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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 090423: UKIRT data further analysis
  2. GRB 090423: Enhanced Swift-XRT position
  3. GRB 090423: Swift-BAT refined analysis
  4. GRB 090422: Swift/UVOT Upper Limits
  5. GRB 090423: UKIRT K-band observations
  6. GRB 090423: P60 Observations
  7. GRB 090423: Faulkes Telescope South observations
  8. GRB 090418A: R and I band observation
  9. GRB 090423: Swift detection of a burst
  10. GRB 090422: Liverpool Telescope possible candidate
  11. GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
  12. GRB 090422: Swift-BAT refined analysis
  13. GRB 090422: Enhanced Swift-XRT position
  14. GRB 090410: Erratum in GCN 9189
  15. GRB 090408A: Erratum in GCN 9188
  16. GRB 090418B: RTT150 optical observations
  17. GRB 090418A: RTT150 optical observations
  18. GRB 080410: GAO 150cm telescope Optical Observation
  19. GRB 080408A: GAO 150cm telescope Optical Observation
  20. GRB 090422: Liverpool Telescope observations
  21. GRB 090418B: Suzaku WAM observation of the prompt emission
  22. GRB 090422: Swift detection of a burst
  23. GRB 090418C: Fermi GBM Detection
  24. GRB 090418A: Swift/UVOT Detection of the Neighbouring Galaxy
  25. Swift-BAT trigger 349718 is not a burst
  26. GRB 090418B: GRAS002 observatios
  27. GRB 090417B: Optical observation
  28. GRB 090418A: optical observations
  29. GRB 090418B: GROND observations
  30. GRB 090419: Swift/UVOT Observations
  31. GRB 090418B: Faulkes Telescope North observations
  32. GRB 090418A: Swift/UVOT Observations
  33. GRB 090417B: Swift/UVOT Upper Limits
  34. GRB 090417B Correction to the BAT refined analysis position
  35. GRB 090419: Swift-XRT refined analysis
  36. Konus-Wind observation of GRB 090418B
  37. GRB 090418: Erratum in GCN 9168
  38. GRB 090419: GROND detection of afterglow candidate
  39. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  40. GRB 090419: Swift-BAT refined analysis
  41. VLA radio detection of GRB 090418
  42. VLA radio upper limit on GRB 090417B
  43. GRB 090419: Enhanced Swift-XRT position
  44. GRB 090418: Swift XRT refined analysis
  45. GRB 090418A: ROTSE-III Refined Analysis
  46. GRB 090419: Swift detection of a burst
  47. VLA observations of short burst GRB 090417A
  48. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  49. GRB 090417B: Gemini imaging
  50. GRB 090418: Swift-BAT refined analysis
  51. GRB 090417B: Galaxy redshift
  52. GRB 090417B: Swift-XRT refined analysis
  53. GRB 090418: Enhanced Swift-XRT position
  54. GRB 090417B: Swift-BAT further refined analysis
  55. GRB 090418: PAIRITEL NIR detection
  56. GRB 090418 Lick Redshift
  57. GRB 090418: ROTSE-III Confirmation of Optical Counterpart
  58. GRB 090418: Swift detection of a burst with optical afterglow
  59. GRB 090418 OA candidate
  60. GRB 090411B: Suzaku WAM observation of the prompt emission
  61. GRB 090411A: Suzaku WAM observation of the prompt emission
  62. GRB 090417B: Subaru NIR Observations
  63. GRB 090417B: Liverpool Telescope observations
  64. GRB 090417B: MITSuME Okayama optical upper limits
  65. GRB090417B: Xinglong TNT optical upper limit
  66. GRB 090417B: optical observations
  67. GRB090417B: optical observations
  68. GRB 090417B: Swift-BAT refined analysis
  69. GRB 090417A: Swift-BAT refined analysis
  70. GRB 090417A: Early-type nature of the putative host
  71. GRB 090417A: nearby galaxy redshift
  72. GRB 090417B: Swift detection of a burst
  73. GRB 090417: 2MASS galaxy within BAT Localization
  74. GRB 090417: Swift detection of a short burst
  75. GRB 090412: Fermi GBM detection
  76. GRB 090411B: Fermi GBM detection
  77. GRB 090411A: Fermi GBM detection
  78. GRB 090410: Suzaku WAM observation of the prompt emission
  79. GRB 090410: GROND upper limits
  80. Fermi GBM trigger 261106787 is not a GRB
  81. GRB 090410: MITSuME optical upper limits
  82. GRB 090408b: IPN Triangulation
  83. GRB 090328b: IPN Triangulation
  84. GRB 090410: Swift-BAT refined analysis
  85. GRB 090410: Swift detection of a burst
  86. Konus-Wind and Konus-RF observations of GRB 090408b
  87. GRB090408 : TAOS optical observations
  88. GRB 090409: Fermi GBM detection
  89. Swift-BAT Trigger 348781 is not a GRB
  90. Swift-BAT Trigger 348720 is not a GRB
  91. GRB 090406: pseudo-z= 0.91 from prompt emission spectrum
  92. GRB090408, RIMOTS optical upper limits
  93. GRB 090408: Xinglong TNT optical Upper Limit
  94. Swift-BAT trigger 348781: almost certainly not a burst
  95. Fermi GBM Detection of a weak source
  96. GRB 090408B: MASTER II-Kourovka optical observations
  97. GRB 090408: Swift detection of a burst
  98. GRB 090407: GROND upper limits
  99. GRB 090407: VLT observations
  100. GRB 090407: Swift-XRT refined analysis

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