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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 130427A, LBT optical spectrum
  2. GRB 130505B: Further Swift observations
  3. GRB 130504C: Swift-XRT afterglow confirmation
  4. GRB 130505A: MITSuME Akeno Optical observation
  5. GRB 130504C: Suzaku WAM observation of the prompt emission
  6. GRB 130504B: Suzaku WAM observation of the prompt emission
  7. GRB 130505A: Suzaku WAM observation of the prompt emission
  8. GRB 130427A, Watcher afterglow detection
  9. GRB 130427A: Excess optical emission consistent with an emerging supernova
  10. GRB 130427A: Amateur observations from Sweden
  11. GRB 130505A: RATIR Optical and NIR Observations
  12. GRB 130505B: Swift Candidate Afterglow
  13. GRB 130505A: Tautenburg afterglow observations
  14. GRB 130427A: Tautenburg afterglow observations
  15. Refined IPN Triangulation of GRB 130502B
  16. GRB 130427A: RHESSI observations
  17. GRB 130505A, Swift-BAT refined analysis
  18. GRB 130504C: further Swift-XRT observations
  19. Konus-Wind observation of GRB 130504C
  20. GRB 130505B: MAXI/GSC detection
  21. GRB 130505A: optical observations
  22. GRB 130504C: Swift-XRT observations
  23. GRB 130504C: Fermi GBM detection
  24. GRB 130427A: optical observations in CrAO
  25. GRB 130502A: optical upper limit
  26. GRB 130505A: E_iso record retraction
  27. GRB 130427A: correction to GCN 14487
  28. GRB 130505A: correction to GCN 14575
  29. GRB 130505A: Swift-XRT refined Analysis
  30. GRB 130505A: Largest E_iso ever measured
  31. Konus-Wind observation of GRB 130505A
  32. GRB 130504C: Fermi-LAT detection of a burst
  33. Swift/UVOT observations of GRB130505A
  34. GRB 130505A: iTelescope T12 optical observations
  35. GRB 130505A: Xinglong TNT optical observations
  36. GRB 130505A; Weihai optical observations
  37. GRB 130505A: Enhanced Swift-XRT position
  38. GRB 130505A: MITSuME Okayama Optical Observation
  39. GRB 130505A - Gemini-N/GMOS redshift determination
  40. GRB 130505A: MAXI/GSC detection
  41. Konus-Wind observation of GRB 130504B
  42. GRB 130504A: IAC80 optical candidate
  43. GRB 130505A: Swift detection of a burst with optical afterglow
  44. GRB 130504A: MITSuME Okayama upper limits
  45. IPN Triangulation of GRB 130504B
  46. GRB 130504B: Fermi GBM detection
  47. GRB 130504A: Bassano Bresciano Observatory optical upper limit
  48. GRB 130504A: Enhanced XRT position
  49. GRB 130502B: Suzaku WAM observation of the prompt emission
  50. GRB 130504A: Swift/UVOT Upper Limits
  51. GRB 130502B: Swift-XRT refined Analysis
  52. GRB 130504A, Swift-BAT refined analysis
  53. Swift-XRT X-ray afterglow candidate for GRB 130504A (BAT trigger 555096)
  54. GRB 130502B: possible TNG counterpart
  55. Trigger 555096: Swift detection of a possible burst
  56. GRB 130502A: Swift-BAT refined analysis
  57. GRB 130427A: Non-observation of VHE emission with HAWC
  58. GRB130502A: MASTER-Net optical observations
  59. GRB 130502A: Swift-XRT refined Analysis
  60. IPN Triangulation of GRB 130502B
  61. GRB 130502A: Fermi GBM detection
  62. GRB 130502B: Swift/UVOT Upper Limits
  63. GRB 130502A: Swift/UVOT Upper Limits
  64. Konus-Wind observation of GRB 130502B
  65. GRB 130502B: P60 Observations
  66. GRB 130502B Swift-XRT observations
  67. GRB 130502A: RATIR Optical and NIR Observations
  68. GRB 130427A: Pan-STARRS 1 optical observations
  69. GRB 130418A: TNG NIR observations
  70. GRB 130502A: Enhanced Swift-XRT position
  71. GRB 130502A: OSN and IAC80 I-band observations
  72. GRB 130427A: MITSuME Ishigakijima Optical Observation after 5 days
  73. GRB 130502A: z-band observations from GTC
  74. GRB 130502B: Fermi LAT Detection
  75. GRB 130502A: TNG candidate counterpart
  76. GRB 130502B: Fermi GBM detection of a burst
  77. GRB 130502A: T100 Observations
  78. GRB 130502A: Swift detection of a burst
  79. GRB 130427A: Predictions about the occurrence of a supernova
  80. GRB 130427A: KAIT optical observations
  81. GRB 130425A: Suzaku WAM observation of the prompt emission
  82. GRB 130427A: SARA-N optical observations
  83. GRB 130427A: VLA 20 GHz detection
  84. GRB 130427A: ABT optical observations
  85. GRB 130427A: High-energy neutrino search
  86. GRB 130427A: GMRT radio detection
  87. GRB 130427A: Continued GMG optical observations
  88. GRB 130427A: Nishi-Harima Optical Spectroscopic Observations
  89. GRB 130427A: photo-z of possible SDSS host galaxy
  90. GRB 130427A: high energy gamma-ray detection by AGILE
  91. GRB 130427A: Continued RATIR Optical and NIR Observations
  92. GRB 130427A: MITSuME Ishigakijima Optical Observation after 2 days
  93. Swift-BAT trigger 554135 is noise
  94. GRB 130427A: Challis Observatory optical observations
  95. GRB 130427A: Continued Skynet/PROMPT Observations
  96. GRB 130427A: further GMG observations
  97. GRB 130427A: Fermi-LAT refined analysis
  98. GRB 130427A: SARA-N detection
  99. GRB 130427A: Continued RATIR Optical and NIR Observations
  100. GRB 130427A: CrAO RT-22 36 GHz observation

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