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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"

28079 results found.

  1. VLA radio upper limit on GRB 090102
  2. GRB 090102: GRT Optical Observation
  3. Swift triggered on the HMXB 1A 1118-61
  4. GRB 081229: Fermi GBM detection
  5. GRB 090102: Hobby-Eberly Telescope Spectroscopy
  6. GRB 090102: P60 Imaging and P200 Spectroscopy
  7. GRB 090102 Observations from IAC80
  8. GRB 090102: GROND observations of the optical afterglow
  9. Swift UVOT observations of GRB 090102
  10. GRB 090102: Swift XRT refined analysis
  11. GRB 090102: NOT redshift
  12. GRB 090102: Enhanced Swift-XRT position
  13. GRB 090102: TAROT Calern observatory optical light curve
  14. GRB 090102: REM observations of a bright afterglow
  15. GRB 090102: Swift detection of a burst with an optical counterpart
  16. GRB 081230: GROND confirmation of the afterglow
  17. GRB081230: Swift-XRT refined analysis
  18. GRB 081230 Swift/UVOT Observations
  19. GRB 081230: Enhanced Swift-XRT position
  20. GRB 081230: Swift/UVOT Detection of an Optical Afterglow
  21. GRB 081230: ROTSE-III Detection of Optical Counterpart
  22. GRB 081230: Swift detection of a burst
  23. GRB 081228: GROND confirmation of the optical/NIR afterglow
  24. GRB 081226C: Fermi GBM detection
  25. VLA radio detection of GRB 081221
  26. GRB 081228: Swift/UVOT Upper Limits
  27. GRB 081228: Swift-XRT Team refined analysis
  28. GRB 081228: detection by GROND
  29. GRB 081228: Enhanced Swift-XRT position
  30. GRB 081228: TAROT Calern observatory optical observations
  31. GRB 081228: Swift detection of a burst
  32. VLA radio observation of GRB 081221
  33. GRB 081226B: Swift XRT and UVOT upper limits
  34. GRB 081226: Swift-XRT refined analysis
  35. GRB 081226A: Swift UVOT Upper Limits
  36. GRB 081226: Second epoch of Gemini-South imaging
  37. GRB 081226: Gemini-South spectrum of possible afterglow
  38. GRB 081226: Gemini-South imaging
  39. GRB 081226: GROND afterglow candidate
  40. GRB 081226: ROTSE-III Optical Limits
  41. GRB 081226: Swift detection of a possible short-hard burst
  42. GRB 080810: optical observations
  43. GRB 081211B: optical observations
  44. GRB081224: LAT retraction
  45. GRB 081224: Swift-XRT observation
  46. GRB 081222: MITSuME optical observation
  47. GRB 081224: Fermi GBM Detection & LAT Localization
  48. GRB 080810: optical observations
  49. GRB 081223: Fermi GBM detection
  50. GRB 081221: GROND observations
  51. GRB 081222: Gemini-N confirmation of redshift z=2.77
  52. GRB 081222:Optical afterglow observation
  53. VLA radio upper limit on GRB 081222
  54. GRB 081222: Gemini-South absorption redshift
  55. GRB081222: Swift/UVOT further observations
  56. GRB 081221: Probable host galaxy in Keck imaging
  57. GRB 081204C: Fermi GBM detection
  58. GRB 081222: Swift XRT refined analysis
  59. GRB081221: Fermi GBM observation
  60. Swift/UVOT observations of GRB 081221
  61. GRB 081221: Swift-XRT Refined Analysis
  62. GRB 081222: Faulkes Telescope South observations
  63. GRB 081221: Gemini-N nIR imaging
  64. GRB081222: Swift/UVOT detection of an optical afterglow
  65. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  66. GRB081222: REM candidate afterglow
  67. GRB 081222: Swift detection of a burst with a bright optical afterglow
  68. GRB 081221: Enhanced Swift-XRT position
  69. GRB 081221: further NOT observations
  70. GRB 081221: NOT observations
  71. GRB 081221: Swift detection of a burst
  72. GRB 081217: Fermi GBM detection
  73. GRB081215A: Fermi-LAT observations
  74. GRB 081211B: Further Swift-XRT analysis
  75. GRB 081215B: Fermi GBM detection
  76. GRB 081215A: Fermi GBM detection (correction to event fluence)
  77. GRB 081215A: Fermi GBM detection
  78. GRB 081118: Zadko observations
  79. Possible GRB 081211B: Swift/UVOT Upper Limits
  80. GRB 081213: Fermi GBM detection
  81. GRB 081210: optical observations
  82. Possible GRB 081211B - Swift-XRT analysis
  83. GRB 081207: Fermi GBM detection
  84. GRB 081209: Fermi GBM detection
  85. GRB 081007: Detection of a Supernova
  86. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  87. GRB 081210: Xinglong TNT R band Upper Limits
  88. GRB 081210, SMARTS optical/IR observations
  89. GRB 081211: Swift XRT refined analysis
  90. GRB 081211: Swift/UVOT detection of an optical afterglow
  91. GRB 081211: Enhanced Swift-XRT position
  92. GRB 081210: Swift/UVOT refined analysis
  93. GRB 081211: Swift detection of a burst
  94. GRB 081210: Swift-XRT refined analysis
  95. GRB 081210: Enhanced Swift-XRT position
  96. GRB 081210: Swift detection of a burst with optical afterglow
  97. GRB 081203A: optical observations
  98. GRB 081206C: Fermi GBM detection
  99. Radio observation of GRB 081121 with ATCA
  100. Radio observation of GRB 081118 with ATCA

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