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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 071104: Swift-XRT Team Refined Analysis
  2. GRB 071104: Possible Swift UVOT Afterglow Candidate
  3. GRB 071104: Swift-XRT position
  4. GRB 071104: Gamma Ray Burst Localization by SuperAGILE
  5. GRB071010b: optical observation
  6. Swift XRT and UVOT observations of GRB071028B
  7. GRB 071101, Swift-BAT refined analysis
  8. GRB 071101: Swift-XRT Team refined analysis
  9. GRB071101: Optical and NIR upper limits by KANATA
  10. GRB0711101: Two new source from Xinglong TNT observation
  11. GRB 071101: TAROT Calern observatory optical observations
  12. GRB 071101: Swift XRT position
  13. GRB071101 LOAO B,V,R,I observation
  14. GRB 071101: BOOTES-2 prompt optical observations
  15. GRB 071101: a nearby galaxy
  16. GRB 071101: Swift detection of a burst
  17. GRB 071031, Swift-BAT refined analysis
  18. GRB 071031: Swift/UVOT detection of afterglow
  19. GRB 071031: Swift-XRT Team refined analysis
  20. GRB 071020: MITSuME Akeno optical observations
  21. GRB 071031: REM NIR and Optical observation
  22. GRB 071031, SMARTS afterglow observations
  23. GRB 071031: VLT high-resolution spectroscopy
  24. GRB071031: Rapid PROMPT Detections
  25. GRB 071031: GROND detection in all bands
  26. GRB 071031: Swift detection of a burst with an optical counterpart
  27. GRB 071028B Swift-BAT detection of a burst
  28. GRB071025: Optical+NIR observations
  29. GRB 071028: SARA observations of variable source
  30. Swift UVOT upper limits to GRB071028
  31. GRB071028: Xinglong EST V-band upper limit
  32. GRB 071028: Swift-XRT Team refined analysis
  33. GRB 071028, Swift-BAT refined analysis
  34. GRB 071028: Swift detection of a burst
  35. GRB 071025: Kuiper Telescope Optical Observations
  36. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  37. GRB 071018: Revised BAT position
  38. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  39. GRB071021: MARGE Optical Limits
  40. GRB071020, optical upper limit
  41. GRB 071025: SARA VRI upper limits
  42. GRB 071025 Milagro GeV/TeV Observations
  43. GRB 071025: SQIID JHK photometry
  44. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  45. GRB071025: Optical Pre-imaging from Palomar
  46. Swift UVOT upper limits
  47. GRB071025: Xinglong TNT I-band upper limit
  48. GRB 071025: Swift-XRT Team refined analysis
  49. GRB 060602A: host redshift
  50. GRB 071025, Swift-BAT refined analysis
  51. GRB 071025: Early Super-LOTIS Observations
  52. GRB 071025: R/I-band update
  53. GRB071021 : CFHT Ks-band observation
  54. GRB 071025: ROTSE-III Refined Analysis
  55. GRB 071025: I-detection, R-dropout?
  56. GRB 071025: Swift XRT refined position
  57. GRB 071025a: PAIRITEL observations
  58. GRB071025: REM NIR afterglow
  59. GRB 071025: ROTSE-III Detection of Optical Counterpart
  60. GRB 071025: Swift detection of a burst
  61. GRB 071021: R-band detection and analysis
  62. GRB 071020: BTA spectroscopy
  63. GRB071021: Optical+NIR observations
  64. Possible radio detection of GRB 071021 with the VLA
  65. Optical observations of GRB 071020
  66. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  67. GRB 071020: SARA observations
  68. Radio detection of GRB 071020 with the VLA
  69. GRB071010b: optical observation
  70. GRB 071021: Subaru NIR observation
  71. GRB071021: MITSuME Okayama Optical Upper Limits
  72. GRB 071021: Magellan i-band observation
  73. GRB 071021: Magellan R-band observation
  74. GRB 071021: Z-band detection
  75. GRB 071021: correction to GCNC 6968
  76. GRB 071020: Fading slowly?
  77. GRB 071010B: Fading quickly
  78. GRB 071021: optical and NIR observations
  79. GRB 071021: possible high-z burst
  80. GRB 071021, Swift-BAT refined analysis
  81. GRB071018: 2nd epoch obsevations of Xinglong TNT
  82. GRB 071021: retraction of Faulkes Telescope South candidate
  83. GRB 071021: Swift-XRT Team refined analysis
  84. GRB 071021: Xinglong TNT optical Upper Limit
  85. GRB 071021 : Lulin R-band limit
  86. Konus-Wind observation of GRB 071020
  87. GRB 071021: Faulkes Telescope South optical candidate
  88. GRB 071021: Swift detection of a burst
  89. GRB 071010B: Independent Confirmation of Break
  90. GRB071020A: Xinglong TNT Optical afterglow observations
  91. GRB 071020: Swift-XRT refined analysis
  92. GRB 071020, Swift-BAT refined analysis
  93. GRB 071020A: IR Imaging with PAIRITEL
  94. GRB 071020: VLT spectroscopy
  95. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  96. GRB071020 - SDSS Pre-burst Observations
  97. GRB 071020: Swift detection of a bright burst
  98. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  99. GRB 071018: Mercator Telescope optical observations
  100. Swift autonomous slewing re-enabled

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