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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. GRB 070508: TAROT La Silla observatory optical observations
  2. GRB 070508: Swift detection of an intense burst with an optical counterpart
  3. GRB070412: MAGIC telescope GeV observation
  4. Swift-BAT trigger 278809 is not a GRB
  5. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  6. GRB 070506: VLT redshift
  7. GRB070506: Swift/UVOT Observations
  8. GRB070506: Swift XRT refined analysis
  9. GRB 070506, Swift-BAT Refined Analysis
  10. GRB 070506: Swift detection of a burst with optical afterglow
  11. GRB 070412, deep LBT imaging
  12. GRB 070429A: Swift XRT further analysis
  13. GRB070429B: VLT observations
  14. GRB 070429A: optical observations
  15. GRB070429B: position correction
  16. GRB 070309: Swift-XRT afterglow confirmation
  17. GRB070429B: possible host galaxy detection
  18. VLA observation of GRB 070429B
  19. Swift/UVOT observations of GRB070429B
  20. GRB 070429B, Swift-BAT refined analysis
  21. Swift/UVOT observations of GRB070429A
  22. GRB 070429A: Swift XRT refined analysis
  23. GRB 070429A, Swift-BAT refined analysis
  24. GRB 070429A: optical and NIR observations
  25. GRB 070429B: Swift XRT refined analysis
  26. GRB 070429B: ROTSE-III Optical Limits
  27. GRB 070429B: Swift detection of a short burst
  28. GRB 070429: What's the temperature?
  29. GRB 070429: ROTSE-III Optical Limits
  30. GRB 070429: Swift detection of a burst
  31. GRB 070427, Swift-BAT Refined Analysis
  32. LT monitoring of GRB070412
  33. GRB 070427: Swift detection of a burst
  34. GRB 070411, further deep LBT photometry
  35. GRB 070411: Late-time Keck imaging
  36. GRB 070411 : Planned XMM-Newton observation
  37. GRB070419B: Suzaku WAM observation of the prompt emission
  38. GRB 070420, SMARTS optical/IR afterglow observations
  39. GRB 070411, deep LBT photometry
  40. GRB 070420: pseudo-z~1.56 from spectral parameters of the prompt
  41. Konus-Wind observation of GRB 070420
  42. GRB 070411: break in the optical light curve
  43. GRB 070420 Swift-BAT Refined Analysis
  44. GRB070419A: Kuiper Optical detection
  45. GRB070419a: Swift UVOT observations
  46. GRB 070419A: MARGE Observations
  47. GRB 070420: optical rebrightening observed at Mt. John
  48. GRB 070420: Swift XRT refined analysis
  49. GRB070420: Swift UVOT continuing observations
  50. GRB 070411: BART early limit
  51. GRB 070420: Faulkes Telescope South Observations
  52. GBR 070419A: Swift/XRT refined analysis
  53. GRB 070420: TAROT La Silla observatory optical observations
  54. GRB 070420: NIR and optical afterglow confirmed
  55. GRB 070420: Swift detection of a burst with optical afterglow
  56. GRB 070419A: MITSuME Okayama Observations
  57. GRB 070419A: Early Super-LOTIS Observations
  58. GRB 070419B, Swift-BAT refined analysis
  59. GRB 070419A Swift-BAT Refined Analysis
  60. GRB070419B: Confirmation of Optical Transient
  61. GRB 070419A: RAPTOR Detection of Early Emission
  62. GRB 070419B: Swift XRT refined analysis
  63. GRB 070419: Keck/LRIS Absorption Redshift
  64. GRB 070419B: optical afterglow confirmation
  65. GRB 070419A, Optical observations
  66. GRB 070411: Deep VLT detection
  67. GRB070419 - SDSS Pre-Burst Observations
  68. GRB 070419A: SARA observations
  69. GRB 070419A: NAYUTA Optical Observation
  70. GRB 070419A: Faulkes Telescope North Optical Observations
  71. GRB 070419B optical afterglow candidate
  72. GRB 070419A: Optical and IR observations with KANATA
  73. GRB 070419B: optical afterglow candidate
  74. GRB 070419A: Lulin Optical observation
  75. GRB070419A, optical observation
  76. Infrared detection of GRB070419A with UKIRT
  77. GRB 070419A: Kiso Optical observation
  78. GRB070330: Correction to UVOT position
  79. GRB 070419: P60 Confirmation of Optical Afterglow
  80. GRB 070419B: Swift detection of a burst
  81. GRB 070419 optical afterglow candidate
  82. GRB 070419A: ROTSE-III Optical Limits
  83. GRB 070419: Swift detection of a burst
  84. Swift-BAT Trigger 276045 is a Cosmic Ray Shower event
  85. GRB 070418: Optical and IR observations with KANATA
  86. Trigger 276045: Swift detection of a possible burst
  87. GRB 070406: Swift XRT refined analysis
  88. IBAS Alert n.4202: not a real GRB
  89. GRB 070318, SMARTS optical/IR afterglow observations
  90. GRB 070411: TLS data shows plateau, flares
  91. GRB070412: UKIRT-WFCAM JHK upper limits
  92. GRB070412: Swift UVOT observations
  93. IBAS Alert n.4199: Not a GRB
  94. GRB 070411: Swift/UVOT observations
  95. GRB 070412, Swift-BAT refined analysis
  96. GRB 070412 Liverpool Telescope optical limit
  97. GRB 070411: Optical photometry at Crni Vrh
  98. GRB 070412: Swift-XRT refined analysis
  99. GRB 070411: Swift-XRT refined analysis
  100. GRB 070412: further reanalysis of NOT images

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