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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 080702b: LCO optical observations
  2. Swift/UVOT observation of GRB080702A
  3. GRB 080702B: Swift XRT and UVOT observations
  4. GRB 080625: Suzaku WAM observation of the prompt emission
  5. GRB 080702A: MITSuME Akeno optical upper limits
  6. GRB 080701A: Early RAPTOR optical limits
  7. Swift Trigger 315630: Swift/UVOT Upper Limits
  8. GRB 080702A, Swift-BAT refined analysis
  9. GRB 080702A: Swift-XRT Team refined analysis
  10. GRB 080702B : Burst detected in BAT during Swift slew
  11. GRB 080702A: Enhanced Swift-XRT position
  12. Swift Trigger 315630: TLS R-band observation
  13. Swift Trigger 315630: Probably not a GRB
  14. GRB 080702: Swift detection of a short burst
  15. GRB 080701: Swift-XRT refined analysis
  16. GRB 080701A, VATT optical upper limit
  17. TLS I-Band Observation of GRB 080701A
  18. GRB 080701A: Swift/UVOT Upper Limits
  19. GRB 080701A: Early Super-LOTIS Observations
  20. GRB 080701: Enhanced Swift-XRT position
  21. GRB 080701A, Swift-BAT refined analysis
  22. Trigger 315630: Swift detection of a possible burst
  23. GRB 080701: Swift-XRT Prompt Analysis
  24. GRB 080701: Swift detection of a burst
  25. GRB 080623: Suzaku WAM observation of the prompt emission
  26. GRB 080625: Swift/UVOT Follow-Up Observations
  27. GRB 080625: Further observations from OSN
  28. GRB 080625:Swift-XRT detection of the afterglow
  29. GRB 080625: Swift/UVOT Detection of an Optical Afterglow
  30. GRB 080625: Observations at OSN
  31. GRB 080625: Gamma Ray Burst Localization by SuperAGILE
  32. GRB 080623: GROND upper limits
  33. GRB080623: Swift UVOT followup observations
  34. GRB 080623: Swift-XRT refined analysis
  35. GRB 080623, Swift-BAT refined analysis
  36. GRB 080623: Enhanced Swift-XRT position
  37. GRB 080623: TAROT La Silla observatory optical observations
  38. GRB 080623: Swift/UVOT Non-Detection of an Optical Afterglow
  39. GRB 080623: Swift XRT prompt analysis
  40. GRB 080623: Swift detection of a burst
  41. Swift trigger 314975 is not a GRB
  42. Swift-BAT trigger 314975 possible burst
  43. GRB080607: optical observation
  44. GRB 080603b: optical observation
  45. GRB 070809: Putative host galaxy and redshift
  46. VLA upper limit on INTEGRAL burst GRB 080613A
  47. GRB 0800603A: optical observation
  48. GRB080613B: MITSuME upper limits
  49. GRB080613A: Optical upper limits with Okayama MITSuME telescope
  50. Konus-Wind observation of GRB 080613B
  51. GRB 080603A: optical observations on June 04
  52. GRB 080613A: Swift-XRT detection of the afterglow
  53. GRB080613A: Swift/UVOT Upper Limits
  54. GRB 080613A: GROND Confirmation of the Afterglow Candidate
  55. GRB 080613B: GROND Upper Limits
  56. GRB 080613B - NOT optical and IR nondetections
  57. GRB080613B: Swift/UVOT Upper Limits
  58. GRB 080613B, Swift-BAT refined analysis
  59. GRB 080613B: Swift-XRT refined analysis
  60. GRB 080514B: Spectroscopic constraints and probable host galaxy
  61. GRB 080613B: Swift detection of a burst
  62. GRB 080613: Faulkes Telescope North optical candidate
  63. GRB 080613 : a long GRB detected with INTEGRAL
  64. GRB 080603A: Late-time Keck imaging and spectroscopy
  65. GRB 080603b: optical observation
  66. Swift observations of BAT Slew Survey event (Trigger=010)
  67. GRB 080603A: final Swift-XRT observations.
  68. GRB 080607: AGILE-MCAL observation of the prompt emission
  69. GRB 080603B - TLS 2nd Epoch: Another Break
  70. GRB 080605: TLS 3rd Epoch - Source Confusion
  71. GRB080605: optical observation with the MITSuME-OAO telescope
  72. Konus-Wind observation of GRB 080607
  73. GRB080607: RTT150 optical observations
  74. GRB 080603A: optical observations
  75. GRB 080607: Swift-XRT refined analysis
  76. Swift/UVOT Observations of GRB080607
  77. GRB 080605: optical observations
  78. GRB 080607 KAIT observations
  79. VLA detection of INTEGRAL burst GRB 080603A
  80. Konus-Wind observation of GRB 080605
  81. GRB 080607: Enhanced Swift-XRT position
  82. GRB 080607, Swift-BAT refined analysis
  83. GRB 080605: GROND 2nd epoch observations
  84. GRB 080607 - PAIRITEL NIR detection
  85. GRB 080607: Keck/LRIS spectroscopy and redshift
  86. GRB 080607: Super-LOTIS early observations
  87. GRB 080607: Swift detection of a burst with optical afterglow
  88. GRB 080607: ROTSE-III Detection of Optical Counterpart
  89. GRB 080605: TLS RRM Analysis, Plateau/Rebrightening, Red OT
  90. GRB 080605: Swift-UVOT refined analysis
  91. Possible VLA radio detection on INTEGRAL burst GRB 080603A
  92. GRB 080604: VLA radio upper limit
  93. GRB 080605, Swift-BAT refined analysis
  94. GRB 080603B: VLA radio upper limit
  95. GRB 080605, Swift-BAT refined analysis
  96. GRB 080605: Swift-XRT refined analysis
  97. GRB080605: observation by BOOTES
  98. GRB 080605: MASTER VWF 46 s AT observation
  99. GRB 080605: Enhanced Swift-XRT position
  100. GRB 080605: GROND detection of the optical afterglow candidate

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