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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 120514A: Enhanced Swift-XRT position
  2. GRB 120514A: Swift-BAT refined analysis
  3. GRB 120514A: TAROT Calern observatory optical observations
  4. GRB 120514A: Swift detection of a burst
  5. GRB 120422A: Konkoly optical observations
  6. Fermi GBM Trigger 358364818 is not a GRB
  7. Fermi Trigger 358364818: BOOTES-4 observations
  8. GRB 120510B/Fermi Trigger 358364818: MASTER possible OT candidate
  9. GRB 120510A: Swift XRT and UVOT observations
  10. GRB 120510A: MASTER follow up observations
  11. GRB 120510A: MAXI/GSC detection of a burst
  12. GRB 120422A: SN identification from GTC
  13. Fermi/GBM detection of a burst from the magnetar 1E 2259+5
  14. GRB 120422A: P200 NIR detection
  15. GRB 120422A: CARMA 3mm observations
  16. GRB 120422A: VLT/X-shooter spectroscopic evidence for a SN
  17. GRB 120422A: Gemini-N detection of a supernova
  18. GRB 120422A: i-band re-brightening and possible SN detection
  19. GRB 120427A: MASTER follow up observations
  20. GRB 120422A: optical observations
  21. Konus-Wind observation of GRB 120427A
  22. IPN Triangulation of GRB 120427A
  23. Swift detection of 4U 1630-47
  24. GRB 120422A, the review of the sky area in plate archives
  25. Konus-Wind observation of GRB 120426A
  26. GRB 120422A: Additional Gemini observations and Keck/LRIS spectroscopy
  27. IPN Triangulation of bright GRB 120426A
  28. Swift Trigger 520928 is a noise event
  29. GRB 120422A: MITSuME Ishigakijima upper limit
  30. Swift Trigger 520928 is probably not a burst
  31. GRB 120424A: MAXI/GSC detection of a burst
  32. GRB 120422A: 272 GHz observations from SMA
  33. GRB 120422A: JCMT SCUBA-2 sub-mm observation
  34. GRB 120422A: RAPTOR Limits During Gamma-ray Emitting Interval
  35. GRB 120422A: VLT/X-shooter spectroscopy of the GRB counterpart
  36. GRB 120422A GROND observations
  37. GRB 120422A: Super-LOTIS early observations
  38. GRB 120422A: EVLA Detection
  39. GRB 120422A: Xinglong TNT optical upper limit
  40. GRB 120422A: NOT optical observations
  41. GRB 120422A: Gemini redshift of candidate host
  42. GRB 120422A: Zadko observatory - Gingin optical observations
  43. GRB 120422A: Swift-XRT refined Analysis
  44. GRB 120422A: A Swift/UVOT Detection
  45. GRB 120422A: Enhanced Swift-XRT position
  46. GRB 120422A: Swift-BAT refined analysis
  47. GRB 120422A: Gemini observations
  48. GRB 120422A: Faulkes Telescope North observations
  49. GRB 120422A: Swift detection of a burst
  50. GRB 120419A: Swift-XRT and UVOT observations
  51. GRB 120419A: A long GRB detected by INTEGRAL
  52. Swift Trigger 519874 is a noise event
  53. SGR1806-20, Swift-BAT refined analysis (Trigger 519868)
  54. Swift Trigger 519874 is probably a noise event
  55. Trigger 519868: Swift detection of SGR1806-20
  56. GRB 120404A: optical observations in Mondy observatory
  57. GRB 120404A: optical observations
  58. GRB 120404A, Optical Observations
  59. GRB 120404A: JCMT SCUBA-2 sub-mm observation
  60. GRB 120404A: SMARTS optical/IR observations
  61. GRB 120404A: EVLA Detection
  62. GRB 120404A: MASTER OT observations
  63. GRB120404A: GROND observations show steeply decaying afterglow
  64. GRB120404A: MOA optical observations of the initial rise afterglow
  65. GRB 120404A: VLT/X-shooter redshift confirmation
  66. GRB 120404A: Swift/UVOT Detection
  67. GRB 120404A: MITSuME Ishigakijima Optical Observation
  68. GRB 120404A: MITSuME Okayama Optical Observation
  69. GRB 120403B: Swift-XRT refined Analysis
  70. GRB 120404A: Swift-XRT refined Analysis
  71. GRB 120404A : TNT optical observation
  72. GRB 120404A: Swift-BAT refined analysis
  73. GRB 120401A: GROND Detection of an optical/NIR afterglow candidate
  74. GRB 120404A: Enhanced Swift-XRT position
  75. GRB 120404A: Gemini-N Redshift correction
  76. GRB 120402B: MASTER early OT limit
  77. GRB 120403B: TAROT La Silla observatory optical observations
  78. GRB 120403B: Fermi GBM Observation
  79. GRB 120404A: Gemini-N Redshift
  80. GRB 120403B: AAT nIR observations
  81. GRB 120404A: MITSuME Akeno Optical upper limits
  82. GRB 120404A: MASTER early OT limit
  83. GRB 120404A: Faulkes Telescope North afterglow confirmation
  84. GRB 120404A: Swift detection of a burst with an optical counterpart
  85. GRB 120403B: Swift-BAT refined analysis
  86. GRB 120403B: Swift/UVOT Upper Limits
  87. GRB 120403B: Enhanced Swift-XRT position
  88. GRB 120403A: Swift/BAT spectral lag analysis
  89. GRB 120403B: Swift detection of a burst
  90. BAT trigger 519207 was a burst from Cyg X-1, was not GRB 120402A
  91. GRB 120326A, the review of the sky area in plate archives
  92. GRB 120402A: optical upper limit
  93. GRB 120320A: optical upper limit in Mondy observatory
  94. GRB 120320A: early optical upper limit
  95. GRB 120403A: MASTER follow up observations
  96. GRB 120402A: MASTER follow up observations
  97. GRB 120403A, Swift-BAT refined analysis
  98. GRB 120402B: Fermi GBM detection
  99. GRB 120328B: Pi of the Sky simultaneous upper limits
  100. GRB 120326A: Bassano Bresciano Observatory - correction for GCN Cir 13178

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