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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. GRB071122: Gemini Absorption redshift
  2. GRB 071122: P60 Optical Afterglow Candidate
  3. GRB 071122: ROTSE-III Optical Limits
  4. GRB 071122: Swift detection of a burst
  5. GRB 071118: P60 Observations
  6. GRB071118 MITSuME OAO optical observation
  7. GRB 071118: Observations from OSN
  8. GRB 071117: VLT observations and probable redshift
  9. Swift/UVOT observations of GRB071118
  10. GRB 071117: Swift-XRT revised position
  11. Konus-Wind and Konus-A observations of GRB 071117
  12. Swift XRT follow-up observations of GRB071008
  13. Swift/UVOT upper limits for GRB 071117
  14. GRB071118: Swift XRT refined analysis
  15. GRB 071117: Gemini Optical Afterglow Discovery
  16. GRB 071118, Swift-BAT refined analysis
  17. GRB 071117: TAROT La Silla observatory optical observations
  18. GRB 071112B: Gemini Image Differencing
  19. GRB 071118: Swift detection of a burst
  20. GRB 071117: Gemini Observations
  21. GRB 071117: Las Campanas optical observations
  22. GRB 071117: Swift-XRT refined analysis
  23. GRB 071117, Swift-BAT refined analysis
  24. VLT FORS2 observations of short hard GRB071112B
  25. GRB 071117: Swift/XRT position
  26. GRB 071117: Initial Swift/UVOT observations
  27. GRB 071117: Swift detection of a bright burst
  28. Swift detection of MXB 0656-072
  29. VLA radio upper limit on GRB 071112C
  30. ATCA radio observations of short hard burst GRB 071112B
  31. GRB 071112C: Optical and NIR data observed with KANATA
  32. Correction to the Swift-BAT Transient Identification (trigger=296683)
  33. GRB 071112C: WSRT Radio Observations
  34. GRB071112C: Errata of MITSuME Ic band photometry
  35. GRB 071112C: optical observation
  36. GRB 071112C: optical observation
  37. GRB 071112C: emission lines and refined VLT redshift
  38. GRB 071112C MITSuME Akeno early optical observation
  39. GRB 071112C: Gemini Absorption Redshift
  40. GRB 071112B: 2nd epoch of Magellan i-band imaging
  41. GRB 071112C: SARA upper limit
  42. GRB 071112C : Second Epoch Lulin R-band observations
  43. GRB071112C MITSuME Okayama Optical Observation
  44. GRB 071112C: Swift-BAT refined analysis
  45. GRB 071112C: Swift/UVOT observations
  46. GRB 071112C: Swift XRT refined analysis
  47. GRB 071112C: Optical observations at Crni Vrh
  48. Swift UVOT upper limits of GRB071112B
  49. GRB 071112C: VLT redshift
  50. GRB 071112B: Magellan i-band imaging
  51. GRB 071112B: Gemini Optical Imaging (Correction)
  52. GRB 071112B: Gemini Optical Imaging
  53. GRB 071112B: Swift-XRT preliminary analysis
  54. GRB 071112B, Swift-BAT partial refined analysis of the SHB
  55. GRB071112C: NOT observations
  56. GRB 071112C: Palomar Pre-Imaging
  57. Swift-BAT trigger 296491 is not a GRB
  58. GRB 071112C : Lulin R-band observation
  59. GRB 071112C: RTT150 optical observations
  60. GRB 071112C: TAROT Calern observatory optical observations
  61. Swift XRT follow-up observations of GRB071028B
  62. GRB071112C Xinglong_TNT_and_EST_afterglow observations
  63. GRB 071112C: Optical and NIR afterglows observed with KANATA
  64. GRB 071112C: ROTSE-III Confirmation of Optical Counterpart
  65. GRB 071112B: ROTSE-III Rapid Optical Limits
  66. GRB 071112C: Swift detection of a burst with an optical counterpart
  67. GRB 071112B: Swift detection of a short hard burst
  68. GRB 071112: Swift detection of a possible burst
  69. GRB071109: Super-LOTIS observations
  70. VLA IInd observation of INTEGRAL burst GRB 071109
  71. Swift/UVOT initial analysis of GRB071109
  72. GRB 071109: further Swift-XRT analysis
  73. GRB 071109: TAROT Calern observatory optical observations
  74. No radio detection at Swift-XRT position
  75. GRB 071109: Swift-XRT possible X-ray counterpart
  76. VLA prompt radio detection of the INTEGRAL burst 071109
  77. GRB 071109: IBIS refined analysis
  78. GRB 071109: BOOTES-2 prompt optical observations
  79. GRB 071109: A long GRB detected by INTEGRAL
  80. GRB 071104: Swift-XRT Team Refined Analysis
  81. GRB 071104: Possible Swift UVOT Afterglow Candidate
  82. GRB 071104: Swift-XRT position
  83. GRB 071104: Gamma Ray Burst Localization by SuperAGILE
  84. GRB071010b: optical observation
  85. Swift XRT and UVOT observations of GRB071028B
  86. GRB 071101, Swift-BAT refined analysis
  87. GRB 071101: Swift-XRT Team refined analysis
  88. GRB071101: Optical and NIR upper limits by KANATA
  89. GRB0711101: Two new source from Xinglong TNT observation
  90. GRB 071101: TAROT Calern observatory optical observations
  91. GRB 071101: Swift XRT position
  92. GRB071101 LOAO B,V,R,I observation
  93. GRB 071101: BOOTES-2 prompt optical observations
  94. GRB 071101: a nearby galaxy
  95. GRB 071101: Swift detection of a burst
  96. GRB 071031, Swift-BAT refined analysis
  97. GRB 071031: Swift/UVOT detection of afterglow
  98. GRB 071031: Swift-XRT Team refined analysis
  99. GRB 071020: MITSuME Akeno optical observations
  100. GRB 071031: REM NIR and Optical observation

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