important information is the observation of optical afterglow in

early time – even before gamma emission itself , it cannot be

realized by classical robotic telescopes

51

SPIE , 2 September 2005

http://grb.fuw.edu.pl/


GCN Network

problems :

time of signal propagation from satellite to ground telescope

intertia of telescope

only in 2 cases obseervation seconds after gamma detecion

SPIE , 2 September 2005

http://grb.fuw.edu.pl/


Full Version of Detector

cover wide field of view of the SWIFT satellite ( 2 srad ) - observe

burst area also before the gamma emission

2 x 16 cameras , each covering 20° x 20°

two sets of cameras in places separated by ~100 km in order

to reject artificial satellites ( parallax )

Short exposures : 5-10 sec.

on-line flash recognition algorithm – multilevel trigger system

with high efficiency and effective background reduction

Possibility to re-examine the images in case of late trigger arrival

from the GCN

SPIE , 2 September 2005

http://grb.fuw.edu.pl/


PROTOTYPE OF DETECTOR

Paralactic m ou n t, step en gin es

5 s teps / arc s ec

Two cam eras of sp ecial d esign :

- low noise ( 16 e )

- Peltier coolin g

- fast read ou t 2MHz / p ixel

- m echan ical sh u tter 10 m ln cycles

- objective of focal len gth :

f = 50 m m , f/ d = 1.4

- 2000x2000 CCD ch ip of p ixel siz e

15µm

- field of view ( FOV )

33˚ x 33˚

m

- lim itin g m agn itu d e 11 ( on 10s) ,

m

an d 12- 1 3 for 20 su m m ed fram es

Cu rrently installed at

Las Cam p an as Observatory

( Ch ile ) , very good con d ition s

90% of observin g n igh ts


Pi apparatus in ASAS dome


Background Reduction

1.00E+010

1.00E+009

1.00E+008

1.00E+007

1.00E+006

1.00E+005

1.00E+004

1.00E+003

1.00E+002

Camera K2A

Camera K2B

COSMICS REJECTION

11 events

1.00E+001

Total

Tn

Tv

MinPrev

Overlap

Hot

If More

Coinc

Satellite

Star

Tracks

Shape

Number of objects after selection

Selection Criteria


-2 -1

0 1

2

Cosmic

Meteor

Plane

Satellite

SPIE, 2 September 2005

http:://grb.fuw.edu.pl


Event Type

Event#

Flash 112

Satellites 887

Planes 234

Flash or satellite 50

Satellite or plane 150

Cosmics 48

Clouds 391

Fluctuation 210

Blooming 17

Meteor 32

Movement 78

Dome 5

Other 861

Total 3075


Summary of observed flashes :

Outburs t of flare s tar CN Leo

92 flashes of unknown origin visible on both cam eras,

but on single 10 s im age

7 flashes visible on 2 consecutive fram es

3 increases of star brightness was d etected

novae star exp losions have been observed

no correlation of our flashes with GRB events was found

interesting background events : bolid exp losion

SPIE , 2 September 2005

http://grb.fuw.edu.pl/


Flare Star V* CN Leo : 20050402

-1 0 +1 +2

+3 +4 +5 +6

SPIE, 2 September 2005

http:://grb.fuw.edu.pl


Flare Star V* CN Leo : 20050402

Increase of brightness from 13.5m to 9.0m , ∆m=4.5m ( ~ 100 times )

SPIE , 2 September 2005

http://grb.fuw.edu.pl/


Conclusions

Pi of the Sky” prototype is working since June-2004,

~ 1 mln images has been collected, gives a very

good lesson before construction of full system

system is cap able of d etectin g op tical flash es

fu ll system will cover field of view of SWIFT satellite

m ore GRB will be in ou r FOV ( n ow on ly 2 even ts )

works on fu ll system h as started ...

http:/ / grb.fuw .edu.pl/

SPIE , 2 September 2005

http://grb.fuw.edu.pl/

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