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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 071021: Z-band detection
  2. GRB 071021: correction to GCNC 6968
  3. GRB 071020: Fading slowly?
  4. GRB 071010B: Fading quickly
  5. GRB 071021: optical and NIR observations
  6. GRB 071021: possible high-z burst
  7. GRB 071021, Swift-BAT refined analysis
  8. GRB071018: 2nd epoch obsevations of Xinglong TNT
  9. GRB 071021: retraction of Faulkes Telescope South candidate
  10. GRB 071021: Swift-XRT Team refined analysis
  11. GRB 071021: Xinglong TNT optical Upper Limit
  12. GRB 071021 : Lulin R-band limit
  13. Konus-Wind observation of GRB 071020
  14. GRB 071021: Faulkes Telescope South optical candidate
  15. GRB 071021: Swift detection of a burst
  16. GRB 071010B: Independent Confirmation of Break
  17. GRB071020A: Xinglong TNT Optical afterglow observations
  18. GRB 071020: Swift-XRT refined analysis
  19. GRB 071020, Swift-BAT refined analysis
  20. GRB 071020A: IR Imaging with PAIRITEL
  21. GRB 071020: VLT spectroscopy
  22. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  23. GRB071020 - SDSS Pre-burst Observations
  24. GRB 071020: Swift detection of a bright burst
  25. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  26. GRB 071018: Mercator Telescope optical observations
  27. Swift autonomous slewing re-enabled
  28. GRB071010b: optical observations
  29. GRB 071018: SARA observations
  30. GRB 071018: Swift-XRT observation
  31. GRB 071017 - Swift XRT observations
  32. VLA radio observation of GRB 071018
  33. GRB071018: Correction to the GCN 6936
  34. GRB071018: Correction to the GCN 6936
  35. GRB071018: Correction to the GCN 6936
  36. GRB071018: Correction to the title of the GCN 6936
  37. GRB 071018: Possible OT from Xinglong TNT observation
  38. GRB 071010B: Light Curve Break Confirmed
  39. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  40. GRB 071018, Swift-BAT refined analysis
  41. GRB 071018?: Swift detection of a possible burst
  42. GRB 071010B: Suzaku WAM observation of the prompt emission
  43. GRB 071013: 3rd TLS Epoch - constraints on variability
  44. GRB 071013: TNT optical data refined analysis
  45. GRB 071010B: Keck/DEIMOS emission-line redshift
  46. GRB 071017: a SHORT GRB detected by INTEGRAL
  47. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  48. GRB071013: optical observations
  49. GRB 071010B: Optical observations of EST
  50. GRB 071010B: TLS 3rd Epoch - finally a break??
  51. GRB 071011: MITSuME Optical Observations
  52. GRB 070920A: deep optical observations at the NOT
  53. GRB 071010B: Photometry after 1.6 days
  54. GRB 071010B: Keck/LRIS Photometry
  55. GRB 071010B: TLS 2nd Epoch, refined analysis
  56. GRB 071013: TLS Upper Limit
  57. Correction to GCN circular no. # 6915 for GRB 071010B
  58. VLA detection of radio afterglow of GRB 071010B
  59. VLA non-detection of GRB 071011
  60. GRB 071013: Optical observations
  61. GRB 071013: optical observations at NOT
  62. GRB 071013, Swift-BAT refined analysis
  63. GRB071013: optical limit
  64. GRB071010B, BVRcIc field calibration
  65. GRB 20071013: Xinglong TNT optical Upper Limit
  66. GRB 071013: Swift detection of a burst
  67. GRB 071010C Swift-BAT detection of a burst
  68. GRB 071011: Optical Limit after 13.95hrs
  69. GRB 071011: Xinglong TNT Optical afterglow observations
  70. GRB 071010B correction to GCN 6892 optical observations
  71. GRB 071011: Swift-XRT refined analysis
  72. VLA non-detection of GRB 071010A
  73. GRB 071011: NAYUTA Optical Observation, correction to GCN6886
  74. GRB 071011, Optical afterglow
  75. GRB 071011: Confirmation of P60 optical afterglow
  76. GRB 071010B: Optical Detection
  77. GRB 071011: Kanazawa Optical limits
  78. GRB 071011: P60 Optical Afterglow Candidate
  79. GRB 071011: MARGE Optical Limits
  80. GRB 071010B: Super-LOTIS upper limit
  81. GRB 071010B optical photometry
  82. GRB 071011: XRT afterglow detection
  83. GRB 071010B: Keck/LRIS Spectroscopy
  84. GRB 071011, Swift-BAT refined analysis
  85. GRB 071010B: Gemini Spectroscopic Observations
  86. GRB 071011: Early Super-LOTIS Observations
  87. GRB 071011: NAYUTA Optical Observation
  88. GRB 071010A: Continued Keck Imaging
  89. GRB 071010B: Bright OT confirmed with TLS
  90. GRB 071011: Optical afterglow candidate
  91. GRB 071011: Swift detection of a burst
  92. Optical Observation: GRB 071010
  93. Optical observations: GRB 071010A
  94. Konus-Wind observation of GRB 071010B
  95. GRB071010B: Swift/XRT detection
  96. GRB 071010B, Swift-BAT refined analysis
  97. GRB 071010A: bright NIR afterglow
  98. GRB 071006, Swift-BAT refined analysis
  99. GRB071008: optical observations
  100. GRB 071010B possible optical transient

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