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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. GRB090310: Fermi GBM detection
  2. GRB 090205: Zadko Telescope late-time observations
  3. GRB 090309A: GROND upper limits
  4. GRB 090307A: TAROT Calern observatory optical observations
  5. GRB 090309: Swift/UVOT Upper Limits
  6. GRB090305B: Fermi GBM detection
  7. GRB 090309B: Fermi GBM detection
  8. GRB 090309: Swift-XRT refined analysis
  9. GRB 090309: Enhanced Swift-XRT position
  10. GRB 090306B: INTEGRAL SPI-ACS light curve
  11. GRB 090309, Swift-BAT refined analysis
  12. GRB 090308: GROND observations
  13. GRB 090308: Gemini GMOS Observations
  14. GRB 090309: Swift detection of a burst
  15. GRB 090308B: Fermi GBM detection
  16. GRB 090308: Swift/UVOT Upper Limits
  17. GRB 090307B: Fermi GBM detection
  18. GRB 090306C: Fermi GBM detection
  19. GRB 090307: GROND Upper Limits
  20. GRB 090306B: GROND Upper Limits
  21. GRB 090305C: Suzaku WAM observation of the prompt emission
  22. GRB 090308: Swift-XRT refined analysis
  23. Radio observation of GRB 090201 with ATCA
  24. Radio observation of GRB 090117 with ATCA
  25. Radio observation of GRB 081226b with ATCA
  26. Radio observation of GRB 081226a with ATCA
  27. Radio observation of GRB 081007 with ATCA
  28. ATCA observation of SGR J1550-5418
  29. GRB 090308: Swift-BAT refined analysis
  30. GRB 090308: Swift detection of a burst
  31. GRB 090306B: Possible XRT afterglow
  32. GRB 090307: Swift-XRT afterglow confirmation and analysis
  33. GRB 090307: Swift-BAT refined analysis of trigger 345551
  34. GRB 090306B: Burst detection from Swift-BAT slew data
  35. Swift Trigger 345551 is probably not a GRB
  36. Swift-BAT trigger 345396 is not a GRB
  37. IPN localization of short GRB 090305C
  38. Fermi GBM trigger 090305784 is not a GRB
  39. GRB 090306: Swift detection of a possible burst
  40. GRB 090305: Swift/UVOT Upper Limits
  41. GRB 090305: Swift-XRT refined analysis
  42. GRB 090305, Swift-BAT refined analysis
  43. GRB 090227A: Suzaku WAM observation of the prompt emission
  44. GRB 090305: Magellan confirmation of the optical afterglow
  45. GRB090305: GMOS-S Candidate Optical Afterglow
  46. GRB 090305: Swift detection of a short burst
  47. GRB 090303: Fermi GBM detection
  48. GRB 090304: Fermi GBM detection
  49. GRB 090301A: Suzaku WAM observation of the prompt emission
  50. Konus-RF catches first GRB and SGR bursts
  51. GRB 090228B: Fermi GBM detection
  52. Konus-Wind observation of bright short GRB 090227B
  53. IPN localization of short bright GRB 090227B
  54. Konus-Wind observation of GRB 090301A
  55. GRB 090301A: Swift-BAT refined analysis
  56. GRB 090301B: Fermi GBM detection
  57. GRB 090227B: Fermi GBM detection
  58. GRB 090301: Swift detection of a burst
  59. Swift_BAT_Lightcurve Notice for Trigger Number 344565 is not valid
  60. GRB 090228: Fermi GBM detection
  61. GRB 090227: Fermi GBM detection
  62. GRB 090206: Fermi GBM detection
  63. SGR J1550-5418
  64. GRB 081211B: Nearby cluster
  65. Ongoing activity of AXP/SGR 1E1547.0-5408
  66. GRB 090222: Fermi GBM detection
  67. GRB 090219: Fermi GBM detection
  68. Swift Restored
  69. Swift Trigger 343319 is not a GRB
  70. GRB 090217: Suzaku WAM observation of the prompt emission
  71. GRB090217: XRT analysis
  72. Konus-Wind observation of GRB 090217
  73. IPN localization of GRB 090217
  74. GRB 090213: Fermi GBM detection
  75. GRB090217: Fermi-LAT Detection
  76. GRB 090217: Fermi GBM detection
  77. SGR activity seen by BAT during ICSP Ionospheric Events
  78. Detailed lightcurves of ICSP VLF Observation of SGR/AXP 1E1547.0-5408
  79. GRB 090207 - Fermi GBM Observations
  80. Fermi Gamma-ray Burst Monitor trigger 255729682 is not a GRB
  81. GRB 090129: Fermi GBM detection
  82. VLA radio upper limit on GRB 090205
  83. GRB 090205: VLT optical decay
  84. Fermi Gamma-ray Burst Monitor trigger 255541748 cannot be classified
  85. GRB 090205: Swift/UVOT Upper Limits
  86. GRB 090205: VLT refined redshift
  87. GRB 090205: Swift-XRT refined analysis
  88. GRB 090205: Swift burst of interest
  89. GRB 090205: VLT spectroscopic redshift
  90. GRB 090205: GROND observations and photometric redshift estimate
  91. GRB 090205: VLT candidate afterglow
  92. GRB 090205: Swift-BAT refined analysis
  93. GRB 090205: Enhanced Swift-XRT position
  94. GRB 090205: Swift detection of a burst
  95. GRB 080319B: IceCube upper limit on high-energy neutrino flux
  96. GRB 090131: Suzaku WAM observation of the prompt emission
  97. ICSP VLF observation of the signatures of SGR/AXP 1E1547.0-5408 bursts
  98. GRB 090126A: Swift-XRT afterglow confirmation
  99. Fermi Gamma-ray Burst Monitor trigger 255342766 is not a GRB
  100. Konus-Wind observation of GRB 090201

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