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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: ATCA 34GHz upper limit
  2. GRB 120521C: Early Tautenburg limits
  3. GRB 120521C: EVLA 22 GHz Upper Limit
  4. GRB 120521A: GROND Upper limits
  5. GRB 120521C: Swift-XRT refined Analysis
  6. GRB 120521C: Swift-BAT refined analysis
  7. GRB 120521C: Keck Observations
  8. GRB 120521C: Swift/UVOT Upper Limits
  9. GRB 120521B: Swift/UVOT Upper Limits
  10. GRB 120521C: MASTER optical limit
  11. GRB 120521B: GROND Upper limits
  12. GRB 120521A: XRT light curve (Correction to GCN 13326)
  13. GRB 120521A: Swift-XRT refined Analysis
  14. GRB 120521C: PAIRITEL NIR Upper Limits
  15. GRB 120521C: Enhanced Swift-XRT position
  16. GRB 120521C: BOOTES-1 optical observations
  17. GRB 120521C: WHT optical observations
  18. GRB 120521C - NOT optical limits
  19. GRB120521C: Liverpool Telescope observations
  20. GRB 120521C: TAROT Calern observatory optical observations
  21. GRB 120521C: Swift detection of a burst
  22. GRB 120521B: Swift-BAT refined analysis
  23. GRB 120521B: Swift-XRT refined Analysis
  24. Konus-Wind observation of GRB 120519A
  25. Swift starts a new program to find fainter transients
  26. IPN Triangulation of GRB 120519A (short/hard)
  27. GRB 120521A: Swift/UVOT Upper Limits
  28. GRB 120521B: Enhanced Swift-XRT position
  29. GRB 120521A: Swift-BAT refined analysis
  30. GRB 120521B/Fermi Trigger 359284074: early MASTER-ICATE optical limit
  31. Correction to GCN 13307 (GRB120521B)
  32. GRB120521B: Faulkes Telescope South observations
  33. GRB 120521B: TAROT La Silla observatory optical observations
  34. GRB 120521B: Swift detection of a burst
  35. GRB 120521A: Enhanced Swift-XRT position
  36. GRB 120521A: TAROT La Silla observatory optical observations
  37. GRB 120521A: Swift detection of a short burst
  38. GRB 120514A : Suzaku WAM observation of the prompt emission
  39. GRB 120512A: A long GRB detected by INTEGRAL
  40. Swift Trigger 522245 is a noise fluctuation near IGR J17091-3624
  41. GRB 120514A: GROND upper limits
  42. GRB 120514A: Swift/UVOT Upper Limits
  43. GRB 120514A: UKIRT IR observations
  44. Konus-Wind observation of GRB 120510A
  45. GRB 120514A: Swift-XRT refined Analysis
  46. GRB 120514A: APEX observations of the submm counterpart
  47. GRB 120514A: Enhanced Swift-XRT position
  48. GRB 120514A: Swift-BAT refined analysis
  49. GRB 120514A: TAROT Calern observatory optical observations
  50. GRB 120514A: Swift detection of a burst
  51. GRB 120422A: Konkoly optical observations
  52. Fermi GBM Trigger 358364818 is not a GRB
  53. Fermi Trigger 358364818: BOOTES-4 observations
  54. GRB 120510B/Fermi Trigger 358364818: MASTER possible OT candidate
  55. GRB 120510A: Swift XRT and UVOT observations
  56. GRB 120510A: MASTER follow up observations
  57. GRB 120510A: MAXI/GSC detection of a burst
  58. GRB 120422A: SN identification from GTC
  59. Fermi/GBM detection of a burst from the magnetar 1E 2259+5
  60. GRB 120422A: P200 NIR detection
  61. GRB 120422A: CARMA 3mm observations
  62. GRB 120422A: VLT/X-shooter spectroscopic evidence for a SN
  63. GRB 120422A: Gemini-N detection of a supernova
  64. GRB 120422A: i-band re-brightening and possible SN detection
  65. GRB 120427A: MASTER follow up observations
  66. GRB 120422A: optical observations
  67. Konus-Wind observation of GRB 120427A
  68. IPN Triangulation of GRB 120427A
  69. Swift detection of 4U 1630-47
  70. GRB 120422A, the review of the sky area in plate archives
  71. Konus-Wind observation of GRB 120426A
  72. GRB 120422A: Additional Gemini observations and Keck/LRIS spectroscopy
  73. IPN Triangulation of bright GRB 120426A
  74. Swift Trigger 520928 is a noise event
  75. GRB 120422A: MITSuME Ishigakijima upper limit
  76. Swift Trigger 520928 is probably not a burst
  77. GRB 120424A: MAXI/GSC detection of a burst
  78. GRB 120422A: 272 GHz observations from SMA
  79. GRB 120422A: JCMT SCUBA-2 sub-mm observation
  80. GRB 120422A: RAPTOR Limits During Gamma-ray Emitting Interval
  81. GRB 120422A: VLT/X-shooter spectroscopy of the GRB counterpart
  82. GRB 120422A GROND observations
  83. GRB 120422A: Super-LOTIS early observations
  84. GRB 120422A: EVLA Detection
  85. GRB 120422A: Xinglong TNT optical upper limit
  86. GRB 120422A: NOT optical observations
  87. GRB 120422A: Gemini redshift of candidate host
  88. GRB 120422A: Zadko observatory - Gingin optical observations
  89. GRB 120422A: Swift-XRT refined Analysis
  90. GRB 120422A: A Swift/UVOT Detection
  91. GRB 120422A: Enhanced Swift-XRT position
  92. GRB 120422A: Swift-BAT refined analysis
  93. GRB 120422A: Gemini observations
  94. GRB 120422A: Faulkes Telescope North observations
  95. GRB 120422A: Swift detection of a burst
  96. GRB 120419A: Swift-XRT and UVOT observations
  97. GRB 120419A: A long GRB detected by INTEGRAL
  98. Swift Trigger 519874 is a noise event
  99. SGR1806-20, Swift-BAT refined analysis (Trigger 519868)
  100. Swift Trigger 519874 is probably a noise event

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