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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 110205A : Lulin optical observation
  2. GRB110205A: MITSuME Ishigakijima Optical Observation
  3. GRB110205A: MITSuME Okayama Optical Observation
  4. GRB110205A: SMA 1.3mm Observations
  5. GRB 110205A: Swift/UVOT Continuing Observations
  6. GRB 110205A: Lulin optical observations and temporal decay index
  7. Observations GRB 110205A
  8. GRB 110205A: Swift-BAT refined analysis
  9. GRB 110205A: Newcastle Observatory Optical Observations
  10. GRB 110205A: Swift-XRT refined Analysis
  11. GRB 110205A: LOAO B/R Observation
  12. GRB 101225A is likely at z~0
  13. GRB 110205A: optical flare confirmation
  14. GRB 110205A: NOT redshift confirmation
  15. GRB 110205A: Enhanced Swift-XRT position
  16. GRB 110205A: FAST Redshift
  17. GRB 110205A: GRAS005 optical observations
  18. GRB 110205A: PAIRITEL NIR Afterglow Detection
  19. GRB 110205A: Possible Lick/Kast redshift
  20. GRB 110205A: Swift/UVOT Confirmation of Flaring Afterglow
  21. GRB 110205A: Liverpool Telescope Afterglow Confirmation
  22. GRB 110205A: TAROT Calern observatory detection of an optical flare
  23. GRB 110205A: ROTSE-III, Optical Counterpart is flaring to ~14 mag
  24. GRB 110205A: TAROT Calern observatory optical detection
  25. GRB 110205A: Swift detection of a burst with an optical candidate
  26. GRB 110128A: Fermi GBM detection
  27. GRB 110201A: Swift-XRT refined Analysis
  28. GRB110201A: MITSuME Okayama optical upper limits
  29. Swift/UVOT observations of GRB110201A
  30. GRB 110201A: Swift-BAT refined analysis
  31. GRB 110201A: MASTER optical observations
  32. GRB 110201A: Swift detection of a burst
  33. GRB110112B: EVLA Observations
  34. GRB101224A: EVLA Observations
  35. GRB110112A: EVLA Observations
  36. GRB110128A: MITSuME Okayama optical upper limits
  37. GRB 110125A: Fermi GBM detection
  38. GRB 101112A: Maidanak and CrAO optical observations
  39. GRB110128A: TNG NIR observations
  40. GRB 110128A, Swift-BAT refined analysis
  41. GRB 110128A: TAROT-Calern refined analysis
  42. GRB 110128A: Swift/UVOT observations
  43. GRB 110128A: Swift-XRT refined Analysis
  44. GRB 110120A: Suzaku WAM observation of the prompt emission
  45. GRB 110128A: WHT redshifts of nearby field galaxies
  46. GRB 110128A: VLT/X-shooter redshift
  47. GRB 110128A: Enhanced Swift-XRT position
  48. GRB 110128A: Afterglow detection from NOT
  49. GRB 110128A: TAROT Calern observatory upper limits
  50. GRB 110128A: Swift detection of a burst
  51. IBAS Alerts n. 6130 and 6131 are not due to a GRB
  52. Konus-Wind observation of GRB 110120A
  53. GRB 110123A: Fermi GBM detection
  54. GRB 110106B, radio observations
  55. GRB 110120A: MASTER optical observations
  56. GRB 110120A: Fermi LAT detection
  57. GRB 101224A, the review of the sky area in plate archives
  58. IPN triangulation of GRB 110120A
  59. GRB 101225A: CQUEAN optical observation
  60. GRB 110106A: CrAO optical observations
  61. GRB 110119A: Fermi GBM detection
  62. GRB 110120A: Fermi GBM detection
  63. GRB 110119A: Suzaku WAM observation of the prompt emission
  64. GRB 110112A: optical upper limit
  65. GRB 110120A: MASTER optical observations
  66. GRB110119: Swift/UVOT Detection
  67. GRB 110119A: Swift-XRT refined Analysis
  68. GRB110119A: MITSuME Okayama optical upper limits
  69. GRB 110119A: Swift-BAT refined analysis
  70. GRB 110119A: PAIRITEL NIR Afterglow Detection
  71. GRB 110119A: Enhanced Swift-XRT position
  72. GRB 110119A: Swift detection of a burst with an optical detection
  73. GRB110106A, mm-radio observations
  74. GRB 101219B: tentative redshift and spectroscopic supernova detection
  75. GRB 101219B: GROND detection of a SN signature
  76. Swift-BAT trigger 442771 is a noise fluctuation
  77. GRB 101219B: correction
  78. GRB 101219B: Likely the GRB host emission dominates now in the uvw2 filter
  79. New feature in Fermi GBM GRB Ground Position Notices
  80. Swift-BAT Trigger 442539 is not a GRB
  81. Swift Trigger 442539 is probably not a GRB
  82. Short GRB 110112B : early optical limit by "Pi of the Sky"
  83. GRB101225A - timing analysis
  84. GRB 110112B: Fermi GBM observation
  85. The Christmas burst GRB 101225A - optical spectroscopy with GTC
  86. GRB 110112B: Swift XRT and UVOT observations of the INTEGRAL burst
  87. GRB 110112A: MITSuME Akeno and Okayama optical upper limits
  88. GRB 110107A: Swift-XRT afterglow confirmation
  89. GRB 101225A: HST observations - no host detected
  90. GRB 101225A: Redshift retraction and results of additional photometric follow-up at the NOT
  91. GRB 110112B: A short GRB detected by INTEGRAL
  92. GRB 110112A: Swift-XRT refined Analysis
  93. GRB 110112A: Swift/UVOT upper limits
  94. GRB 110112A: WHT candidate afterglow/host galaxy
  95. GRB 110112A: MASTER optical observations
  96. GRB 110112A: Swift-BAT refined analysis
  97. GRB 110112A: Enhanced Swift-XRT position
  98. GRB 110106B: MASTER optical observations
  99. GRB110112A: TNT optical afterglow candidate
  100. GRB 110112A: Swift detection of a possible short burst

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