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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. GRB061210: Swift/UVOT observations
  2. Swift-BAT Trigger 250908 is a Cosmic Ray Shower event
  3. GRB 061210: Optical sources near XRT positions
  4. GRB 061210: Swift XRT analysis - Possible counterparts
  5. GRB 061210 : Faulkes North Telescope optical limit
  6. GRB 061214(?): ROTSE-III Optical Limits
  7. GRB 061214(?): Swift detection of a possible burst
  8. GRB 061210: Suzaku WAM observation of the prompt emission
  9. Swift/BAT trigger #250033 is due to a known source during loss of
  10. GRB 061213: MASTER-VWF-Kislovodsk OT candidate retraction
  11. GRB 061213: MASTER-VWF-Kislovodsk optical candidate
  12. GRB 061213: MASTER-VWF-Kislovodsk observations
  13. GRB 061210: Gemini/GMOS Observations
  14. GRB 061126: Radio Observations
  15. GRB061210: Radio Observations
  16. GRB061201, VLT optical decay: correction
  17. GRB 061126: a GRB detected off-axis by INTEGRAL
  18. GRB 061202: Suzaku WAM observation of the prompt emission
  19. GRB 061210: MDM Observation
  20. GRB 061210, Swift-BAT refined analysis of the SHB
  21. GRB 061210: Swift-BAT detection of a short burst
  22. Optical Afterglow observations of GRB 061126
  23. GRB061126: optical observations
  24. GRB 060926: MASTER: discovery of the optical flare
  25. GRB061126: update on the Swift-XRT afterglow light curve
  26. Corrections for Swift/UVOT Exposure Times for GRBs 061110B and 061121
  27. GRB 061201: UVOT Observations of a Fading Optical Afterglow
  28. GRB 061202: TORTOREM optical upper limits
  29. GRB 061201: VLT optical decay
  30. GRB 061201: SOAR Confirmation of Candidate Afterglow
  31. GRB061126 : NMSU 1.0m observations
  32. GRB 061202: Swift XRT refined analysis
  33. GRB061202: FRAM early follow-up limit
  34. GRB061202 optical limit by "Pi of the Sky"
  35. Konus-Wind observation of GRB 061201
  36. GRB061202: optical/NIR observations with REM
  37. GRB061202: Swift/UVOT Upper Limits
  38. GRB 061202, Swift-BAT refined analysis
  39. GRB 061202: Swift detection of a burst
  40. GRB 061201: Swift XRT Team refined analysis
  41. GRB 061201: VLT optical observations
  42. GRB 061201: Initial UVOT Observations
  43. GRB 061201, Swift-BAT refined analysis of the SHB
  44. GRB 061201: Swift detection of a short hard burst
  45. GRB 061201: Coincidence with a Galaxy Cluster
  46. GRB 061122: GETS observation
  47. GRB 061121, SMARTS optical/IR observations
  48. GRB 061121: flattening of the decay
  49. INT+WFC observations of GRB 061126
  50. GRB 061126: Possible Jet Break
  51. GRB 061121: Second Epoch ATCA Radio Observations
  52. GRB 061126: RAPTOR Optical Detection During Gamma-Ray Emission
  53. Swift XRT on-board boresight update
  54. GRB 061121: ATCA & WSRT Radio Observations
  55. GRB061121: optical observations
  56. GRB 061126: Early Super-LOTIS Observations
  57. GRB 061126: optical observation
  58. RHESSI Spectrum of GRB061126
  59. GRB 061126: Tautenburg afterglow observations
  60. GRB061126: Optical afterglow observations from MIRO
  61. GRB061126: Optical afterglow observations from MIRO
  62. GRB 061126 : SDSS Pre-Burst Observations
  63. GRB 061126: Swift-XRT refined analysis
  64. GRB 061126: Swift/UVOT Observations
  65. GRB 061126, Swift-BAT refined analysis
  66. GRB 061126: SARA Observations
  67. GRB 061126: Early Detection of the IR Afterglow
  68. GRB 061126: Faulkes Telescope North Optical Observations
  69. GRB 061126: Swift/UVOT Afterglow Detection
  70. GRB 061126: XRT position
  71. GRB 061126: Swift detection of a burst
  72. GRB 061121: MDM Continued Monitoring
  73. GRB 061122: Confirmation of X-ray/Optical Afterglow
  74. GRB 061121: MDM Continuing Optical Decay
  75. GRB061121: optical observations
  76. GRB 061122: Candidate Optical Afterglow
  77. GRB 061121: Ep,i - Eiso correlation
  78. GRB 061121: MDM Optical Decay
  79. GRB061122: Swift/UVOT Optical Observations
  80. GRB 061121: ART detection in Ic
  81. GRB061121: P60 Observations
  82. Radio detection of GRB 061121
  83. GRB061122: Swift-XRT position
  84. Konus-Wind observation of GRB 061122
  85. GRB 061121: MDM Optical Observations
  86. GRB 061121 declared "Burst of Interest" by Swift team
  87. RHESSI Spectrum of GRB061121
  88. Konus-Wind and Konus-A observations of GRB 061121
  89. INTEGRAL results on GRB 061122
  90. Swift-BAT trigger 239987 is not a GRB
  91. GRB 061122A: a long GRB detected by INTEGRAL
  92. GRB 061121: Swift/UVOT Observations
  93. GRB 061121: Swift-XRT Team Refined Analysis
  94. GRB 061121, Swift-BAT refined analysis
  95. GRB061121, optical observation
  96. GRB 061121 : Planned XMM-Newton observation
  97. GRB 061121: Optical observation at the KANATA 1.5m telescope
  98. GRB 061121: Faulkes Telescope North Optical Observation
  99. GRB061121: Spectroscopic Redshift
  100. GRB061121: Keck spectroscopic observations

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