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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"

19949 results found.

  1. GRB 241218A: REM optical upper limit
  2. GRB 241217A/EP241217b: REM optical/NIR upper limits
  3. EP241217a: REM optical/NIR upper limits
  4. GRB 241218a: Liverpool Telescope optical follow-up
  5. GRB 241217a: Liverpool Telescope optical follow-up
  6. GRB 241218A: Swift-XRT refined Analysis
  7. GRB 241209A: ATCA radio follow-up observations
  8. GRB 241218A: LCOGT Optical Upper Limit
  9. GRB 241218A: Enhanced Swift-XRT position
  10. GRB 241218A: Swift detection of a burst
  11. GRB 241217A : SVOM/VT optical afterglow detection
  12. GRB 241217A: Swift-XRT afterglow detection
  13. EP241217a: Swift-XRT Detection
  14. GRB 241214A: GRBAlpha detection
  15. GRB 241213A (EP241213a): GRBAlpha detection
  16. GRB 241209D: GRBAlpha detection
  17. GRB 241213A: Swift-BAT refined analysis
  18. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  19. Konus-Wind detection of GRB 241213A (EP 241213a)
  20. GRB 241212A: Swift-XRT observations
  21. GRB 241213B: Swift-XRT observations
  22. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  23. GRB 241213A: SVOM/VT optical candidate
  24. GRB 241213B: Tiled Swift observations
  25. GRB 241213A: Swift/UVOT Upper Limits
  26. GRB 241213A: Swift-XRT refined Analysis
  27. GRB 241212A: Swift ToO observations
  28. GRB 241213A: LCOGT Optical Upper Limits
  29. EP241213a: EP detection of An X-ray Transient
  30. GRB 241213A: REM optical/NIR upper limits
  31. GRB 241213A: Enhanced Swift-XRT position
  32. Swift GRB 241213A: Global MASTER-Net observations report
  33. GRB 241213A: Swift detection of a burst
  34. GRB 241209A: Chandra X-ray Detection
  35. Konus-Wind detection of GRB 241209B
  36. GRB 241209B: GRBAlpha detection
  37. GRB 241129A: Fermi GBM Observation
  38. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  39. GRB 241209D: REM optical/NIR upper limits
  40. Konus-Wind detection of GRB 241209D
  41. GRB 241209B: Swift-XRT afterglow detection
  42. GRB 241209C: Fermi GBM Observation
  43. GRB 241209A: Swift-XRT refined Analysis
  44. GRB 241209D: AstroSat CZTI detection
  45. GRB 241209A: EP-FXT follow-up observations
  46. GRB 241209B: SVOM/VT afterglow detection
  47. GRB 241207B: Fermi GBM Observation
  48. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  49. GRB 241209D: Swift-XRT refined Analysis
  50. GRB 241209D: Fermi GBM Observation
  51. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  52. GRB 241209D: COLIBRÍ detection of the afterglow
  53. GRB 241209A: COLIBRÍ Optical Upper Limit
  54. GRB 241209A: Fermi GBM Observation
  55. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  56. GRB 241209A: GRANDMA/TAROT upper limit
  57. Swift GRB 241209D: Global MASTER-Net observations report
  58. GRB 241209B: Swift ToO observations
  59. GRB 241209A: REM optical/NIR observations
  60. GRB 241209D: Enhanced Swift-XRT position
  61. GRB 241209D: Swift detection of a burst
  62. GRB 241209A: Enhanced Swift-XRT position
  63. GRB 241209A: GOTO optical upper limits
  64. GRB 241209A: Prompt enhanced Swift-XRT position
  65. GRB 241209A: Swift detection of a short burst
  66. Swift GRB241209.23: Global MASTER-Net observations report
  67. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  68. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  69. GRB 241206A: DDOTI Upper Limit on the Afterglow
  70. GRB 241207C: Tiled Swift observations
  71. GRB 241206A: Fermi GBM observation
  72. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  73. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  74. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  75. GRB 241128A: Swift/UVOT Upper Limits
  76. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  77. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  78. SVOM/GRM observation of a short burst from soft gamma repeater Kes 73
  79. GRB 241128A: Swift-BAT refined analysis
  80. GRB 241127A: Swift-BAT refined analysis
  81. GRB 241127A: PRIME near-infrared detection
  82. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  83. Swift-XRT observations of IceCube -241127A
  84. Swift GRB 241128A: Global MASTER-Net observations report
  85. GRB 241128A: Swift-XRT refined Analysis
  86. GRB 241128A: Enhanced Swift-XRT position
  87. GRB 241128A: 1.5m OSN optical afterglow detection
  88. GRB 241128A: Swift-XRT afterglow detection
  89. GRB 241128A: Swift detection of a burst
  90. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  91. GRB 241127A: Swift/UVOT Detection
  92. GRB 241127A: Swift-XRT refined Analysis
  93. GRB 241127A: SVOM/GRM observation
  94. GRB 241127A: Enhanced Swift-XRT position
  95. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  96. Swift GRB241127.91: Global MASTER-Net OT detection
  97. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  98. GRB 241127A: Swift detection of a burst with an optical counterpart
  99. Swift GRB241127.91: Global MASTER-Net observations report
  100. Swift GRB241127.91: Global MASTER-Net OT detection

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