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

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