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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. Swift/UVOT Observations of GRB100814A - a clearer table.
  2. GRB 100814A: Swift-XRT refined analysis
  3. Swift/UVOT observations of GRB100814A
  4. GRB 100814A, Swift-BAT refined analysis
  5. GRB 100814A: CQUEAN r- and i-band Observation
  6. GRB 100814A: Enhanced Swift-XRT position
  7. GRB 100814A: GROND Detection of the Optical/NIR Afterglow
  8. GRB 100814A: IAC80 R-band observations
  9. GRB100814A: Magellan Echellette Observations
  10. GRB 100814A: Swift UVOT observations of the optical afterglow
  11. GRB 100814A: Swift detection of a burst with an optical afterglow
  12. GRB 100814A: ROTSE-III Detection of Optical Counterpart
  13. Swift-BAT trigger 431582 likely is IGR J17464-2811
  14. GRB 100805A: the 4-th epoch of SAO RAS optical observations
  15. GRB 100805A: optical observation in CrAO (correction to the GCN 11077 and second epoch)
  16. GRB 100802A: further NOT observation
  17. GRB 100805A: Swift/UVOT Observations of a Possible Late-Time Brightening
  18. GRB 100807A: P200 Infrared Observations
  19. GRB 100805A: the 3-rd epoch of SAO RAS optical observations
  20. GRB100807A: optical observation in CrAO
  21. GRB 100805A: optical observation in CrAO
  22. GRB 100805A: 2-nd epoch of SAO RAS optical observations
  23. GRB100807A: MITSuME optical upper limits
  24. GRB 100807A: Swift XRT refined analysis
  25. GRB 100807A: P60 Optical Afterglow Discovery
  26. GRB 100807A: Swift/UVOT Upper Limits
  27. GRB 100805A: SAO RAS optical observations
  28. GRB 100807A: Enhanced Swift-XRT position
  29. GRB 100807A: Swift-BAT refined analysis
  30. GRB 100807A: ROTSE-III Optical Limits
  31. GRB 100807A: Swift detection of a burst
  32. GRB 100805A: IAC80 and 1.5m OSN optical observations
  33. GRB 100805A: Xinglong TNT optical observation
  34. GRB 100805A: Early RAPTOR Observations
  35. GRB 100805A: ROTSE-III Optical detection
  36. GRB 100805A: Swift/UVOT Observations of the Optical Afterglow
  37. GRB 100802A: WIYN observations
  38. GRB 100805A: IAC80 BVR-band observations
  39. Swift-BAT trigger 430975 is not a burst
  40. GRB 100805A: Swift-BAT refined analysis
  41. GRB 100805A: Swift-XRT Refined Analysis
  42. GRB 100805A: GRAS 002 optical observations
  43. Trigger 430975: Swift detection of a possible burst
  44. GRB 100805A: I-band detection from 1.23m CAHA telescope.
  45. GRB 100805A: Enhanced Swift-XRT position
  46. GRB 100805A: Liverpool Telescope afterglow observations
  47. GRB 100805A: Further P60 Monitoring
  48. GRB 100805A: P60 Optical Afterglow Candidate
  49. GRB 100805A: Enhanced Swift-XRT position
  50. GRB 100805A: ROTSE-III Optical Limits
  51. GRB 100805A: Swift detection of a burst with an optical counterpart
  52. GRB 100802A: Fermi GBM observation
  53. GRB 100728B: optical photometry of ISON-NM
  54. GRB 100713A: second epoch Maidanak optical observation
  55. GRB 100713A: CrAO optical limits
  56. GRB 100802A: NOT optical observation
  57. GRB100802A: MITSuME optical upper limits
  58. GRB 100802A: P60 Observations
  59. GRB 100802A: XRT refined analysis
  60. GRB 100802A: Swift/UVOT Possible Optical Afterglow
  61. GRB 100728A: Suzaku WAM observation of the prompt emission
  62. GRB 100802A: Enhanced Swift-XRT position
  63. GRB 100802A: Swift-BAT refined analysis
  64. GRB 100802A: Liverpool Telescope observations
  65. GRB 100802A: ROTSE-III Optical Limits
  66. GRB 100802A: Possible Swift/UVOT Detection of Optical Afterglow
  67. GRB 100802A: Swift detection of a burst
  68. GRB 100725B: TELMA optical observation
  69. GRB 100728B: Swift/UVOT Observations (correction to GCN 11028)
  70. GRB 100728B: Swift/UVOT Observations (correction)
  71. GRB 100728B - NOT optical observation
  72. GRB 100728B: Swift/UVOT Observations
  73. GRB 100728B: Lick Observations
  74. GRB 100728B: Continued KAIT observations
  75. GRB 100728B, Swift-BAT refined analysis
  76. GRB 100728B: Swift-XRT Refined Analysis
  77. Konus-Wind observation of GRB 100728A
  78. GRB 100728A: GROND Detection of the NIR Afterglow Candidate
  79. GRB 100727A: Swift/UVOT Upper Limits
  80. GRB 100728A, Swift-BAT refined analysis
  81. GRB 100728B: Enhanced Swift-XRT position
  82. GRB 100728A: Swift/UVOT Upper Limits
  83. GRB 100728B: Fermi GBM observation
  84. GRB 100728A: Swift-XRT refined analysis
  85. GRB 100728B: GROND Detection of the NIR Afterglow
  86. GRB 100728B: optical detection
  87. GRB 100728B: Skynet/PROMPT Detections (correction)
  88. GRB 100728B: KAIT optical afterglow detection (correction)
  89. GRB 100728B: Swift detection of a burst with an optical counterpart
  90. GRB 100728A: Skynet/PROMPT Detections
  91. GRB 100728A: KAIT optical afterglow detection
  92. GRB 100728A: Fermi GBM observation
  93. GRB 100728A: Enhanced Swift-XRT position
  94. GRB 100728A: Swift detection of a burst
  95. GRB 100727A: Swift XRT refined analysis
  96. GRB 100727A: Fermi GBM observation
  97. GRB 100727A, Swift-BAT refined analysis
  98. GRB 100727A: Enhanced Swift-XRT position
  99. GRB100727A: MOA optical upper limit
  100. GRB 100727A: Swift detection of a burst

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