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

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