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

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