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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. GRB0711101: Two new source from Xinglong TNT observation
  2. GRB 071101: TAROT Calern observatory optical observations
  3. GRB 071101: Swift XRT position
  4. GRB071101 LOAO B,V,R,I observation
  5. GRB 071101: BOOTES-2 prompt optical observations
  6. GRB 071101: a nearby galaxy
  7. GRB 071101: Swift detection of a burst
  8. GRB 071031, Swift-BAT refined analysis
  9. GRB 071031: Swift/UVOT detection of afterglow
  10. GRB 071031: Swift-XRT Team refined analysis
  11. GRB 071020: MITSuME Akeno optical observations
  12. GRB 071031: REM NIR and Optical observation
  13. GRB 071031, SMARTS afterglow observations
  14. GRB 071031: VLT high-resolution spectroscopy
  15. GRB071031: Rapid PROMPT Detections
  16. GRB 071031: GROND detection in all bands
  17. GRB 071031: Swift detection of a burst with an optical counterpart
  18. GRB 071028B Swift-BAT detection of a burst
  19. GRB071025: Optical+NIR observations
  20. GRB 071028: SARA observations of variable source
  21. Swift UVOT upper limits to GRB071028
  22. GRB071028: Xinglong EST V-band upper limit
  23. GRB 071028: Swift-XRT Team refined analysis
  24. GRB 071028, Swift-BAT refined analysis
  25. GRB 071028: Swift detection of a burst
  26. GRB 071025: Kuiper Telescope Optical Observations
  27. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  28. GRB 071018: Revised BAT position
  29. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  30. GRB071021: MARGE Optical Limits
  31. GRB071020, optical upper limit
  32. GRB 071025: SARA VRI upper limits
  33. GRB 071025 Milagro GeV/TeV Observations
  34. GRB 071025: SQIID JHK photometry
  35. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  36. GRB071025: Optical Pre-imaging from Palomar
  37. Swift UVOT upper limits
  38. GRB071025: Xinglong TNT I-band upper limit
  39. GRB 071025: Swift-XRT Team refined analysis
  40. GRB 060602A: host redshift
  41. GRB 071025, Swift-BAT refined analysis
  42. GRB 071025: Early Super-LOTIS Observations
  43. GRB 071025: R/I-band update
  44. GRB071021 : CFHT Ks-band observation
  45. GRB 071025: ROTSE-III Refined Analysis
  46. GRB 071025: I-detection, R-dropout?
  47. GRB 071025: Swift XRT refined position
  48. GRB 071025a: PAIRITEL observations
  49. GRB071025: REM NIR afterglow
  50. GRB 071025: ROTSE-III Detection of Optical Counterpart
  51. GRB 071025: Swift detection of a burst
  52. GRB 071021: R-band detection and analysis
  53. GRB 071020: BTA spectroscopy
  54. GRB071021: Optical+NIR observations
  55. Possible radio detection of GRB 071021 with the VLA
  56. Optical observations of GRB 071020
  57. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  58. GRB 071020: SARA observations
  59. Radio detection of GRB 071020 with the VLA
  60. GRB071010b: optical observation
  61. GRB 071021: Subaru NIR observation
  62. GRB071021: MITSuME Okayama Optical Upper Limits
  63. GRB 071021: Magellan i-band observation
  64. GRB 071021: Magellan R-band observation
  65. GRB 071021: Z-band detection
  66. GRB 071021: correction to GCNC 6968
  67. GRB 071020: Fading slowly?
  68. GRB 071010B: Fading quickly
  69. GRB 071021: optical and NIR observations
  70. GRB 071021: possible high-z burst
  71. GRB 071021, Swift-BAT refined analysis
  72. GRB071018: 2nd epoch obsevations of Xinglong TNT
  73. GRB 071021: retraction of Faulkes Telescope South candidate
  74. GRB 071021: Swift-XRT Team refined analysis
  75. GRB 071021: Xinglong TNT optical Upper Limit
  76. GRB 071021 : Lulin R-band limit
  77. Konus-Wind observation of GRB 071020
  78. GRB 071021: Faulkes Telescope South optical candidate
  79. GRB 071021: Swift detection of a burst
  80. GRB 071010B: Independent Confirmation of Break
  81. GRB071020A: Xinglong TNT Optical afterglow observations
  82. GRB 071020: Swift-XRT refined analysis
  83. GRB 071020, Swift-BAT refined analysis
  84. GRB 071020A: IR Imaging with PAIRITEL
  85. GRB 071020: VLT spectroscopy
  86. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  87. GRB071020 - SDSS Pre-burst Observations
  88. GRB 071020: Swift detection of a bright burst
  89. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  90. GRB 071018: Mercator Telescope optical observations
  91. Swift autonomous slewing re-enabled
  92. GRB071010b: optical observations
  93. GRB 071018: SARA observations
  94. GRB 071018: Swift-XRT observation
  95. GRB 071017 - Swift XRT observations
  96. VLA radio observation of GRB 071018
  97. GRB071018: Correction to the GCN 6936
  98. GRB071018: Correction to the GCN 6936
  99. GRB071018: Correction to the GCN 6936
  100. GRB071018: Correction to the title of the GCN 6936

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