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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"

28047 results found.

  1. GRB 100526A: optical upper limit
  2. GRB 100528A: Faulkes Telescope North Detection
  3. GRB 100528A: GROND detection in all bands
  4. GRB 100528A: NOT optical observation
  5. Swift UVOT and UVOT-enhanced XRT position for GRB 100528A
  6. GRB100526B: GROND Upper limits
  7. GRB 100528A: SuperAGILE Localization of a Long GRB
  8. GRB 100526B: Swift-XRT confirmation of fading afterglow
  9. GRB 100526B: Swift/UVOT Upper Limits
  10. GRB 100526A: Swift/UVOT Upper Limits
  11. GRB 100526A: Gemini/NIRI infrared afterglow candidate
  12. GRB 100526A: NOT optical upper limit
  13. GRB 100526A: Swift XRT refined analysis
  14. GRB 100526B: Swift-BAT refined analysis
  15. GRB 100526B: Swift XRT/UVOT observations
  16. GRB 100526A: Swift-BAT refined analysis
  17. GRB 100526A: Enhanced Swift-XRT position
  18. GRB 100526A: MASTER-Net optical alert observations
  19. GRB 100526A: Swift detection of a burst
  20. GRB100522A: Suzaku WAM observation of the prompt emission
  21. GRB 100418A: Subaru late-time optical imaging and spectroscopy
  22. GRB 100522A: GROND observations, upper limits
  23. GRB 100522A: Fermi GBM observation
  24. GRB 100522A: Swift XRT refined analysis
  25. GRB 100522A, Swift-BAT refined analysis
  26. GRB 100522A: Enhanced Swift-XRT position
  27. GRB 100522A: NIR observations from CAHA
  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-XRT refined analysis
  32. GRB 100518A: optical afterglow decay
  33. GRB 100518A: BOOTES-3 optical observations
  34. Update to the configuration of the Fermi-LAT onboard GRB search
  35. GRB 100518A: Swift target of opportunity observation of the INTEGRAL burst
  36. GRB 100513A: MITSuME Akeno Optical Observation
  37. GRB 100518A: a long GRB detected with INTEGRAL
  38. Swift Trigger 422437 is probably not a GRB
  39. GRB 100517A: MASTER-Net wide field camera prompt optical observations
  40. GRB 100514A: optical afterglow confirmation
  41. GRB 100514A: Swift/UVOT Observations
  42. GRB 100514A: YNAO-GMG observations
  43. GRB 100514A: Swift XRT refined analysis
  44. GRB 100514A: Enhanced Swift-XRT position
  45. GRB 100514A: Swift-BAT refined analysis
  46. GRB 100514A: Swift detection of a burst
  47. GRB 100513A: Swift/UVOT upper limits
  48. GRB 100513A, RIMOTS optical upper limits
  49. GRB 100513A: Swift XRT refined analysis
  50. GRB 100513A: Swift-BAT refined analysis
  51. GRB 100513A: Enhanced Swift-XRT position
  52. GRB 100513A: SARA-N Upper Limit
  53. GRB 100513A: Swift detection of a burst
  54. GRB 100510A: Fermi GBM detection/observation
  55. GRB 100511A: Fermi GBM detection/observation
  56. GRB 100511A: Super-LOTIS early observations
  57. Swift-BAT trigger 421695 is likely not astrophysical
  58. GRB100504A: Optical upper limits at IAO
  59. GRB 100510A: MAXI/GSC detection
  60. GRB 100511A, RIMOTS optical upper limits
  61. Trigger 421695: Swift detection of a possible burst
  62. GRB100503A: Suzaku WAM observation of the prompt emission
  63. GRB 100508A: GROND Detection of the optical afterglow
  64. GRB 100508A: Swift-XRT Refined analysis
  65. GRB 100508A: Swift-BAT refined analysis
  66. GRB 100508A: Enhanced Swift-XRT position
  67. GRB100508A: Swift/UVOT Detection of the Afterglow
  68. GRB 100508A: ROTSE-III Optical Limits
  69. GRB 100508A: Swift detection of a burst
  70. GRB 100418A: Keck imaging
  71. GRB 100418A: RTT150 optical observations
  72. Swift-BAT refined analysis of trigger 421262
  73. An SGR-like burst from the magnetar 1E 1841-04.5 in Kes 73
  74. GRB 100504A: Swift/UVOT Observations
  75. GRB 100504A: Swift-XRT refined analysis
  76. GRB 100504A: Enhanced Swift-XRT position
  77. GRB 100504A: GROND Upper limits
  78. GRB 100504A: Swift-BAT refined analysis
  79. GRB 100504A: SARA-South Upper Limit
  80. GRB 100503A: Fermi GBM detection
  81. GRB 100504A: Swift detection of a burst
  82. INTEGRAL observations of Swift GRB trigger 421072
  83. GRB100423A : Suzaku WAM observation of the prompt emission
  84. Trigger 421072: Possible Swift detection of a GRB or transient
  85. GRB 100420A: Terskol optical upper limit
  86. GRB 100427A: Swift XRT and UVOT Upper Limits
  87. GRB 100427A: Fermi GBM detection
  88. GRB 100414A : EVLA Radio Detection
  89. GRB 100414A : WSRT Radio Detection
  90. GRB 100423A: CrAO optical observations
  91. GRB 100418A: Terskol optical observations
  92. GRB 100424A: CrAO optical observations
  93. GRB 100424A: NIR Afterglow Confirmation
  94. GRB 100425A: Swift XRT refined analysis
  95. GRB 100424A: Gemini/NIRI H-band observations
  96. GRB100425A: Swift/UVOT Upper Limits
  97. GRB 100424A: Swift/UVOT Upper Limits
  98. GRB 100424A: Liverpool Telescope Upper Limits
  99. GRB 100425A: Enhanced Swift-XRT position
  100. GRB 100425A: Swift-BAT refined analysis

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Download all Circulars as a .tar.gz archive (updated once a day):
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