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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 070406: Gemini South Imaging and XRT analysis
  2. GRB070406: Swift UVOT observations
  3. GRB 070406: further analysis of NOT images.
  4. Short GRB 070406 - Possible Bright Host Galaxy
  5. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  6. GRB 070406: NOT observations
  7. GRB 070406: Optical candidate
  8. GRB 070406: The exprosure time of Xinglong TNT optical Upper Limit
  9. GRB 070406: SARA upper limit
  10. GRB 070406: Xinglong TNT optical Upper Limit
  11. GRB 070406: photo-z of a bright galaxy in BAT error circle
  12. GRB 070406: Swift detection of a burst
  13. GRB 070402: Suzaku WAM observation of the prompt emission
  14. GRB 070311, deep optical photometry
  15. GRB 070402: pseudo-z~3.36 from spectral parameters of the prompt
  16. Konus-Wind and Konus-A observations of GRB 070402
  17. IPN triangulation of GRB070402 - correction
  18. IPN triangulation of GRB070402
  19. GRB 070328: Suzaku WAM observation of the prompt emission
  20. INTEGRAL ToO Observation of SGR1806-20
  21. UVOT observations of GRB070330
  22. GRB 070330, Swift-BAT refined analysis
  23. GRB 070330, SMARTS optical/IR observations
  24. GRB 070330: TAROT La Silla observatory optical observations
  25. GRB 070330: Swift-XRT refined analysis
  26. GRB 070330 - Watcher Observations
  27. GRB 070330: Swift detection of a burst
  28. GRB 070328: pseudo-z~2.75 from spectral parameters of the prompt
  29. Konus-Wind observation of GRB 070328
  30. GRB 070328: Swift/UVOT Upper Limits
  31. long burst from SGR 1806-20 detected on March 26
  32. GRB 070328: Swift/XRT Refined Analysis
  33. GRB 070328 : Suzaku ToO follow up starts
  34. GRB 070328, Swift-BAT refined analysis
  35. GRB 070328: Swift detection of a burst
  36. GRB070220: optical observations
  37. GRB070208: optical observations
  38. GRB070223: confirmation of nIR and optical afterglow
  39. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  40. GRB 070311, deep optical photometry
  41. Short-Hard GRB 070209: PROMPT Observations
  42. GRB 070318: Gemini + Magellan spectra
  43. GRB 070318: absorption-line redshift
  44. GRB070318: Swift UVOT continuing observations
  45. GRB070318: Swift-XRT refined analysis
  46. GRB 070318: Swift/UVOT Continued Observations
  47. GRB 070318, Swift-BAT refined analysis
  48. IBAS Alert n. 4176: not a GRB
  49. GRB 070318: Swift detection of a burst with an optical afterglow
  50. GRB 070311: Late Central Engine Activity Optical Flare??
  51. GRB 070311: MDM Optical Monitoring
  52. VLA observation of GRB 070311
  53. GRB 070311: Tautenburg sees afterglow fading
  54. IBAS Alert n. 4169: not a GRB
  55. GRB 070311: Optical observation.
  56. GRB 070311: Optical Brightening
  57. GRB 070306: possible emission-line redshift
  58. GRB 070311: SARA upper limit
  59. GRB 070309: variability of the XRT afterglow candidate
  60. GRB 070311: MDM Optical Follow-up
  61. GRB 070311: RAPTOR Detection of Optical Emission
  62. GRB070311: FRAM early follow-up limit
  63. GRB 070311: P60 Observations
  64. GRB 070311: MDM Optical Detection
  65. GRB 070311: Swift/UVOT Upper Limits
  66. GRB 070311: MITSuME Okayama Optical Observation
  67. GRB 070311: Swift-XRT refined analysis
  68. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  69. GRB 070311: REM candidate afterglow
  70. GRB 070311: a long GRB detected by INTEGRAL
  71. GRB060901: Candidate optical afterglow
  72. GRB070309: Swift/XRT possible afterglow detection
  73. GRB 070125: Chandra X-ray Confirmation of Jet Break
  74. GRB 070309: Swift/UVOT Upper Limits
  75. GRB 070306, optical observation
  76. Swift UVOT Finding Charts for GRB 070309
  77. GRB 070309: A long GRB detected by INTEGRAL
  78. GRB 070125: X-ray light curve analysis
  79. VLA observation of GRB 070306
  80. IBAS Alert 4162: Not a GRB
  81. GRB 070306: NOT observations
  82. GRB 070306 Swift/UVOT refined analysis
  83. GRB070306: confirmation of near infrared afterglow
  84. GRB 070306: ART-3 early optical and near infrared constraints
  85. GRB 070306: IR observations and candidate afterglow
  86. GRB 070306, Swift-BAT refined analysis
  87. GRB 070306: XRT Team Refined Analysis
  88. GRB 070306: Optical and IR observations with KANATA
  89. GRB070306 - SDSS Pre-burst Observations
  90. GRB 070306: Swift detection of a burst
  91. GRB 070223: NIR observations at WHT
  92. GRB070227: Swift-XRT refined analysis
  93. GRB 060605 new redshift
  94. GRB 070125, deep late-time optical observation
  95. VLA observation of GRB 070224
  96. GRB 070227: optical observations
  97. GRB 070223: Optical Observations
  98. GRB 070227: optical observations
  99. GRB 070227: Swift/UVOT Upper Limits
  100. GRB 070227: TAROT La Silla observatory optical observations

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