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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 070411: Optical observations at Crni Vrh
  2. GRB 070411: ROTSE-III Detection of Optical Counterpart
  3. GRB 070411: Tautenburg RRM Afterglow Confirmation
  4. GRB 070411: Swift detection of a burst with optical afterglow
  5. GRB 070406: "Star" in XRT error circle S2 is an AGN?
  6. GRB 070406: Swift XRT team further analysis
  7. Suzaku ToO observation of SGR 1806-20
  8. GRB 070406: Astrometrically Refined XRT Position, Unfading Source
  9. GRB 070406: Bright galaxy in XRT error circle is a quasar
  10. GRB 070406, Swift-BAT refined analysis
  11. GRB 070406: Correction to the optical candidate in GCN6253
  12. GRB 070406: Gemini South Imaging and XRT analysis
  13. GRB070406: Swift UVOT observations
  14. GRB 070406: further analysis of NOT images.
  15. Short GRB 070406 - Possible Bright Host Galaxy
  16. GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
  17. GRB 070406: NOT observations
  18. GRB 070406: Optical candidate
  19. GRB 070406: The exprosure time of Xinglong TNT optical Upper Limit
  20. GRB 070406: SARA upper limit
  21. GRB 070406: Xinglong TNT optical Upper Limit
  22. GRB 070406: photo-z of a bright galaxy in BAT error circle
  23. GRB 070406: Swift detection of a burst
  24. GRB 070402: Suzaku WAM observation of the prompt emission
  25. GRB 070311, deep optical photometry
  26. GRB 070402: pseudo-z~3.36 from spectral parameters of the prompt
  27. Konus-Wind and Konus-A observations of GRB 070402
  28. IPN triangulation of GRB070402 - correction
  29. IPN triangulation of GRB070402
  30. GRB 070328: Suzaku WAM observation of the prompt emission
  31. INTEGRAL ToO Observation of SGR1806-20
  32. UVOT observations of GRB070330
  33. GRB 070330, Swift-BAT refined analysis
  34. GRB 070330, SMARTS optical/IR observations
  35. GRB 070330: TAROT La Silla observatory optical observations
  36. GRB 070330: Swift-XRT refined analysis
  37. GRB 070330 - Watcher Observations
  38. GRB 070330: Swift detection of a burst
  39. GRB 070328: pseudo-z~2.75 from spectral parameters of the prompt
  40. Konus-Wind observation of GRB 070328
  41. GRB 070328: Swift/UVOT Upper Limits
  42. long burst from SGR 1806-20 detected on March 26
  43. GRB 070328: Swift/XRT Refined Analysis
  44. GRB 070328 : Suzaku ToO follow up starts
  45. GRB 070328, Swift-BAT refined analysis
  46. GRB 070328: Swift detection of a burst
  47. GRB070220: optical observations
  48. GRB070208: optical observations
  49. GRB070223: confirmation of nIR and optical afterglow
  50. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  51. GRB 070311, deep optical photometry
  52. Short-Hard GRB 070209: PROMPT Observations
  53. GRB 070318: Gemini + Magellan spectra
  54. GRB 070318: absorption-line redshift
  55. GRB070318: Swift UVOT continuing observations
  56. GRB070318: Swift-XRT refined analysis
  57. GRB 070318: Swift/UVOT Continued Observations
  58. GRB 070318, Swift-BAT refined analysis
  59. IBAS Alert n. 4176: not a GRB
  60. GRB 070318: Swift detection of a burst with an optical afterglow
  61. GRB 070311: Late Central Engine Activity Optical Flare??
  62. GRB 070311: MDM Optical Monitoring
  63. VLA observation of GRB 070311
  64. GRB 070311: Tautenburg sees afterglow fading
  65. IBAS Alert n. 4169: not a GRB
  66. GRB 070311: Optical observation.
  67. GRB 070311: Optical Brightening
  68. GRB 070306: possible emission-line redshift
  69. GRB 070311: SARA upper limit
  70. GRB 070309: variability of the XRT afterglow candidate
  71. GRB 070311: MDM Optical Follow-up
  72. GRB 070311: RAPTOR Detection of Optical Emission
  73. GRB070311: FRAM early follow-up limit
  74. GRB 070311: P60 Observations
  75. GRB 070311: MDM Optical Detection
  76. GRB 070311: Swift/UVOT Upper Limits
  77. GRB 070311: MITSuME Okayama Optical Observation
  78. GRB 070311: Swift-XRT refined analysis
  79. GRB 070311: PAIRITEL confirmation of variability of REM candidate
  80. GRB 070311: REM candidate afterglow
  81. GRB 070311: a long GRB detected by INTEGRAL
  82. GRB060901: Candidate optical afterglow
  83. GRB070309: Swift/XRT possible afterglow detection
  84. GRB 070125: Chandra X-ray Confirmation of Jet Break
  85. GRB 070309: Swift/UVOT Upper Limits
  86. GRB 070306, optical observation
  87. Swift UVOT Finding Charts for GRB 070309
  88. GRB 070309: A long GRB detected by INTEGRAL
  89. GRB 070125: X-ray light curve analysis
  90. VLA observation of GRB 070306
  91. IBAS Alert 4162: Not a GRB
  92. GRB 070306: NOT observations
  93. GRB 070306 Swift/UVOT refined analysis
  94. GRB070306: confirmation of near infrared afterglow
  95. GRB 070306: ART-3 early optical and near infrared constraints
  96. GRB 070306: IR observations and candidate afterglow
  97. GRB 070306, Swift-BAT refined analysis
  98. GRB 070306: XRT Team Refined Analysis
  99. GRB 070306: Optical and IR observations with KANATA
  100. GRB070306 - SDSS Pre-burst Observations

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