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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"

27557 results found.

  1. GRB 090323: RTT150 optical observations
  2. GRB 090323: Lick observations
  3. GRB 090323: Optical observation of xinglong TNT
  4. GRB 090323 TLS detection - still bright
  5. GRB 090323: UVOT Detection of Afterglow
  6. GRB 090323: Swift-XRT refined analysis
  7. GRB 090323 Gemini-South Redshift
  8. GRB 090323: P60 Afterglow Confirmation
  9. GRB 090323: GROND Detection of the Afterglow and Photo-z
  10. GRB 090323: Possible XRT Counterpart
  11. GRB 090320C: Fermi GBM Detection
  12. GRB 090320B: Fermi GBM detection.
  13. GRB 090319: Fermi GBM detection
  14. GRB 090320A: Fermi GBM detection
  15. GRB 090313: WSRT Radio Detection
  16. X-shooter observations of GRB 090313
  17. GRB 090313: VLT spectroscopy
  18. GRB090313: radio detection with the VLA
  19. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  20. GRB 090313, SMARTS optical/IR observations
  21. Further Swift/UVOT observations of GRB 090313
  22. GRB 090313: detection with CARMA in 3mm band
  23. Radio detection of GRB090313
  24. GRB 090313: MITSuME Okayama observation
  25. GRB 090313: Additional Gemini-S photometry
  26. GRB 090313: WSRT Radio Observations
  27. GRB 090313: Light curve steepening
  28. GRB 090313: TAROT La Silla observatory optical detection
  29. GRB 090313: Gemini-S photometry
  30. GRB 090313: Zadko Telescope observations
  31. GRB 090313 - PAIRITEL NIR detections
  32. GRB 090313: Gemini-S redshift
  33. GRB 090313 optical observations
  34. GRB 090313: Ongoing plateau phase
  35. GRB 090313: Swift-XRT refined analysis
  36. GRB 090313: Swift/UVOT upper limits
  37. GRB 090313: Faulkes Telescope North observations
  38. GRB 090306B: Confirmation of the X-ray afterglow
  39. GRB 090313: Sustained optical brightness
  40. GRB 090313: SDSS object underlying the optical afterglow position
  41. GRB 090313, GROND observations
  42. GRB 090313: Swift detection of a burst
  43. GRB 090313: Swift detection of a burst
  44. GRB090310: Fermi GBM detection
  45. GRB 090205: Zadko Telescope late-time observations
  46. GRB 090309A: GROND upper limits
  47. GRB 090307A: TAROT Calern observatory optical observations
  48. GRB 090309: Swift/UVOT Upper Limits
  49. GRB090305B: Fermi GBM detection
  50. GRB 090309B: Fermi GBM detection
  51. GRB 090309: Swift-XRT refined analysis
  52. GRB 090309: Enhanced Swift-XRT position
  53. GRB 090308: GROND observations
  54. GRB 090308: Gemini GMOS Observations
  55. GRB 090309: Swift detection of a burst
  56. GRB 090308B: Fermi GBM detection
  57. GRB 090308: Swift/UVOT Upper Limits
  58. GRB 090307B: Fermi GBM detection
  59. GRB 090306C: Fermi GBM detection
  60. GRB 090307: GROND Upper Limits
  61. GRB 090306B: GROND Upper Limits
  62. GRB 090308: Swift-XRT refined analysis
  63. Radio observation of GRB 090201 with ATCA
  64. Radio observation of GRB 081226a with ATCA
  65. Radio observation of GRB 081007 with ATCA
  66. GRB 090308: Swift detection of a burst
  67. GRB 090306B: Possible XRT afterglow
  68. GRB 090307: Swift-XRT afterglow confirmation and analysis
  69. GRB 090307: Swift-BAT refined analysis of trigger 345551
  70. GRB 090306B: Burst detection from Swift-BAT slew data
  71. Swift Trigger 345551 is probably not a GRB
  72. GRB 090306: Swift detection of a possible burst
  73. GRB 090305: Swift/UVOT Upper Limits
  74. GRB 090305: Swift-XRT refined analysis
  75. GRB 090305, Swift-BAT refined analysis
  76. GRB 090305: Magellan confirmation of the optical afterglow
  77. GRB090305: GMOS-S Candidate Optical Afterglow
  78. GRB 090305: Swift detection of a short burst
  79. GRB 090303: Fermi GBM detection
  80. GRB 090304: Fermi GBM detection
  81. GRB 090228B: Fermi GBM detection
  82. GRB 090301B: Fermi GBM detection
  83. GRB 090227B: Fermi GBM detection
  84. GRB 090301: Swift detection of a burst
  85. GRB 090228: Fermi GBM detection
  86. GRB 090227: Fermi GBM detection
  87. GRB 090206: Fermi GBM detection
  88. GRB 081211B: Nearby cluster
  89. GRB 090222: Fermi GBM detection
  90. GRB 090219: Fermi GBM detection
  91. GRB 090217: Suzaku WAM observation of the prompt emission
  92. GRB090217: XRT analysis
  93. GRB 090213: Fermi GBM detection
  94. GRB090217: Fermi-LAT Detection
  95. GRB 090217: Fermi GBM detection
  96. SGR activity seen by BAT during ICSP Ionospheric Events
  97. GRB 090129: Fermi GBM detection
  98. VLA radio upper limit on GRB 090205
  99. GRB 090205: VLT optical decay
  100. GRB 090205: Swift/UVOT Upper Limits

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