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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 160410A: Skynet PROMPT-CTIO observations of the optical afterglow
  2. GRB 160410A: Swift-BAT refined analysis of the short GRB
  3. GRB 160410A: Swift/UVOT Detection
  4. GRB 160410A: VLT/X-shooter redshift
  5. GRB 160410A: Enhanced Swift-XRT position
  6. GRB 160410A: GROND optical detection
  7. GRB 160410A: Swift detection of a (possibly-short) burst with an optical counterpart
  8. GRB 160408A: GMG observation limit
  9. GRB 160408A: Gemini afterglow confirmation
  10. GRB 160408A: TLS Tautenburg observations
  11. GRB 160408A: Swift/UVOT Upper Limits
  12. GRB 160408A: Swift-XRT refined Analysis
  13. GRB 160408A: Fermi GBM detection
  14. GRB 160406A: Fermi GBM observation
  15. GRB 160408A: Swift-BAT refined analysis
  16. GRB 160408A: Gemini optical observations
  17. GRB 160408A: Enhanced Swift-XRT position
  18. GRB 160408A: Swift detection of a short burst
  19. IPN Triangulation of GRB 160406A (short/hard)
  20. LIGO/Virgo G211117: 10.4m GTC follow-up of PS15dpn
  21. GRB 160401A: Swift-XRT observations
  22. GRB 160401A: Swift/UVOT Upper Limits
  23. GRB 160401A: Zadko observatory - Gingin optical observations
  24. GRB 160401A: LT observations
  25. GRB 160401A: Swift ToO observations
  26. GRB 160401A: MASTER-IAC prompt optical observations
  27. GRB 160401A: a long GRB detected by INTEGRAL
  28. GRB 160327A: Continued RATIR Optical and NIR Observations
  29. LIGO/Virgo G211117: LOFAR follow-up
  30. GRB 160324A: CALET Gamma-Ray Burst Monitor detection
  31. GRB 160327A: Early RAPTOR Limits
  32. GRB 160327A: JCMT SCUBA-2 sub-mm observation
  33. GRB 160327A: Imaging and spectroscopy from GTC
  34. Konus-Wind observation of GRB 160325A
  35. GRB 160327A: Continued RATIR Optical and NIR Observations
  36. GRB 160327A: KAIT optical afterglow confirmation
  37. GRB 160327A: Mondy optical upper limit
  38. GRB 160327A: Swift-BAT refined analysis
  39. GRB 160327A: Swift/UVOT Upper Limits
  40. GRB 160327A: Swift-XRT refined Analysis
  41. GRB 160327A: Enhanced Swift-XRT position
  42. GRB 160327A: RATIR Optical and NIR Afterglow Detection
  43. GRB 160327A: Swift detection of a burst
  44. GRB 160325A, Swift-BAT refined analysis
  45. GRB 160325A: GROND Upper Limits
  46. GRB 160325A: Swift-XRT refined Analysis
  47. GRB 160325A: Further Swift/UVOT Observations
  48. GRB 160325A: afterglow confirmation
  49. GRB 160325A: Enhanced Swift-XRT position
  50. GRB160325A Swift/UVOT Detection
  51. GRB 160325A: Fermi-LAT detection
  52. Swift Trigger 680457 is not a GRB
  53. LIGO/Virgo G211117: CALET GBM Observations
  54. GRB 160325A: Fermi GBM detection
  55. GRB160325A: REM NIR observations
  56. GRB 160325A: Swift detection of a burst
  57. Swift detects GX 301-2 in very high state
  58. Fermi Gamma-ray Burst Monitor trigger 160323546 is not a GRB
  59. GRB 160321A: AbAO optical observations
  60. GRB 160321A: Possible RATIR Optical and NIR Detections
  61. GRB 160321A: Swift/UVOT Upper Limits
  62. GRB 160321A: Swift-BAT refined analysis
  63. GRB 160321A: Swift-XRT refined Analysis
  64. GRB 160316A: CALET Gamma-Ray Burst Monitor detection
  65. GRB 160321A: Enhanced Swift-XRT position
  66. GRB 160321A: MASTER observations zero Galaxy latitude GRB
  67. GRB 160321A: Swift detection of a probable burst
  68. GRB 160310A: Terskol 2-m observations
  69. IPN Triangulation of GRB 160310A
  70. LIGO/Virgo G211117: EWE for NOWT follow-up of northern sky
  71. SGR 0755-2933, Swift-BAT refined analysis
  72. GRB 160131A: 15 GHz upper limits from AMI-LA
  73. GRB 160310A: A further Swift-XRT observation, no afterglow detected
  74. Swift detection of a likely new SGR: SGR 0755-2933
  75. GRB 160314A: Continued RATIR Optical and NIR Observations
  76. GRB 160313A: Mondy optical upper limit
  77. GRB 160314A: GROND optical/NIR observations
  78. GRB 160314A: ISON-Ussuriysk optical upper limit, updated photometry and correction of GCN 19184
  79. GRB 160314B: Fermi GBM observation
  80. GRB 160314B: Fermi-LAT detection
  81. GRB 160314A: RATIR Optical and NIR Observations
  82. GRB 160314A: Mondy optical observations
  83. GRB 160313A: Swift/UVOT Upper Limits
  84. LIGO/Virgo G194575: EWE for NOWT follow-up of northern sky
  85. GRB 160314A: VLT/X-shooter redshift
  86. GRB 160314A: NOT afterglow observations
  87. GRB 160314A: Swift-XRT refined Analysis
  88. GRB 160314A: Optical observations from OSN
  89. GRB 160314A: Swift-BAT refined analysis
  90. GRB 160314A: Swift/UVOT Detection
  91. GRB 160228A: GROND afterglow confirmation and X-shooter host candidate redshift
  92. GRB 160314A: Enhanced Swift-XRT position
  93. GRB 160314A: ISON-Ussuriysk optical upper limit
  94. GRB 160314A: Weihai optical upper limit
  95. GRB 160314A: Swift detection of a burst
  96. GRB 160313A, Swift-BAT refined analysis
  97. Fermi GBM trigger 479509107/160312874 is not a GRB
  98. GRB 160313A: Chante-Perdrix Observatory optical observations
  99. GRB 160313A: MASTER-Net optical observations
  100. GRB 160313A: LT observations

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