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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. Swift-BAT refined analysis of short GRB 071227
  2. GRB 071227: Swift detection of a burst
  3. GRB071020: optical observations
  4. GRB 070429B: Possible UVOT Detection of an Optical Afterglow
  5. Swift-BAT trigger 298308 is not a GRB
  6. GRB 071208?: Swift detection of a possible burst
  7. IBAS Alert #4772 in not a GRB
  8. GRB 071125: Suzaku WAM observation of the prompt emission
  9. GRB 070429B: Probable host galaxy and redshift
  10. GRB 071129, Swift-BAT refined analysis
  11. GRB 071129: Swift detection of a burst
  12. Konus-Wind and Konus-A observations of GRB 071125
  13. IPN triangulation of very bright GRB 071125
  14. GRB 071112C: Optical/NIR observations
  15. Disregard the "GRB 071126" position
  16. GRB 071126: Enhanced Swift-XRT position
  17. VLA radio detection of GRB 071122
  18. GRB071122: Swift/UVOT Observations
  19. GRB071104: NIR Afterglow Candidate at TNG
  20. GRB 071122: MASTER optical observation
  21. GRB 071122, Swift-BAT refined analysis
  22. GRB 071122 Swift XRT position update sent in error.
  23. GRB 071122 Swift-XRT refined analysis
  24. GRB 071122: Corrected P60 Coordinates
  25. GRB071122: Gemini Absorption redshift
  26. GRB 071122: P60 Optical Afterglow Candidate
  27. GRB 071122: ROTSE-III Optical Limits
  28. GRB 071122: Swift detection of a burst
  29. GRB 071118: P60 Observations
  30. GRB071118 MITSuME OAO optical observation
  31. GRB 071118: Observations from OSN
  32. GRB 071117: VLT observations and probable redshift
  33. Swift/UVOT observations of GRB071118
  34. GRB 071117: Swift-XRT revised position
  35. Konus-Wind and Konus-A observations of GRB 071117
  36. Swift XRT follow-up observations of GRB071008
  37. Swift/UVOT upper limits for GRB 071117
  38. GRB071118: Swift XRT refined analysis
  39. GRB 071117: Gemini Optical Afterglow Discovery
  40. GRB 071118, Swift-BAT refined analysis
  41. GRB 071117: TAROT La Silla observatory optical observations
  42. GRB 071112B: Gemini Image Differencing
  43. GRB 071118: Swift detection of a burst
  44. GRB 071117: Gemini Observations
  45. GRB 071117: Las Campanas optical observations
  46. GRB 071117: Swift-XRT refined analysis
  47. GRB 071117, Swift-BAT refined analysis
  48. VLT FORS2 observations of short hard GRB071112B
  49. GRB 071117: Swift/XRT position
  50. GRB 071117: Initial Swift/UVOT observations
  51. GRB 071117: Swift detection of a bright burst
  52. Swift detection of MXB 0656-072
  53. VLA radio upper limit on GRB 071112C
  54. ATCA radio observations of short hard burst GRB 071112B
  55. GRB 071112C: Optical and NIR data observed with KANATA
  56. Correction to the Swift-BAT Transient Identification (trigger=296683)
  57. GRB 071112C: WSRT Radio Observations
  58. GRB071112C: Errata of MITSuME Ic band photometry
  59. GRB 071112C: optical observation
  60. GRB 071112C: optical observation
  61. GRB 071112C: emission lines and refined VLT redshift
  62. GRB 071112C MITSuME Akeno early optical observation
  63. GRB 071112C: Gemini Absorption Redshift
  64. GRB 071112B: 2nd epoch of Magellan i-band imaging
  65. GRB 071112C: SARA upper limit
  66. GRB 071112C : Second Epoch Lulin R-band observations
  67. GRB071112C MITSuME Okayama Optical Observation
  68. GRB 071112C: Swift-BAT refined analysis
  69. GRB 071112C: Swift/UVOT observations
  70. GRB 071112C: Swift XRT refined analysis
  71. GRB 071112C: Optical observations at Crni Vrh
  72. Swift UVOT upper limits of GRB071112B
  73. GRB 071112C: VLT redshift
  74. GRB 071112B: Magellan i-band imaging
  75. GRB 071112B: Gemini Optical Imaging (Correction)
  76. GRB 071112B: Gemini Optical Imaging
  77. GRB 071112B: Swift-XRT preliminary analysis
  78. GRB 071112B, Swift-BAT partial refined analysis of the SHB
  79. GRB071112C: NOT observations
  80. GRB 071112C: Palomar Pre-Imaging
  81. Swift-BAT trigger 296491 is not a GRB
  82. GRB 071112C : Lulin R-band observation
  83. GRB 071112C: RTT150 optical observations
  84. GRB 071112C: TAROT Calern observatory optical observations
  85. Swift XRT follow-up observations of GRB071028B
  86. GRB071112C Xinglong_TNT_and_EST_afterglow observations
  87. GRB 071112C: Optical and NIR afterglows observed with KANATA
  88. GRB 071112C: ROTSE-III Confirmation of Optical Counterpart
  89. GRB 071112B: ROTSE-III Rapid Optical Limits
  90. GRB 071112C: Swift detection of a burst with an optical counterpart
  91. GRB 071112B: Swift detection of a short hard burst
  92. GRB 071112: Swift detection of a possible burst
  93. GRB071109: Super-LOTIS observations
  94. VLA IInd observation of INTEGRAL burst GRB 071109
  95. Swift/UVOT initial analysis of GRB071109
  96. GRB 071109: further Swift-XRT analysis
  97. GRB 071109: TAROT Calern observatory optical observations
  98. No radio detection at Swift-XRT position
  99. GRB 071109: Swift-XRT possible X-ray counterpart
  100. VLA prompt radio detection of the INTEGRAL burst 071109

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