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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"

20391 results found.

  1. GRB 090117 - Fermi GBM Observations
  2. GRB 090117: GROND Upper Limits
  3. GRB090117 Swift/UVOT upper limits
  4. GRB090117: Swift-XRT detection of a possible candidate afterglow
  5. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  6. GRB 090113: Swift UVOT upper limits
  7. GRB 090113: GROND Upper Limits
  8. GRB 090113: Observations from NOT
  9. GRB 090113: Enhanced Swift-XRT position
  10. GRB 090113: ROTSE-III Optical Limits
  11. GRB 090113: Swift detection of a burst
  12. GRB 090112: Fermi GBM detection
  13. GRB 090111: Swift UVOT Upper Limits
  14. GRB 090111: Swift-XRT refined analysis
  15. GRB 090111: Enhanced Swift-XRT position
  16. GRB 090111: Swift detection of a burst
  17. GRB 090107B: Swift XRT afterglow confirmation
  18. GRB 090107B: Swift/UVOT Observations
  19. GRB 090107B: Swift-XRT detection of possible afterglow
  20. VLA radio upper limit on GRB 090102
  21. GRB 090102: GRT Optical Observation
  22. Swift triggered on the HMXB 1A 1118-61
  23. GRB 090102: P60 Imaging and P200 Spectroscopy
  24. GRB 090102 Observations from IAC80
  25. GRB 090102: GROND observations of the optical afterglow
  26. GRB 090102: Swift-BAT refined analysis
  27. GRB 090102: NOT redshift
  28. GRB 090102: Enhanced Swift-XRT position
  29. GRB 090102: REM observations of a bright afterglow
  30. GRB 090102: Swift detection of a burst with an optical counterpart
  31. GRB 090102: TAROT Calern observatory optical observations
  32. GRB 081230: GROND confirmation of the afterglow
  33. GRB081230: Swift-XRT refined analysis
  34. GRB 081230 Swift/UVOT Observations
  35. GRB 081230: Enhanced Swift-XRT position
  36. GRB 081230: Swift detection of a burst
  37. GRB 081228, Swift-BAT refined analysis
  38. VLA radio detection of GRB 081221
  39. GRB 081228: Swift/UVOT Upper Limits
  40. GRB 081228: Swift-XRT Team refined analysis
  41. GRB 081228: detection by GROND
  42. GRB 081228: Enhanced Swift-XRT position
  43. GRB 081228: TAROT Calern observatory optical observations
  44. GRB 081228: Swift detection of a burst
  45. VLA radio observation of GRB 081221
  46. GRB 081226B: Swift XRT and UVOT upper limits
  47. GRB 081226: Swift-XRT refined analysis
  48. GRB 081226A: Swift UVOT Upper Limits
  49. GRB 081226: GROND afterglow candidate
  50. GRB 081226: ROTSE-III Optical Limits
  51. GRB 081226: Swift detection of a possible short-hard burst
  52. GRB 080810: optical observations
  53. GRB 081211B: optical observations
  54. GRB 081224: Swift-XRT observation
  55. GRB 081222: MITSuME optical observation
  56. GRB 081221: GROND observations
  57. VLA radio upper limit on GRB 081222
  58. GRB 081221: Probable host galaxy in Keck imaging
  59. GRB 081222, Swift-BAT refined analysis
  60. GRB081222 optical limit by "Pi of the Sky"
  61. Konus-Wind observation of very bright GRB 081215A
  62. GRB 081222: Swift XRT refined analysis
  63. IPN triangulation of bright GRB 081215A
  64. GRB 081222: Faulkes Telescope South observations
  65. GRB 081221: Gemini-N nIR imaging
  66. GRB081222, optical observation
  67. GRB081203A: BTA observation
  68. Konus-Wind observation of GRB 081221
  69. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  70. GRB081222: REM candidate afterglow
  71. GRB 081222: Swift detection of a burst with a bright optical afterglow
  72. GRB 081221: Enhanced Swift-XRT position
  73. GRB 081221: further NOT observations
  74. GRB 081221: NOT observations
  75. GRB 081221: Swift detection of a burst
  76. GRB 081118: Zadko observations
  77. Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
  78. GRB 0811215A: MASTER prompt optical observations
  79. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  80. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  81. Possible GRB 081211B: Swift/UVOT Upper Limits
  82. Possible GRB 081211B - Swift-XRT analysis
  83. GRB 081207: Fermi GBM detection
  84. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  85. GRB 081210, SMARTS optical/IR observations
  86. GRB 081211: Enhanced Swift-XRT position
  87. GRB 081211: Swift detection of a burst
  88. GRB081203B: optical observations
  89. GRB 081210: Enhanced Swift-XRT position
  90. GRB 081210: Swift detection of a burst with optical afterglow
  91. IPN triangulation of short hard GRB 081209
  92. GRB 081203A: optical observations
  93. GRB 081128: afterglow observations
  94. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  95. GRB 081128: optical observation in CrAO
  96. GRB081203A: Optical observations at Ishigaki
  97. GRB 081204: GROND Observations
  98. Radio detection of GRB 081203B with the VLA
  99. GRB081203A: Radio upper limit at 15 GHz
  100. GRB 081204B: Fermi GBM detection

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