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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. GRB100526B: GROND Upper limits
  2. GRB 100528A: Fermi GBM observation
  3. GRB 100528A: SuperAGILE Localization of a Long GRB
  4. GRB 100526B: Swift-XRT confirmation of fading afterglow
  5. GRB 100526B: Swift/UVOT Upper Limits
  6. GRB 100526A: Swift/UVOT Upper Limits
  7. GRB 100526A: Gemini/NIRI infrared afterglow candidate
  8. GRB 100526A: NOT optical upper limit
  9. GRB 100526A: Swift XRT refined analysis
  10. GRB 100526B: Swift-BAT refined analysis
  11. GRB 100526B: Swift XRT/UVOT observations
  12. GRB 100526A: Swift-BAT refined analysis
  13. GRB 100526A: Enhanced Swift-XRT position
  14. GRB 100526B: Swift detection of a probable GRB
  15. GRB 100526A: MASTER-Net optical alert observations
  16. GRB 100526A: Swift detection of a burst
  17. Konus-Wind observation of GRB 100522A
  18. GRB100522A: Suzaku WAM observation of the prompt emission
  19. GRB 100418A: Subaru late-time optical imaging and spectroscopy
  20. GRB 100522A: GROND observations, upper limits
  21. Swift/UVOT observations of GRB100522A.
  22. GRB 100522A: Fermi GBM observation
  23. GRB 100522A: Swift XRT refined analysis
  24. GRB 100522A, Swift-BAT refined analysis
  25. GRB 100522A: Enhanced Swift-XRT position
  26. GRB 100522A: NIR observations from CAHA
  27. GRB 100522A: BOOTES-2 optical limit
  28. GRB 100522A: Swift detection of a burst
  29. GRB 100418A: CrAO optical observations
  30. GRB 100518A: GROND afterglow observation and photo-z
  31. GRB 100518A: Swift/UVOT Upper Limits
  32. GRB 100518A: Swift-XRT refined analysis
  33. GRB 100518A: optical afterglow decay
  34. GRB 100518A: BOOTES-3 optical observations
  35. Update to the configuration of the Fermi-LAT onboard GRB search
  36. GRB 100518A: Faulkes Telescope North Afterglow Candidate
  37. GRB 100518A: Swift target of opportunity observation of the INTEGRAL burst
  38. GRB 100513A: MITSuME Akeno Optical Observation
  39. Swift-BAT trigger 422437 is not anything astrophysical
  40. GRB 100518A: a long GRB detected with INTEGRAL
  41. Swift Trigger 422437 is probably not a GRB
  42. Fermi/GBM trigger 295791986 - unreliable location
  43. GRB 100517A: MASTER-Net wide field camera prompt optical observations
  44. GRB 100513A: EVLA radio observation
  45. GRB 100514A: optical afterglow confirmation
  46. GRB 100514A: Swift/UVOT Observations
  47. GRB 100514A: YNAO-GMG observations
  48. GRB 100514A: Swift XRT refined analysis
  49. GRB 100514A: MASTER-Net optical observations
  50. GRB 100514A: Enhanced Swift-XRT position
  51. GRB 100514A: Swift-BAT refined analysis
  52. GRB 100514A: Faulkes Telescope South observations
  53. GRB 100514A: Swift detection of a burst
  54. GRB 100513A: Faulkes Telescope South observations
  55. GRB 100513A: Swift/UVOT upper limits
  56. GRB 100513A, RIMOTS optical upper limits
  57. GRB 100513A: Swift XRT refined analysis
  58. GRB 100513A: Swift-BAT refined analysis
  59. GRB 100513A: Gemini/GMOS Spectroscopic Redshift
  60. GRB 100513A: Enhanced Swift-XRT position
  61. GRB 100513A: Lick observations and R-band dropout
  62. GRB 100513A: PAIRITEL continued observations and confirmation of fading
  63. GRB 100513A: SARA-N Upper Limit
  64. GRB 100513A: PAIRITEL NIR afterglow candidate
  65. GRB 100513A: Swift detection of a burst
  66. GRB 100510A: Fermi GBM detection/observation
  67. GRB 100511A: Fermi GBM detection/observation
  68. GRB 100511A: Super-LOTIS early observations
  69. Swift-BAT trigger 421695 is likely not astrophysical
  70. GRB100504A: Optical upper limits at IAO
  71. GRB 100510A: MAXI/GSC detection
  72. GRB 100511A, RIMOTS optical upper limits
  73. Trigger 421695: Swift detection of a possible burst
  74. GRB100508A: Further Swift/UVOT Observations
  75. GRB100503A: Suzaku WAM observation of the prompt emission
  76. GRB 100508A: GROND Detection of the optical afterglow
  77. GRB 100508A: Swift-XRT Refined analysis
  78. GRB 100508A: Swift-BAT refined analysis
  79. GRB 100508A: Enhanced Swift-XRT position
  80. GRB100508A: Swift/UVOT Detection of the Afterglow
  81. GRB 100508A: ROTSE-III Optical Limits
  82. GRB 100508A: Swift detection of a burst
  83. GRB 100418A: Keck imaging
  84. GRB 100418A: RTT150 optical observations
  85. Fermi Gamma-ray Burst Monitor trigger 294712621 is not a GRB
  86. Swift-BAT refined analysis of trigger 421262
  87. GRB 100504A: Fermi GBM observation
  88. An SGR-like burst from the magnetar 1E 1841-04.5 in Kes 73
  89. GRB 100504A: Swift/UVOT Observations
  90. GRB 100418A: Flattening of the Swift/UVOT Optical Light Curve
  91. GRB 100504A: Swift-XRT refined analysis
  92. GRB 100504A: Enhanced Swift-XRT position
  93. GRB 100504A: GROND Upper limits
  94. GRB 100504A: Swift-BAT refined analysis
  95. GRB 100504A: SARA-South Upper Limit
  96. GRB 100503A: Fermi GBM detection
  97. GRB 100504A: UVOT-enhanced XRT position
  98. GRB 100504A: Swift detection of a burst
  99. Swift-BAT trigger 421072 is not astrophyical
  100. INTEGRAL observations of Swift GRB trigger 421072

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