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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 060111B: MITSuME detection of optical afterglow
  2. GRB 060111B: TAROT optical observation
  3. GRB060111A: RTT150 optical observations
  4. GRB060111B: RTT150, possible host galaxy
  5. GRB 060111B: Refined analysis of the Swift-BAT burst
  6. GRB 060110: MARGE observations
  7. GRB 060111(a): P60 Observations
  8. GRB 060111B: Gualba observatory limit
  9. GRB 060111B: ROTSE-III Detection of Optical Counterpart Flare
  10. GRB 060111B: Swift detection of a burst
  11. GRB 060111: Swift-BAT Refined Analysis
  12. GRB060111.2:_MASTER optical limit
  13. GRB 060108: VLT K-band observations
  14. GRB 060111: TAROT optical observation
  15. GRB 060111: possible UVOT counterpart
  16. GRB060111 : XRT refined analysis
  17. GRB 060111: ROTSE-III Optical Limits
  18. GRB 060111: Swift detection of a burst
  19. GRB 060110: Mitsume optical observations
  20. GRB 060110: Swift-BAT refined analysis
  21. GRB 060109: Swift-BAT refined analysis
  22. GRB 060108: z-band imaging from Gemini-North
  23. GRB 060110a: RAPTOR detection of early optical emission.
  24. GRB 060110: UKIRT K-band observations
  25. GRB 060110: ROTSE-III Confirmation of Optical Counterpart
  26. GRB 060110: IR Candidate Afterglow
  27. GRB060110, optical observation
  28. GRB 060110: Super-LOTIS observations
  29. GRB 060110: Optical observation
  30. GRB 060110: Correction
  31. Correction to GRB 060109 XRT analysis
  32. GRB 050110: IR Observations
  33. GRB 060110: Optical limit
  34. GRB 060110: Swift-BAT detection of a burst
  35. GRB 060109: Refined Swift-XRT analysis
  36. GRB 060109: Swift/UVOT upper limits
  37. GRB060109, optical observation
  38. GRB 060108: ISAS early observations and near IR upper limit
  39. GRB060108: P200 Ks Observations
  40. GRB 060108: early UKIRT K-band observations
  41. Swift UVOT correction to GCN 4455
  42. GRB 060109: Swift Detection of a long burst
  43. GRB 060108: a dark burst?
  44. GRB 060108: Refined XRT analysis
  45. GRB 060108: VLT J-band observations
  46. GRB 060108: Mitsume optical observations
  47. GRB 060108: Swift/UVOT upper limits
  48. GRB 060105: quick look analysis of the Suzaku/XIS afterglow observation
  49. GRB060108: SDSS pre-burst observations
  50. GRB060108: Faulkes Telescope observation
  51. GRB060108, optical observation
  52. GRB 060108: Refined analysis of the Swift-BAT burst
  53. GRB 060108: Swift XRT position
  54. GRB060108: Swift detection of its 100th GRB
  55. GRB 060105: pseudo-z from spectral parameters of the prompt emission
  56. GRB 060105: Radio observations
  57. GRB 060105: MDM Observation
  58. Konus-Wind observation of GRB 060105
  59. GRB 060105: ISAS observations and near IR upper limit
  60. GRB 060105: Swift/UVOT upper limits
  61. GRB 060105: Mitsume optical observations
  62. GRB 060105: BAT refined analysis
  63. GRB 060102 - no XRT afterglow
  64. GRB 060105: XRT refined analysis
  65. GRB060105: Suzaku-XIS and -HXD observation plan
  66. GRB060105, optical observation
  67. GRB060105 : Kiso optical observation
  68. GRB060105: Swift detection of a bright long burst
  69. Swift-BAT trigger 175653 is not an astrophysical source
  70. GRB 060102: MDM Observation
  71. Swift-BAT trigger 175653 is probably not a GRB
  72. GRB 060102: Swift-BAT refined analysis
  73. Time Correction to GRB 060102
  74. GRB 060102: Swift-BAT detection of a burst
  75. GRB051211B: optical observations
  76. GRB051227: SARA Observations
  77. GRB 051221B: Optical Observations with Kuiper 1.54m
  78. GRB 051227: Likely host galaxy underlying afterglow position
  79. GRB 051227: optical observation
  80. GRB051221B: Radio observations
  81. GRB 051221A: VLA Radio Observations
  82. GRB051227: Radio Observations
  83. GRB 051227: Confirmed fading from Gemini observations
  84. GRB051227: further analysis of VLT images
  85. GRB 051227: optical afterglow
  86. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  87. GRB 051227: Gemini observations
  88. GRB 051227: Keck Spectroscopy
  89. GRB 051227: Magellan r'-band Imaging/Astrometry
  90. GRB 051227: refined analysis of VLT images
  91. GRB 051227: P60 Observations
  92. GRB 051227: MDM Observation
  93. GRB 051227: R-band object in the XRT error circle
  94. GRB 051227: Joint Swift-HETE Spectral Analysis
  95. GRB 051227: XRT refined analysis
  96. GRB 051227: Further analysis of the Swift-BAT burst
  97. GRB 051227: Refined analysis of the Swift-BAT burst
  98. GRB051227: SDSS pre-burst observations
  99. GRB 051227, optical observation
  100. GRB 051227: Swift detection of a burst

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