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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 141212B: Swift-BAT refined analysis
  2. GRB 141212A: Swift-BAT refined analysis
  3. GRB 141212B: Enhanced Swift-XRT position
  4. Swift detection of 4U 1700+24 (= V934 Her)
  5. GRB 141212A: MITSuME Okayama upper limits
  6. GRB 141212A: Swift-XRT refined Analysis
  7. GRB 141212A: extended object within the XRT error circle
  8. GRB141212A: xinglong TNT upper limit
  9. GRB 141212A: Khureltogot optical upper limit
  10. GRB 141212A: 1.23m CAHA I-band observations
  11. GRB 141212B: initial Swift/UVOT observations
  12. GRB 141212B: Swift/XRT preliminary localization
  13. GRB 141212A: Enhanced Swift-XRT position
  14. GRB 141212A: Correction to GCN 17162
  15. GRB 141212A: MASTER early optical observations
  16. GRB 141212A: Skynet R-COP Observations
  17. GRB 141212A: MITSuME Akeno upper limits
  18. GRB 141212B: Swift detection of a burst
  19. GRB 141212A: Swift detection of a short burst
  20. GRB 141207A: Swift-XRT afterglow candidate detection
  21. GRB 141121A: further VLA observations
  22. Konus-Wind observation of GRB 141207A
  23. GRB141208.63: MASTER OT Detection During the Fermi Error Box inspection
  24. GRB141202A: Discovery Channel Telescope Optical Observations
  25. GRB141207A: Discovery Channel Telescope Optical Observations
  26. GRB 141207A: Swift-UVOT Observations
  27. GRB 141207A: Fermi GBM detection
  28. GRB 141207A: Swift-XRT observations
  29. Konus-Wind observation of GRB 141130A
  30. GRB 141207A Tiled Swift observations
  31. GRB 141207A: Fermi-LAT Detection
  32. GRB141121A: Discovery Channel Telescope Optical Observations
  33. GRB 141205A: Swift/UVOT Upper Limits
  34. GRB 141205A: Fermi GBM detection
  35. GRB 141205A: Nanshan optical upper limit
  36. GRB 141205A: XRT observations
  37. GRB 141205A Swift-BAT refined analysis
  38. GRB 141202A: Swift/UVOT Detection of a Variable Source Near the IPN Error Box
  39. GRB 141121A: Mondy optical observations
  40. GRB 141205A Short hard GRB found in ground analysis of BAT data
  41. Konus-Wind observation of GRB 141202A
  42. GRB 141130A: Mondy optical observations
  43. GRB 141202A: Swift XRT observations
  44. GRB 141202A: Fermi GBM Detection
  45. GRB 141202A Tiled Swift observations
  46. IPN Triangulation of GRB 141202A (short/hard)
  47. GRB 141130A: Mondy optical light curve
  48. GRB 141030A: Nanshan very early optical observations
  49. GRB 141121A: Continued RATIR Optical Observations
  50. GRB 141130A: Swift-BAT refined analysis
  51. GRB 141130A: Swift/UVOT Detection
  52. GRB 141130A: Swift-XRT refined Analysis
  53. GRB 141121A: VLA radio detection
  54. GRB 141130A: Enhanced Swift-XRT position
  55. GRB 141130A: Nanshan optical observations
  56. GRB 141130A: Mondy optical observations
  57. GRB 141130A: Swift detection of a burst with an optical counterpart
  58. GRB 141121A: Continued RATIR Optical Observations
  59. GRB 141121A: Mondy optical observations
  60. GRB 141121A: TSHAO optical observations
  61. GRB 141121A: Continued RATIR Optical Observations
  62. GRB 141121A: RATIR Optical Observations - Errata for GCN 17105
  63. GRB 141121A: MITSuME Ishigakijima Optical Observation after 7 days
  64. GRB 141121A: Khureltogot optical observations
  65. IPN Triangulation of GRB 141121A (initial episode)
  66. GRB 141121A: Mondy optical observations
  67. GRB 141121A: SPI-ACS/INTEGRAL observations
  68. GRB 141121A: RATIR Optical and NIR Observations
  69. Konus-Wind observation of GRB 141121A
  70. IPN Triangulation of GRB 141125A (short/hard)
  71. GRB 141121A: three epochs of SAO RAS optical observations
  72. GRB 141121A: Continued RATIR Optical Observations
  73. GRB 141121A: WSRT radio detection
  74. GRB 141121A: TSHAO optical observations
  75. GRB 141121A: Continued Mondy optical observations
  76. GRB 141121A: Continued RATIR Optical Observations
  77. GRB 141121A: RATIR Optical Observations - Steeper Fading
  78. GRB 141121A: AMI 15 GHz detection
  79. GRB 141121A: MITSuME Ishigakijima Optical Observation after 3 days
  80. GRB 141124A​: iPTF upper limits​
  81. GRB 141121A: RATIR Optical Observations - Fading Again
  82. GRB141124A: MASTER Detection of New Flare of QSO NVSS J075043+790917 During the Fermi Error Box inspection
  83. GRB 141118A: Fermi GBM Detection
  84. GRB 141121A: Mondy optical observations
  85. GRB 141121A: LCO-FTN rebrightening confirmation
  86. GRB 141121A: MITSuME Ishigakijima Optical Observation
  87. GRB 141121A: Continued RATIR Optical Observations - Rebrightening
  88. GRB 141121A: AAO optical observations
  89. GRB 141121A: MITSuME Akeno Optical observation
  90. GRB 141121A: Continued RATIR Optical Observations
  91. GRB 141121A: Swift-XRT refined Analysis
  92. GRB 141121A: Swift/UVOT Detections
  93. GRB 141121A: RATIR Optical Observations
  94. GRB 141121A: Swift-BAT refined analysis
  95. GRB 141121A: LCO-FTN observations
  96. GRB 141121A: Keck redshift
  97. GRB 141121A: Enhanced Swift-XRT position
  98. GRB 141118A: iPTF Optical Observations
  99. GRB 141121A: GROND Afterglow candidate
  100. GRB 141121A: MAXI/GSC detection

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