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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 110206A: Swift detection of a probable X-ray afterglow
  2. GRB 110206A: TAROT La Silla observatory optical observations
  3. GRB 110205A: Lightbuckets Optical Observations
  4. GRB 110206A: a long GRB detected by INTEGRAL
  5. GRB 110205A : Lulin optical observation
  6. GRB110205A: MITSuME Ishigakijima Optical Observation
  7. GRB110205A: MITSuME Okayama Optical Observation
  8. GRB110205A: SMA 1.3mm Observations
  9. GRB 110205A: Swift/UVOT Continuing Observations
  10. GRB 110205A: Lulin optical observations and temporal decay index
  11. Observations GRB 110205A
  12. GRB 110205A: Swift-BAT refined analysis
  13. GRB 110205A: Newcastle Observatory Optical Observations
  14. GRB 110205A: Swift-XRT refined Analysis
  15. GRB 110205A: LOAO B/R Observation
  16. GRB 101225A is likely at z~0
  17. GRB 110205A: optical flare confirmation
  18. GRB 110205A: NOT redshift confirmation
  19. GRB 110205A: Enhanced Swift-XRT position
  20. GRB 110205A: FAST Redshift
  21. GRB 110205A: GRAS005 optical observations
  22. GRB 110205A: PAIRITEL NIR Afterglow Detection
  23. GRB 110205A: Possible Lick/Kast redshift
  24. GRB 110205A: Swift/UVOT Confirmation of Flaring Afterglow
  25. GRB 110205A: Liverpool Telescope Afterglow Confirmation
  26. GRB 110205A: TAROT Calern observatory detection of an optical flare
  27. GRB 110205A: ROTSE-III, Optical Counterpart is flaring to ~14 mag
  28. GRB 110205A: TAROT Calern observatory optical detection
  29. GRB 110205A: Swift detection of a burst with an optical candidate
  30. GRB 110128A: Fermi GBM detection
  31. GRB 110201A: Swift-XRT refined Analysis
  32. GRB110201A: MITSuME Okayama optical upper limits
  33. Swift/UVOT observations of GRB110201A
  34. GRB 110201A: Swift-BAT refined analysis
  35. GRB 110201A: MASTER optical observations
  36. GRB 110201A: Swift detection of a burst
  37. GRB110112B: EVLA Observations
  38. GRB101224A: EVLA Observations
  39. GRB110112A: EVLA Observations
  40. GRB110128A: MITSuME Okayama optical upper limits
  41. GRB 110125A: Fermi GBM detection
  42. GRB 101112A: Maidanak and CrAO optical observations
  43. GRB110128A: TNG NIR observations
  44. GRB 110128A, Swift-BAT refined analysis
  45. GRB 110128A: TAROT-Calern refined analysis
  46. GRB 110128A: Swift/UVOT observations
  47. GRB 110128A: Swift-XRT refined Analysis
  48. GRB 110120A: Suzaku WAM observation of the prompt emission
  49. GRB 110128A: WHT redshifts of nearby field galaxies
  50. GRB 110128A: VLT/X-shooter redshift
  51. GRB 110128A: Enhanced Swift-XRT position
  52. GRB 110128A: Afterglow detection from NOT
  53. GRB 110128A: TAROT Calern observatory upper limits
  54. GRB 110128A: Swift detection of a burst
  55. IBAS Alerts n. 6130 and 6131 are not due to a GRB
  56. Konus-Wind observation of GRB 110120A
  57. GRB 110123A: Fermi GBM detection
  58. GRB 110106B, radio observations
  59. GRB 110120A: MASTER optical observations
  60. GRB 110120A: Fermi LAT detection
  61. GRB 101224A, the review of the sky area in plate archives
  62. IPN triangulation of GRB 110120A
  63. GRB 101225A: CQUEAN optical observation
  64. GRB 110106A: CrAO optical observations
  65. GRB 110119A: Fermi GBM detection
  66. GRB 110120A: Fermi GBM detection
  67. GRB 110119A: Suzaku WAM observation of the prompt emission
  68. GRB 110112A: optical upper limit
  69. GRB 110120A: MASTER optical observations
  70. GRB110119: Swift/UVOT Detection
  71. GRB 110119A: Swift-XRT refined Analysis
  72. GRB110119A: MITSuME Okayama optical upper limits
  73. GRB 110119A: Swift-BAT refined analysis
  74. GRB 110119A: PAIRITEL NIR Afterglow Detection
  75. GRB 110119A: Enhanced Swift-XRT position
  76. GRB 110119A: Swift detection of a burst with an optical detection
  77. GRB110106A, mm-radio observations
  78. GRB 101219B: tentative redshift and spectroscopic supernova detection
  79. GRB 101219B: GROND detection of a SN signature
  80. Swift-BAT trigger 442771 is a noise fluctuation
  81. GRB 101219B: correction
  82. GRB 101219B: Likely the GRB host emission dominates now in the uvw2 filter
  83. New feature in Fermi GBM GRB Ground Position Notices
  84. Swift-BAT Trigger 442539 is not a GRB
  85. Swift Trigger 442539 is probably not a GRB
  86. Short GRB 110112B : early optical limit by "Pi of the Sky"
  87. GRB101225A - timing analysis
  88. GRB 110112B: Fermi GBM observation
  89. The Christmas burst GRB 101225A - optical spectroscopy with GTC
  90. GRB 110112B: Swift XRT and UVOT observations of the INTEGRAL burst
  91. GRB 110112A: MITSuME Akeno and Okayama optical upper limits
  92. GRB 110107A: Swift-XRT afterglow confirmation
  93. GRB 101225A: HST observations - no host detected
  94. GRB 101225A: Redshift retraction and results of additional photometric follow-up at the NOT
  95. GRB 110112B: A short GRB detected by INTEGRAL
  96. GRB 110112A: Swift-XRT refined Analysis
  97. GRB 110112A: Swift/UVOT upper limits
  98. GRB 110112A: WHT candidate afterglow/host galaxy
  99. GRB 110112A: MASTER optical observations
  100. GRB 110112A: Swift-BAT refined analysis

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