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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"

32506 results found.

  1. INT+WFC observations of GRB 061126
  2. GRB 061126: Possible Jet Break
  3. GRB 061121: Second Epoch ATCA Radio Observations
  4. GRB 061126: RAPTOR Optical Detection During Gamma-Ray Emission
  5. Swift XRT on-board boresight update
  6. GRB 061121: ATCA & WSRT Radio Observations
  7. GRB061121: optical observations
  8. GRB 061126: Early Super-LOTIS Observations
  9. GRB 061126: optical observation
  10. RHESSI Spectrum of GRB061126
  11. GRB 061126: Tautenburg afterglow observations
  12. GRB061126: Optical afterglow observations from MIRO
  13. GRB061126: Optical afterglow observations from MIRO
  14. GRB 061126 : SDSS Pre-Burst Observations
  15. GRB 061126: Swift-XRT refined analysis
  16. GRB 061126: Swift/UVOT Observations
  17. GRB 061126, Swift-BAT refined analysis
  18. GRB 061126: SARA Observations
  19. GRB 061126: Early Detection of the IR Afterglow
  20. GRB 061126: Faulkes Telescope North Optical Observations
  21. GRB 061121: MDM Continued Monitoring
  22. GRB 061122: Confirmation of X-ray/Optical Afterglow
  23. GRB 061121: MDM Continuing Optical Decay
  24. GRB061121: optical observations
  25. GRB 061122: Candidate Optical Afterglow
  26. GRB 061121: Ep,i - Eiso correlation
  27. GRB 061121: MDM Optical Decay
  28. GRB061122: Swift/UVOT Optical Observations
  29. GRB 061121: ART detection in Ic
  30. GRB061121: P60 Observations
  31. Radio detection of GRB 061121
  32. GRB061122: Swift-XRT position
  33. Konus-Wind observation of GRB 061122
  34. GRB 061121: MDM Optical Observations
  35. GRB 061121 declared "Burst of Interest" by Swift team
  36. RHESSI Spectrum of GRB061121
  37. Konus-Wind and Konus-A observations of GRB 061121
  38. INTEGRAL results on GRB 061122
  39. GRB 061121: Swift/UVOT Observations
  40. GRB 061121: Swift-XRT Team Refined Analysis
  41. GRB 061121, Swift-BAT refined analysis
  42. GRB061121, optical observation
  43. GRB 061121: Optical observation at the KANATA 1.5m telescope
  44. GRB 061121: Faulkes Telescope North Optical Observation
  45. GRB061121: Spectroscopic Redshift
  46. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  47. GRB 060605: NIR Observations
  48. GRB 050915B: optical afterglow
  49. GRB 060111B: Swift UVOT Refined Magnitudes
  50. GRB061110A: Correction to GCN5817
  51. GRB 061110A: refined R-band analysis
  52. GRB 061110B: NIR Observations
  53. Swift/UVOT Upper Limits for GRB061110b
  54. Swift/UVOT Upper Limits for GRB061110a
  55. GRB 061110B: Swift XRT refined analysis
  56. GRB 061110B, Swift-BAT refined analysis
  57. GRB 061110B: VLT redshift
  58. GRB 061110B: NOT optical observations
  59. GRB 061110A: Swift XRT refined analysis
  60. GRB 061110B: Swift/XRT position
  61. GRB 061110B : Liverpool Telescope Optical Afterglow Detection
  62. GRB 061110A, Swift-BAT refined analysis
  63. GRB 061110: ROTSE-III Optical Limits
  64. Swift-BAT Trigger 237821 is a Cosmic Ray Shower event
  65. GRB 061109: optical observation
  66. GRB061028: MAGIC telescope GeV observation
  67. GRB 061007: Third Epoch ATCA Radio Observations
  68. GRB061019: second epoch CrAO observations
  69. GRB 061028: Swift/XRT Astrometry Correction
  70. GRB 061102: Swift/UVOT Magnitude Upper Limits
  71. GRB 061102, XRT refined analysis
  72. GRB 061004: Further VLT/NTT observations
  73. Swift-BAT Trigger 236481 is a Cosmic Ray Shower event
  74. GRB061102B: Super-LOTIS observations
  75. GRB 061028: Optical R passband observations
  76. GRB 061102, Swift-BAT refined analysis
  77. GRB 061028: VLA Observation
  78. GRB 061004: Swift/XRT Astrometry Correction
  79. GRB 060801: Swift/XRT Astrometry Correction
  80. GRB 061028: Futher P200 Observations
  81. GRB 061028: MDM Observations
  82. GRB 061028: P200 Observations
  83. GRB 061028: SARA upper limit
  84. GRB 061028: z band imaging
  85. GRB061028: XRT refined analysis
  86. GRB 061028: Swift/UVOT Observations
  87. GRB 061028, Swift-BAT refined analysis
  88. GRB 061027, Swift refined analysis of a possible burst
  89. GRB061025: ROTSE-III Confirmation of Optical Counterpart
  90. GRB061025: Swift XRT refined analysis
  91. GRB061025: Swift/UVOT observations
  92. GRB 061019: MITSuME upper limits
  93. GRB 061025: REM observations
  94. GRB 061025: Gemini-S observations
  95. GRB061025: Swift XRT position
  96. GRB 061025: ROTSE-III Optical Limits
  97. Swift XRT boresight update
  98. GRB 061021, Swift-BAT Lag analysis
  99. Konus-Wind observation of GRB 061021
  100. GRB 061021 - VLT spectrum without lines

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