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

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