1 / 16

Low-Resolution Spectroscopy of Gamma-Ray Burst Optical Afterglows: Biases in the Swift Sample

Low-Resolution Spectroscopy of Gamma-Ray Burst Optical Afterglows: Biases in the Swift Sample. ( ApJ Supplement, 2009, 185, 526-573). Palli Jakobsson Centre for Astrophysics & Cosmology University of Iceland.

bran
Download Presentation

Low-Resolution Spectroscopy of Gamma-Ray Burst Optical Afterglows: Biases in the Swift Sample

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. Low-Resolution Spectroscopy of Gamma-Ray Burst Optical Afterglows: Biases in the Swift Sample (ApJ Supplement, 2009, 185, 526-573) PalliJakobsson Centre for Astrophysics & Cosmology University of Iceland

  2. Low-Resolution Spectroscopy of Gamma-Ray Burst Optical Afterglows: Biases in the Swift Sample (ApJ Supplement, 2009, 185, 526-573) PalliJakobsson Centre for Astrophysics & Cosmology University of Iceland

  3. The dark burst diagram (βOX) Jakobsson et al. (2004)

  4. Definition of βOX Optical X-ray Sari et al. (1998)

  5. Definition of βOX 2.0 < p < 2.5 Optical X-ray Sari et al. (1998)

  6. The dark burst diagram (βOX) Swift Identification of Dark Gamma-Ray Bursts: Jakobsson et al. (2004)

  7. The dark burst diagram (βOX)

  8. The sample 1. A Swift-detected GRB with t90 > 2 s. 2. XRT afterglow position distributed within 12 hours. 3. Small foreground Galactic extinction: AV < 0.5 mag. 4. Favorable declination: -70° < δ < 70°. 5. Sun-to-field distance larger than 55°. March 2005 – September 2008: 146 GRBs 75% have an optical/NIR afterglow

  9. The 3 sub-samples 1. GRBs with redshifts measured from OA spectroscopy. 72 • GRBs with detected optical/NIR afterglow, but no • afterglow-based redshift. 35 3. GRBs with no detection of the OA. 39

  10. The dark burst diagram (βOX) [z from OA] 14% [OA but no z] 38% [no OA] >39% 080913 (z = 6.7) 050904 (z = 6.3)

  11. XRT excess absorption distribution KS test probability (1 and 2): 2 x 10-3 KS test probability (1 and 3): 7 x 10-7

  12. βOX vs. X-ray excess absorption dark bursts

  13. Redshift distribution: 146 GRBs Grupe et al. (2007) < 18% @ z > 7 <z> = 2.2

  14. Cumulative redshift distribution

More Related