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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: Bright galaxy in XRT error circle is a quasar
  2. GRB 070406, Swift-BAT refined analysis
  3. GRB 070406: Correction to the optical candidate in GCN6253
  4. GRB 070406: Gemini South Imaging and XRT analysis
  5. GRB070406: Swift UVOT observations
  6. GRB 070406: further analysis of NOT images.
  7. Short GRB 070406 - Possible Bright Host Galaxy
  8. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  9. GRB 070406: NOT observations
  10. GRB 070406: Optical candidate
  11. GRB 070406: The exprosure time of Xinglong TNT optical Upper Limit
  12. GRB 070406: SARA upper limit
  13. GRB 070406: Xinglong TNT optical Upper Limit
  14. GRB 070406: photo-z of a bright galaxy in BAT error circle
  15. GRB 070406: Swift detection of a burst
  16. GRB 070402: Suzaku WAM observation of the prompt emission
  17. GRB 070311, deep optical photometry
  18. GRB 070402: pseudo-z~3.36 from spectral parameters of the prompt
  19. Konus-Wind and Konus-A observations of GRB 070402
  20. IPN triangulation of GRB070402 - correction
  21. IPN triangulation of GRB070402
  22. GRB 070328: Suzaku WAM observation of the prompt emission
  23. INTEGRAL ToO Observation of SGR1806-20
  24. UVOT observations of GRB070330
  25. GRB 070330, Swift-BAT refined analysis
  26. GRB 070330, SMARTS optical/IR observations
  27. GRB 070330: TAROT La Silla observatory optical observations
  28. GRB 070330: Swift-XRT refined analysis
  29. GRB 070330 - Watcher Observations
  30. GRB 070330: Swift detection of a burst
  31. GRB 070328: pseudo-z~2.75 from spectral parameters of the prompt
  32. Konus-Wind observation of GRB 070328
  33. GRB 070328: Swift/UVOT Upper Limits
  34. long burst from SGR 1806-20 detected on March 26
  35. GRB 070328: Swift/XRT Refined Analysis
  36. GRB 070328 : Suzaku ToO follow up starts
  37. GRB 070328, Swift-BAT refined analysis
  38. GRB 070328: Swift detection of a burst
  39. GRB070220: optical observations
  40. GRB070208: optical observations
  41. GRB070223: confirmation of nIR and optical afterglow
  42. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  43. GRB 070311, deep optical photometry
  44. Short-Hard GRB 070209: PROMPT Observations
  45. GRB 070318: Gemini + Magellan spectra
  46. GRB 070318: absorption-line redshift
  47. GRB070318: Swift UVOT continuing observations
  48. GRB070318: Swift-XRT refined analysis
  49. GRB 070318: Swift/UVOT Continued Observations
  50. GRB 070318, Swift-BAT refined analysis
  51. IBAS Alert n. 4176: not a GRB
  52. GRB 070318: Swift detection of a burst with an optical afterglow
  53. GRB 070311: Late Central Engine Activity Optical Flare??
  54. GRB 070311: MDM Optical Monitoring
  55. VLA observation of GRB 070311
  56. GRB 070311: Tautenburg sees afterglow fading
  57. IBAS Alert n. 4169: not a GRB
  58. GRB 070311: Optical observation.
  59. GRB 070311: Optical Brightening
  60. GRB 070306: possible emission-line redshift
  61. GRB 070311: SARA upper limit
  62. GRB 070309: variability of the XRT afterglow candidate
  63. GRB 070311: MDM Optical Follow-up
  64. GRB 070311: RAPTOR Detection of Optical Emission
  65. GRB070311: FRAM early follow-up limit
  66. GRB 070311: P60 Observations
  67. GRB 070311: MDM Optical Detection
  68. GRB 070311: Swift/UVOT Upper Limits
  69. GRB 070311: MITSuME Okayama Optical Observation
  70. GRB 070311: Swift-XRT refined analysis
  71. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  72. GRB 070311: REM candidate afterglow
  73. GRB 070311: a long GRB detected by INTEGRAL
  74. GRB060901: Candidate optical afterglow
  75. GRB070309: Swift/XRT possible afterglow detection
  76. GRB 070125: Chandra X-ray Confirmation of Jet Break
  77. GRB 070309: Swift/UVOT Upper Limits
  78. GRB 070306, optical observation
  79. Swift UVOT Finding Charts for GRB 070309
  80. GRB 070309: A long GRB detected by INTEGRAL
  81. GRB 070125: X-ray light curve analysis
  82. VLA observation of GRB 070306
  83. IBAS Alert 4162: Not a GRB
  84. GRB 070306: NOT observations
  85. GRB 070306 Swift/UVOT refined analysis
  86. GRB070306: confirmation of near infrared afterglow
  87. GRB 070306: ART-3 early optical and near infrared constraints
  88. GRB 070306: IR observations and candidate afterglow
  89. GRB 070306, Swift-BAT refined analysis
  90. GRB 070306: XRT Team Refined Analysis
  91. GRB 070306: Optical and IR observations with KANATA
  92. GRB070306 - SDSS Pre-burst Observations
  93. GRB 070306: Swift detection of a burst
  94. GRB 070223: NIR observations at WHT
  95. GRB070227: Swift-XRT refined analysis
  96. GRB 060605 new redshift
  97. GRB 070125, deep late-time optical observation
  98. VLA observation of GRB 070224
  99. GRB 070227: optical observations
  100. GRB 070223: Optical Observations

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