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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"

2626 results found.

  1. GRB 090726: Swift-XRT position of probable counterpart
  2. GRB 090720: Gemini-North Imaging and Optical Afterglow
  3. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  4. GRB 090621B: MTM-500 optical observations
  5. Possible GRB090705: Swift-XRT observations
  6. GRB 090705: PAIRITEL NIR Observations
  7. GRB 090705: Swift detection of a possible burst
  8. GRB 090404: Deep optical imaging and possible host association (correction)
  9. GRB 090404: Deep optical imaging and possible host association
  10. GRB 090628: Swift detection of a burst
  11. GRB 090621A: Swift-BAT refined analysis
  12. Ignore GCN/Swift-BAT Lightcurve Notices for trigger 353567
  13. GRB 090531: Swift-BAT refined analysis
  14. GRB 090529: Swift-BAT refined analysis
  15. GRB 090516B: Fermi GBM detection
  16. GRB090510: VLT/FORS2 spectroscopic redshift
  17. GRB 090510: Swift/UVOT host galaxy candidates
  18. GRB 090418A: optical observation
  19. GRB 090424: optical observations
  20. GRB090429B: Gemini-N infrared IR candidate
  21. GRB 090423: pseudo burst at z=1 and its relation to GRB 080913
  22. GRB 090423: Swift/BAT spectral lag results
  23. GRB 090422: Liverpool Telescope possible candidate
  24. VLA observations of short burst GRB 090417A
  25. GRB 090417B: optical observations
  26. GRB 090412: Fermi GBM detection
  27. Swift-BAT trigger 348781: almost certainly not a burst
  28. Fermi GBM Detection of a weak source
  29. GRB 090404: Swift detection of a burst
  30. GRB 090401B: Swift detection of a burst
  31. GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
  32. GRB 090401: Swift detection of a burst
  33. GRB090323: Optical observations from NOT
  34. GRB 090328: Possible Swift/XRT detection
  35. GRB 090323: TLS detection at 5 days, no break
  36. GRB 090320B: MASTER-Net prompt optical observations
  37. GRB 090323 TLS detection - still bright
  38. GRB 090323: Possible XRT Counterpart
  39. GRB 090313: VLT spectroscopy
  40. GRB090305B: MASTER-net prompt optical short burst observations
  41. GRB 090306B: Possible XRT afterglow
  42. GRB 090306: Swift detection of a possible burst
  43. GRB 090303: Fermi GBM detection
  44. GRB 081211B: Nearby cluster
  45. GRB 090201: Swift-XRT detection of the possible X-ray afterglow
  46. AXP 1E1547.0-5408: Fermi GBM observations
  47. Trigger 340734: Swift detection of a possible short burst
  48. GRB 090118 (BATSS): GRT Optical Observation
  49. GRB 090118: GROND Upper Limits
  50. GRB 090118: Possible burst detection from Swift-BAT slew data
  51. GRB090117: Swift-XRT detection of a possible candidate afterglow
  52. GRB090113: XRT position
  53. GRB 090112: Fermi GBM detection
  54. GRB 090107B: Swift-XRT detection of possible afterglow
  55. GRB 090107: Swift detection of a burst
  56. GRB 081228, Swift-BAT refined analysis
  57. GRB 081228: Swift-XRT Team refined analysis
  58. GRB 081226: Swift-XRT refined analysis
  59. GRB 081226A: Swift UVOT Upper Limits
  60. GRB 081226: Gemini-South spectrum of possible afterglow
  61. GRB 081226: Swift detection of a possible short-hard burst
  62. GRB 081211B: Further Swift-XRT analysis
  63. Possible GRB 081211B: Swift/UVOT Upper Limits
  64. Possible GRB 081211B - Swift-XRT analysis
  65. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  66. GRB 081211: Swift-BAT refined analysis
  67. GRB 081210: Swift-BAT refined analysis
  68. GRB 081128: optical observation in CrAO
  69. GRB 081204: Swift XRT afterglow candidate
  70. GRB 081203B: Swift-XRT candidate afterglow.
  71. GRB 081130B: MASTER prompt optical observations
  72. GRB 081128: optical observation
  73. GRB 081130B: Fermi GBM detection
  74. GRB 081128A: optical observations
  75. Trigger 335971: Swift possible detection of a burst
  76. GRB081128 : Lulin optical follow-ups
  77. GRB 081128: Swift detection of a burst
  78. GRB 081126: Confirmation of the Optical Afterglow
  79. Fermi GBM detection of a weak source
  80. GRB 081118: optical afterglow candidate
  81. GRB 081109A: confirmation of possible detection host galaxy
  82. GRB 081024B: Swift-XRT late-time observations
  83. Swift-BAT refined analysis of trigger 334129
  84. GRB 081109A: Possible Swift-UVOT detection
  85. GRB 081109A: Faulkes Telescope South observations
  86. GRB 081109A: Swift-XRT refined analysis
  87. Swift-BAT Trigger 334129: possible burst
  88. GRB 081101 (or SGR 0623-0006 ): Fermi GBM detection
  89. GRB 081024B: new Swift-XRT observations
  90. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow (Corrected)
  91. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow
  92. GRB 081025: TLS upper limits
  93. GRB 081024B: Swift-XRT further observations
  94. GRB 081025: Swift-XRT position
  95. GRB 081024B: Swift-XRT observations
  96. GRB 081024: Swift-XRT refined analysis
  97. Swift detection of a possible burst (trigger 332287)
  98. GRB 081011: Swift XRT refined analysis
  99. GRB 081016: Swift-XRT candidate afterglow detection
  100. GRB 081007 and GRB 081007B: Fermi GBM detection

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