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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 071112C: Swift detection of a burst with an optical counterpart
  2. GRB 071112B: Swift detection of a short hard burst
  3. GRB 071112: Swift detection of a possible burst
  4. GRB071109: Super-LOTIS observations
  5. VLA IInd observation of INTEGRAL burst GRB 071109
  6. Swift/UVOT initial analysis of GRB071109
  7. GRB 071109: further Swift-XRT analysis
  8. GRB 071109: TAROT Calern observatory optical observations
  9. No radio detection at Swift-XRT position
  10. GRB 071109: Swift-XRT possible X-ray counterpart
  11. VLA prompt radio detection of the INTEGRAL burst 071109
  12. GRB 071109: IBIS refined analysis
  13. GRB 071109: BOOTES-2 prompt optical observations
  14. GRB 071109: A long GRB detected by INTEGRAL
  15. GRB 071104: Swift-XRT Team Refined Analysis
  16. GRB 071104: Possible Swift UVOT Afterglow Candidate
  17. GRB 071104: Swift-XRT position
  18. GRB 071104: Gamma Ray Burst Localization by SuperAGILE
  19. GRB071010b: optical observation
  20. Swift XRT and UVOT observations of GRB071028B
  21. GRB 071101, Swift-BAT refined analysis
  22. GRB 071101: Swift-XRT Team refined analysis
  23. GRB071101: Optical and NIR upper limits by KANATA
  24. GRB0711101: Two new source from Xinglong TNT observation
  25. GRB 071101: TAROT Calern observatory optical observations
  26. GRB 071101: Swift XRT position
  27. GRB071101 LOAO B,V,R,I observation
  28. GRB 071101: BOOTES-2 prompt optical observations
  29. GRB 071101: a nearby galaxy
  30. GRB 071101: Swift detection of a burst
  31. GRB 071031, Swift-BAT refined analysis
  32. GRB 071031: Swift/UVOT detection of afterglow
  33. GRB 071031: Swift-XRT Team refined analysis
  34. GRB 071020: MITSuME Akeno optical observations
  35. GRB 071031: REM NIR and Optical observation
  36. GRB 071031, SMARTS afterglow observations
  37. GRB 071031: VLT high-resolution spectroscopy
  38. GRB071031: Rapid PROMPT Detections
  39. GRB 071031: GROND detection in all bands
  40. GRB 071031: Swift detection of a burst with an optical counterpart
  41. GRB 071028B Swift-BAT detection of a burst
  42. GRB071025: Optical+NIR observations
  43. GRB 071028: SARA observations of variable source
  44. Swift UVOT upper limits to GRB071028
  45. GRB071028: Xinglong EST V-band upper limit
  46. GRB 071028: Swift-XRT Team refined analysis
  47. GRB 071028, Swift-BAT refined analysis
  48. GRB 071028: Swift detection of a burst
  49. GRB 071025: Kuiper Telescope Optical Observations
  50. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  51. GRB 071018: Revised BAT position
  52. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  53. GRB071021: MARGE Optical Limits
  54. GRB071020, optical upper limit
  55. GRB 071025: SARA VRI upper limits
  56. GRB 071025 Milagro GeV/TeV Observations
  57. GRB 071025: SQIID JHK photometry
  58. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  59. GRB071025: Optical Pre-imaging from Palomar
  60. Swift UVOT upper limits
  61. GRB071025: Xinglong TNT I-band upper limit
  62. GRB 071025: Swift-XRT Team refined analysis
  63. GRB 060602A: host redshift
  64. GRB 071025, Swift-BAT refined analysis
  65. GRB 071025: Early Super-LOTIS Observations
  66. GRB 071025: R/I-band update
  67. GRB071021 : CFHT Ks-band observation
  68. GRB 071025: ROTSE-III Refined Analysis
  69. GRB 071025: I-detection, R-dropout?
  70. GRB 071025: Swift XRT refined position
  71. GRB 071025a: PAIRITEL observations
  72. GRB071025: REM NIR afterglow
  73. GRB 071025: ROTSE-III Detection of Optical Counterpart
  74. GRB 071025: Swift detection of a burst
  75. GRB 071021: R-band detection and analysis
  76. GRB 071020: BTA spectroscopy
  77. GRB071021: Optical+NIR observations
  78. Possible radio detection of GRB 071021 with the VLA
  79. Optical observations of GRB 071020
  80. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  81. GRB 071020: SARA observations
  82. Radio detection of GRB 071020 with the VLA
  83. GRB071010b: optical observation
  84. GRB 071021: Subaru NIR observation
  85. GRB071021: MITSuME Okayama Optical Upper Limits
  86. GRB 071021: Magellan i-band observation
  87. GRB 071021: Magellan R-band observation
  88. GRB 071021: Z-band detection
  89. GRB 071021: correction to GCNC 6968
  90. GRB 071020: Fading slowly?
  91. GRB 071010B: Fading quickly
  92. GRB 071021: optical and NIR observations
  93. GRB 071021: possible high-z burst
  94. GRB 071021, Swift-BAT refined analysis
  95. GRB071018: 2nd epoch obsevations of Xinglong TNT
  96. GRB 071021: retraction of Faulkes Telescope South candidate
  97. GRB 071021: Swift-XRT Team refined analysis
  98. GRB 071021: Xinglong TNT optical Upper Limit
  99. GRB 071021 : Lulin R-band limit
  100. Konus-Wind observation of GRB 071020

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