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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. GRB071021 : CFHT Ks-band observation
  2. GRB 071025: ROTSE-III Refined Analysis
  3. GRB 071025: I-detection, R-dropout?
  4. GRB 071025: Swift XRT refined position
  5. GRB 071025a: PAIRITEL observations
  6. GRB071025: REM NIR afterglow
  7. GRB 071025: ROTSE-III Detection of Optical Counterpart
  8. GRB 071025: Swift detection of a burst
  9. GRB 071021: R-band detection and analysis
  10. GRB 071020: BTA spectroscopy
  11. GRB071021: Optical+NIR observations
  12. Possible radio detection of GRB 071021 with the VLA
  13. Optical observations of GRB 071020
  14. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  15. GRB 071020: SARA observations
  16. Radio detection of GRB 071020 with the VLA
  17. GRB071010b: optical observation
  18. GRB 071021: Subaru NIR observation
  19. GRB071021: MITSuME Okayama Optical Upper Limits
  20. GRB 071021: Magellan i-band observation
  21. GRB 071021: Magellan R-band observation
  22. GRB 071021: Z-band detection
  23. GRB 071021: correction to GCNC 6968
  24. GRB 071020: Fading slowly?
  25. GRB 071010B: Fading quickly
  26. GRB 071021: optical and NIR observations
  27. GRB 071021: possible high-z burst
  28. GRB 071021, Swift-BAT refined analysis
  29. GRB071018: 2nd epoch obsevations of Xinglong TNT
  30. GRB 071021: retraction of Faulkes Telescope South candidate
  31. GRB 071021: Swift-XRT Team refined analysis
  32. GRB 071021: Xinglong TNT optical Upper Limit
  33. GRB 071021 : Lulin R-band limit
  34. Konus-Wind observation of GRB 071020
  35. GRB 071021: Faulkes Telescope South optical candidate
  36. GRB 071021: Swift detection of a burst
  37. GRB 071010B: Independent Confirmation of Break
  38. GRB071020A: Xinglong TNT Optical afterglow observations
  39. GRB 071020: Swift-XRT refined analysis
  40. GRB 071020, Swift-BAT refined analysis
  41. GRB 071020A: IR Imaging with PAIRITEL
  42. GRB 071020: VLT spectroscopy
  43. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  44. GRB071020 - SDSS Pre-burst Observations
  45. GRB 071020: Swift detection of a bright burst
  46. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  47. GRB 071018: Mercator Telescope optical observations
  48. Swift autonomous slewing re-enabled
  49. GRB071010b: optical observations
  50. GRB 071018: SARA observations
  51. GRB 071018: Swift-XRT observation
  52. GRB 071017 - Swift XRT observations
  53. VLA radio observation of GRB 071018
  54. GRB071018: Correction to the GCN 6936
  55. GRB071018: Correction to the GCN 6936
  56. GRB071018: Correction to the GCN 6936
  57. GRB071018: Correction to the title of the GCN 6936
  58. GRB 071018: Possible OT from Xinglong TNT observation
  59. GRB 071010B: Light Curve Break Confirmed
  60. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  61. GRB 071018, Swift-BAT refined analysis
  62. GRB 071018?: Swift detection of a possible burst
  63. GRB 071010B: Suzaku WAM observation of the prompt emission
  64. GRB 071013: 3rd TLS Epoch - constraints on variability
  65. GRB 071013: TNT optical data refined analysis
  66. GRB 071010B: Keck/DEIMOS emission-line redshift
  67. GRB 071017: a SHORT GRB detected by INTEGRAL
  68. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  69. GRB071013: optical observations
  70. GRB 071010B: Optical observations of EST
  71. GRB 071010B: TLS 3rd Epoch - finally a break??
  72. GRB 071011: MITSuME Optical Observations
  73. GRB 070920A: deep optical observations at the NOT
  74. GRB 071010B: Photometry after 1.6 days
  75. GRB 071010B: Keck/LRIS Photometry
  76. GRB 071010B: TLS 2nd Epoch, refined analysis
  77. GRB 071013: TLS Upper Limit
  78. Correction to GCN circular no. # 6915 for GRB 071010B
  79. VLA detection of radio afterglow of GRB 071010B
  80. VLA non-detection of GRB 071011
  81. GRB 071013: Optical observations
  82. GRB 071013: optical observations at NOT
  83. GRB 071013, Swift-BAT refined analysis
  84. GRB071013: optical limit
  85. GRB071010B, BVRcIc field calibration
  86. GRB 20071013: Xinglong TNT optical Upper Limit
  87. GRB 071013: Swift detection of a burst
  88. GRB 071010C Swift-BAT detection of a burst
  89. GRB 071011: Optical Limit after 13.95hrs
  90. GRB 071011: Xinglong TNT Optical afterglow observations
  91. GRB 071010B correction to GCN 6892 optical observations
  92. GRB 071011: Swift-XRT refined analysis
  93. VLA non-detection of GRB 071010A
  94. GRB 071011: NAYUTA Optical Observation, correction to GCN6886
  95. GRB 071011, Optical afterglow
  96. GRB 071011: Confirmation of P60 optical afterglow
  97. GRB 071010B: Optical Detection
  98. GRB 071011: Kanazawa Optical limits
  99. GRB 071011: P60 Optical Afterglow Candidate
  100. GRB 071011: MARGE Optical Limits

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