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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 060114: A long GRB detected by INTEGRAL
  2. GRB060114: Faulkes North observation
  3. GRB 060108: IR observations of afterglow
  4. GRB060108: Faulkes North afterglow evidence
  5. GRB 060108: further analysis of VLT images
  6. GRB 060108: Evidence for an XRT Position Offset
  7. GRB 060110: KAIT observations
  8. GRB 060111B: Swift XRT refined analysis
  9. GRB 060111A: refined UVOT anaysis
  10. GRB 060111B: MITSuME detection of optical afterglow
  11. GRB 060111B: TAROT optical observation
  12. GRB060111A: RTT150 optical observations
  13. GRB060111B: RTT150, possible host galaxy
  14. GRB 060111B: Refined analysis of the Swift-BAT burst
  15. GRB 060110: MARGE observations
  16. GRB 060111(a): P60 Observations
  17. GRB 060111B: Gualba observatory limit
  18. GRB 060111B: ROTSE-III Detection of Optical Counterpart Flare
  19. GRB 060111B: Swift detection of a burst
  20. GRB 060111: Swift-BAT Refined Analysis
  21. GRB060111.2:_MASTER optical limit
  22. GRB 060108: VLT K-band observations
  23. GRB 060111: TAROT optical observation
  24. GRB 060111: possible UVOT counterpart
  25. GRB060111 : XRT refined analysis
  26. GRB 060111: ROTSE-III Optical Limits
  27. GRB 060111: Swift detection of a burst
  28. GRB 060110: Mitsume optical observations
  29. GRB 060110: Swift-BAT refined analysis
  30. GRB 060109: Swift-BAT refined analysis
  31. GRB 060108: z-band imaging from Gemini-North
  32. GRB 060110a: RAPTOR detection of early optical emission.
  33. GRB 060110: UKIRT K-band observations
  34. GRB 060110: ROTSE-III Confirmation of Optical Counterpart
  35. GRB 060110: IR Candidate Afterglow
  36. GRB060110, optical observation
  37. GRB 060110: Super-LOTIS observations
  38. GRB 060110: Optical observation
  39. GRB 060110: Correction
  40. Correction to GRB 060109 XRT analysis
  41. GRB 050110: IR Observations
  42. GRB 060110: Optical limit
  43. GRB 060110: Swift-BAT detection of a burst
  44. GRB 060109: Refined Swift-XRT analysis
  45. GRB 060109: Swift/UVOT upper limits
  46. GRB060109, optical observation
  47. GRB 060108: ISAS early observations and near IR upper limit
  48. GRB060108: P200 Ks Observations
  49. GRB 060108: early UKIRT K-band observations
  50. Swift UVOT correction to GCN 4455
  51. GRB 060109: Swift Detection of a long burst
  52. GRB 060108: a dark burst?
  53. GRB 060108: Refined XRT analysis
  54. GRB 060108: VLT J-band observations
  55. GRB 060108: Mitsume optical observations
  56. GRB 060108: Swift/UVOT upper limits
  57. GRB 060105: quick look analysis of the Suzaku/XIS afterglow observation
  58. GRB060108: SDSS pre-burst observations
  59. GRB060108: Faulkes Telescope observation
  60. GRB060108, optical observation
  61. GRB 060108: Refined analysis of the Swift-BAT burst
  62. GRB 060108: Swift XRT position
  63. GRB060108: Swift detection of its 100th GRB
  64. GRB 060105: pseudo-z from spectral parameters of the prompt emission
  65. GRB 060105: Radio observations
  66. GRB 060105: MDM Observation
  67. Konus-Wind observation of GRB 060105
  68. GRB 060105: ISAS observations and near IR upper limit
  69. GRB 060105: Swift/UVOT upper limits
  70. GRB 060105: Mitsume optical observations
  71. GRB 060105: BAT refined analysis
  72. GRB 060102 - no XRT afterglow
  73. GRB 060105: XRT refined analysis
  74. GRB060105: Suzaku-XIS and -HXD observation plan
  75. GRB060105, optical observation
  76. GRB060105 : Kiso optical observation
  77. GRB060105: Swift detection of a bright long burst
  78. Swift-BAT trigger 175653 is not an astrophysical source
  79. GRB 060102: MDM Observation
  80. Swift-BAT trigger 175653 is probably not a GRB
  81. GRB 060102: Swift-BAT refined analysis
  82. Time Correction to GRB 060102
  83. GRB 060102: Swift-BAT detection of a burst
  84. GRB051211B: optical observations
  85. GRB051227: SARA Observations
  86. GRB 051221B: Optical Observations with Kuiper 1.54m
  87. GRB 051227: Likely host galaxy underlying afterglow position
  88. GRB 051227: optical observation
  89. GRB051221B: Radio observations
  90. GRB 051221A: VLA Radio Observations
  91. GRB051227: Radio Observations
  92. GRB 051227: Confirmed fading from Gemini observations
  93. GRB051227: further analysis of VLT images
  94. GRB 051227: optical afterglow
  95. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  96. GRB 051227: Gemini observations
  97. GRB 051227: Keck Spectroscopy
  98. GRB 051227: Magellan r'-band Imaging/Astrometry
  99. GRB 051227: refined analysis of VLT images
  100. GRB 051227: P60 Observations

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