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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"

25988 results found.

  1. Swift Trigger 880127 is not a GRB
  2. GRB 181228A: Swift-XRT refined Analysis
  3. GRB 181228A: Swift-BAT refined analysis
  4. GRB 181222B: Swift follow-up observations of MASTER optical transient J204928.79+245744.0
  5. GRB 181228A: Swift/UVOT Upper Limits
  6. GRB 181228A: TSHAO optical upper limit
  7. GRB 181228A: Fermi GBM observation
  8. GRB 181228A: Global MASTER Net OT detection
  9. GRB 181228A: REM NIR detection
  10. GRB 181228A: Enhanced Swift-XRT position
  11. GRB 181225A: KAIT Follow-Up Observations with Upper Limit
  12. GRB 181228A: Swift detection of a burst
  13. GRB 181227A: Fermi GBM detection
  14. GRB 181225A: Swift observations and X-ray candidate afterglow
  15. GRB 181225A: Fermi GBM detection
  16. GRB 181225A: Fermi-LAT Detection
  17. GRB 181224A: Swift-BAT refined analysis
  18. GRB 181224A: Swift detection of a burst
  19. GRB 181222B : Fermi GBM detection
  20. Swift Trigger 878504 is not astrophysical
  21. GRB 181222A: Fermi GBM observation
  22. GRB 181222A: MAXI/GSC detection
  23. GRB 181217A: Insight-HXMT/HE detection
  24. GRB 181213A: Swift/UVOT Observations
  25. GRB 181213A: Mondy optical observations
  26. GRB 181213A: continued TSHAO optical observations
  27. GRB 181213A:Insight-HXMT/HE detection
  28. GRB 181212A:Insight-HXMT/HE detection
  29. GRB 181213A: AbAO optical observations
  30. GRB 181213A: HMM-0.5m, NEXT-0.6m, CNEOST-1m optical observations
  31. GRB 181213A: NOT optical observations
  32. GRB 181213A: Swift-XRT refined Analysis
  33. GRB 181213A: Enhanced Swift-XRT position
  34. IPN Triangulation of GRB 181212A (long)
  35. GRB 181213A: Swift-BAT refined analysis
  36. GRB 181213A : TSHAO optical observations
  37. GRB181213A: Swift/UVOT Detection
  38. GRB 181213A: Swift-XRT observations
  39. GRB 181213A: Swift detection of a burst
  40. GRB 181212A: Fermi GBM Detection
  41. GRB 181126B: KAIT Follow-Up Observations of a Fermi Short GRB (Trigger 564897175)
  42. MASTER OT J063515.49-624002.9 of Fermi trigger 565936249: optical observations in SAAO
  43. MASTER: OTs detection during Fermi alert trigger 565936249 early observations
  44. INTEGRAL observations of the events in the GWTC-1 catalog
  45. GRB 181203A: GROND detection of the afterglow
  46. GRB 181126B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 564897175)
  47. GRB 181205A: a long GRB detected by INTEGRAL
  48. GRB181201A: Optical afterglow measurements by GROWTH-India
  49. Swift Trigger 874754 is likely not an astrophysical event
  50. Fermi-GBM Observations During Four New GW-Detected BBH Mergers (Correction)
  51. GRB 181201A: continued optical observations in TSHAO
  52. Fermi-GBM Observations During Four New GW-Detected BBH Mergers
  53. GRB 181203A: Swift/UVOT Upper Limits
  54. GRB 181201A: Continued GROND observations show that afterglow is still bright
  55. GRB181201A: GOTO optical observations
  56. GRB 181203A: Swift-XRT refined Analysis
  57. GRB 181203A: Swift-BAT refined analysis
  58. GRB 181201A: Swift/UVOT Detection
  59. GRB 181202A: Swift/UVOT Detection
  60. GRB 181202A: RATIR Optical and NIR Observations
  61. GRB 181203A: Enhanced Swift-XRT position
  62. GRB 181203A: Swift detection of a burst
  63. GRB 181201A: Further COATLI Optical Monitoring
  64. GRB 181201A: Insight-HXMT/HE detection
  65. GRB 181202A: Swift-BAT refined analysis
  66. GRB 181202A: Swift-XRT refined Analysis
  67. GRB 181201A: GROND detection of the afterglow and redshift upper limit of z < 3
  68. GRB 181201A: optical observations in Chilescope observatory
  69. GRB 181202A: Enhanced Swift-XRT position
  70. GRB 181202A: Swift detection of a burst with an optical counterpart
  71. GRB 181201A: COATLI Optical Detection
  72. GRB 181201A: Fermi-LAT detection
  73. GRB 181201A: Zeiss-1000/CrAO optical observations
  74. GRB 181201A: NOT optical observations
  75. GRB 181201A: optical observations in SAAO
  76. GRB 181201A: iTelescope optical afterglow detection
  77. GRB 181201A: Swift-XRT afterglow detection
  78. GRB 181201A: Swift-XRT afterglow
  79. GRB 181201A MASTER-Net OT detection
  80. GRB 181201A: a long GRB detected by INTEGRAL
  81. Short-duration GRB 181121.4: MASTER-Tavrida possible OT detection near the PGC galaxy during large Fermi error box inspection
  82. GRB 181127A : a long GRB detected by INTEGRAL
  83. GRB 181126A: Swift-BAT refined analysis
  84. GRB 181123B: Keck further near-infrared imaging
  85. GRB 181126A: Swift/UVOT Upper Limits
  86. GRB 181126A: Swift-XRT refined Analysis
  87. GRB 181126A deep Gemini imaging
  88. GRB 181126A: Enhanced Swift-XRT position
  89. GRB 181126A: Swift detection of a burst
  90. GRB 181125A: Fermi GBM observation
  91. GRB 181125A: Swift-BAT refined analysis
  92. GRB 181125A: Swift detection of a burst
  93. GRB 181123B: Global MASTER Net optical inspection
  94. GRB 181123A, Swift-BAT refined analysis
  95. GRB 181123B: Keck near-infrared imaging
  96. GRB 181123B: Swift/UVOT Upper Limits
  97. GRB 181123B: Swift-XRT refined Analysis
  98. GRB 181123B: Enhanced Swift-XRT position
  99. GRB 181123B: Swift detection of a short burst
  100. GRB 181119A: Insight-HXMT/HE detection

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