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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. XRF 100701A : MAXI/GSC detection of a probable XRF
  2. GRB 100213B: Detection of Fading Optical Afterglow
  3. GRB 100625A: Fermi GBM detection
  4. GRB 100628A: Second epoch of Magellan near-IR observations
  5. GRB 100628A: GROND optical/NIR observations of the host candidate
  6. GRB 100628A: Gemini North Observations
  7. GRB 100628A: Coincidence of source "G1" with revised XRT error circle
  8. GRB 100628A: Swift XRT refined position
  9. GRB100625A: GROND confirmation of constant source
  10. GRB 100625A Gemini-South 2nd epoch imaging
  11. GRB100628A : MOA optical upper limit
  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 XRT detection of a possible X-ray afterglow
  17. GRB 100628A: INTEGRAL SPI-ACS light curve
  18. GRB 100625A: Magellan near-IR Observations
  19. GRB 100628A: Swift-BAT refined analysis
  20. GRB 100628A: Swift detection of a short hard burst
  21. Swift-BAT trigger 426048 is not a burst
  22. GRB 100614A: CrAO optical limit
  23. GRB 100625A: Swift/UVOT Upper Limits
  24. GRB 100625A: Swift-BAT refined analysis
  25. Konus-Wind observation of GRB 100625A
  26. GRB 100625A : IRSF/SIRIUS NIR upper limit
  27. GRB 100625A: Swift-XRT Team refined analysis
  28. GRB 100625A: Gemini candidate afterglow
  29. GRB 100625A: Enhanced Swift-XRT position
  30. GRB100625A : MOA optical upper limit
  31. GRB 100625A: Swift detection of a short hard burst
  32. GRB 100418A: late time optical observations
  33. Konus-Wind observation of GRB 100621A
  34. GRB 100621A: IRSF/SIRIUS NIR Observation
  35. GRB 100621A MOA-II optical limit
  36. GRB 100619A: Correction to the Fermi GBM trigger time
  37. GRB 100621A: Swift/UVOT observations
  38. GRB 100621A: Swift XRT refined analysis
  39. GRB 100621A: VLT/X-shooter redshift
  40. GRB 100621A: Swift-BAT refined analysis
  41. GRB 100621A: GROND observation of bright NIR afterglow
  42. GRB 100621A: Enhanced Swift-XRT position
  43. GRB 100621A: Prompt enhanced Swift-XRT position
  44. GRB 100621A: ROTSE-III Optical Limits
  45. GRB 100621A: Swift detection of a burst
  46. GRB 100606A: Optical Limits
  47. GRB 100619A: Fermi GBM detection
  48. GRB 100619A: Swift/UVOT Upper Limits
  49. GRB 100619A: Swift-XRT refind analysis
  50. GRB 100619A: Enhanced Swift-XRT position
  51. GRB 100619A: Swift-BAT refined analysis
  52. GRB 100619A: Swift detection of a burst
  53. GRB 100614A: Gemini/NIRI Observations
  54. GRB 100615A: Gemini/NIRI Observations
  55. XRF 100616a : MAXI/GSC detection of a probable XRF
  56. Fermi GBM trigger 100612038 is not a GRB
  57. GRB 100615A: Swift/UVOT Upper Limits
  58. GRB 100614A: Swift/UVOT Upper Limits
  59. GRB 100614A: NOT optical upper limits
  60. GRB 100614A: MASTER-Net optical alert observations
  61. GRB 100614A: Swift-BAT refined analysis
  62. GRB 100615A: Fermi GBM detection
  63. GRB 100615A: Swift-BAT refined analysis
  64. GRB 100614A: Enhanced Swift-XRT position
  65. GRB 100615A: Enhanced Swift-XRT position
  66. GRB 100615A: Swift-XRT refined analysis
  67. GRB 100614A: Swift-XRT refined analysis
  68. GRB 100614 : XMM-Newton observation
  69. GRB 100615A: GROND observations, upper limits
  70. GRB 100615A: PAIRITEL NIR Upper Limits
  71. GRB 100615A: NTT/Ultracam imaging
  72. GRB 100615A: Swift detection of a burst
  73. GRB 100614A: WHT I-band observations
  74. GRB 100614A: BOOTES-2/TELMA optical observations
  75. GRB 100614A: Liverpool Telescope Observations
  76. GRB 100614A: Swift detection of a burst
  77. GRB 100606A: Suzaku WAM observation of the prompt emission
  78. GRB 100606A: GROND observations
  79. Trigger 424161: Swift/BAT trigger on XTE J1946+274/GRO J1944+26
  80. Konus-Wind observation of GRB 100606A
  81. Radio detection of GRB100418a with ATCA
  82. GRB 100606A: Gemini-South imaging
  83. GRB 100606A: Swift/UVOT Upper Limits
  84. GRB 100606A Swift-XRT refined analysis
  85. GRB 100606A: Swift-BAT refined analysis
  86. GRB 100606A: Enhanced Swift-XRT position
  87. Swift Trigger 424040 is not a GRB
  88. GRB 100606A: Prompt enhanced Swift-XRT position
  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. Konus-Wind observation of GRB 100528A
  97. GRB 100528A: Faulkes Telescope North Detection
  98. GRB 100528A: GROND detection in all bands
  99. GRB 100528A: NOT optical observation
  100. Swift UVOT and UVOT-enhanced XRT position for GRB 100528A

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