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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. GRB071025: Optical Pre-imaging from Palomar
  2. Swift UVOT upper limits
  3. GRB071025: Xinglong TNT I-band upper limit
  4. GRB 071025: Swift-XRT Team refined analysis
  5. GRB 060602A: host redshift
  6. GRB 071025, Swift-BAT refined analysis
  7. GRB 071025: Early Super-LOTIS Observations
  8. GRB 071025: R/I-band update
  9. GRB071021 : CFHT Ks-band observation
  10. GRB 071025: ROTSE-III Refined Analysis
  11. GRB 071025: I-detection, R-dropout?
  12. GRB 071025: Swift XRT refined position
  13. GRB 071025a: PAIRITEL observations
  14. GRB071025: REM NIR afterglow
  15. GRB 071025: ROTSE-III Detection of Optical Counterpart
  16. GRB 071025: Swift detection of a burst
  17. GRB 071021: R-band detection and analysis
  18. GRB 071020: BTA spectroscopy
  19. GRB071021: Optical+NIR observations
  20. Possible radio detection of GRB 071021 with the VLA
  21. Optical observations of GRB 071020
  22. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  23. GRB 071020: SARA observations
  24. Radio detection of GRB 071020 with the VLA
  25. GRB071010b: optical observation
  26. GRB 071021: Subaru NIR observation
  27. GRB071021: MITSuME Okayama Optical Upper Limits
  28. GRB 071021: Magellan i-band observation
  29. GRB 071021: Magellan R-band observation
  30. GRB 071021: Z-band detection
  31. GRB 071021: correction to GCNC 6968
  32. GRB 071020: Fading slowly?
  33. GRB 071010B: Fading quickly
  34. GRB 071021: optical and NIR observations
  35. GRB 071021: possible high-z burst
  36. GRB 071021, Swift-BAT refined analysis
  37. GRB071018: 2nd epoch obsevations of Xinglong TNT
  38. GRB 071021: retraction of Faulkes Telescope South candidate
  39. GRB 071021: Swift-XRT Team refined analysis
  40. GRB 071021: Xinglong TNT optical Upper Limit
  41. GRB 071021 : Lulin R-band limit
  42. Konus-Wind observation of GRB 071020
  43. GRB 071021: Faulkes Telescope South optical candidate
  44. GRB 071021: Swift detection of a burst
  45. GRB 071010B: Independent Confirmation of Break
  46. GRB071020A: Xinglong TNT Optical afterglow observations
  47. GRB 071020: Swift-XRT refined analysis
  48. GRB 071020, Swift-BAT refined analysis
  49. GRB 071020A: IR Imaging with PAIRITEL
  50. GRB 071020: VLT spectroscopy
  51. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  52. GRB071020 - SDSS Pre-burst Observations
  53. GRB 071020: Swift detection of a bright burst
  54. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  55. GRB 071018: Mercator Telescope optical observations
  56. Swift autonomous slewing re-enabled
  57. GRB071010b: optical observations
  58. GRB 071018: SARA observations
  59. GRB 071018: Swift-XRT observation
  60. GRB 071017 - Swift XRT observations
  61. VLA radio observation of GRB 071018
  62. GRB071018: Correction to the GCN 6936
  63. GRB071018: Correction to the GCN 6936
  64. GRB071018: Correction to the GCN 6936
  65. GRB071018: Correction to the title of the GCN 6936
  66. GRB 071018: Possible OT from Xinglong TNT observation
  67. GRB 071010B: Light Curve Break Confirmed
  68. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  69. GRB 071018, Swift-BAT refined analysis
  70. GRB 071018?: Swift detection of a possible burst
  71. GRB 071010B: Suzaku WAM observation of the prompt emission
  72. GRB 071013: 3rd TLS Epoch - constraints on variability
  73. GRB 071013: TNT optical data refined analysis
  74. GRB 071010B: Keck/DEIMOS emission-line redshift
  75. GRB 071017: a SHORT GRB detected by INTEGRAL
  76. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  77. GRB071013: optical observations
  78. GRB 071010B: Optical observations of EST
  79. GRB 071010B: TLS 3rd Epoch - finally a break??
  80. GRB 071011: MITSuME Optical Observations
  81. GRB 070920A: deep optical observations at the NOT
  82. GRB 071010B: Photometry after 1.6 days
  83. GRB 071010B: Keck/LRIS Photometry
  84. GRB 071010B: TLS 2nd Epoch, refined analysis
  85. GRB 071013: TLS Upper Limit
  86. Correction to GCN circular no. # 6915 for GRB 071010B
  87. VLA detection of radio afterglow of GRB 071010B
  88. VLA non-detection of GRB 071011
  89. GRB 071013: Optical observations
  90. GRB 071013: optical observations at NOT
  91. GRB 071013, Swift-BAT refined analysis
  92. GRB071013: optical limit
  93. GRB071010B, BVRcIc field calibration
  94. GRB 20071013: Xinglong TNT optical Upper Limit
  95. GRB 071013: Swift detection of a burst
  96. GRB 071010C Swift-BAT detection of a burst
  97. GRB 071011: Optical Limit after 13.95hrs
  98. GRB 071011: Xinglong TNT Optical afterglow observations
  99. GRB 071010B correction to GCN 6892 optical observations
  100. GRB 071011: Swift-XRT refined analysis

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