bat2 grb catalog prompt emission properties of swift grbs
DESCRIPTION
BAT2 GRB Catalog Prompt Emission Properties of Swift GRBs. T. Sakamoto (CRESST/UMBC/GSFC) on behalf of Swift/BAT team. Contents. BAT2 GRB catalog Overview of the BAT2 GRB catalog Short GRBs vs. Long GRBs Observed properties vs. redshift Summary. BAT2 GRB Catalog. - PowerPoint PPT PresentationTRANSCRIPT
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
BAT2 GRB CatalogBAT2 GRB CatalogPrompt Emission Properties of Prompt Emission Properties of
Swift GRBsSwift GRBs
T. Sakamoto (CRESST/UMBC/GSFC)
on behalf of Swift/BAT team
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
ContentsContents
BAT2 GRB catalog Overview of the BAT2 GRB catalog Short GRBs vs. Long GRBs Observed properties vs. redshift Summary
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
BAT2 GRB CatalogBAT2 GRB Catalog
• 476 GRBs (from GRB 041219 to GRB 091221)- including 25 GRBs found in ground processing
476 GRBs
426 Long-duration GRBs (L-GRBs)
41 Short-duration GRBs (S-GRBs)
9 Short-duration GRBs with extended emissions (S-GRBs w/ E.E.)
(89%)
(9%)
(2%)
• 3323 time-resolved spectra
Working definition of L-GRB vs. S-GRB: L-GRB: T902 s S-GRB: T90 < 2 s
• 146 known-z GRBs
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
Overview of BAT2 GRB CatalogOverview of BAT2 GRB Catalog Updates on BAT In-orbit Calibration GRB Sky map Duration
– Duration distribution– Duration vs. Hardness (BAT/BATSE/HETE-2)
Peak flux and fluence– Peak flux vs. fluence
– fluence vs. fluence (BAT/BATSE/HETE-2) BAT time-averaged spectral properties
– BAT PL Photon index distribution (short vs. long)– BAT Epeak (CPL fit) distribution
BAT time-resolved spectral properties– PL Photon index distribution (time-ave vs. time-res)– Line of death problem
Observed prompt emission properties vs. redshift
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
Short GRBs vs. Long GRBsShort GRBs vs. Long GRBs
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
(15-150 keV)
(25 - 5000 keV)
70 s
32 s
0.5 s
TT9090 Duration Duration
S-GRBs: 9%
S-GRBs: 25%
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
(Total 402)
(Total 38)
(Averaged -1.6)
(Averaged -1.2)
BAT Time-ave PL Photon indexBAT Time-ave PL Photon index
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
Discussion: Short on S-GRBs in BATDiscussion: Short on S-GRBs in BAT
BAT: 10% S-GRBs (90% L-GRBs)
BATSE: 25% S-GRBs (75% L-GRBs)
Factor of 2.5 small # on S-GRBs in BAT
Histograms of 50-100 keV fluence of S-GRBs
BAT
BATSE
No significant difference in the S-GRBs fluence distribution …
1. BAT is not missing S-GRBs
2. BAT is missing S-GRBs
Possibility
BATSE’s missIDs: TGFs, SGRs, …
Might be a room to improve S-GRB detection in BAT
BATSE- Rate trigger
BAT- Rate trigger- Imaging
vs.
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
Discussion: Short on S-GRBs in BATDiscussion: Short on S-GRBs in BAT
BAT: 10% S-GRBs (90% L-GRBs)
BATSE: 25% S-GRBs (75% L-GRBs)
Factor of 2.5 small # on S-GRBs in BAT
Histograms of 50-100 keV fluence of S-GRBs
BAT
BATSE
No significant difference in the S-GRBs fluence distribution …
1. BAT is not missing S-GRBs
2. BAT is missing S-GRBs
Possibility
BATSE’s missIDs: TGFs, SGRs, …
Might be a room to improve S-GRB detection in BAT
BATSE- Rate trigger
BAT- Rate trigger- Imaging
vs.
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
Prompt Emission Properties Prompt Emission Properties vs. vs.
RedshiftRedshift
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
TT9090 vs. Redshift vs. Redshift
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
TT9090 vs. Redshift vs. Redshift
z=2 z=3z=4 z=5 z=6 z=7 z=8
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
TT9090 vs. Redshift vs. Redshift
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
BAT PL PhIndex vs. RedshiftBAT PL PhIndex vs. Redshift
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
BAT PL PhIndex vs. RedshiftBAT PL PhIndex vs. RedshiftEpeak- relation(Sakamoto et al. 2009)
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
Discussion: BAT High-z GRBsDiscussion: BAT High-z GRBs
• T90 is not all long.• Observed spectrum is not soft.
BAT High-z GRBs:
If you are interested in hunting high-z GRBs…
• Detector with a softer energy band (e.g. X-ray) might not help.• Detector with a large effective area (high sensitivity).• Large FOV (high-z GRB is rare).• Sophisticated on-board trigger/localization software.
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2010. 4. 19. 2010 Kyoto GRB Conference Swift
SummarySummaryL-GRBs vs. S-GRBs
• BAT <T90> = 70 s (BATSE <T90> = 30 s)• Significantly longer duration in BAT (softer energy band)
• BAT S-GRBs are harder than L-GRBs (large overlap)• Lack of S-GRBs in BAT:
• BAT S-GRBs 10% (BATSE S-GRBs 25% )
Observed properties vs. Redshift (BAT high-z GRBs)
• T90 is not all long• Observed spectrum is not soft
Stay tune for the BAT2 GRB catalog!Stay tune for the BAT2 GRB catalog!