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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 071109: A long GRB detected by INTEGRAL
  2. GRB 071104: Swift-XRT Team Refined Analysis
  3. GRB 071104: Possible Swift UVOT Afterglow Candidate
  4. GRB 071104: Swift-XRT position
  5. GRB 071104: Gamma Ray Burst Localization by SuperAGILE
  6. GRB071010b: optical observation
  7. Swift XRT and UVOT observations of GRB071028B
  8. GRB 071101, Swift-BAT refined analysis
  9. GRB 071101: Swift-XRT Team refined analysis
  10. GRB071101: Optical and NIR upper limits by KANATA
  11. GRB0711101: Two new source from Xinglong TNT observation
  12. GRB 071101: TAROT Calern observatory optical observations
  13. GRB 071101: Swift XRT position
  14. GRB071101 LOAO B,V,R,I observation
  15. GRB 071101: BOOTES-2 prompt optical observations
  16. GRB 071101: a nearby galaxy
  17. GRB 071101: Swift detection of a burst
  18. GRB 071031, Swift-BAT refined analysis
  19. GRB 071031: Swift/UVOT detection of afterglow
  20. GRB 071031: Swift-XRT Team refined analysis
  21. GRB 071020: MITSuME Akeno optical observations
  22. GRB 071031: REM NIR and Optical observation
  23. GRB 071031, SMARTS afterglow observations
  24. GRB 071031: VLT high-resolution spectroscopy
  25. GRB071031: Rapid PROMPT Detections
  26. GRB 071031: GROND detection in all bands
  27. GRB 071031: Swift detection of a burst with an optical counterpart
  28. GRB 071028B Swift-BAT detection of a burst
  29. GRB071025: Optical+NIR observations
  30. GRB 071028: SARA observations of variable source
  31. Swift UVOT upper limits to GRB071028
  32. GRB071028: Xinglong EST V-band upper limit
  33. GRB 071028: Swift-XRT Team refined analysis
  34. GRB 071028, Swift-BAT refined analysis
  35. GRB 071028: Swift detection of a burst
  36. GRB 071025: Kuiper Telescope Optical Observations
  37. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  38. GRB 071018: Revised BAT position
  39. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  40. GRB071021: MARGE Optical Limits
  41. GRB071020, optical upper limit
  42. GRB 071025: SARA VRI upper limits
  43. GRB 071025 Milagro GeV/TeV Observations
  44. GRB 071025: SQIID JHK photometry
  45. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  46. GRB071025: Optical Pre-imaging from Palomar
  47. Swift UVOT upper limits
  48. GRB071025: Xinglong TNT I-band upper limit
  49. GRB 071025: Swift-XRT Team refined analysis
  50. GRB 060602A: host redshift
  51. GRB 071025, Swift-BAT refined analysis
  52. GRB 071025: Early Super-LOTIS Observations
  53. GRB 071025: R/I-band update
  54. GRB071021 : CFHT Ks-band observation
  55. GRB 071025: ROTSE-III Refined Analysis
  56. GRB 071025: I-detection, R-dropout?
  57. GRB 071025: Swift XRT refined position
  58. GRB 071025a: PAIRITEL observations
  59. GRB071025: REM NIR afterglow
  60. GRB 071025: ROTSE-III Detection of Optical Counterpart
  61. GRB 071025: Swift detection of a burst
  62. GRB 071021: R-band detection and analysis
  63. GRB 071020: BTA spectroscopy
  64. GRB071021: Optical+NIR observations
  65. Possible radio detection of GRB 071021 with the VLA
  66. Optical observations of GRB 071020
  67. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  68. GRB 071020: SARA observations
  69. Radio detection of GRB 071020 with the VLA
  70. GRB071010b: optical observation
  71. GRB 071021: Subaru NIR observation
  72. GRB071021: MITSuME Okayama Optical Upper Limits
  73. GRB 071021: Magellan i-band observation
  74. GRB 071021: Magellan R-band observation
  75. GRB 071021: Z-band detection
  76. GRB 071021: correction to GCNC 6968
  77. GRB 071020: Fading slowly?
  78. GRB 071010B: Fading quickly
  79. GRB 071021: optical and NIR observations
  80. GRB 071021: possible high-z burst
  81. GRB 071021, Swift-BAT refined analysis
  82. GRB071018: 2nd epoch obsevations of Xinglong TNT
  83. GRB 071021: retraction of Faulkes Telescope South candidate
  84. GRB 071021: Swift-XRT Team refined analysis
  85. GRB 071021: Xinglong TNT optical Upper Limit
  86. GRB 071021 : Lulin R-band limit
  87. Konus-Wind observation of GRB 071020
  88. GRB 071021: Faulkes Telescope South optical candidate
  89. GRB 071021: Swift detection of a burst
  90. GRB 071010B: Independent Confirmation of Break
  91. GRB071020A: Xinglong TNT Optical afterglow observations
  92. GRB 071020: Swift-XRT refined analysis
  93. GRB 071020, Swift-BAT refined analysis
  94. GRB 071020A: IR Imaging with PAIRITEL
  95. GRB 071020: VLT spectroscopy
  96. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  97. GRB071020 - SDSS Pre-burst Observations
  98. GRB 071020: Swift detection of a bright burst
  99. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  100. GRB 071018: Mercator Telescope optical observations

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