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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 141004A: Monte Agliale Observatory optical observations
  2. GRB 141005A: RATIR Optical Observations
  3. GRB 141005A: P60 probable afterglow deteaction
  4. GRB 141004A: Enhanced Swift-XRT position
  5. GRB 141005A: Swift detection of a burst
  6. GRB 141004A: TNG photometric and spectroscopic observations
  7. GRB 141004A: 1.23m CAHA optical observations
  8. GRB 141004A: a long GRB detected by INTEGRAL
  9. GRB 141004A: Swift detection of a burst with an optical counterpart
  10. Swift observations of HD 305560
  11. GRB 140928A: Swift-XRT follow-up observations
  12. GRB 140930B: MASTER early possible OT detection
  13. Swift possible detection of the Be star HD 305560
  14. GRB 140930B: Gemini South Spectroscopy
  15. GRB 140930B: GROND observations
  16. GRB 140930A/MAXI J2259+524: MASTER optical observations
  17. GRB 140930B Swift-BAT refined analysis
  18. GRB 140930B: Swift/UVOT Upper Limits
  19. Konus-Wind observation of GRB 140930B
  20. GRB 140930B: Keck NIR imaging
  21. GRB 140930B: Swift-XRT refined Analysis
  22. GRB 140930B: Enhanced Swift-XRT position
  23. GRB 140928A: MAXI-GSC detection
  24. GRB 140930B: MMT confirmation of the optical afterglow
  25. GRB 140930B: ISON-Kislovodsk observations
  26. GRB 140930B: WHT detection of candidate afterglow
  27. GRB 140930B: 1.23m CAHA optical observations
  28. GRB 140930B: Prompt enhanced Swift-XRT position
  29. GRB 140930B: MASTER early optical observations
  30. GRB 140930B: Swift detection of a short burst
  31. GRB140928A: Gemini-South observation
  32. GRB 140930A/MAXI J2259+524: MAXI-GSC detection
  33. Konus-Wind observation of GRB 140928A
  34. GRB 140928A: LCO-Cerro Tololo further observations
  35. IPN Triangulation of GRB 140928A
  36. GRB 140928A: LCO-Cerro Tololo observations
  37. GRB 140928A: Fermi GBM detection
  38. GRB 140928A: GROND Afterglow Candidate
  39. GRB 140928A: Swift-XRT observations
  40. GRB 140928A: Fermi-LAT detection
  41. GRB 140927A: Swift-UVOT analysis
  42. GRB 140927A: Swift-BAT refined analysis
  43. GRB 140927A: Swift-XRT refined Analysis
  44. GRB 140927A: Enhanced Swift-XRT position
  45. GRB 140927A: Swift detection of a burst
  46. Swift Trigger 613581 is not an astrophysical event
  47. Swift Trigger 613516 is not an astrophysical event
  48. GRB 140919A, Swift-BAT refined analysis
  49. GRB 140919A: Swift-XRT refined Analysis
  50. GRB 140919A: Swift/UVOT Detection
  51. GRB 140919A: GROND afterglow candidate
  52. GRB 140919A: Fermi GBM observation
  53. GRB 140919A: Enhanced Swift-XRT position
  54. GRB 140919A: Swift/UVOT observations
  55. GRB 140919A: Swift-XRT observations
  56. GRB 140919A: Swift detection of a burst
  57. GRB 140916B: LOT and iPTF follow-up of optical afterglow candidates
  58. Swift detection of outburst from 4U 1700+24
  59. GRB 140916A: Swift/UVOT Upper Limits
  60. GRB 140916A: Swift-BAT refined analysis
  61. GRB 140916A: UKIRT J-band observations
  62. GRB 140916A: Swift-XRT refined Analysis
  63. GRB 140916A: Enhanced Swift-XRT position
  64. GRB 140916A: MITSuME Okayama upper limits
  65. GRB 140916B: iPTF Optical Observations
  66. GRB 140916A: FTS observations
  67. GRB 140916A: Prompt enhanced Swift-XRT position
  68. GRB 140916A: Swift detection of a burst
  69. GRB 140907A: Continued DCT Observations
  70. Fermi GBM trigger 140913075 is not a GRB
  71. GRB 140909A: Confirmation of the Swift-XRT afterglow
  72. Possible radio detection of GRB 140903A with the GMRT
  73. GRB 140907A: Mondy optical observations
  74. GRB 140903A: Chandra detection of the afterglow
  75. GRB 140909A: Swift/UVOT Upper Limits
  76. GRB 140909A: Swift-XRT observations
  77. GRB 140907A: 1.23m CAHA optical observations
  78. GRB 140907A: TShAO observations
  79. GRB 140909A: Swift detection of a GRB
  80. Konus-Wind observation of GRB 140906C
  81. GRB 140907A: MASTER optical observations
  82. Refined IPN Triangulation of GRB 140906C
  83. GRB 140907A: Nishi-Harima NIR Observations
  84. GRB 140907A: MITSuME Akeno Optical Observation
  85. GRB 140907A: Discovery Channel Telescope observations
  86. IPN Triangulation of GRB 140906C (short/hard)
  87. GRB 140907A: T100 observations
  88. GRB 140907A: Swift-BAT refined analysis
  89. GRB 140907A: Fermi GBM Detection
  90. GRB 140907A: redshift from the 10.4m GTC telescope
  91. GRB 140907A: Swift-XRT refined Analysis
  92. GRB 140907A: Enhanced Swift-XRT position
  93. GRB 140907A: MITSuME Ishigakijima Optical Observation
  94. GRB140907A: MITSuME Okayama Optical Observation
  95. GRB 140907A : Virtual Telescope optical observations
  96. GRB140907A: Swift UVOT detection
  97. GRB 140906B: Fermi GBM Detection of a Long GRB
  98. GRB 140907A : Optical observations from Nanshan
  99. GRB 140907A: Swift detection of a burst with an optical counterpart
  100. GRB 140906A - Fermi GBM Detection

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