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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 060111: possible UVOT counterpart
  2. GRB060111 : XRT refined analysis
  3. GRB 060111: ROTSE-III Optical Limits
  4. GRB 060111: Swift detection of a burst
  5. GRB 060110: Mitsume optical observations
  6. GRB 060110: Swift-BAT refined analysis
  7. GRB 060109: Swift-BAT refined analysis
  8. GRB 060108: z-band imaging from Gemini-North
  9. GRB 060110a: RAPTOR detection of early optical emission.
  10. GRB 060110: UKIRT K-band observations
  11. GRB 060110: ROTSE-III Confirmation of Optical Counterpart
  12. GRB 060110: IR Candidate Afterglow
  13. GRB060110, optical observation
  14. GRB 060110: Super-LOTIS observations
  15. GRB 060110: Optical observation
  16. GRB 060110: Correction
  17. Correction to GRB 060109 XRT analysis
  18. GRB 050110: IR Observations
  19. GRB 060110: Optical limit
  20. GRB 060110: Swift-BAT detection of a burst
  21. GRB 060109: Refined Swift-XRT analysis
  22. GRB 060109: Swift/UVOT upper limits
  23. GRB060109, optical observation
  24. GRB 060108: ISAS early observations and near IR upper limit
  25. GRB060108: P200 Ks Observations
  26. GRB 060108: early UKIRT K-band observations
  27. Swift UVOT correction to GCN 4455
  28. GRB 060109: Swift Detection of a long burst
  29. GRB 060108: a dark burst?
  30. GRB 060108: Refined XRT analysis
  31. GRB 060108: VLT J-band observations
  32. GRB 060108: Mitsume optical observations
  33. GRB 060108: Swift/UVOT upper limits
  34. GRB 060105: quick look analysis of the Suzaku/XIS afterglow observation
  35. GRB060108: SDSS pre-burst observations
  36. GRB060108: Faulkes Telescope observation
  37. GRB060108, optical observation
  38. GRB 060108: Refined analysis of the Swift-BAT burst
  39. GRB 060108: Swift XRT position
  40. GRB060108: Swift detection of its 100th GRB
  41. GRB 060105: pseudo-z from spectral parameters of the prompt emission
  42. GRB 060105: Radio observations
  43. GRB 060105: MDM Observation
  44. Konus-Wind observation of GRB 060105
  45. GRB 060105: ISAS observations and near IR upper limit
  46. GRB 060105: Swift/UVOT upper limits
  47. GRB 060105: Mitsume optical observations
  48. GRB 060105: BAT refined analysis
  49. GRB 060102 - no XRT afterglow
  50. GRB 060105: XRT refined analysis
  51. GRB060105: Suzaku-XIS and -HXD observation plan
  52. GRB060105, optical observation
  53. GRB060105 : Kiso optical observation
  54. GRB060105: Swift detection of a bright long burst
  55. Swift-BAT trigger 175653 is not an astrophysical source
  56. GRB 060102: MDM Observation
  57. Swift-BAT trigger 175653 is probably not a GRB
  58. GRB 060102: Swift-BAT refined analysis
  59. Time Correction to GRB 060102
  60. GRB 060102: Swift-BAT detection of a burst
  61. GRB051211B: optical observations
  62. GRB051227: SARA Observations
  63. GRB 051221B: Optical Observations with Kuiper 1.54m
  64. GRB 051227: Likely host galaxy underlying afterglow position
  65. GRB 051227: optical observation
  66. GRB051221B: Radio observations
  67. GRB 051221A: VLA Radio Observations
  68. GRB051227: Radio Observations
  69. GRB 051227: Confirmed fading from Gemini observations
  70. GRB051227: further analysis of VLT images
  71. GRB 051227: optical afterglow
  72. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  73. GRB 051227: Gemini observations
  74. GRB 051227: Keck Spectroscopy
  75. GRB 051227: Magellan r'-band Imaging/Astrometry
  76. GRB 051227: refined analysis of VLT images
  77. GRB 051227: P60 Observations
  78. GRB 051227: MDM Observation
  79. GRB 051227: R-band object in the XRT error circle
  80. GRB 051227: Joint Swift-HETE Spectral Analysis
  81. GRB 051227: XRT refined analysis
  82. GRB 051227: Further analysis of the Swift-BAT burst
  83. GRB 051227: Refined analysis of the Swift-BAT burst
  84. GRB051227: SDSS pre-burst observations
  85. GRB 051227, optical observation
  86. GRB 051227: Swift detection of a burst
  87. GRB051117B: optical observation
  88. IBAS_alert n. 2719 : not a real GRB
  89. Konus-Wind observation of GRB 051221A
  90. GRB051221A: Suzaku WAM observation of the prompt emission
  91. GRB 051221A: MDM Optical Observations
  92. GRB051016: analysis of the XMM-Newton observation
  93. GRB 051221A: Detection at 251nm with Swift UVOT
  94. GRB 051221A: Chandra Afterglow Position
  95. GRB 051221A: Refined spectral and temporal analysis of the Swift-BAT short hard burst
  96. GRB 051221B: ROTSE-III Optical Limits
  97. GRB 051221B: TAROT optical limits
  98. GRB 051221A: WSRT Radio Observations
  99. GRB 051221: Redshift from Gemini
  100. GRB 051221: Continued fading of optical afterglow

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