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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 070420: optical rebrightening observed at Mt. John
  2. GRB 070420: Swift XRT refined analysis
  3. GRB070420: Swift UVOT continuing observations
  4. GRB 070411: BART early limit
  5. GRB 070420: Faulkes Telescope South Observations
  6. GBR 070419A: Swift/XRT refined analysis
  7. GRB 070420: TAROT La Silla observatory optical observations
  8. GRB 070420: NIR and optical afterglow confirmed
  9. GRB 070420: Swift detection of a burst with optical afterglow
  10. GRB 070419A: MITSuME Okayama Observations
  11. GRB 070419A: Early Super-LOTIS Observations
  12. GRB 070419B, Swift-BAT refined analysis
  13. GRB 070419A Swift-BAT Refined Analysis
  14. GRB070419B: Confirmation of Optical Transient
  15. GRB 070419A: RAPTOR Detection of Early Emission
  16. GRB 070419B: Swift XRT refined analysis
  17. GRB 070419: Keck/LRIS Absorption Redshift
  18. GRB 070419B: optical afterglow confirmation
  19. GRB 070419A, Optical observations
  20. GRB 070411: Deep VLT detection
  21. GRB070419 - SDSS Pre-Burst Observations
  22. GRB 070419A: SARA observations
  23. GRB 070419A: NAYUTA Optical Observation
  24. GRB 070419A: Faulkes Telescope North Optical Observations
  25. GRB 070419B optical afterglow candidate
  26. GRB 070419A: Optical and IR observations with KANATA
  27. GRB 070419B: optical afterglow candidate
  28. GRB 070419A: Lulin Optical observation
  29. GRB070419A, optical observation
  30. Infrared detection of GRB070419A with UKIRT
  31. GRB 070419A: Kiso Optical observation
  32. GRB070330: Correction to UVOT position
  33. GRB 070419: P60 Confirmation of Optical Afterglow
  34. GRB 070419B: Swift detection of a burst
  35. GRB 070419 optical afterglow candidate
  36. GRB 070419A: ROTSE-III Optical Limits
  37. GRB 070419: Swift detection of a burst
  38. Swift-BAT Trigger 276045 is a Cosmic Ray Shower event
  39. GRB 070418: Optical and IR observations with KANATA
  40. Trigger 276045: Swift detection of a possible burst
  41. GRB 070406: Swift XRT refined analysis
  42. IBAS Alert n.4202: not a real GRB
  43. GRB 070318, SMARTS optical/IR afterglow observations
  44. GRB 070411: TLS data shows plateau, flares
  45. GRB070412: UKIRT-WFCAM JHK upper limits
  46. GRB070412: Swift UVOT observations
  47. IBAS Alert n.4199: Not a GRB
  48. GRB 070411: Swift/UVOT observations
  49. GRB 070412, Swift-BAT refined analysis
  50. GRB 070412 Liverpool Telescope optical limit
  51. GRB 070411: Optical photometry at Crni Vrh
  52. GRB 070412: Swift-XRT refined analysis
  53. GRB 070411: Swift-XRT refined analysis
  54. GRB 070412: further reanalysis of NOT images
  55. GRB 070412: Optical observations at Crni Vrh
  56. GRB 070411: OA redshift
  57. GRB 070412: Swift-XRT refined position
  58. GRB 070412: further NOT observations
  59. GRB 070412: Gemini/GMOS afterglow candidate
  60. GRB 070412: IAC80 optical afterglow candidate
  61. GRB 070411: Magellan/Clay photometry
  62. GRB 070411: Magellan/IMACS photometry
  63. GRB 070412: NOT observations
  64. GRB 070412: Nearby bright galaxy
  65. GRB 070411, Swift-BAT refined analysis
  66. GRB 070412: Swift detection of a burst
  67. GRB 070411: IAC80 optical observations
  68. GRB 070411 : Liverpool Telescope Observations
  69. GRB 070411: Optical observations at Crni Vrh
  70. GRB 070411: ROTSE-III Detection of Optical Counterpart
  71. GRB 070411: Tautenburg RRM Afterglow Confirmation
  72. GRB 070411: Swift detection of a burst with optical afterglow
  73. GRB 070406: "Star" in XRT error circle S2 is an AGN?
  74. GRB 070406: Swift XRT team further analysis
  75. Suzaku ToO observation of SGR 1806-20
  76. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  77. GRB 070406: Bright galaxy in XRT error circle is a quasar
  78. GRB 070406, Swift-BAT refined analysis
  79. GRB 070406: Correction to the optical candidate in GCN6253
  80. GRB 070406: Gemini South Imaging and XRT analysis
  81. GRB070406: Swift UVOT observations
  82. GRB 070406: further analysis of NOT images.
  83. Short GRB 070406 - Possible Bright Host Galaxy
  84. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  85. GRB 070406: NOT observations
  86. GRB 070406: Optical candidate
  87. GRB 070406: The exprosure time of Xinglong TNT optical Upper Limit
  88. GRB 070406: SARA upper limit
  89. GRB 070406: Xinglong TNT optical Upper Limit
  90. GRB 070406: photo-z of a bright galaxy in BAT error circle
  91. GRB 070406: Swift detection of a burst
  92. GRB 070402: Suzaku WAM observation of the prompt emission
  93. GRB 070311, deep optical photometry
  94. GRB 070402: pseudo-z~3.36 from spectral parameters of the prompt
  95. Konus-Wind and Konus-A observations of GRB 070402
  96. IPN triangulation of GRB070402 - correction
  97. IPN triangulation of GRB070402
  98. GRB 070328: Suzaku WAM observation of the prompt emission
  99. INTEGRAL ToO Observation of SGR1806-20
  100. UVOT observations of GRB070330

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