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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. Radio detection of GRB100418a with ATCA
  2. GRB 100606A: Gemini-South imaging
  3. GRB 100606A: Swift/UVOT Upper Limits
  4. GRB 100606A Swift-XRT refined analysis
  5. GRB 100606A: Swift-BAT refined analysis
  6. GRB 100606A: Enhanced Swift-XRT position
  7. Swift Trigger 424040 is not a GRB
  8. GRB 100606A: Prompt enhanced Swift-XRT position
  9. GRB 100606A: Swift detection of a burst
  10. Swift detection of outburst from the SFXT IGR J18410-0535
  11. GRB 100111A: Maidanak optical observations
  12. GRB 100418A: Maidanak optical observations
  13. GRB 100513A: CrAO optical observations
  14. GRB 100514A: CrAO optical observations
  15. GRB 100526A: optical upper limit
  16. Konus-Wind observation of GRB 100528A
  17. GRB 100528A: Faulkes Telescope North Detection
  18. GRB 100528A: GROND detection in all bands
  19. GRB 100528A: NOT optical observation
  20. Swift UVOT and UVOT-enhanced XRT position for GRB 100528A
  21. GRB100526B: GROND Upper limits
  22. GRB 100528A: Fermi GBM observation
  23. GRB 100528A: SuperAGILE Localization of a Long GRB
  24. GRB 100526B: Swift-XRT confirmation of fading afterglow
  25. GRB 100526B: Swift/UVOT Upper Limits
  26. GRB 100526A: Swift/UVOT Upper Limits
  27. GRB 100526A: Gemini/NIRI infrared afterglow candidate
  28. GRB 100526A: NOT optical upper limit
  29. GRB 100526A: Swift XRT refined analysis
  30. GRB 100526B: Swift-BAT refined analysis
  31. GRB 100526B: Swift XRT/UVOT observations
  32. GRB 100526A: Swift-BAT refined analysis
  33. GRB 100526A: Enhanced Swift-XRT position
  34. GRB 100526B: Swift detection of a probable GRB
  35. GRB 100526A: MASTER-Net optical alert observations
  36. GRB 100526A: Swift detection of a burst
  37. Konus-Wind observation of GRB 100522A
  38. GRB100522A: Suzaku WAM observation of the prompt emission
  39. GRB 100418A: Subaru late-time optical imaging and spectroscopy
  40. GRB 100522A: GROND observations, upper limits
  41. Swift/UVOT observations of GRB100522A.
  42. GRB 100522A: Fermi GBM observation
  43. GRB 100522A: Swift XRT refined analysis
  44. GRB 100522A, Swift-BAT refined analysis
  45. GRB 100522A: Enhanced Swift-XRT position
  46. GRB 100522A: NIR observations from CAHA
  47. GRB 100522A: BOOTES-2 optical limit
  48. GRB 100522A: Swift detection of a burst
  49. GRB 100418A: CrAO optical observations
  50. GRB 100518A: GROND afterglow observation and photo-z
  51. GRB 100518A: Swift/UVOT Upper Limits
  52. GRB 100518A: Swift-XRT refined analysis
  53. GRB 100518A: optical afterglow decay
  54. GRB 100518A: BOOTES-3 optical observations
  55. Update to the configuration of the Fermi-LAT onboard GRB search
  56. GRB 100518A: Faulkes Telescope North Afterglow Candidate
  57. GRB 100518A: Swift target of opportunity observation of the INTEGRAL burst
  58. GRB 100513A: MITSuME Akeno Optical Observation
  59. Swift-BAT trigger 422437 is not anything astrophysical
  60. GRB 100518A: a long GRB detected with INTEGRAL
  61. Swift Trigger 422437 is probably not a GRB
  62. Fermi/GBM trigger 295791986 - unreliable location
  63. GRB 100517A: MASTER-Net wide field camera prompt optical observations
  64. GRB 100513A: EVLA radio observation
  65. GRB 100514A: optical afterglow confirmation
  66. GRB 100514A: Swift/UVOT Observations
  67. GRB 100514A: YNAO-GMG observations
  68. GRB 100514A: Swift XRT refined analysis
  69. GRB 100514A: MASTER-Net optical observations
  70. GRB 100514A: Enhanced Swift-XRT position
  71. GRB 100514A: Swift-BAT refined analysis
  72. GRB 100514A: Faulkes Telescope South observations
  73. GRB 100514A: Swift detection of a burst
  74. GRB 100513A: Faulkes Telescope South observations
  75. GRB 100513A: Swift/UVOT upper limits
  76. GRB 100513A, RIMOTS optical upper limits
  77. GRB 100513A: Swift XRT refined analysis
  78. GRB 100513A: Swift-BAT refined analysis
  79. GRB 100513A: Gemini/GMOS Spectroscopic Redshift
  80. GRB 100513A: Enhanced Swift-XRT position
  81. GRB 100513A: Lick observations and R-band dropout
  82. GRB 100513A: PAIRITEL continued observations and confirmation of fading
  83. GRB 100513A: SARA-N Upper Limit
  84. GRB 100513A: PAIRITEL NIR afterglow candidate
  85. GRB 100513A: Swift detection of a burst
  86. GRB 100510A: Fermi GBM detection/observation
  87. GRB 100511A: Fermi GBM detection/observation
  88. GRB 100511A: Super-LOTIS early observations
  89. Swift-BAT trigger 421695 is likely not astrophysical
  90. GRB100504A: Optical upper limits at IAO
  91. GRB 100510A: MAXI/GSC detection
  92. GRB 100511A, RIMOTS optical upper limits
  93. Trigger 421695: Swift detection of a possible burst
  94. GRB100508A: Further Swift/UVOT Observations
  95. GRB100503A: Suzaku WAM observation of the prompt emission
  96. GRB 100508A: GROND Detection of the optical afterglow
  97. GRB 100508A: Swift-XRT Refined analysis
  98. GRB 100508A: Swift-BAT refined analysis
  99. GRB 100508A: Enhanced Swift-XRT position
  100. GRB100508A: Swift/UVOT Detection of the Afterglow

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