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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"

26042 results found.

  1. GRB 210919A: Maidanak optical observations
  2. GRB 210919A: SPI-ACS/INTEGRAL observation and evaluation of Ep
  3. Konus-Wind detection of GRB 220203A
  4. GRB 220203A: GECAM detection
  5. GRB 220203A: Swift/BAT-GUANO detection outside the coded FOV
  6. IPN triangulation of GRB 220203A (short)
  7. IPN triangulation of GRB 220130A
  8. Swift Reaction Wheel Anomaly Update (4 Feb 2022)
  9. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  10. GRB 220131B: Swift/BAT-GUANO detection outside the coded FOV
  11. IPN triangulation of GRB 220128A (long)
  12. IPN triangulation of GRB 220124A
  13. GRB 220117A, GROND observations
  14. GRB 220117A: Terskol and AbAO optical upper limits
  15. GRB 220118A: TARGET optical upper limit
  16. GRB 220117B: TARGET optical upper limit
  17. GRB 220117A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
  18. IPN triangulation of GRB 211226A
  19. GRB 220117C: Fermi GBM Observation
  20. GRB 220118A: 2.2m CAHA/CAFOS detections
  21. GRB 220118A: Fermi GBM detection
  22. GRB 220118A: COATLI Optical Observations
  23. GRB 220101A: KAO optical-R observation
  24. GRB 211221A: No V & R detection, KAO telescope
  25. GRB 220118A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  26. GRB 220117C: Swift/BAT-GUANO arcminute localization
  27. Swift currently in safe hold with science slews disabled
  28. GRB 220118A: Swift-BAT refined analysis
  29. GRB 220118A: Swift/UVOT Detection
  30. GRB 220118A: GIT optical observations
  31. GRB 220118A: Enhanced Swift-XRT position
  32. Swift GRB220118.50: Global MASTER-Net observations report
  33. GRB 220118A: MITSuME Akeno optical observation
  34. GRB 220117B: z-band limit
  35. Swift GRB 220118A: Global MASTER-Net observations report
  36. GRB 220118A: Swift detection of a burst with an optical counterpart
  37. GRB 220117A: MITSuME Akeno optical upper limits
  38. Fermi GBM Sub-Threshold Detection of GRB 220117A
  39. GRB 220117B: Swift-BAT refined analysis
  40. GRB 220117A: Swift-BAT refined analysis
  41. GRB 220117B: Swift/UVOT Upper Limits
  42. GRB 220117A: Swift/UVOT Upper Limits
  43. GRB 220117A: LCO Optical Observations
  44. GRB 220117A: VLT/X-shooter optical afterglow and redshift
  45. GRB 220117B: Swift-XRT refined Analysis
  46. GRB 220117A: Swift-XRT refined Analysis
  47. GRB 220117B: Nanshan/NEXT optical upper limit
  48. GRB 220117B: MITSuME Akeno optical upper limits
  49. GRB 220117B: Enhanced Swift-XRT position
  50. GRB 220117A: Enhanced Swift-XRT position
  51. GRB 220101A: TSHAO optical observation, Terskol, AbAO upper limits
  52. Swift GRB 220117A: Global MASTER-Net observations report
  53. Swift GRB 220117B: Global MASTER-Net observations report
  54. GRB 220117B: Swift detection of a burst
  55. GRB 220117A: Nanshan/NEXT optical observations and a nearby PanSTARRS source
  56. GRB 220117A: Swift detection of a burst
  57. GRB 220101A: The most powerful GRB and BDHN I in 26 years
  58. GRB 210919A: LBT spectroscopic redshift of the host galaxy candidates
  59. GRB 220101A: continued 1.3m DFOT optical observations of a high-redshift afterglow
  60. Konus-Wind detection of GRB 220101A
  61. GRB 220107A: SAO RAS optical observations
  62. Konus-Wind detection of GRB 220107A
  63. Confirmation of the X-ray afterglow of GRB 220107B
  64. GRB 220107A: further SAO RAS optical observations
  65. GRB 220101A: Additional Liverpool telescope photometry
  66. GRB 220107A: 6m BTA spectroscopic redshift
  67. GRB 220107A: SAO RAS optical observations
  68. GRB 220108A: Swift/BAT-GUANO detection outside the coded FOV
  69. GRB 220101A: SAO RAS optical observations
  70. GRB 220107A: AbAO and Terskol optical observations
  71. GRB 220107B: MITSuME Akeno optical upper limits
  72. GRB 220107B: Nanshan/NEXT optical upper limits and host galaxy candidate
  73. GRB 220107A: Nanshan/NEXT optical observations
  74. GRB 220107A: Swift/UVOT Detection
  75. GRB 220107A: MITSuME Akeno optical observation
  76. GRB 220107B: AstroSat CZTI detection
  77. GRB 220107B: Swift-XRT afterglow detection
  78. GRB 220107A: Swift-XRT afterglow detection
  79. GRB 220107B: Fermi-LAT detection
  80. GRB 220107A: AstroSat CZTI detection
  81. GRB 220107B: Tiled Swift observations
  82. GRB 220107A: Fermi GBM observations
  83. GRB 220107A: Swift ToO observations
  84. GRB 220107A: Swift/BAT-GUANO arcminute localization
  85. GRB 220101A: Tautenburg observations
  86. GRB 220101A: Continued Mondy optical observations
  87. GRB 220101A: further TNG NIR observations
  88. GRB 220101A: continued 1.3m DFOT Optical Observations
  89. GRB 220101A: Mondy optical observations
  90. GRB 220101A: 3rd LCO Optical Observation
  91. GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection
  92. GRB 220101A: iTelescope optical observations
  93. GRB 211227A: Lijiang 2.4m Telescope Optical Observations
  94. GRB 220101A: 1.3m DFOT observations
  95. GRB 220101A: LCO Continued Optical Observations
  96. GRB 211229B: Fermi GBM observation
  97. GRB 211227A: Gemini South Optical Observations
  98. GRB 211229B: Swift/BAT-GUANO detection outside the coded FOV
  99. GRB 220101A: TNG NIR afterglow detection
  100. GRB 220101A: LCO Optical Observations

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