Prompt GRB Optical Follow-upExperiments

 

Hye-Sook Park

Lawrence Livermore National LaboratoryLivermore, CA USA

Hye-Sook Park

Upper Limits on the Prompt Optical Emission

From G. G. William’s PhD thesis (2000)

Hye-Sook Park

• Gamma Ray Bursts are flashes of γ-ray radiationabove 0.1 MeV emanating from point sources,isotropically but inhomogenously distributed inthe universe and lasting 1~1000 seconds

• The BATSE detectors on the CGRO satellitedetect ~1 GRB everyday

• Most Powerful Explosion Since the Big Bang !!— NASA press release May 6, 1998

• Dedicated and automated system• Rapid response utilizing GCN• Wide field-of-view system to cover error box of

early time notice

Experimental Goal & Method

LOTISat LLNL

GRB satellites

LOTIS

GCN

LOTIS attempts to detect optical radiation simultaneously with the γ -raybursts to understand γ -ray burst production mechanism

Hye-Sook Park

LOTIS GRB Counterpart Search Experiments

- 17.6 x 17.6 deg Total FOV- Canon Telephoto f/1.8 lenses (200 mm focal length, 11 cm aperture)- 4 of 2048 x 2048 CCD cameras- Rapidly slewing mount- Weather-proof clam shell housing- Weather station

- Limiting mV ~ 15- GRB response time: < 5 sec- Simultaneous γ to optical flux ratios- Site: LLNL’s test site in California- Operation: Oct ‘96 ~ current- 100% automated system

Hye-Sook Park

Simultaneous GRB Counterpart Searches with LOTIS

GRB970223

GRB970919 GRB971006Time since trigger (sec)

Gam

ma

ray

inte

nsity

(c/

sec)

0 10 20 30

Hye-Sook Park

• There are only 2 events that attempted to seeprompt optical signal along with other follow-upsduring CGRO/BeppoSAX/IPN era

• GRB971227 by LOTIS – no optical flash (Williams et al., ApJ 519, L25)• GRB990123 by ROTSE – optical flash (Akerlof et al. 1999, Nature, 398, 400)

Prompt optical signal and afterglows

Hye-Sook Park

GRB971227:LOTIS obtained 500 images of the X-ray afterglow area from 10 sec to 6 hours;Quasi-simultaneous (10 sec after the burst) limit ~ mV=12.3 (GCNC #19)

GRB971227

Cala Alto 2.2 m telescopeimage; 24 hrs later; J-Band

BeppoSAX1.5 arcminerror circle

mV=12.3

LOTIS Image;10 sec after

mV=10.1

Hye-Sook Park

GRB971227 LOTIS Result mag = 12.3 at 10 sec after the burst mag = 14.2 at 20 min after the burst

LOTIS

γ-ray(Band fit)

X-ray(SAX NFI)

R-bandCastro-Tirado

Williams et al., ApJ 519, L25

Hye-Sook Park

Gamma-ray fluxes notcorrelated with thesimultaneous optical

R-Band Light Curve

GRB990123: Prompt optical flash observed by ROTSE

Akerlof et al. 1999, Nature, 398, 400

P01322-hsp-u-011

ROTSE Observation (Jan 23, 1999)

Galama et al. 1999, Nature, 398,394;Briggs, Band et al. 1999, astro-ph/9903247

Gamma-ray spectracan’t beextrapolated

GRB990123Prompt Spectrum

Hye-Sook Park

Prompt counterparts of Gamma-Ray Bursts:Current understandings and outstanding scientific questions

• Bright optical flash signal:— Is GRB990123 an unique

event?— Is Prompt broadband

spectrum produced by theexternal reverse shock?(Sari & Piran ApJ 520, 641)

• No optical flashing events:— ~30 events do not have prompt

optical signals (Williams ApJ 519 L25, Akerlof ApJ 532 L25)

— Can prompt signal tell story aboutprogenitors?

— Is prompt signal obscured by GRBbirth-site environment?

— Is prompt signal dimmer thanmag~15?

— Why early and later time lightcurves are different?

— When does afterglow start?– 20 sec? 20 min? 2 hours?

More prompt measurements are needed

Hye-Sook Park

Prompt Optical Flash- may be explained by reverse shock (Sari, Soderberg, Ramirez-Ruiz)

• Great energy (1051-53ergs) released in asmall volume -> Relativistic outflow

— Progenitor unknown• Gamma-Ray Burst

— Inhomogeneities within the outflowresult in “internal” shock

• Optical, radio, x-ray Afterglows— “External” shock forms where the

outflow plows into the surroundingmedium

• Prompt Optical— “Reverse” shock propagates back into

the relativistic medium (Sari & PiranApJ, 520, 641)

Synchrotron spectra fromreverse shock model:

E52=5.0; tA=10.0; εe=εB=0.5; S=2.33x10-7 ergcm-2

A: n1=0.02, Γ=200B: n1=0.02; Γ=400C: n1=0.1; Γ=400D: n1=0.1; Γ=400

Hye-Sook Park

LOTIS upper-limits vs. GRB990123

LOTIS upper limits are inconsistent with predictedmagnitude by extrapolating grb990123 flux or peak flux

Similar results by ROTSE (Akerlof ApJ 532, L25)

990123

Hye-Sook Park

Predicted magnitude of the Prompt Optical Flashes

Parameters:γo = Lorentz factorn1 = circumburster material densityεe = fraction of equipartition electron energyεB = magnetic fieldColors = LOTIS detection probability

LOTIS upper limits favor small n1 and large γ0 as well as large εe and small εB.

εe=0.005 εe=0.05 εe=0.5

εB=0.5

εB=0.05

εB=0.005

Fixed Variables:E52 = 5.0tA = 10.0 sgamma-ray fluence = 5.0 x 10-7

Hye-Sook Park

Super-LOTIS for HETE era

Super-LOTIS- Follow-up observations for HETE2, Swift, Integral missions- 0.6 meter aperture: Boller-Chivens telescope-< 30 sec response time : light curve measurement from 30sec to 4 hours- 2048 x 2048 CCD on prime focus- 0.8 x 0.8 deg FOV (1.5 arcsec/pixel)- Sensitivity: mV= 17 ~ 20- V,R,I,Clear filter wheel- Moved to Kitt Peak in April 2000

S-LOTIS

WYNSolar Observatory

SpaceWatch

Kitt Peak, Arizona (USA)

Hye-Sook Park

M88

Sombrero (M104)

The Whirlpool Galaxy (M51)

M31

51’FOV

Super-LOTIS Image Gallery

Hye-Sook Park

Super-LOTIS detected GRB010222 afterglow 23.6 hours afterthe burst. 13 summed image revealed the afterglow at R=20.0.

Super-LOTIS Afterglow Detections: GRB010222

Hye-Sook Park

Super-LOTIS for HETE era

Super-LOTIS- Follow-up observations for HETE2, Swift, Integral missions- 0.6 meter aperture: Boller-Chivens telescope-< 30 sec response time : light curve measurement from 30sec to 4 hours- 2048 x 2048 CCD on prime focus- 0.8 x 0.8 deg FOV (1.5 arcsec/pixel)- Sensitivity: mV= 17 ~ 20- V,R,I,Clear filter wheel- Moved to Kitt Peak in April 2000

S-LOTIS

WYNSolar Observatory

SpaceWatch

Kitt Peak, Arizona (USA)

Hye-Sook Park

M88

Sombrero (M104)

The Whirlpool Galaxy (M51)

M31

51’FOV

Super-LOTIS Image Gallery

Hye-Sook Park

Super-LOTIS detected GRB010222 afterglow 23.6 hours afterthe burst. 13 summed image revealed the afterglow at R=20.0.

Super-LOTIS Afterglow Detections: GRB010222

Hye-Sook Park

M88

Sombrero (M104)

The Whirlpool Galaxy (M51)

M31

51’FOV

Super-LOTIS Image Gallery

Hye-Sook Park

Super-LOTIS detected GRB010222 afterglow 23.6 hours afterthe burst. 13 summed image revealed the afterglow at R=20.0.

Super-LOTIS Afterglow Detections: GRB010222

Hye-Sook Park

Super-LOTIS detected GRB010222 afterglow 23.6 hours afterthe burst. 13 summed image revealed the afterglow at R=20.0.

Super-LOTIS Afterglow Detections: GRB010222

Hye-Sook Park

LOTIS observed the GRB 010921 optical afterglow area reported in GCNC #1107 on09/21/2001 at 06:08:31 (52 min after the burst) during a routine sky patrol. Wesearched for an optical counterpart in the region of GRB 010921 and we found nosource. The 10 sigma limits are: clear filter = 15.5 +/- 0.15; V filter = 15.9 +/- 0.15.

LOTIS Clear Filter LOTIS V Filter DSS Image

Afterglow reported inthis area (GCNC 1107)

20’

20’

N

E

V=13.0

GRB010921: HETE/IPN localizationLOTIS observation 52 min after the burst

Hye-Sook Park

GRB010921- Super-LOTIS afterglow observation

2.5’

Super-LOTIS: T0+21.8 hr Super-LOTIS: T0+25.2hr

Super-LOTIS: T0+45.8 hr

Super-LOTIS: T0+49.2 hr DSS Image DPOSS R Image

http://www.srl.caltech.edu/~react/fits/GRB010921f.fits

2.5’

NE

Super-LOTIS detected GRB010921 afterglow 21.8 hours after theburst. The measured afterglow intensities are: V=19.4 ± 0.2.

Hye-Sook Park

GRB010921 light curve

H. S. Park et al, ApjL, will be published on June 1, 2002.

LOTIS data shows that the power-law decay curve for theafterglow cannot be extended to the early time.

Hye-Sook Park

Other prompt optical counterpart search experimentsExperiment Location Aper

(cm) FOV Pixel

Scale (arcsec)

Sensitivity (V)

Integration (sec)

Response Time (sec)

Status

LOTIS CA 11 8.8 x 8.8° 15 15 10 1~5 operating Super-LOTIS

AZ 60 0.8 x 0.8° 1.5 17 ~ 20 10 ~ 300 30 operating

TAROT France 25 2 x 2° 17 10 3 operating ROTSE-III Austrailia 45 1.9 x 1.9° 3.4 18 10 60

Raptor outer

NM 7.1 4 x 19.5 x 19.5°

34 12 60 1.5 under construction

Raptor center

14.2 4 x 4° 7.2 16 60

Bootes Spain 30 0.6 x 0.6° 4.2 operating

ROTSETAROT RaptorBOOTES-II

Hye-Sook Park

Current & future space programs to solve GRB mysteries

• HETE-2— FREGATE: NaI detector : 6 to 400 keV— WXM : coded aperture camera : 2 to 25 keV— SXM : CCD camera: 0.5 to 10 keV

• SWIFT— BAT: CZT detector : 50 to 300 keV— XRT: X-ray telescope: 0.2 to 10 keV— UVOT: CCD camera: 170 to 650 nm

No infrared measurements!

Mission Agency Coordinate

Error Not ice t ime

delay Event Rate Mission

Schedule BATSE/CGRO N A S A 1 -10 ° 3~5 sec 300 / year Current , Mission ended

on June 3, 2000 SAX Italian-Dutch 10 ’ (WFC) 1~12 hrs 1 / month Mission ended on

April 30, 2002 HETE-2 N A S A 10” ~ 10 ’ real -t i m e 15 / year Current

Launched on Oct. 2, 2000

INTEGRAL International 12 ’ 1~10 min 20~40 / year October , 2002 SWIFT N A S A <4’ 15 sec 100 / year 2003 AGILE European <2’ 1~2/month 2004 GLAST N A S A 5 ’ Real-t ime 100/year 2005

Hye-Sook Park

S-LOTIS Prompt NIR and Optical GRB CounterpartSearches

invar spider frame

coma corrector

focus stage

mountmotordrives

CCD camera

filter wheelinvar spider frame

secondary mirror

CCD camerafocus stageIR camera

dichroic beam splitter

Current system Planned upgrade system

•Focal plane upgrade to install a CCD camera AND an NIR camera•Candidate NIR FPA array

—Rockwell HAWAII HgCdTe array;18.5 µm pitch, 77K cooling, 10 e- RO noise—I,J,H,K filters

•Secondary optics to produce f/7 system—NIR camera FOV will be 8’x8’ (512 x 512 array)—Optical CCD FOV will be 22’x 22’ (2048 x 2048 array)

Utilize already existing Super-LOTIS optics, mount, control system

Hye-Sook Park

Super-LOTIS upgrade Filters

0 0.5 1 1.5 2 2.5 30

0.2

0.4

0.6

0.8

11.0

0

T V λ( )

T R λ( )

T I λ( )

T J λ( )

T H λ( )

T K λ( )

T B λ( )

HawaiiQE λ( )

LoralQE λ( )

tr atm λ( )

30.4 λ

µm

ΚHJΙR

Atmospheric Transmission

HgCdTe QE

Front illuminatedCCD QE

Hye-Sook Park

Super-LOTIS NIR camera expected performance

10 12 14 16 181

10

100

1 .103894.799

1

SNR J mstar 30 sec⋅, 2,( )

SNR H mstar 30 sec⋅, 2,( )

SNR K mstar 30 sec⋅, 2,( )

1810 mstar

Assumptions:G-type starAtmospheric transmissionMirror reflectivityTransmission efficiency through filtersHgCdTe array quantum efficiencyConstant sky background

Sensitivity @ 30 sec & SNR = 10J = 16.5H = 16.2K = 15.8

Hye-Sook Park

REM Telescope:prompt NIR counterpart search experiment at la Silla

• Ritchey-Chretien system• 60 cm, f/2.2 primary, f/8 effective• Alt-azi mount• Dichroic beam splitter• One FPA: HgCdTe 512 x 512 array with

JHK filters, 18 µm pitch, Stirling cyropump cooling

• Other FPA: Optical spectroscophy witha prism and a CCD camera

• Site: la Silla Observatory• Expect to start October 2002

ROSS spectroscophy

NIR camera

F. M Zerbi et al., astro-ph/0203034

Hye-Sook Park

SummaryEarly-time light curves are still mystery

• Simultaneous optical light curve measurementwill provide clues to understand GRB’sprogenitors and their environment

• We need many more prompt / simultaneousGRB counterpart detections

• S-LOTIS and a few other automatic telescopescan measure prompt optical afterglowstriggered by HETE 2

• Prompt IR follow-ups by upgraded S-LOTIS andREM will be important measurements for Swift

LOTIS

SLOTIS

?