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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 110128A: Swift detection of a burst
  2. IBAS Alerts n. 6130 and 6131 are not due to a GRB
  3. Konus-Wind observation of GRB 110120A
  4. GRB 110123A: Fermi GBM detection
  5. GRB 110106B, radio observations
  6. GRB 110120A: MASTER optical observations
  7. GRB 110120A: Fermi LAT detection
  8. GRB 101224A, the review of the sky area in plate archives
  9. IPN triangulation of GRB 110120A
  10. GRB 101225A: CQUEAN optical observation
  11. GRB 110106A: CrAO optical observations
  12. GRB 110119A: Fermi GBM detection
  13. GRB 110120A: Fermi GBM detection
  14. GRB 110119A: Suzaku WAM observation of the prompt emission
  15. GRB 110112A: optical upper limit
  16. GRB 110120A: MASTER optical observations
  17. GRB110119: Swift/UVOT Detection
  18. GRB 110119A: Swift-XRT refined Analysis
  19. GRB110119A: MITSuME Okayama optical upper limits
  20. GRB 110119A: Swift-BAT refined analysis
  21. GRB 110119A: PAIRITEL NIR Afterglow Detection
  22. GRB 110119A: Enhanced Swift-XRT position
  23. GRB 110119A: Swift detection of a burst with an optical detection
  24. GRB110106A, mm-radio observations
  25. GRB 101219B: tentative redshift and spectroscopic supernova detection
  26. GRB 101219B: GROND detection of a SN signature
  27. Swift-BAT trigger 442771 is a noise fluctuation
  28. GRB 101219B: correction
  29. GRB 101219B: Likely the GRB host emission dominates now in the uvw2 filter
  30. New feature in Fermi GBM GRB Ground Position Notices
  31. Swift-BAT Trigger 442539 is not a GRB
  32. Swift Trigger 442539 is probably not a GRB
  33. Short GRB 110112B : early optical limit by "Pi of the Sky"
  34. GRB101225A - timing analysis
  35. GRB 110112B: Fermi GBM observation
  36. The Christmas burst GRB 101225A - optical spectroscopy with GTC
  37. GRB 110112B: Swift XRT and UVOT observations of the INTEGRAL burst
  38. GRB 110112A: MITSuME Akeno and Okayama optical upper limits
  39. GRB 110107A: Swift-XRT afterglow confirmation
  40. GRB 101225A: HST observations - no host detected
  41. GRB 101225A: Redshift retraction and results of additional photometric follow-up at the NOT
  42. GRB 110112B: A short GRB detected by INTEGRAL
  43. GRB 110112A: Swift-XRT refined Analysis
  44. GRB 110112A: Swift/UVOT upper limits
  45. GRB 110112A: WHT candidate afterglow/host galaxy
  46. GRB 110112A: MASTER optical observations
  47. GRB 110112A: Swift-BAT refined analysis
  48. GRB 110112A: Enhanced Swift-XRT position
  49. GRB 110106B: MASTER optical observations
  50. GRB110112A: TNT optical afterglow candidate
  51. GRB 110112A: Swift detection of a possible short burst
  52. GRB 110106B: early optical and near-IR observations
  53. GRB 110107A: Swift/UVOT upper limits
  54. GRB 101225a
  55. GRB 101219b. Possible radio afterglow detection.
  56. GRB 110106B: MASTER early optical observations
  57. GRB 110107A: Swift-XRT Afterglow Candidate
  58. GRB 110107A: Swift-BAT refined analysis
  59. GRB 110107A detected in ground analysis of BAT slew data
  60. GRB 101213A: Gemini-N galaxy redshift
  61. GRB 110106B: Fermi GBM detection
  62. Short GRB 110106A: MASTER OT observations
  63. GRB 110106B: Swift-XRT refined Analysis
  64. GRB 110106B: Gemini-North / WHT detection of a fading afterglow
  65. GRB 110106A: TNG NIR observations
  66. GRB 110106B Gemini-N galaxy redshift
  67. GRB 110106B: Liverpool Telescope observations
  68. GRB 110106A: ISAS-Kanazawa optical upper limit
  69. GRB 110106A: MITSuME Okayama optical upper limits
  70. GRB 110106B: WHT candidate afterglow
  71. GRB 110106B: Swift-BAT refined analysis
  72. GRB 110106B: Enhanced Swift-XRT position
  73. GRB 110106A: Swift/UVOT Upper Limits
  74. GRB 110106A: TNG redshift of the closeby galaxy
  75. GRB 110106A: Swift-XRT refined Analysis
  76. GRB110106B: Xinglong TNT upper limit
  77. GRB 110106A: Swift-BAT refined analysis
  78. GRB 110106A: Enhanced Swift-XRT position
  79. GRB 110106B: Swift detection of a burst
  80. GRB 110106A: TNG optical observations and candidate counterparts
  81. GRB 110106A: MASTER optical observations
  82. GRB 101225A: Keck redshift
  83. GRB110106A: Xinglong TNT upper limit
  84. GRB 110106A: Swift detection of a burst
  85. GRB 101225A: Host galaxy
  86. GRB 101219A: Gemini-North host redshift
  87. GRB 110102A: Swift-XRT refined Analysis
  88. GRB 101219B: After 2 weeks still detected by Swift/UVOT
  89. Konus-Wind observation of GRB 110102A
  90. GRB110102A: Swift/UVOT observations
  91. GRB110102A: MITSuME Okayama Optical Observation
  92. GRB 110102A: Fermi GBM observation
  93. GRB 110102A: Swift-BAT refined analysis
  94. GRB 110102A: Enhanced Swift-XRT position
  95. GRB 110102A: Swift detection of a burst with an optical detection
  96. GRB 101225A: optical break from NOT observation
  97. GRB 101225A: MMT spectroscopy
  98. GRB 101225A: P60 Observations
  99. GRB 101225A: MAXI/GSC observations
  100. GRB 101225A Late-time emission observed by Swift-BAT

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