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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: Swift/UVOT Observations
  2. GRB071104: NIR Afterglow Candidate at TNG
  3. GRB 071122: MASTER optical observation
  4. GRB 071122, Swift-BAT refined analysis
  5. GRB 071122 Swift XRT position update sent in error.
  6. GRB 071122 Swift-XRT refined analysis
  7. GRB 071122: Corrected P60 Coordinates
  8. GRB071122: Gemini Absorption redshift
  9. GRB 071122: P60 Optical Afterglow Candidate
  10. GRB 071122: ROTSE-III Optical Limits
  11. GRB 071122: Swift detection of a burst
  12. GRB 071118: P60 Observations
  13. GRB071118 MITSuME OAO optical observation
  14. GRB 071118: Observations from OSN
  15. GRB 071117: VLT observations and probable redshift
  16. Swift/UVOT observations of GRB071118
  17. GRB 071117: Swift-XRT revised position
  18. Konus-Wind and Konus-A observations of GRB 071117
  19. Swift XRT follow-up observations of GRB071008
  20. Swift/UVOT upper limits for GRB 071117
  21. GRB071118: Swift XRT refined analysis
  22. GRB 071117: Gemini Optical Afterglow Discovery
  23. GRB 071118, Swift-BAT refined analysis
  24. GRB 071117: TAROT La Silla observatory optical observations
  25. GRB 071112B: Gemini Image Differencing
  26. GRB 071118: Swift detection of a burst
  27. GRB 071117: Gemini Observations
  28. GRB 071117: Las Campanas optical observations
  29. GRB 071117: Swift-XRT refined analysis
  30. GRB 071117, Swift-BAT refined analysis
  31. VLT FORS2 observations of short hard GRB071112B
  32. GRB 071117: Swift/XRT position
  33. GRB 071117: Initial Swift/UVOT observations
  34. GRB 071117: Swift detection of a bright burst
  35. Swift detection of MXB 0656-072
  36. VLA radio upper limit on GRB 071112C
  37. ATCA radio observations of short hard burst GRB 071112B
  38. GRB 071112C: Optical and NIR data observed with KANATA
  39. Correction to the Swift-BAT Transient Identification (trigger=296683)
  40. GRB 071112C: WSRT Radio Observations
  41. GRB071112C: Errata of MITSuME Ic band photometry
  42. GRB 071112C: optical observation
  43. GRB 071112C: optical observation
  44. GRB 071112C: emission lines and refined VLT redshift
  45. GRB 071112C MITSuME Akeno early optical observation
  46. GRB 071112C: Gemini Absorption Redshift
  47. GRB 071112B: 2nd epoch of Magellan i-band imaging
  48. GRB 071112C: SARA upper limit
  49. GRB 071112C : Second Epoch Lulin R-band observations
  50. GRB071112C MITSuME Okayama Optical Observation
  51. GRB 071112C: Swift-BAT refined analysis
  52. GRB 071112C: Swift/UVOT observations
  53. GRB 071112C: Swift XRT refined analysis
  54. GRB 071112C: Optical observations at Crni Vrh
  55. Swift UVOT upper limits of GRB071112B
  56. GRB 071112C: VLT redshift
  57. GRB 071112B: Magellan i-band imaging
  58. GRB 071112B: Gemini Optical Imaging (Correction)
  59. GRB 071112B: Gemini Optical Imaging
  60. GRB 071112B: Swift-XRT preliminary analysis
  61. GRB 071112B, Swift-BAT partial refined analysis of the SHB
  62. GRB071112C: NOT observations
  63. GRB 071112C: Palomar Pre-Imaging
  64. Swift-BAT trigger 296491 is not a GRB
  65. GRB 071112C : Lulin R-band observation
  66. GRB 071112C: RTT150 optical observations
  67. GRB 071112C: TAROT Calern observatory optical observations
  68. Swift XRT follow-up observations of GRB071028B
  69. GRB071112C Xinglong_TNT_and_EST_afterglow observations
  70. GRB 071112C: Optical and NIR afterglows observed with KANATA
  71. GRB 071112C: ROTSE-III Confirmation of Optical Counterpart
  72. GRB 071112B: ROTSE-III Rapid Optical Limits
  73. GRB 071112C: Swift detection of a burst with an optical counterpart
  74. GRB 071112B: Swift detection of a short hard burst
  75. GRB 071112: Swift detection of a possible burst
  76. GRB071109: Super-LOTIS observations
  77. VLA IInd observation of INTEGRAL burst GRB 071109
  78. Swift/UVOT initial analysis of GRB071109
  79. GRB 071109: further Swift-XRT analysis
  80. GRB 071109: TAROT Calern observatory optical observations
  81. No radio detection at Swift-XRT position
  82. GRB 071109: Swift-XRT possible X-ray counterpart
  83. VLA prompt radio detection of the INTEGRAL burst 071109
  84. GRB 071109: IBIS refined analysis
  85. GRB 071109: BOOTES-2 prompt optical observations
  86. GRB 071109: A long GRB detected by INTEGRAL
  87. GRB 071104: Swift-XRT Team Refined Analysis
  88. GRB 071104: Possible Swift UVOT Afterglow Candidate
  89. GRB 071104: Swift-XRT position
  90. GRB 071104: Gamma Ray Burst Localization by SuperAGILE
  91. GRB071010b: optical observation
  92. Swift XRT and UVOT observations of GRB071028B
  93. GRB 071101, Swift-BAT refined analysis
  94. GRB 071101: Swift-XRT Team refined analysis
  95. GRB071101: Optical and NIR upper limits by KANATA
  96. GRB0711101: Two new source from Xinglong TNT observation
  97. GRB 071101: TAROT Calern observatory optical observations
  98. GRB 071101: Swift XRT position
  99. GRB071101 LOAO B,V,R,I observation
  100. GRB 071101: BOOTES-2 prompt optical observations

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