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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 070412: Swift-XRT refined analysis
  2. GRB 070411: Swift-XRT refined analysis
  3. GRB 070412: further reanalysis of NOT images
  4. GRB 070412: Optical observations at Crni Vrh
  5. GRB 070411: OA redshift
  6. GRB 070412: Swift-XRT refined position
  7. GRB 070412: further NOT observations
  8. GRB 070412: Gemini/GMOS afterglow candidate
  9. GRB 070412: IAC80 optical afterglow candidate
  10. GRB 070411: Magellan/Clay photometry
  11. GRB 070411: Magellan/IMACS photometry
  12. GRB 070412: NOT observations
  13. GRB 070412: Nearby bright galaxy
  14. GRB 070411, Swift-BAT refined analysis
  15. GRB 070412: Swift detection of a burst
  16. GRB 070411: IAC80 optical observations
  17. GRB 070411 : Liverpool Telescope Observations
  18. GRB 070411: Optical observations at Crni Vrh
  19. GRB 070411: ROTSE-III Detection of Optical Counterpart
  20. GRB 070411: Tautenburg RRM Afterglow Confirmation
  21. GRB 070411: Swift detection of a burst with optical afterglow
  22. GRB 070406: "Star" in XRT error circle S2 is an AGN?
  23. GRB 070406: Swift XRT team further analysis
  24. Suzaku ToO observation of SGR 1806-20
  25. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  26. GRB 070406: Bright galaxy in XRT error circle is a quasar
  27. GRB 070406, Swift-BAT refined analysis
  28. GRB 070406: Correction to the optical candidate in GCN6253
  29. GRB 070406: Gemini South Imaging and XRT analysis
  30. GRB070406: Swift UVOT observations
  31. GRB 070406: further analysis of NOT images.
  32. Short GRB 070406 - Possible Bright Host Galaxy
  33. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  34. GRB 070406: NOT observations
  35. GRB 070406: Optical candidate
  36. GRB 070406: The exprosure time of Xinglong TNT optical Upper Limit
  37. GRB 070406: SARA upper limit
  38. GRB 070406: Xinglong TNT optical Upper Limit
  39. GRB 070406: photo-z of a bright galaxy in BAT error circle
  40. GRB 070406: Swift detection of a burst
  41. GRB 070402: Suzaku WAM observation of the prompt emission
  42. GRB 070311, deep optical photometry
  43. GRB 070402: pseudo-z~3.36 from spectral parameters of the prompt
  44. Konus-Wind and Konus-A observations of GRB 070402
  45. IPN triangulation of GRB070402 - correction
  46. IPN triangulation of GRB070402
  47. GRB 070328: Suzaku WAM observation of the prompt emission
  48. INTEGRAL ToO Observation of SGR1806-20
  49. UVOT observations of GRB070330
  50. GRB 070330, Swift-BAT refined analysis
  51. GRB 070330, SMARTS optical/IR observations
  52. GRB 070330: TAROT La Silla observatory optical observations
  53. GRB 070330: Swift-XRT refined analysis
  54. GRB 070330 - Watcher Observations
  55. GRB 070330: Swift detection of a burst
  56. GRB 070328: pseudo-z~2.75 from spectral parameters of the prompt
  57. Konus-Wind observation of GRB 070328
  58. GRB 070328: Swift/UVOT Upper Limits
  59. long burst from SGR 1806-20 detected on March 26
  60. GRB 070328: Swift/XRT Refined Analysis
  61. GRB 070328 : Suzaku ToO follow up starts
  62. GRB 070328, Swift-BAT refined analysis
  63. GRB 070328: Swift detection of a burst
  64. GRB070220: optical observations
  65. GRB070208: optical observations
  66. GRB070223: confirmation of nIR and optical afterglow
  67. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  68. GRB 070311, deep optical photometry
  69. Short-Hard GRB 070209: PROMPT Observations
  70. GRB 070318: Gemini + Magellan spectra
  71. GRB 070318: absorption-line redshift
  72. GRB070318: Swift UVOT continuing observations
  73. GRB070318: Swift-XRT refined analysis
  74. GRB 070318: Swift/UVOT Continued Observations
  75. GRB 070318, Swift-BAT refined analysis
  76. IBAS Alert n. 4176: not a GRB
  77. GRB 070318: Swift detection of a burst with an optical afterglow
  78. GRB 070311: Late Central Engine Activity Optical Flare??
  79. GRB 070311: MDM Optical Monitoring
  80. VLA observation of GRB 070311
  81. GRB 070311: Tautenburg sees afterglow fading
  82. IBAS Alert n. 4169: not a GRB
  83. GRB 070311: Optical observation.
  84. GRB 070311: Optical Brightening
  85. GRB 070306: possible emission-line redshift
  86. GRB 070311: SARA upper limit
  87. GRB 070309: variability of the XRT afterglow candidate
  88. GRB 070311: MDM Optical Follow-up
  89. GRB 070311: RAPTOR Detection of Optical Emission
  90. GRB070311: FRAM early follow-up limit
  91. GRB 070311: P60 Observations
  92. GRB 070311: MDM Optical Detection
  93. GRB 070311: Swift/UVOT Upper Limits
  94. GRB 070311: MITSuME Okayama Optical Observation
  95. GRB 070311: Swift-XRT refined analysis
  96. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  97. GRB 070311: REM candidate afterglow
  98. GRB 070311: a long GRB detected by INTEGRAL
  99. GRB060901: Candidate optical afterglow
  100. GRB070309: Swift/XRT possible afterglow detection

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