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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: Swift detection of a burst with optical afterglow
  2. GRB 070419A: MITSuME Okayama Observations
  3. GRB 070419A: Early Super-LOTIS Observations
  4. GRB 070419B, Swift-BAT refined analysis
  5. GRB 070419A Swift-BAT Refined Analysis
  6. GRB070419B: Confirmation of Optical Transient
  7. GRB 070419A: RAPTOR Detection of Early Emission
  8. GRB 070419B: Swift XRT refined analysis
  9. GRB 070419: Keck/LRIS Absorption Redshift
  10. GRB 070419B: optical afterglow confirmation
  11. GRB 070419A, Optical observations
  12. GRB 070411: Deep VLT detection
  13. GRB070419 - SDSS Pre-Burst Observations
  14. GRB 070419A: SARA observations
  15. GRB 070419A: NAYUTA Optical Observation
  16. GRB 070419A: Faulkes Telescope North Optical Observations
  17. GRB 070419B optical afterglow candidate
  18. GRB 070419A: Optical and IR observations with KANATA
  19. GRB 070419B: optical afterglow candidate
  20. GRB 070419A: Lulin Optical observation
  21. GRB070419A, optical observation
  22. Infrared detection of GRB070419A with UKIRT
  23. GRB 070419A: Kiso Optical observation
  24. GRB070330: Correction to UVOT position
  25. GRB 070419: P60 Confirmation of Optical Afterglow
  26. GRB 070419B: Swift detection of a burst
  27. GRB 070419 optical afterglow candidate
  28. GRB 070419A: ROTSE-III Optical Limits
  29. GRB 070419: Swift detection of a burst
  30. Swift-BAT Trigger 276045 is a Cosmic Ray Shower event
  31. GRB 070418: Optical and IR observations with KANATA
  32. Trigger 276045: Swift detection of a possible burst
  33. GRB 070406: Swift XRT refined analysis
  34. IBAS Alert n.4202: not a real GRB
  35. GRB 070318, SMARTS optical/IR afterglow observations
  36. GRB 070411: TLS data shows plateau, flares
  37. GRB070412: UKIRT-WFCAM JHK upper limits
  38. GRB070412: Swift UVOT observations
  39. IBAS Alert n.4199: Not a GRB
  40. GRB 070411: Swift/UVOT observations
  41. GRB 070412, Swift-BAT refined analysis
  42. GRB 070412 Liverpool Telescope optical limit
  43. GRB 070411: Optical photometry at Crni Vrh
  44. GRB 070412: Swift-XRT refined analysis
  45. GRB 070411: Swift-XRT refined analysis
  46. GRB 070412: further reanalysis of NOT images
  47. GRB 070412: Optical observations at Crni Vrh
  48. GRB 070411: OA redshift
  49. GRB 070412: Swift-XRT refined position
  50. GRB 070412: further NOT observations
  51. GRB 070412: Gemini/GMOS afterglow candidate
  52. GRB 070412: IAC80 optical afterglow candidate
  53. GRB 070411: Magellan/Clay photometry
  54. GRB 070411: Magellan/IMACS photometry
  55. GRB 070412: NOT observations
  56. GRB 070412: Nearby bright galaxy
  57. GRB 070411, Swift-BAT refined analysis
  58. GRB 070412: Swift detection of a burst
  59. GRB 070411: IAC80 optical observations
  60. GRB 070411 : Liverpool Telescope Observations
  61. GRB 070411: Optical observations at Crni Vrh
  62. GRB 070411: ROTSE-III Detection of Optical Counterpart
  63. GRB 070411: Tautenburg RRM Afterglow Confirmation
  64. GRB 070411: Swift detection of a burst with optical afterglow
  65. GRB 070406: "Star" in XRT error circle S2 is an AGN?
  66. GRB 070406: Swift XRT team further analysis
  67. Suzaku ToO observation of SGR 1806-20
  68. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  69. GRB 070406: Bright galaxy in XRT error circle is a quasar
  70. GRB 070406, Swift-BAT refined analysis
  71. GRB 070406: Correction to the optical candidate in GCN6253
  72. GRB 070406: Gemini South Imaging and XRT analysis
  73. GRB070406: Swift UVOT observations
  74. GRB 070406: further analysis of NOT images.
  75. Short GRB 070406 - Possible Bright Host Galaxy
  76. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  77. GRB 070406: NOT observations
  78. GRB 070406: Optical candidate
  79. GRB 070406: The exprosure time of Xinglong TNT optical Upper Limit
  80. GRB 070406: SARA upper limit
  81. GRB 070406: Xinglong TNT optical Upper Limit
  82. GRB 070406: photo-z of a bright galaxy in BAT error circle
  83. GRB 070406: Swift detection of a burst
  84. GRB 070402: Suzaku WAM observation of the prompt emission
  85. GRB 070311, deep optical photometry
  86. GRB 070402: pseudo-z~3.36 from spectral parameters of the prompt
  87. Konus-Wind and Konus-A observations of GRB 070402
  88. IPN triangulation of GRB070402 - correction
  89. IPN triangulation of GRB070402
  90. GRB 070328: Suzaku WAM observation of the prompt emission
  91. INTEGRAL ToO Observation of SGR1806-20
  92. UVOT observations of GRB070330
  93. GRB 070330, Swift-BAT refined analysis
  94. GRB 070330, SMARTS optical/IR observations
  95. GRB 070330: TAROT La Silla observatory optical observations
  96. GRB 070330: Swift-XRT refined analysis
  97. GRB 070330 - Watcher Observations
  98. GRB 070330: Swift detection of a burst
  99. GRB 070328: pseudo-z~2.75 from spectral parameters of the prompt
  100. Konus-Wind observation of GRB 070328

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