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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"

20355 results found.

  1. GRB 100728B: GROND Detection of the NIR Afterglow
  2. GRB 100728B: optical detection
  3. GRB 100728B: Swift detection of a burst with an optical counterpart
  4. GRB 100728A: Enhanced Swift-XRT position
  5. GRB 100728A: Swift detection of a burst
  6. GRB 100727A: Enhanced Swift-XRT position
  7. GRB 100727A: Swift detection of a burst
  8. GRB100725B: MITSuME optical upper limits
  9. GRB 100724B: Suzaku WAM observation of the prompt emission
  10. GRB 100724B: gamma-ray detection by AGILE
  11. GRB 100725A: GROND upper limits
  12. GRB 100725B: Swift/UVOT Upper Limits
  13. GRB 100725A: Swift/UVOT Upper Limits
  14. GRB 100725A: Swift XRT refined analysis
  15. GRB 100725B: Enhanced Swift-XRT position
  16. GRB 100725A: Enhanced Swift-XRT position
  17. GRB 100725B: Swift detection of a burst
  18. Konus-Wind observation of GRB 100724B
  19. GRB 100725A: Swift detection of a burst
  20. GRB 100724A: Enhanced Swift-XRT position
  21. GRB 100724A: Swift/UVOT observations
  22. GRB 100724A: Swift detection of a burst
  23. GRB 100614A: 10.4-m GTC deep-optical limit
  24. GRB 100718A: MASTER-Net optical prompt and alert observations
  25. GRB 100713A: optical observation in Maidanak
  26. GRB 100713A: Swift XRT refined analysis
  27. GRB 100713A: GROND upper limits
  28. GRB 100713A: TNG optical observations
  29. GRB100713A: Swift X-ray afterglow detection
  30. GRB 100628A: Chandra observations
  31. GRB 100704: Swift/UVOT Upper Limits
  32. GRB100704A: MOA optical upper limit
  33. GRB 100704A: Enhanced Swift-XRT position
  34. GRB 100704A: Swift detection of a burst
  35. GRB 100615A: Additional Gemini/NIRI observations
  36. GRB 100526A: Gemini/NIRI afterglow confirmation and host galaxy
  37. Swift/UVOT observations of GRB100702A
  38. GRB 100702A: Second epoch of Magellan near-IR observations and afterglow limits
  39. GRB 100702A: Magellan near-IR observations
  40. GRB 100702A: VLT optical observations
  41. GRB 100702: ROTSE-III Optical Limits
  42. GRB 100702A: Swift detection of a short burst
  43. GRB 100615A: Chandra X-ray ToO Observation
  44. XRF 100701A : MAXI/GSC detection of a probable XRF
  45. GRB 100213B: Detection of Fading Optical Afterglow
  46. GRB 100628A: GROND optical/NIR observations of the host candidate
  47. GRB 100628A: Gemini North Observations
  48. GRB100625A: GROND confirmation of constant source
  49. GRB 090709A: Host galaxy detection
  50. GRB 100628A: Swift/UVOT Upper Limits
  51. GRB100628A: RTT150 optical observations
  52. GRB 100628A: Swift detection of a short hard burst
  53. GRB 100614A: CrAO optical limit
  54. GRB 100625A: Swift/UVOT Upper Limits
  55. GRB 100625A: Swift-XRT Team refined analysis
  56. GRB 100625A: Gemini candidate afterglow
  57. GRB 100625A: Enhanced Swift-XRT position
  58. GRB 100625A: Swift detection of a short hard burst
  59. GRB 100418A: late time optical observations
  60. GRB 100621A: IRSF/SIRIUS NIR Observation
  61. GRB 100621A: Swift/UVOT observations
  62. GRB 100621A: GROND observation of bright NIR afterglow
  63. GRB 100621A: Enhanced Swift-XRT position
  64. GRB 100621A: ROTSE-III Optical Limits
  65. GRB 100621A: Swift detection of a burst
  66. GRB 100606A: Optical Limits
  67. GRB 100619A: Swift/UVOT Upper Limits
  68. GRB 100619A: Enhanced Swift-XRT position
  69. GRB 100619A: Swift detection of a burst
  70. GRB 100614A: Gemini/NIRI Observations
  71. GRB 100615A: Gemini/NIRI Observations
  72. XRF 100616a : MAXI/GSC detection of a probable XRF
  73. GRB 100615A: Swift/UVOT Upper Limits
  74. GRB 100614A: Swift/UVOT Upper Limits
  75. GRB 100614A: NOT optical upper limits
  76. GRB 100614A: Enhanced Swift-XRT position
  77. GRB 100615A: Enhanced Swift-XRT position
  78. GRB 100615A: PAIRITEL NIR Upper Limits
  79. GRB 100615A: NTT/Ultracam imaging
  80. GRB 100615A: Swift detection of a burst
  81. GRB 100614A: Swift detection of a burst
  82. GRB 100606A: GROND observations
  83. Trigger 424161: Swift/BAT trigger on XTE J1946+274/GRO J1944+26
  84. Radio detection of GRB100418a with ATCA
  85. GRB 100606A: Swift/UVOT Upper Limits
  86. GRB 100606A Swift-XRT refined analysis
  87. GRB 100606A: Enhanced Swift-XRT position
  88. Swift Trigger 424040 is not a GRB
  89. GRB 100606A: Swift detection of a burst
  90. Swift detection of outburst from the SFXT IGR J18410-0535
  91. GRB 100111A: Maidanak optical observations
  92. GRB 100418A: Maidanak optical observations
  93. GRB 100513A: CrAO optical observations
  94. GRB 100514A: CrAO optical observations
  95. GRB 100526A: optical upper limit
  96. GRB 100528A: Faulkes Telescope North Detection
  97. GRB 100528A: GROND detection in all bands
  98. GRB 100528A: NOT optical observation
  99. Swift UVOT and UVOT-enhanced XRT position for GRB 100528A
  100. GRB100526B: GROND Upper limits

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