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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. Konus-Wind observation of GRB 140323A
  2. GRB 140323A: Fermi-LAT detection
  3. GRB 140323A: Swift-XRT refined Analysis
  4. GRB 140323A: Fermi GBM observation
  5. GRB 140323A: BOOTES-3 optical upper limit.
  6. GRB 140323A: Swift/UVOT Upper Limits
  7. GRB 140323A: Swift-BAT refined analysis
  8. GRB 140323A: Enhanced Swift-XRT position
  9. GRB 140323A: Swift detection of a burst
  10. GRB 140320A: RATIR Optical and NIR Observations
  11. Konus-Wind observation of GRB 140320D
  12. GRB 140320B: P60 detection of a very red afterglow
  13. IPN Triangulation of very intense GRB 140320D
  14. GRB 140320C: Mini-GWAC prompt observation
  15. GRB 140320C: Swift/UVOT Upper Limits
  16. GRB 140320A: Swift-BAT refined analysis
  17. GRB 140320B: Swift/UVOT Upper Limits
  18. GRB 140320A: Swift/UVOT Upper Limits
  19. GRB 140320C: Swift-XRT observations
  20. GRB 140320A: Confirmation of a fading X-ray afterglow
  21. GRB 140320C: Swift-XRT detection of the X-ray afterglow
  22. GRB 140320A: Fermi GBM detection
  23. GRB 140320B: Swift-XRT detection of the afterglow
  24. GRB 140320C: Mondy optical observations
  25. GRB 140320A: Enhanced Swift-XRT position
  26. GRB 140320A: Swift-XRT detection of an afterglow candidate
  27. GRB 140320C: MASTER optical observations
  28. GRB 140320C: FTN optical observations
  29. GRB 140320C: A long GRB detected by INTEGRAL
  30. GRB 140320B: Xinglong TNT upper limit
  31. GRB 140320B: ISON-NM optical observations
  32. GRB 140320B: A long GRB detected by INTEGRAL
  33. GRB 140320B: FTN optical afterglow candidate
  34. Swift Trigger 592558 is not an astrophysical source
  35. GRB 140320A: Fermi GBM observations suggest a short GRB
  36. GRB 140320A: Swift detection of a burst
  37. GRB 140318A: Continued RATIR Optical and NIR Observations
  38. GRB 140318A: Mondy optical limit
  39. GRB 140318A: Swift/UVOT Upper Limits
  40. GRB 140318A: Swift-BAT refined analysis
  41. GRB 140311B: Mondy optical limit
  42. GRB 140311A: Mondy optical limits
  43. GRB 140318A: Swift-XRT refined Analysis
  44. GRB 140318A: Liverpool Telescope optical observations
  45. GRB 140318A: Enhanced Swift-XRT position
  46. GRB 140318A: RATIR Optical and NIR Detections
  47. GRB140318A: Discovery Channel Telescope Optical Detection
  48. GRB 140318A: WHT spectroscopy
  49. GRB 140318A: NOT detection of the afterglow
  50. GRB 140318A: Swift detection of a burst
  51. GRB 140311A: VLA Detection
  52. GRB140308A: Suzaku WAM observation of the prompt emission
  53. GRB 140311C: MASTER optical observations
  54. GRB 140311C: Swift-XRT and UVOT observations
  55. GRB 140311C: MASTER before, during and after trigger optical observations
  56. GRB 140311A: further NOT observations
  57. GRB 140311B: Swift-BAT refined analysis
  58. GRB 140311A: RATIR Optical and NIR Detection
  59. GRB 140311C: Fermi GBM Detection
  60. GRB 140311A: Montarrenti Observatory optical upper limit
  61. GRB 140311B: Fermi GBM Detection
  62. GRB 140311A: Kottamia I-band observation
  63. GRB 140311A: Swift/UVOT Upper Limits
  64. GRB 140311B: Swift/UVOT Upper Limits
  65. Fermi416242156: possible iPTF counterpart
  66. GRB 140311B: RATIR Optical and NIR Observations
  67. GRB 140311A: Bassano Bresciano Observatory optical upper limit
  68. GRB 140311A: Swift-XRT refined Analysis
  69. GRO J1744-28: Fermi GBM observation
  70. GRB 140311A: Gemini-North redshift
  71. GRB 140302A: GROND confirmation of the afterglow
  72. GRB 140311A: NOT redshift confirmation
  73. GRB 140311B: Swift-XRT refined Analysis
  74. GRB 140311A: Swift-BAT refined analysis
  75. GRB 140311A: Gemini-South redshift
  76. GRB 140311B: final MASTER OT light curve
  77. GRB 140311A: Enhanced Swift-XRT position
  78. GRB 140311B: Enhanced Swift-XRT position
  79. GRB 140311A: Recalibration of photometry of OT detected with Kottamia 188cm telescope
  80. GRB 140311A: Nanshan afterglow decay
  81. GRB 140311B: TAROT Calern observatory optical observations
  82. GRB 140311A: Optical follow-up observation with Kottamia 188cm telescope
  83. GRB 140311A: NOT observations of the optical afterglow
  84. GRB 140311A: Zadko observatory - Gingin optical observations
  85. GRB140311B: Swift/XRT position
  86. GRB 140311B: Swift-XRT observations
  87. GRB 140311B: Nanshan afterglow detection
  88. GRB 140311B: MASTER early optical observations
  89. GRB 140311A: Nanshan OT detection
  90. GRB 140311A: MASTER early optical observations
  91. GRB 140311B: Swift detection of a burst
  92. GRB 140311A: Swift detection of a probable burst
  93. Konus-Wind observation of GRB 140308A
  94. GRB 140304A: Suzaku WAM observation of the prompt emission
  95. IPN Triangulation of GRB 140308A
  96. GRB 140306A: Suzaku WAM observation of the prompt emission
  97. Konus-Wind observation of GRB 140306A
  98. IPN Triangulation of GRB 140306A
  99. GRB 140304A: Continued RATIR Optical and NIR Observations
  100. GRB 140304A: 10.4m GTC refined redshift z = 5.283

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