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

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