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

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