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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 120521A: Swift-BAT refined analysis
  2. GRB 120521B/Fermi Trigger 359284074: early MASTER-ICATE optical limit
  3. Correction to GCN 13307 (GRB120521B)
  4. GRB120521B: Faulkes Telescope South observations
  5. GRB 120521B: TAROT La Silla observatory optical observations
  6. GRB 120521B: Swift detection of a burst
  7. GRB 120521A: Enhanced Swift-XRT position
  8. GRB 120521A: TAROT La Silla observatory optical observations
  9. GRB 120521A: Swift detection of a short burst
  10. GRB 120514A : Suzaku WAM observation of the prompt emission
  11. GRB 120512A: A long GRB detected by INTEGRAL
  12. Swift Trigger 522245 is a noise fluctuation near IGR J17091-3624
  13. GRB 120514A: GROND upper limits
  14. GRB 120514A: Swift/UVOT Upper Limits
  15. GRB 120514A: UKIRT IR observations
  16. Konus-Wind observation of GRB 120510A
  17. GRB 120514A: Swift-XRT refined Analysis
  18. GRB 120514A: APEX observations of the submm counterpart
  19. GRB 120514A: Enhanced Swift-XRT position
  20. GRB 120514A: Swift-BAT refined analysis
  21. GRB 120514A: TAROT Calern observatory optical observations
  22. GRB 120514A: Swift detection of a burst
  23. GRB 120422A: Konkoly optical observations
  24. Fermi GBM Trigger 358364818 is not a GRB
  25. Fermi Trigger 358364818: BOOTES-4 observations
  26. GRB 120510B/Fermi Trigger 358364818: MASTER possible OT candidate
  27. GRB 120510A: Swift XRT and UVOT observations
  28. GRB 120510A: MASTER follow up observations
  29. GRB 120510A: MAXI/GSC detection of a burst
  30. GRB 120422A: SN identification from GTC
  31. Fermi/GBM detection of a burst from the magnetar 1E 2259+5
  32. GRB 120422A: P200 NIR detection
  33. GRB 120422A: CARMA 3mm observations
  34. GRB 120422A: VLT/X-shooter spectroscopic evidence for a SN
  35. GRB 120422A: Gemini-N detection of a supernova
  36. GRB 120422A: i-band re-brightening and possible SN detection
  37. GRB 120427A: MASTER follow up observations
  38. GRB 120422A: optical observations
  39. Konus-Wind observation of GRB 120427A
  40. IPN Triangulation of GRB 120427A
  41. Swift detection of 4U 1630-47
  42. GRB 120422A, the review of the sky area in plate archives
  43. Konus-Wind observation of GRB 120426A
  44. GRB 120422A: Additional Gemini observations and Keck/LRIS spectroscopy
  45. IPN Triangulation of bright GRB 120426A
  46. Swift Trigger 520928 is a noise event
  47. GRB 120422A: MITSuME Ishigakijima upper limit
  48. Swift Trigger 520928 is probably not a burst
  49. GRB 120424A: MAXI/GSC detection of a burst
  50. GRB 120422A: 272 GHz observations from SMA
  51. GRB 120422A: JCMT SCUBA-2 sub-mm observation
  52. GRB 120422A: RAPTOR Limits During Gamma-ray Emitting Interval
  53. GRB 120422A: VLT/X-shooter spectroscopy of the GRB counterpart
  54. GRB 120422A GROND observations
  55. GRB 120422A: Super-LOTIS early observations
  56. GRB 120422A: EVLA Detection
  57. GRB 120422A: Xinglong TNT optical upper limit
  58. GRB 120422A: NOT optical observations
  59. GRB 120422A: Gemini redshift of candidate host
  60. GRB 120422A: Zadko observatory - Gingin optical observations
  61. GRB 120422A: Swift-XRT refined Analysis
  62. GRB 120422A: A Swift/UVOT Detection
  63. GRB 120422A: Enhanced Swift-XRT position
  64. GRB 120422A: Swift-BAT refined analysis
  65. GRB 120422A: Gemini observations
  66. GRB 120422A: Faulkes Telescope North observations
  67. GRB 120422A: Swift detection of a burst
  68. GRB 120419A: Swift-XRT and UVOT observations
  69. GRB 120419A: A long GRB detected by INTEGRAL
  70. Swift Trigger 519874 is a noise event
  71. SGR1806-20, Swift-BAT refined analysis (Trigger 519868)
  72. Swift Trigger 519874 is probably a noise event
  73. Trigger 519868: Swift detection of SGR1806-20
  74. GRB 120404A: optical observations in Mondy observatory
  75. GRB 120404A: optical observations
  76. GRB 120404A, Optical Observations
  77. GRB 120404A: JCMT SCUBA-2 sub-mm observation
  78. GRB 120404A: SMARTS optical/IR observations
  79. GRB 120404A: EVLA Detection
  80. GRB 120404A: MASTER OT observations
  81. GRB120404A: GROND observations show steeply decaying afterglow
  82. GRB120404A: MOA optical observations of the initial rise afterglow
  83. GRB 120404A: VLT/X-shooter redshift confirmation
  84. GRB 120404A: Swift/UVOT Detection
  85. GRB 120404A: MITSuME Ishigakijima Optical Observation
  86. GRB 120404A: MITSuME Okayama Optical Observation
  87. GRB 120403B: Swift-XRT refined Analysis
  88. GRB 120404A: Swift-XRT refined Analysis
  89. GRB 120404A : TNT optical observation
  90. GRB 120404A: Swift-BAT refined analysis
  91. GRB 120401A: GROND Detection of an optical/NIR afterglow candidate
  92. GRB 120404A: Enhanced Swift-XRT position
  93. GRB 120404A: Gemini-N Redshift correction
  94. GRB 120402B: MASTER early OT limit
  95. GRB 120403B: TAROT La Silla observatory optical observations
  96. GRB 120403B: Fermi GBM Observation
  97. GRB 120404A: Gemini-N Redshift
  98. GRB 120403B: AAT nIR observations
  99. GRB 120404A: MITSuME Akeno Optical upper limits
  100. GRB 120404A: MASTER early OT limit

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