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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"
  1. GRB060505: Swift/UVOT Observations
  2. GRB 060505: Swift XRT Team Refined Analysis
  3. GRB060425: new MASTER survey method
  4. GRB 060306: Further Analysis of SOAR and APO NIR Observations
  5. GRB 060505: Swift XRT afterglow canditate position
  6. GRB 060502b: Second epoch Gemini observations
  7. GRB 060505: Swift-BAT detection of a weak burst
  8. GRB 060428B: spectroscopy
  9. GRB 060502B: optical observations
  10. GRB 060502B: AROMA refined photometric calibration
  11. GRB 060502B MDM Follow-up Observation
  12. GRB 060502b: Gemini imaging and spectroscopy
  13. GRB060502A, optical observation
  14. GRB 060502B: Swift/UVOT upper limits
  15. GRB 060502A: Swift/UVOT source detection
  16. GRB 060429: Refined IPN error box and Konus-Wind spectrum
  17. GRB 060502B: MDM Optical Observation
  18. GRB 060502B: AROMA optical observations
  19. GRB 060502B: Refined analysis of the Swift-BAT short burst
  20. GRB060502B: Swift XRT Team refined analysis
  21. Short GRB 060502B: Tautenburg Observation
  22. GRB 060427B Milagro GeV/TeV Observations
  23. GRB 060502A: TTT Observations
  24. GRB060502B: correction to XRT position
  25. GRB 060501: P60 Observations and Candidate Retraction
  26. GRB 060502B: Xinglong optical observation
  27. GRB 060502B: MASTER optical observations
  28. GRB 060502B: Swift detection of a short burst
  29. GRB060502: Swift-XRT refined analysis
  30. GRB 060502: Swift-BAT refined analysis
  31. GRB060502: Gemini spectroscopy
  32. GRB 060502: APO Spectroscopic Observations
  33. GRB060501: Swift UVOT followup observations
  34. GRB060502: Super-LOTIS Observations
  35. GRB 060502: P60 Afterglow Confirmation
  36. GRB 060502: Swift detection of a burst with an optical counterpart
  37. GRB 060501: MDM Observations
  38. GRB060501: Super-LOTIS observations
  39. GRB060501: P60 imaging and afterglow candidate
  40. GRB 060501: Refined analysis of the Swift-BAT burst
  41. GRB060501: Swift XRT position
  42. GRB 060501: ROTSE-III Optical Limits
  43. GRB 060501: Swift detection of a burst
  44. IPN triangulation of GRB060429 (short/hard)
  45. Konus-Wind observation of GRB 060427B
  46. GRB060428B - SDSS Pre-Burst Observations
  47. GRB060428B: optical observation
  48. GRB060428B: possible detection of an optical counterpart by Swift/UVOT.
  49. GRB 060428B: MDM Observations
  50. GRB 060428A: PROMPT Observations
  51. GRB 060427B: MASTER optical observations
  52. GRB060428B: Swift XRT Team refined analysis
  53. GRB 060427B: IPN localization of a short hard burst
  54. GRB 060428B: Refined analysis of the Swift-BAT burst
  55. GRB 060428B: Xinglong I-band limit
  56. GRB 060428B: KAIT observations
  57. GRB060425:MASTER optical limit
  58. GRB 051117A: Bright host galaxy not confirmed
  59. GRB060428A: Swift/UVOT observations.
  60. GRB060428B, optical observation
  61. GRB 060428A: Refined analysis of the Swift-BAT burst
  62. GRB 060428b : Kiso R-band limit
  63. GRB060427:MASTER optical limit
  64. GRB 060428b: Optical afterglow candidate
  65. GRB060428A: Swift XRT Team refined analysis
  66. GRB 060428B: Swift detection of a burst
  67. GRB 060427: NIR observations
  68. GRB060427: Xinglong optical Observations
  69. GRB 060428: Swift detection of a burst
  70. GRB 060427: NOT observations
  71. GRB 060427: Swift/UVOT upper limits.
  72. GRB 060427: Refined analysis of the Swift-BAT burst
  73. GRB060427: Swift XRT Team refined analysis
  74. GRB060418: Swift XRT Team Further Refined Analysis
  75. GRB060425:MASTER survey observations
  76. GRB 060427, optical observation
  77. GRB 060427: Swift detection of a burst
  78. GRB 060425: IPN localization and KW spectrum of a short, hard burst
  79. An interactive program for GRB pseudo-redshift computations
  80. GRB060424: optical afterglow detection
  81. GRB060418: Further Analysis of MIKE Spectroscopy
  82. GRB 060424: Refined analysis of the Swift-BAT burst
  83. GRB 060424: Swift detection of a burst
  84. GRB 060421: TTT Observations
  85. OT 060420: Likely Not a New Cosmic Transient
  86. No OT 060420 in MASCOT images
  87. Swift-BAT detection of Mrk 421
  88. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  89. GRB060421: Swift/UVOT observations
  90. GRB 060421: Swift-BAT Refined Analysis
  91. GRB 060421: Swift-XRT refined analysis
  92. GRB 060418: prediction of t_break
  93. GRB060418: optical observations
  94. Konus-Wind observation of GRB 060418
  95. GRB(?)060421:MASTER optical limit
  96. GRB(?)060421 : XRT position
  97. Possible GRB060421: BART limits
  98. GRB(?) 060421: Swift detection of a burst
  99. Erratum of GCN 4983 for GRB 060418 IR follow-up
  100. GRB 060418 : IR afterglow observations

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