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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. GRB 080603A: final Swift-XRT observations.
  2. GRB 080607: AGILE-MCAL observation of the prompt emission
  3. GRB 080603B - TLS 2nd Epoch: Another Break
  4. GRB 080605: TLS 3rd Epoch - Source Confusion
  5. GRB080605: optical observation with the MITSuME-OAO telescope
  6. Konus-Wind observation of GRB 080607
  7. GRB080607: RTT150 optical observations
  8. GRB 080603A: optical observations
  9. GRB 080607: Swift-XRT refined analysis
  10. Swift/UVOT Observations of GRB080607
  11. GRB 080605: optical observations
  12. GRB 080607 KAIT observations
  13. VLA detection of INTEGRAL burst GRB 080603A
  14. Konus-Wind observation of GRB 080605
  15. GRB 080607: Enhanced Swift-XRT position
  16. GRB 080607, Swift-BAT refined analysis
  17. GRB 080605: GROND 2nd epoch observations
  18. GRB 080607 - PAIRITEL NIR detection
  19. GRB 080607: Keck/LRIS spectroscopy and redshift
  20. GRB 080607: Super-LOTIS early observations
  21. GRB 080607: Swift detection of a burst with optical afterglow
  22. GRB 080607: ROTSE-III Detection of Optical Counterpart
  23. GRB 080605: TLS RRM Analysis, Plateau/Rebrightening, Red OT
  24. GRB 080605: Swift-UVOT refined analysis
  25. Possible VLA radio detection on INTEGRAL burst GRB 080603A
  26. GRB 080604: VLA radio upper limit
  27. GRB 080605, Swift-BAT refined analysis
  28. GRB 080603B: VLA radio upper limit
  29. GRB 080605, Swift-BAT refined analysis
  30. GRB 080605: Swift-XRT refined analysis
  31. GRB080605: observation by BOOTES
  32. GRB 080605: MASTER VWF 46 s AT observation
  33. GRB 080605: Enhanced Swift-XRT position
  34. GRB 080605: GROND detection of the optical afterglow candidate
  35. GRB080605: optical observations
  36. GRB 080605: VLT redshift
  37. GRB 080605: Liverpool Telescope optical afterglow candidate
  38. GRB 080605: Swift/UVOT Position of the Optical Afterglow
  39. GRB 080605: TLS RRM Afterglow
  40. GRB 080605: Swift detection of a burst with an optical afterglow
  41. GRB 080603B: PAIRITEL infrared detection
  42. GRB 080603A: PAIRITEL infrared detection
  43. GRB 080604: Xinglong R band observation
  44. GRB 080603A: Xinglong R band observation
  45. GRB 080603B: TLS Afterglow Observation
  46. GRB 080603A: TLS Afterglow Observation
  47. GRB 080604: MITSuME Okayama observation
  48. Swift/UVOT observations of GRB080604
  49. GRB080604: HET redshift retraction
  50. GRB 080604: Gemini-North spectroscopy
  51. GRB 080604, Swift-BAT refined analysis
  52. GRB 080604: Swift-XRT refined analysis
  53. GRB 080603B: Hobby-Eberly Telescope redshift confirmation
  54. GRB 080603B : Xinglong EST observations
  55. GRB 080603B : Liverpool Telescope Observations
  56. Konus-Wind observation of GRB 080603B
  57. GRB 080603B: Swift-XRT refined analysis
  58. GRB 080603A: Swift-XRT detection of the afterglow
  59. GRB 080430: optical observations
  60. GRB 080603B: Swift/UVOT detection of the afterglow
  61. GRB 080604: Enhanced Swift-XRT position
  62. GRB 080603B, Swift-BAT refined analysis
  63. GRB 080604: Hobby-Eberly Telescope spectroscopy
  64. GRB 080603A: Swift/UVOT detection of the afterglow
  65. GRB080603B: RTT150 optical observations, break in light curves
  66. GRB 080604: Early Super-LOTIS Observations
  67. GRB080604: confirmation of optical afterglow
  68. GRB 080604: Swift detection of a burst with an optical afterglow
  69. GRB 080603B: TAROT Calern observatory confirmation of slow optical decay
  70. GRB 080516: TAROT La Silla observatory optical observations
  71. GRB080603B: NOT redshift
  72. GRB 080603B: BOOTES2/TELMA optical observations
  73. GRB 080603B: TAROT Calern observatory detection of a plateau in the light curve
  74. GRB 080603B: Swift detection of a burst with optical afterglow
  75. GRB080603: Super-LOTIS detection of Optical Counterpart
  76. GRB 080603B: ROTSE-III Detection of Optical Counterpart
  77. GRB 080603: Gemini-North redshift
  78. GRB 080603: A long GRB detected by INTEGRAL
  79. GRB 080603 OA candidate
  80. Possible GRB080603: Faulkes Telescope North optical afterglow candidate
  81. SGR 1627-41: Chandra/RXTE/Swift Observations Scheduled
  82. GRB 080602, Swift-BAT refined analysis
  83. GRB 080602: Swift-XRT refined analysis
  84. Konus-Wind observation of GRB 080602
  85. GRB 080602: NOT R-band upper limit
  86. GRB 080602: Enhanced Swift-XRT position
  87. GRB 080602: Swift detection of a burst
  88. Swift analysis of BAT Slew Survey event (Trigger=009)
  89. GRB 080523: afterglow confirmation and redshift constraints
  90. Konus-Wind observation of reactivation of SGR 1627-41
  91. Reactivation of SGR 1627-41
  92. GRB 080524: Swift XRT and UVOT analysis
  93. GRB 080503: 2nd Epoch Chandra X-ray Observations
  94. GRB 080524: Swift-BAT detection of a burst in ground analysis
  95. GRB 080523: Swift-XRT refined analysis
  96. GRB 080523, Swift-BAT refined analysis
  97. GRB 080520: VLT host detection
  98. GRB 080523: VLT optical observations
  99. Swift/UVOT observations of GRB 080523
  100. GRB 080523: Enhanced Swift-XRT position

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