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

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