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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 070419A: Kiso Optical observation
  2. GRB070330: Correction to UVOT position
  3. GRB 070419: P60 Confirmation of Optical Afterglow
  4. GRB 070419B: Swift detection of a burst
  5. GRB 070419 optical afterglow candidate
  6. GRB 070419A: ROTSE-III Optical Limits
  7. GRB 070419: Swift detection of a burst
  8. Swift-BAT Trigger 276045 is a Cosmic Ray Shower event
  9. GRB 070418: Optical and IR observations with KANATA
  10. Trigger 276045: Swift detection of a possible burst
  11. GRB 070406: Swift XRT refined analysis
  12. IBAS Alert n.4202: not a real GRB
  13. GRB 070318, SMARTS optical/IR afterglow observations
  14. GRB 070411: TLS data shows plateau, flares
  15. GRB070412: UKIRT-WFCAM JHK upper limits
  16. GRB070412: Swift UVOT observations
  17. IBAS Alert n.4199: Not a GRB
  18. GRB 070411: Swift/UVOT observations
  19. GRB 070412, Swift-BAT refined analysis
  20. GRB 070412 Liverpool Telescope optical limit
  21. GRB 070411: Optical photometry at Crni Vrh
  22. GRB 070412: Swift-XRT refined analysis
  23. GRB 070411: Swift-XRT refined analysis
  24. GRB 070412: further reanalysis of NOT images
  25. GRB 070412: Optical observations at Crni Vrh
  26. GRB 070411: OA redshift
  27. GRB 070412: Swift-XRT refined position
  28. GRB 070412: further NOT observations
  29. GRB 070412: Gemini/GMOS afterglow candidate
  30. GRB 070412: IAC80 optical afterglow candidate
  31. GRB 070411: Magellan/Clay photometry
  32. GRB 070411: Magellan/IMACS photometry
  33. GRB 070412: NOT observations
  34. GRB 070412: Nearby bright galaxy
  35. GRB 070411, Swift-BAT refined analysis
  36. GRB 070412: Swift detection of a burst
  37. GRB 070411: IAC80 optical observations
  38. GRB 070411 : Liverpool Telescope Observations
  39. GRB 070411: Optical observations at Crni Vrh
  40. GRB 070411: ROTSE-III Detection of Optical Counterpart
  41. GRB 070411: Tautenburg RRM Afterglow Confirmation
  42. GRB 070411: Swift detection of a burst with optical afterglow
  43. GRB 070406: "Star" in XRT error circle S2 is an AGN?
  44. GRB 070406: Swift XRT team further analysis
  45. Suzaku ToO observation of SGR 1806-20
  46. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  47. GRB 070406: Bright galaxy in XRT error circle is a quasar
  48. GRB 070406, Swift-BAT refined analysis
  49. GRB 070406: Correction to the optical candidate in GCN6253
  50. GRB 070406: Gemini South Imaging and XRT analysis
  51. GRB070406: Swift UVOT observations
  52. GRB 070406: further analysis of NOT images.
  53. Short GRB 070406 - Possible Bright Host Galaxy
  54. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  55. GRB 070406: NOT observations
  56. GRB 070406: Optical candidate
  57. GRB 070406: The exprosure time of Xinglong TNT optical Upper Limit
  58. GRB 070406: SARA upper limit
  59. GRB 070406: Xinglong TNT optical Upper Limit
  60. GRB 070406: photo-z of a bright galaxy in BAT error circle
  61. GRB 070406: Swift detection of a burst
  62. GRB 070402: Suzaku WAM observation of the prompt emission
  63. GRB 070311, deep optical photometry
  64. GRB 070402: pseudo-z~3.36 from spectral parameters of the prompt
  65. Konus-Wind and Konus-A observations of GRB 070402
  66. IPN triangulation of GRB070402 - correction
  67. IPN triangulation of GRB070402
  68. GRB 070328: Suzaku WAM observation of the prompt emission
  69. INTEGRAL ToO Observation of SGR1806-20
  70. UVOT observations of GRB070330
  71. GRB 070330, Swift-BAT refined analysis
  72. GRB 070330, SMARTS optical/IR observations
  73. GRB 070330: TAROT La Silla observatory optical observations
  74. GRB 070330: Swift-XRT refined analysis
  75. GRB 070330 - Watcher Observations
  76. GRB 070330: Swift detection of a burst
  77. GRB 070328: pseudo-z~2.75 from spectral parameters of the prompt
  78. Konus-Wind observation of GRB 070328
  79. GRB 070328: Swift/UVOT Upper Limits
  80. long burst from SGR 1806-20 detected on March 26
  81. GRB 070328: Swift/XRT Refined Analysis
  82. GRB 070328 : Suzaku ToO follow up starts
  83. GRB 070328, Swift-BAT refined analysis
  84. GRB 070328: Swift detection of a burst
  85. GRB070220: optical observations
  86. GRB070208: optical observations
  87. GRB070223: confirmation of nIR and optical afterglow
  88. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  89. GRB 070311, deep optical photometry
  90. Short-Hard GRB 070209: PROMPT Observations
  91. GRB 070318: Gemini + Magellan spectra
  92. GRB 070318: absorption-line redshift
  93. GRB070318: Swift UVOT continuing observations
  94. GRB070318: Swift-XRT refined analysis
  95. GRB 070318: Swift/UVOT Continued Observations
  96. GRB 070318, Swift-BAT refined analysis
  97. IBAS Alert n. 4176: not a GRB
  98. GRB 070318: Swift detection of a burst with an optical afterglow
  99. GRB 070311: Late Central Engine Activity Optical Flare??
  100. GRB 070311: MDM Optical Monitoring

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