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

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