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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 070429A, Swift-BAT refined analysis
  2. GRB 070429A: optical and NIR observations
  3. GRB 070429B: Swift XRT refined analysis
  4. GRB 070429B: ROTSE-III Optical Limits
  5. GRB 070429B: Swift detection of a short burst
  6. GRB 070429: What's the temperature?
  7. GRB 070429: ROTSE-III Optical Limits
  8. GRB 070429: Swift detection of a burst
  9. GRB 070427, Swift-BAT Refined Analysis
  10. LT monitoring of GRB070412
  11. GRB 070427: Swift detection of a burst
  12. GRB 070411, further deep LBT photometry
  13. GRB 070411: Late-time Keck imaging
  14. GRB 070411 : Planned XMM-Newton observation
  15. GRB070419B: Suzaku WAM observation of the prompt emission
  16. GRB 070420, SMARTS optical/IR afterglow observations
  17. GRB 070411, deep LBT photometry
  18. GRB 070420: pseudo-z~1.56 from spectral parameters of the prompt
  19. Konus-Wind observation of GRB 070420
  20. GRB 070411: break in the optical light curve
  21. GRB 070420 Swift-BAT Refined Analysis
  22. GRB070419A: Kuiper Optical detection
  23. GRB070419a: Swift UVOT observations
  24. GRB 070419A: MARGE Observations
  25. GRB 070420: optical rebrightening observed at Mt. John
  26. GRB 070420: Swift XRT refined analysis
  27. GRB070420: Swift UVOT continuing observations
  28. GRB 070411: BART early limit
  29. GRB 070420: Faulkes Telescope South Observations
  30. GBR 070419A: Swift/XRT refined analysis
  31. GRB 070420: TAROT La Silla observatory optical observations
  32. GRB 070420: NIR and optical afterglow confirmed
  33. GRB 070420: Swift detection of a burst with optical afterglow
  34. GRB 070419A: MITSuME Okayama Observations
  35. GRB 070419A: Early Super-LOTIS Observations
  36. GRB 070419B, Swift-BAT refined analysis
  37. GRB 070419A Swift-BAT Refined Analysis
  38. GRB070419B: Confirmation of Optical Transient
  39. GRB 070419A: RAPTOR Detection of Early Emission
  40. GRB 070419B: Swift XRT refined analysis
  41. GRB 070419: Keck/LRIS Absorption Redshift
  42. GRB 070419B: optical afterglow confirmation
  43. GRB 070419A, Optical observations
  44. GRB 070411: Deep VLT detection
  45. GRB070419 - SDSS Pre-Burst Observations
  46. GRB 070419A: SARA observations
  47. GRB 070419A: NAYUTA Optical Observation
  48. GRB 070419A: Faulkes Telescope North Optical Observations
  49. GRB 070419B optical afterglow candidate
  50. GRB 070419A: Optical and IR observations with KANATA
  51. GRB 070419B: optical afterglow candidate
  52. GRB 070419A: Lulin Optical observation
  53. GRB070419A, optical observation
  54. Infrared detection of GRB070419A with UKIRT
  55. GRB 070419A: Kiso Optical observation
  56. GRB070330: Correction to UVOT position
  57. GRB 070419: P60 Confirmation of Optical Afterglow
  58. GRB 070419B: Swift detection of a burst
  59. GRB 070419 optical afterglow candidate
  60. GRB 070419A: ROTSE-III Optical Limits
  61. GRB 070419: Swift detection of a burst
  62. Swift-BAT Trigger 276045 is a Cosmic Ray Shower event
  63. GRB 070418: Optical and IR observations with KANATA
  64. Trigger 276045: Swift detection of a possible burst
  65. GRB 070406: Swift XRT refined analysis
  66. IBAS Alert n.4202: not a real GRB
  67. GRB 070318, SMARTS optical/IR afterglow observations
  68. GRB 070411: TLS data shows plateau, flares
  69. GRB070412: UKIRT-WFCAM JHK upper limits
  70. GRB070412: Swift UVOT observations
  71. IBAS Alert n.4199: Not a GRB
  72. GRB 070411: Swift/UVOT observations
  73. GRB 070412, Swift-BAT refined analysis
  74. GRB 070412 Liverpool Telescope optical limit
  75. GRB 070411: Optical photometry at Crni Vrh
  76. GRB 070412: Swift-XRT refined analysis
  77. GRB 070411: Swift-XRT refined analysis
  78. GRB 070412: further reanalysis of NOT images
  79. GRB 070412: Optical observations at Crni Vrh
  80. GRB 070411: OA redshift
  81. GRB 070412: Swift-XRT refined position
  82. GRB 070412: further NOT observations
  83. GRB 070412: Gemini/GMOS afterglow candidate
  84. GRB 070412: IAC80 optical afterglow candidate
  85. GRB 070411: Magellan/Clay photometry
  86. GRB 070411: Magellan/IMACS photometry
  87. GRB 070412: NOT observations
  88. GRB 070412: Nearby bright galaxy
  89. GRB 070411, Swift-BAT refined analysis
  90. GRB 070412: Swift detection of a burst
  91. GRB 070411: IAC80 optical observations
  92. GRB 070411 : Liverpool Telescope Observations
  93. GRB 070411: Optical observations at Crni Vrh
  94. GRB 070411: ROTSE-III Detection of Optical Counterpart
  95. GRB 070411: Tautenburg RRM Afterglow Confirmation
  96. GRB 070411: Swift detection of a burst with optical afterglow
  97. GRB 070406: "Star" in XRT error circle S2 is an AGN?
  98. GRB 070406: Swift XRT team further analysis
  99. Suzaku ToO observation of SGR 1806-20
  100. GRB 070406: Astrometrically Refined XRT Position, Unfading Source

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