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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

36155 results found.

  1. GRB 060502B: MASTER optical observations
  2. GRB 060502B: Swift detection of a short burst
  3. GRB 060502: Swift-BAT refined analysis
  4. GRB060502: Gemini spectroscopy
  5. GRB 060502: APO Spectroscopic Observations
  6. GRB 060502: P60 Afterglow Confirmation
  7. GRB 060502: Swift detection of a burst with an optical counterpart
  8. GRB 060501: MDM Observations
  9. GRB060501: Super-LOTIS observations
  10. GRB 060501: Refined analysis of the Swift-BAT burst
  11. GRB060501: Swift XRT position
  12. GRB 060501: ROTSE-III Optical Limits
  13. GRB 060501: Swift detection of a burst
  14. IPN triangulation of GRB060429 (short/hard)
  15. Konus-Wind observation of GRB 060427B
  16. GRB060428B - SDSS Pre-Burst Observations
  17. GRB060428B: optical observation
  18. GRB060428B: possible detection of an optical counterpart by Swift/UVOT.
  19. GRB 060428B: MDM Observations
  20. GRB 060428A: PROMPT Observations
  21. GRB 060427B: MASTER optical observations
  22. GRB 060427B: IPN localization of a short hard burst
  23. GRB 060428B: Refined analysis of the Swift-BAT burst
  24. GRB 060428B: Xinglong I-band limit
  25. GRB 060428B: KAIT observations
  26. GRB060425:MASTER optical limit
  27. GRB 051117A: Bright host galaxy not confirmed
  28. GRB 060428A: Refined analysis of the Swift-BAT burst
  29. GRB 060428b : Kiso R-band limit
  30. GRB060427:MASTER optical limit
  31. GRB 060428b: Optical afterglow candidate
  32. GRB 060428B: Swift detection of a burst
  33. GRB 060427: NIR observations
  34. GRB 060428: Swift detection of a burst
  35. GRB 060427: NOT observations
  36. GRB 060427: Swift/UVOT upper limits.
  37. GRB 060427: Refined analysis of the Swift-BAT burst
  38. GRB060418: Swift XRT Team Further Refined Analysis
  39. GRB060425:MASTER survey observations
  40. GRB 060427, optical observation
  41. GRB 060427: Swift detection of a burst
  42. GRB 060425: IPN localization and KW spectrum of a short, hard burst
  43. An interactive program for GRB pseudo-redshift computations
  44. GRB060424: optical afterglow detection
  45. GRB060418: Further Analysis of MIKE Spectroscopy
  46. GRB 060424: Refined analysis of the Swift-BAT burst
  47. GRB 060424: Swift detection of a burst
  48. GRB 060421: TTT Observations
  49. GRB 060421: Swift-BAT Refined Analysis
  50. GRB 060421: Swift-XRT refined analysis
  51. GRB 060418: prediction of t_break
  52. GRB060418: optical observations
  53. Konus-Wind observation of GRB 060418
  54. GRB(?)060421:MASTER optical limit
  55. GRB(?)060421 : XRT position
  56. GRB(?) 060421: Swift detection of a burst
  57. Erratum of GCN 4983 for GRB 060418 IR follow-up
  58. GRB 060418 : IR afterglow observations
  59. GRB 060418 : Lulin Optical follow-up
  60. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  61. GRB 060418: Radio Observations
  62. GRB060418, BVRcIc field calibration
  63. GRB060418: Optical Observations
  64. GRB 060418: FRAM early afterglow observation
  65. GRB 060418: Refined Analysis of the Swift-BAT burst
  66. GRB060418: Swift XRT Team Refined Analysis
  67. GRB 060418, SMARTS continuing afterglow observations
  68. GRB 060418: PROMPT Detections
  69. GRB 060418, SMARTS optical/IR afterglow observations
  70. GRB060418: Magellan/MIKE Spectroscopic Redshift
  71. GRB060418 : LT optical afterglow observation
  72. GRB 060418: REM candidate afterglow
  73. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  74. GRB 060413: REM NIR Observations
  75. GRB 060413: Refined analysis of the Swift-BAT burst
  76. GRB 060413: Watcher UBVR observations
  77. GRB 060413: XRT refined analysis
  78. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  79. GRB 060413: Swift detection of a burst
  80. GRB060403: optical observations
  81. GRB 060403 Optical observations
  82. GRB 060403: MITSuME optical observation
  83. GRB060403: XRT refined analysis
  84. GRB 060403: Swift/UVOT upper limits
  85. GRB 060403: Refined analysis of the Swift-BAT burst
  86. GRB 060403: Swift detection of a burst
  87. GRB 060322: LNA optical limit
  88. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  89. GRB 060323 : WIDGET simultaneous optical observations
  90. GRB 060323: Early optical observation at Xinglong
  91. GRB060218, optical observations
  92. GRB 060322: Confirmation of Swift XRT afterglow
  93. GRB 060211A: optical observation
  94. GRB060323: optical limit
  95. GRB060211B: optical observation
  96. GRB060323: NOT optical observations
  97. GRB 060322: IAC80 optical observations
  98. GRB 060322: Swift XRT afterglow candidate
  99. GRB 060323: Swift/UVOT Observations
  100. GRB 060323: optical afterglow confirmed

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