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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. GRB 100518A: Swift-XRT refined analysis
  2. GRB 100518A: optical afterglow decay
  3. GRB 100518A: BOOTES-3 optical observations
  4. Update to the configuration of the Fermi-LAT onboard GRB search
  5. GRB 100518A: Faulkes Telescope North Afterglow Candidate
  6. GRB 100518A: Swift target of opportunity observation of the INTEGRAL burst
  7. GRB 100513A: MITSuME Akeno Optical Observation
  8. Swift-BAT trigger 422437 is not anything astrophysical
  9. GRB 100518A: a long GRB detected with INTEGRAL
  10. Swift Trigger 422437 is probably not a GRB
  11. Fermi/GBM trigger 295791986 - unreliable location
  12. GRB 100517A: MASTER-Net wide field camera prompt optical observations
  13. GRB 100513A: EVLA radio observation
  14. GRB 100514A: optical afterglow confirmation
  15. GRB 100514A: Swift/UVOT Observations
  16. GRB 100514A: YNAO-GMG observations
  17. GRB 100514A: Swift XRT refined analysis
  18. GRB 100514A: MASTER-Net optical observations
  19. GRB 100514A: Enhanced Swift-XRT position
  20. GRB 100514A: Swift-BAT refined analysis
  21. GRB 100514A: Faulkes Telescope South observations
  22. GRB 100514A: Swift detection of a burst
  23. GRB 100513A: Faulkes Telescope South observations
  24. GRB 100513A: Swift/UVOT upper limits
  25. GRB 100513A, RIMOTS optical upper limits
  26. GRB 100513A: Swift XRT refined analysis
  27. GRB 100513A: Swift-BAT refined analysis
  28. GRB 100513A: Gemini/GMOS Spectroscopic Redshift
  29. GRB 100513A: Enhanced Swift-XRT position
  30. GRB 100513A: Lick observations and R-band dropout
  31. GRB 100513A: PAIRITEL continued observations and confirmation of fading
  32. GRB 100513A: SARA-N Upper Limit
  33. GRB 100513A: PAIRITEL NIR afterglow candidate
  34. GRB 100513A: Swift detection of a burst
  35. GRB 100510A: Fermi GBM detection/observation
  36. GRB 100511A: Fermi GBM detection/observation
  37. GRB 100511A: Super-LOTIS early observations
  38. Swift-BAT trigger 421695 is likely not astrophysical
  39. GRB100504A: Optical upper limits at IAO
  40. GRB 100510A: MAXI/GSC detection
  41. GRB 100511A, RIMOTS optical upper limits
  42. Trigger 421695: Swift detection of a possible burst
  43. GRB100508A: Further Swift/UVOT Observations
  44. GRB100503A: Suzaku WAM observation of the prompt emission
  45. GRB 100508A: GROND Detection of the optical afterglow
  46. GRB 100508A: Swift-XRT Refined analysis
  47. GRB 100508A: Swift-BAT refined analysis
  48. GRB 100508A: Enhanced Swift-XRT position
  49. GRB100508A: Swift/UVOT Detection of the Afterglow
  50. GRB 100508A: ROTSE-III Optical Limits
  51. GRB 100508A: Swift detection of a burst
  52. GRB 100418A: Keck imaging
  53. GRB 100418A: RTT150 optical observations
  54. Fermi Gamma-ray Burst Monitor trigger 294712621 is not a GRB
  55. Swift-BAT refined analysis of trigger 421262
  56. GRB 100504A: Fermi GBM observation
  57. An SGR-like burst from the magnetar 1E 1841-04.5 in Kes 73
  58. GRB 100504A: Swift/UVOT Observations
  59. GRB 100418A: Flattening of the Swift/UVOT Optical Light Curve
  60. GRB 100504A: Swift-XRT refined analysis
  61. GRB 100504A: Enhanced Swift-XRT position
  62. GRB 100504A: GROND Upper limits
  63. GRB 100504A: Swift-BAT refined analysis
  64. GRB 100504A: SARA-South Upper Limit
  65. GRB 100503A: Fermi GBM detection
  66. GRB 100504A: UVOT-enhanced XRT position
  67. GRB 100504A: Swift detection of a burst
  68. Swift-BAT trigger 421072 is not astrophyical
  69. INTEGRAL observations of Swift GRB trigger 421072
  70. GRB100423A : Suzaku WAM observation of the prompt emission
  71. Trigger 421072: Possible Swift detection of a GRB or transient
  72. GRB 100420A: EVLA radio observations
  73. GRB 100420A: Gemini discovery of infrared afterglow
  74. GRB 100423A: xinglong TNT optical upper limit
  75. GRB 100420A: Terskol optical upper limit
  76. GRB 100427A: Swift XRT and UVOT Upper Limits
  77. GRB 100427A: Fermi GBM detection
  78. GRB 100424a. Radio observations
  79. GRB 100418A: RTT150 optical observations
  80. GRB 100427A detected in ground analysis of Swift BAT data
  81. GRB 100414A : EVLA Radio Detection
  82. GRB 100414A : WSRT Radio Detection
  83. Konus-Wind observation of GRB 100423A
  84. GRB 100423A: CrAO optical observations
  85. GRB 100418A: Terskol optical observations
  86. GRB 100424A: CrAO optical observations
  87. GRB 100424A: NIR Afterglow Confirmation
  88. GRB 100425A: Swift XRT refined analysis
  89. GRB 100424A: Gemini/NIRI H-band observations
  90. GRB100425A: Swift/UVOT Upper Limits
  91. GRB 100424A: Swift/UVOT Upper Limits
  92. GRB 100424A: Liverpool Telescope Upper Limits
  93. GRB 100425A: Enhanced Swift-XRT position
  94. GRB 100425A: Swift-BAT refined analysis
  95. GRB 100425A: VLT/X-shooter redshift
  96. GRB 100425A: GROND afterglow observation
  97. GRB 100424A: Gemini/NIRI Candidate Afterglow
  98. GRB 100424A: D50 optical limits
  99. GRB 100425A: candidate optical afterglow from the VLT
  100. GRB100424A: MITSuME optical upper limits

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