1 / 13

Daisuke YONETOKU (Kanazawa Univ.) T. Murakami (Kanazawa Univ.),

The Spectral Ep–Lp and Ep–Eiso Relations: The Origin of Dispersion and Its Improvement. Daisuke YONETOKU (Kanazawa Univ.) T. Murakami (Kanazawa Univ.), R. Tsutsui , T. Nakamura (Kyoto Univ.), K. Takahashi (Nagoya Univ.). GRB Cosmology Project. yonetoku@astro.s.kanazawa-u.ac.jp.

kipling
Download Presentation

Daisuke YONETOKU (Kanazawa Univ.) T. Murakami (Kanazawa Univ.),

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. The Spectral Ep–Lp and Ep–Eiso Relations: The Origin of Dispersion and Its Improvement Daisuke YONETOKU (Kanazawa Univ.) T. Murakami (Kanazawa Univ.), R. Tsutsui, T. Nakamura (Kyoto Univ.), K. Takahashi (Nagoya Univ.) GRB Cosmology Project yonetoku@astro.s.kanazawa-u.ac.jp

  2. Introduction 102 known redshift samples with ( Ep, 1 sec peak flux, fluence ). Lp is calculated by 1 sec peak flux in the obs. frame. C.C. = 0.890 d.o.f. = 100 Briggs et al. 2000 ∝ Eα ∝ Eβ νFν ■ Application for the GRB Cosmology ■ Investigate the characteristic of GRB itself ピークエネルギー (Ep)

  3. Cosmic Distance Ladder (Distance Indicators) When we measure the energy density of D-E and D-M, we need “distance” and “redshift”relation. Just after the Big Bang (CMB) z = 8.2 ! Gamma-Ray Bursts z = 1.755 Type Ia Supernovae Tully-Fisher Relation (Rotation–Luminosity) Cepheid Variable (Period–Luminosity) HRdiagram redshift z = 1.755 L ≡ 4πdL2 F parallax

  4. Calibrated Epeak-Luminosity relation 52 GRBs（z<1.755） Peak Luminosity [1051 erg/sec] Lp = 5.93 x 1047 [Epeak (1+z) ]1.85 5.93 x 1047 [ Epeak (1+z) ]1.85 dL2 = 4πF Epeak(1+z) [keV]

  5. (Ωm, ΩΛ) = (1, 0) Hubble Diagram ( 1.8 < z < 8.2) (0.3, 0.7) ■ GRB data (z < 1.755) ■ GRB data (1.755 < z < 8.2) ＋ Type IaSNe (0, 1) 1029 z = 8.2 1028 Luminosity Distance (cm) New! GRB Type IaSNe 1027 Calibrated GRB 1026 0.01 0.1 1 10 Redshift

  6. Tsutsui, DY + (2009) Cosmological Parameters (1.8 < z < 8.2 ) ΩΛ Dark Energy : ΩΛ Poster-094 Tsutsui et al. Matter : Ωm (Ωm, ΩΛ) = ( 0.24±0.10 , 0.76±0.10) ( flat universe ) First Measurement of DM & DEin the early universe of z > 2.

  7. Origin of Data Dispersions We classified 102 GRB events into 3 groups, according to the bolometric peak flux and the redshift. Redshift Peak Flux Ep-Lp Ep-Lp Bright Middle Dim High-z Middle-z Low-z We found aredshift evolution in the Ep-Lp relation in 2 s significance, but there is no peak flux dependence.

  8. Redshift Evolution ? 64msec 512msec 1sec @ z=2 1024msec 1sec @ z=1 Relative Peak Flux in Obs. Frame 1sec @ z=0 Time Scale of Peak Flux (sec) We systematically overestimate the peak luminosityfor higher redshift GRBs.

  9. Redefinition of the peak luminosity ( Lp,GRB ) We searched the best time scalefor the peak luminosity in the GRB frame. 2088 msec ~ 3 sec 58 GRBs Konus & Swift 31 Konus data Correlation Coefficient ~ 3 sec Original Ep – Lp Time Scale of Peak Luminosity in GRB Frame (sec)

  10. 1secPeak Luminosity ( measured in Obs. frame ) Lp = 1048.70 [ Ep(1+z) ]1.46 Cor. Coef = 0.890 Peak Luminosity [erg/sec] Deviation : σsys = 0.213 Ep (1+z) [keV]

  11. 3secPeak Luminosity (measured in GRB frame ) Lp = 1048.18 [ Ep(1+z) ]1.53 Cor. Coef = 0.921 Peak Luminosity [erg/sec] Deviation : σsys = 0.180 Ep (1+z) [keV]

  12. Similar analysis for the Ep – Eiso relation. Fluence Redshift Ep-Eiso Ep-Eiso Bright Middle Dim High-z Middle-z Low-z We found afluence dependence in the Ep-Eiso relation in 2 s significance, but there is no redshift evolution.

  13. Summary ■ We succeeded in extending the cosmic distance ladder toward z=8.2 with the Ep – Lp relation. ■ We measured the cosmological parameters, 1.755 < z < 8.2 ■ Possible origins of data dispersion ( 0.24±0.10 (Ωm, ΩΛ) = , 0.76±0.10) ■ Using the NEW definition of “Lp,GRB (~ 3sec in GRB frame)”, we succeeded in canceling the redshift evolution, and in improving the Ep – Lp relation.

More Related