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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"

21264 results found.

  1. GRB 100702A: Second epoch of Magellan near-IR observations and afterglow limits
  2. GRB 100702A: Magellan near-IR observations
  3. GRB 100702A: VLT optical observations
  4. GRB 100702: ROTSE-III Optical Limits
  5. GRB 100702A: Swift detection of a short burst
  6. GRB 100615A: Chandra X-ray ToO Observation
  7. GRB 100213B: Detection of Fading Optical Afterglow
  8. GRB 100628A: Second epoch of Magellan near-IR observations
  9. GRB 100628A: GROND optical/NIR observations of the host candidate
  10. GRB 100628A: Gemini North Observations
  11. GRB100625A: GROND confirmation of constant source
  12. GRB 090709A: Host galaxy detection
  13. GRB 100628A: Magellan near-IR observations
  14. GRB 100628A: Swift/UVOT Upper Limits
  15. GRB100628A: RTT150 optical observations
  16. GRB 100628A: Swift detection of a short hard burst
  17. GRB 100614A: CrAO optical limit
  18. GRB 100625A: Swift/UVOT Upper Limits
  19. GRB 100625A: Enhanced Swift-XRT position
  20. GRB 100625A: Swift detection of a short hard burst
  21. GRB 100418A: late time optical observations
  22. Konus-Wind observation of GRB 100621A
  23. GRB 100621A: IRSF/SIRIUS NIR Observation
  24. GRB 100621A: Swift/UVOT observations
  25. GRB 100621A: Swift-BAT refined analysis
  26. GRB 100621A: GROND observation of bright NIR afterglow
  27. GRB 100621A: Enhanced Swift-XRT position
  28. GRB 100621A: ROTSE-III Optical Limits
  29. GRB 100621A: Swift detection of a burst
  30. GRB 100606A: Optical Limits
  31. GRB 100619A: Swift/UVOT Upper Limits
  32. GRB 100619A: Enhanced Swift-XRT position
  33. GRB 100619A: Swift detection of a burst
  34. GRB 100614A: Gemini/NIRI Observations
  35. GRB 100615A: Gemini/NIRI Observations
  36. GRB 100615A: Swift/UVOT Upper Limits
  37. GRB 100614A: Swift/UVOT Upper Limits
  38. GRB 100614A: NOT optical upper limits
  39. GRB 100614A: Enhanced Swift-XRT position
  40. GRB 100615A: Enhanced Swift-XRT position
  41. GRB 100614A: Swift-XRT refined analysis
  42. GRB 100615A: PAIRITEL NIR Upper Limits
  43. GRB 100615A: NTT/Ultracam imaging
  44. GRB 100615A: Swift detection of a burst
  45. GRB 100614A: Swift detection of a burst
  46. GRB 100606A: Suzaku WAM observation of the prompt emission
  47. GRB 100606A: GROND observations
  48. Trigger 424161: Swift/BAT trigger on XTE J1946+274/GRO J1944+26
  49. Konus-Wind observation of GRB 100606A
  50. Radio detection of GRB100418a with ATCA
  51. GRB 100606A: Swift/UVOT Upper Limits
  52. GRB 100606A: Enhanced Swift-XRT position
  53. Swift Trigger 424040 is not a GRB
  54. GRB 100606A: Swift detection of a burst
  55. Swift detection of outburst from the SFXT IGR J18410-0535
  56. GRB 100111A: Maidanak optical observations
  57. GRB 100418A: Maidanak optical observations
  58. GRB 100513A: CrAO optical observations
  59. GRB 100514A: CrAO optical observations
  60. GRB 100526A: optical upper limit
  61. Konus-Wind observation of GRB 100528A
  62. GRB 100528A: Faulkes Telescope North Detection
  63. GRB 100528A: GROND detection in all bands
  64. GRB 100528A: NOT optical observation
  65. Swift UVOT and UVOT-enhanced XRT position for GRB 100528A
  66. GRB100526B: GROND Upper limits
  67. GRB 100528A: SuperAGILE Localization of a Long GRB
  68. GRB 100526B: Swift/UVOT Upper Limits
  69. GRB 100526A: Swift/UVOT Upper Limits
  70. GRB 100526A: Gemini/NIRI infrared afterglow candidate
  71. GRB 100526A: NOT optical upper limit
  72. GRB 100526B: Swift XRT/UVOT observations
  73. GRB 100526A: Enhanced Swift-XRT position
  74. GRB 100526A: MASTER-Net optical alert observations
  75. GRB 100526A: Swift detection of a burst
  76. GRB100522A: Suzaku WAM observation of the prompt emission
  77. GRB 100418A: Subaru late-time optical imaging and spectroscopy
  78. GRB 100522A: Fermi GBM observation
  79. GRB 100522A: Enhanced Swift-XRT position
  80. GRB 100522A: NIR observations from CAHA
  81. GRB 100522A: Swift detection of a burst
  82. GRB 100418A: CrAO optical observations
  83. GRB 100518A: GROND afterglow observation and photo-z
  84. GRB 100518A: Swift-XRT refined analysis
  85. GRB 100518A: BOOTES-3 optical observations
  86. Update to the configuration of the Fermi-LAT onboard GRB search
  87. GRB 100518A: Swift target of opportunity observation of the INTEGRAL burst
  88. GRB 100513A: MITSuME Akeno Optical Observation
  89. GRB 100518A: a long GRB detected with INTEGRAL
  90. Swift Trigger 422437 is probably not a GRB
  91. GRB 100517A: MASTER-Net wide field camera prompt optical observations
  92. GRB 100514A: optical afterglow confirmation
  93. GRB 100514A: Swift/UVOT Observations
  94. GRB 100514A: YNAO-GMG observations
  95. GRB 100514A: Enhanced Swift-XRT position
  96. GRB 100514A: Swift detection of a burst
  97. GRB 100513A: Swift/UVOT upper limits
  98. GRB 100513A, RIMOTS optical upper limits
  99. GRB 100513A: Enhanced Swift-XRT position
  100. GRB 100513A: SARA-N Upper Limit

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