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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 090515: Swift-XRT refined analysis
  2. GRB 090515: Enhanced Swift-XRT position
  3. GRB 090509: Fermi GBM observation
  4. GRB 090515: Swift-BAT refined spectral analysis
  5. GRB 090515: Swift-BAT refined analysis
  6. GRB 090509 - Zadko Telescope observations
  7. GRB 090515: Gemini-N upper limit
  8. GRB 090515: WIYN NIR Upper Limit
  9. GRB 090515: Super-LOTIS Upper Limits
  10. GRB 090515: PAIRITEL Upper Limits
  11. GRB 090515: KAIT optical upper limits
  12. GRB 090515: ROTSE-III Optical Limits
  13. GRB 090515: Swift detection of a short burst
  14. GRB 090510: Suzaku WAM observation of the prompt emission
  15. GRB 090510, Radio limits
  16. GRB090510: VLT/FORS2 spectroscopic redshift
  17. GRB 090510: GROND observations
  18. GRB 090510: Swift/UVOT host galaxy candidates
  19. GRB 090510: Fermi-LAT follow-up analysis
  20. GRB 090509, further Swift-BAT refined analysis
  21. Fermi Gamma-ray Burst Monitor trigger 263649437 is not a GRB
  22. GRB 090510B: Fermi GBM detection
  23. GRB 090502: Fermi GBM detection
  24. GRB 090510: correction to GCN 9344
  25. Konus-Wind observation of GRB 090510
  26. AGILE detection of GRB 090510
  27. GRB 090510: UVOT refined analysis
  28. GRB 090510: Swift XRT refined analysis
  29. GRB 090510: correction to coordinates in GCN 9338
  30. GRB 090510: Enhanced Swift-XRT position
  31. GRB 090510: NOT afterglow confirmation
  32. GRB 090510: Swift-BAT refined analysis
  33. GRB 090510: Fermi GBM detection
  34. GRB 090509: Swift-BAT refined analysis
  35. Fermi LAT detection of GRB 090510
  36. GRB 090509, SMARTS optical/IR afterglow observations
  37. GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
  38. GRB 090510: Swift detection of a short hard burst
  39. GRB 090408: optical upper limit
  40. GRB 090418A: optical observation
  41. GRB 090509: GROND further analysis and redshift limit
  42. GRB 090509: REM NIR afterglow
  43. GRB 090509: GROND afterglow candidate
  44. GRB 090509: Swift detection of a burst
  45. GRB 090323: optical observations
  46. GRB 090423: optical limit
  47. GRB 090423: 250 GHz upper limit for a z=8.2 GRB with MAMBO-2 at the IRAM 30m
  48. GRB 080913: 250 GHz upper limit for a z=6.7 GRB with MAMBO-2 at the IRAM 30m
  49. GRB 090424: optical observations
  50. GRB 090427: GROND observations
  51. GRB 090429A: ROVOR magnitude limit
  52. ICSP VLF observation of GRB090427 from two receivers
  53. ICSP VLF observation of GRB090424 from four receivers
  54. Refined analysis of ICSP VLF observation of SGR J1550-5418 bursts on 22nd January, 2009
  55. GRB 090428B: Suzaku WAM observation of the prompt emission
  56. GRB 090424, SMARTS optical/IR afterglow monitoring
  57. GRB 090426: optical observations
  58. GRB 090429D: Fermi GBM detection
  59. GRB 090429C: Fermi GBM detection
  60. GRB 090429B: Swift/UVOT Upper Limits
  61. GRB 090429A: Swift/UVOT Upper Limits
  62. GRB 090427: pseudo-z= 1.48 from prompt emission spectrum
  63. GRB 090429B: Gemini-N further nIR observations
  64. GRB 090424: YNAO-GMG observations
  65. GRB 090429A: Swift-XRT refined analysis
  66. GRB 090429A: GROND upper limits
  67. GRB 090427C: Fermi GBM detection
  68. GRB 090427B: Fermi GBM detection
  69. GRB 090426C: Fermi GBM detection
  70. GRB 090426B: Fermi GBM detection/observation
  71. GRB 090429B: Swift XRT refined analysis
  72. GRB 090429A: Enhanced Swift-XRT position
  73. Konus-Wind observation of very bright GRB 090427
  74. GRB 090428B: Fermi GBM detection
  75. GRB 090428: Fermi GBM detection
  76. GRB 090418A BVRcIc field calibration
  77. GRB 090426: GAO 150cm telescope Optical Observation
  78. GRB 090429B: RIMOTS optical upper limits
  79. GRB 090429B: Swift-BAT refined analysis
  80. GRB 090429A: Swift-BAT refined analysis
  81. GRB 090429B: Enhanced Swift-XRT position
  82. GRB 090429A - Correction to XRT position
  83. GRB090429B: Gemini-N infrared IR candidate
  84. GRB 090426: YNAO-GMG observations
  85. GRB 090429B: VLT upper limits
  86. GRB 090429B: GROND Observations
  87. GRB 090429B: Super-LOTIS early observations
  88. GRB 090429B: Swift detection of a burst
  89. GRB 090429: Swift detection of a burst
  90. GRB 090423: pseudo burst at z=1 and its relation to GRB 080913
  91. GRB 090424 : Multiband Optical observation from Nainital
  92. IPN triangulation of very bright GRB 090427
  93. GRB 090426: R-band limit
  94. GRB 090424: Continued R-band monitoring
  95. GRB 090423: CARMA mm observations
  96. GRB 090423: millimeter detection
  97. GRB 090426: Swift/BAT spectral lag results
  98. GRB 090425: Fermi GBM detection
  99. GRB 090424: Suzaku WAM observation of the prompt emission
  100. GRB 090426: VLT spectroscopy

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