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

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