可視・ X 線・ γ 線同時観測で探る γ 線バースト (Exploring GRBs through Optical, X-ray and Gamma-ray Observations)

GRB_Fermi-WAM-Kanata_2009May.ppt

Tsunefumi Mizuno 1

可視・可視・ XX 線・線・ γγ 線同時観測線同時観測で探るで探る γγ 線バースト線バースト

(Exploring GRBs through (Exploring GRBs through Optical, X-ray and Optical, X-ray and

Gamma-ray Observations)Gamma-ray Observations)

Tsunefumi MizunoTsunefumi MizunoHiroshima Univ.Hiroshima Univ.

7 May 2009, Tokyo Tech, Japan7 May 2009, Tokyo Tech, Japan


Tsunefumi Mizuno 2

OutlineOutline

• Fermi Gamma-ray Space TelescopeFermi LAT and GBMBurst Advocator

• GRBs seen by FermiOverview GRB080916CGRB081024B

• Kanata Telescope for GRB


Tsunefumi Mizuno 3

The Fermi Gamma-ray Space TelescopeThe Fermi Gamma-ray Space Telescope

Spectrum more than 7 energy decades!!

• GBM (GLAST Burst Monitor)Consists of 12 NaI and 2 BGO detectors.

Energy range: 8 keV – 30 MeVField of view: 9.5 str Initial localization: <15 deg in 2s

• Launch on 11 June 2008• LAT (Large Area Telescope)

Energy range: 20 MeV-300 GeVEffective Area: ~8000 cm2

FOV: 2.4 sr (EGRET 0.5 sr)Dead time: 26.5 s (EGRET 100 ms)


Tsunefumi Mizuno 4

Burst AdvocatorBurst Advocator Scientists serve as “Burst Advocator” and cover 24 hrs/day and 7 dyas/week

Japanese B/A consists of young members from 3 institutes;

Masanori Ohno, Rie Sato (ISAS/JAXA), Yoshitaka Hanabata, Takeshi Uehara and Hiromitsu Takahashi (Hiroshima Univ.), Takeshi Nakamori, Takashi Shimokawabe (Tokyo Tech.)

Report on the LAT visibility and check the LAT data

Successfully issued GCN circular for GRB 090217 and GRB090323 which occurred during Japanese shift.


Tsunefumi Mizuno 5

Fermi Detection of GRBsFermi Detection of GRBs

GRB080825C (GCN8183, Bouvier et al.)

GRB080916C* (GCN8246, Tajima et al.) (Abdo et al. 2009 Sci, 323, 1688)

GRB081024B (GCN8407, Omodei et al.) (short GRB w/ GeV photons)

GRB081215A (GCN8684, McEnery et al.)

GRB090217 (GCN8903, Ohno et al.)

GRB090323* (GCN9021, Ohno et al.)

GRB090328* (GCN9044, McEnery et al.; GCN9077, Cutini et al.)

• GBM : GRB detection rate is ~200/yr. (08/11/2008 – 03/10/2009 116 GCN Circulars)

• LAT : 7 GRBs detected until May 2009 and notified to GCN Circulars. Detection rate is ~10/yr.

2 LAT GRBs w/ WAM detection

4 GRBs w/ GeV photons3 GRBs w/ redshift (*)2 GRBs w/ GCN by Japanease BA


Tsunefumi Mizuno 6

GRB080916CGRB080916C

• z=4.35 +/- 0.15 (GROND; GCN8257)

• More than 3000 LAT photons, 145 above 100 MeV and 14 above 1 GeV. Eh=13.2 GeV

• Delayed & temporary extended (t>200s) HE emission

8-260 keV

260 keV-5 MeV

LAT (all)

>100 MeV

>1 GeV


Tsunefumi Mizuno 7

Implications from GR080916CImplications from GR080916C• Delayed & Extended HE emissions• Fitted by a single Band function.

Eiso ~ 8.3 x 1054 ergs, highest ever observed. No conclusive evidence of extra component

• Minimum bulk Lorentz factor840±40 (from opacity in bin-’b’)

• EBL effect not included

min MQG

(GeV)

Pulsar

(Kaaret 99)

GRB

(Ellis 06)

GRB

(Boggs 04)

AGN

(Biller 98)

AGN

(Aharonian 08)

GRB080916C Planck mass

1015 1016 1017 1018 1019

• Lorentz invariance violation– 13.2 GeV @ T0+16.5 s– MQG> (1.5±0.2) x 1018 GeV/c2, 1/10 of the Plank mass


Tsunefumi Mizuno 8

GRB081024BGRB081024B

Preliminary!

Preliminary!

-4 -2 0 2 4 6 8 10

NaI 8 – 260 keV

BGO 260 keV – 5 MeV

LAT all events

LAT > 100 MeV

• The first non-controversial short GRB w/ GeV photons• 11 photons above 100 MeV, Eh=3 GeV

• no redshift

• Single Band function, delayed HE onset & temporary extended HE emission (common feature among LAT GRBs?)

•min~100 (z=0.1), ~700 (z=3.0) (from opacity in bin-”b”)


Tsunefumi Mizuno 9

HOWPol on Kanata TelescopeHOWPol on Kanata Telescope (1)(1)(Hiroshima One-shot Wide-field Polarimeter)

CCD dewer

Focus adj. stage

Focal maskexchanger

Collimatorlens Camera lens

Filter exchanger Prism exchanger

Shutter and pupilPolarmetric

unit exchanger

１露出型偏光撮像（広視野 7’×7’ 、狭視野 1’×15’ ）

• 2008 年 7 月 28-31 日　ファーストライト検出効率： B: 8%, V: 20%, R: 30%, I: 28% ( 望遠鏡、大気込み )

• 2008 年 11 月 4 日～　定常試験観測開始器械偏光 ~4% 　（第三鏡による偏光面回転のみの補正で 0.6%精度が達成）試験観測、超新星観測が主（ GRB アラート対応観測はTRISPEC で）

• 2009 年 5 月 3 日～　 GRB アラート対応自動観測開始


Tsunefumi Mizuno 10

HOWPol on Kanata Telescope (2)HOWPol on Kanata Telescope (2)

• 2008 年度中は HOWPol での GRB 観測は間に合わず　　 TRISPEC での GRB 観測は 9 例、うち 2 例で

detectedGRB t_start –t_end Satel. ⊿t comment--------------------------------------------------------------------080426 13:30:31-13:50:15 Swift, 428 s, Non-detection, shortburst080506 17:49:26-19:22:30 Swift, 185 s, R=17.5-19.3 (Uehara+ in prep)080810 13:16:23-19:39:17 Swift, 371 s, R=13.9-18.7 (Uehara+ in prep)080905 12:01:32-12:58:06 Swift, 157 s, Non-detection081012 13:16:17-14:06:13 Swift, 353 s, Non-detection081211 15:22:22-15:40:37 Swift, 3.6 hr, Non-detection081211B 15:47:29-15:49:02 Swift, 14.5 hr, Non-detection081222 13:09:15-13:21:14 Swift, 8.3 hr, Non-detection090217 14:20:13-16:00:17 Fermi, 9.4 hr, Cloudy, non-detection

090404 16:02:44-16:21:13 Swift, 374 s, Cloudy, non-detection090410 18:48:50-19:01:18 Swift, 1.8 hr, Low-altitude, non-detection090417B 15:31:49-15:38:18 Swift, 706 s, Non-detection090418 12:35:35-12:38:19 Swift, 1.5 hr, Cloudy, non-detection090426 12:54:09-13:28:22 Swift, 322 s, non-detection z=2.609

⊿t は衛星のトリガーから露出開始（ t_start ）までの経過時間


Tsunefumi Mizuno 11

• 2009 年 5 月 3 日から GRB 対応観測（但し狭視野モード用のウォラストンプリズムを視野マスク無しで使用するため背景スカイが 4 倍高くなり観測限界は悪い）

• 2009-2010 年度公募研究「明るいガンマ線バースト初期残光の偏光分光測光同時モニター」にて広視野モード用のウォラストンプリズムを導入予定 ( 川端の講演 )


GRB 080506 ： X 線フレアと相関しない可視残光

GRB 080810 ：ゆっくりと青くなっていく可視残光

可視

・近

赤外

　　

Ｘ線Ｘ線

緑　可視Ｖ青　近赤Ｊ水　近赤Ｋｓ

TRISPEC観

測

TRISPEC観

測


Tsunefumi Mizuno 12

SummarySummary• Fermi GBM detects ~0.5GRB/day and LAT ~10 GRBs/year• 7 LAT GRBs above 100 MeV

4 GRBs w/ GeV photons, one short (GRB081024B)2 GRBs w/ WAM detection, 3 w/ redshift

• GRB080916C w/ maximum Eiso ever observed14 photons > GeV, min>=900, MQG>1.3x1018 GeV/c2

• GRB081024B is the first short GRB with photons above 1 GeV.min=100 (for z=0.1) and 700 (for z=3.0)Single Band function, delayed HE onset and extended HE emission => common feature?

• HOWPol on Kanata Telescope is now ready (on May 3, 2009)9 GRBs observed, 2 GRBs detected in 2008/4-2009/3 by TRISPEC


Tsunefumi Mizuno 13

Backup Slides


Tsunefumi Mizuno 14

Spectral AnalysisSpectral Analysis

Preliminary!

Preliminary!

Spectrum at T0+0.1 – T0+0.8s

No strong evidence of additional high energy component.

α= -0.9053 ± 0.203

β= -1.993 ± 0.0768

Ep = 819.2 ± 547.0 keV

GBM 2nd pulse (including

maximum energy photon of

3.0 GeV) can be fitted by a

Band Function.

103 106 (keV)(1GeV)

104 10510210(1MeV)


Tsunefumi Mizuno 15

Minimum Lorentz FactorMinimum Lorentz Factor

Although z is uncertain,

Γmin(z=0.1) ≒ 100, Γmin(z=3.0) ≒ 700

)1(2

1

4201

1

)1(2

1

2min )()1()]()()

)(([

cm

EEzFEfE

tc

zd

e

ccc

LTΓ

3

11

1

)1(2

2

min )()()1

(

tt

t β= -1.993 ± 0.0768

E0 : The maximum photon energy = 3.0GeV.

Use interval b to derive Gamma minimum as described in GRB080916C paper (Abdo et al, 2009) and Asano-san’s talk.

Δt : The variability time scale = duration/2 = 0.35sec


Tsunefumi Mizuno 16


050820A

050922C

101 102 103 104

Time after burst (sec)

10

15

20

Mag

nitu

de (

V o

r R

or

r')

Polarimetry1min limit

Polarimetry10min limit

Photometry10min limit

060607A

990123

021211

030329

050525A

050801

060111B

060117061007

1000 秒

•Akerlof & Heather (2007) Statistics of 108 Swift GRBs

40% で光学残光　うち t=1000 秒換算での等級が 14 等 ,16等 ,18 等より明るいもの 0.9%,4.6%,16.7%

•4 年間観測を続けると1000 秒後でも 16 等より明るいサンプルを１個 /4 年 (100-1000s の間で偏光の変化を追う )200s で 16 等より明るいサンプルを 3-4 個 (10 分露出で偏光測定 )

=> 年 1 個程度の偏光観測を期待

仮定：　発見レート 100 個 / 年　高度係数 0.33 (>20 度）　夜間係数 0.4

　晴天係数 0.4

• 2008 年 12 月～　ＧＲＢアラート対応観測開始• ⇒ バーストから 100 秒以内の偏光観測開始めざす

1 分露出時

10 分露出時

Δp=0.2%

偏光測定限界

200 秒

Documents

可視・ X 線・ γ 線同時観測で探る γ 線バースト (Exploring GRBs through Optical, X-ray and Gamma-ray Observations)