1 / 10

Different spectral correlation between short and long GRBs with Suzaku

Masnori Ohno (ISAS/JAXA). Different spectral correlation between short and long GRBs with Suzaku. Long/Short GRBs are different ?. There are two GRB classes, Long/Short GRBs in T90 distribution Different origin ? Hardness ratio; short/hard, long/soft (Kouvelioutou et al. 1993)

karl
Download Presentation

Different spectral correlation between short and long GRBs with Suzaku

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Masnori Ohno (ISAS/JAXA) Different spectral correlation between short and long GRBs with Suzaku

  2. Long/Short GRBs are different ? • There are two GRB classes, Long/Short GRBs in T90 distribution • Different origin ? • Hardness ratio; short/hard, long/soft (Kouvelioutou et al. 1993) • Spectral properties • (Paciesas et al. 2003, Ghirlanda et al. 2004, Ohno et al. yesterday’s talk.. etc) • How about z distribution ? • <z>~1 from Swift result • GRB080913 (z=6.7 T90,src~1s), Short ? Long ? • Low statistics Ghirlanda et al. 2004 Paciesas et al. 2001 α Epeak

  3. Epeak-Eiso/Liso correlation • Epeak-Liso as the redshift indicator for long GRBs (Yonetoku et al. 2004) • Short GRBs do not satisyf Epeak-Eiso due to much lower energy • (Amati 2006, 2008, Ohno et al. 2007 …etc) • How about Epeak-Liso for short GRBs ?? Total energy (Eiso) Short (WAM) Ep-Eiso relation for Redshift-”unknown” Short GRBs by the WAM Long Long (Amati 2006) Long (WAM sample)

  4. Epeak-Eiso/Liso correlation for short GRBs • Both z and Epeak information • z from Swift, but Swift can not determine Epeak • Wide-band and good statistics is needed for short GRB Epeak Joint analysis between Swift/BAT and Suzaku Wide-band All-sky Monitor is very useful to test these correlations for short GRBs

  5. Suzaku Wide-band All-sky Monitor Suzaku/HXD is surrounded by thick (4cm), large (40cm) 20 high-z BGO crystals for active shielding. Wide-band All-sky Monitor (Suzaku/WAM) cross section top view Yamaoka et al. 09 Energy band: 50—5000 keV Effective area: 400cm2@1MeV Suzaku HXD-WAM Powerful tool for short GRB spectrum

  6. WAM Short GRB correlations (1) sample Swift leads redshift measurement even for short GRBs WAM provides Epeak for 6 redshift-measured short GRBs ! GRB060801 Z=1.13 T90=0.44 GRB051221A Z=0.545 T90=0.22 GRB061006 Z=0.44 T90=0.42 1sec GRB061210 Z=0.41 T90=0.05 GRB070714B Z=0.92 T90=2.56 GRB071227 Z=0.383 T90=0.8 ※T90:50-5000 keV

  7. WAM Short GRB correlations (2) spectral analysis Epeak is obtained from WAM/BAT joint spectral analysis Cutoff PL model is best fit for all sample Lpeak from WAM light curve (16ms time scale) GRB060801 Z=1.13 T90=0.44 GRB051221A Z=0.545 T90=0.22 GRB061006 Z=0.44 T90=0.42 WAM BAT GRB061210 Z=0.41 T90=0.05 GRB070714B Z=0.92 T90=2.56 GRB071227 Z=0.383 T90=0.8

  8. WAM short GRB correlations (3) Epeak-Eiso correlation • Ghirlanda et al. (arXiv 0902.0983) • Long • Short WAM short GRBs Short GRBs do not satisfy Amati relation due to its much lower total energy Similar result to Ghirlanda et al. 2009 Eiso (1052 erg) 10-5 10-4 10-3 0.01 0.1 1 10 100 1000

  9. WAM short GRB correlations (4)Epeak-Liso correlation GRB071227 WAM Short GRBs • Almost data seem to be consistent • within dispersion of Ghirlanda et al result. • Tend to be harder than long GRBs ? • GRB 071227 is clear outlier. • different correlation ? • systematics ? • It is difficult to conclude that short GRBs follow • the Epeak-Liso relation, need more sample ! Lpeak(1sec) (1052 erg) 10-5 10-4 10-3 0.01 0.1 1 10 100 1000

  10. Summary We performed correlation analysis such as Epeak-Eiso and Epeak-Liso relation for short GRBs using BAT/WAM sample. (1) Short GRBs do not satisfy Epeak-Eiso relation (2) Roughly consistent with Epeak-Liso relation, however…. - large dispersion - tend to locate at harder Epeak regime - outlier ? (GRB071227)  different correlation ? It is difficult to conclude that we can use the Epeak-Liso relation as the redshift indicator for short GRBs. Need more samples !

More Related