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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"

18633 results found.

  1. GRB 241228A: Swift-XRT refined Analysis
  2. GRB 241228A: Swift/UVOT Upper Limits
  3. GRB 241228A: Enhanced Swift-XRT position
  4. GRB 241228A: Swift detection of a burst
  5. GRB 241223A: Swift-XRT observations
  6. GRB241113A: 7DT Optical upper limits
  7. GRB 241223A: GOTO optical observations summary
  8. GRB 241223A: Swift ToO observations
  9. GRB 241218A: Mondy AZT-33IK optical upper limit
  10. GRB 241218A: Swift/UVOT Upper Limits
  11. EP241217a: optical upper limit with the Liverpool Telescope
  12. GRB 241209B: EP-FXT afterglow detection
  13. GRB 241218A: NOT optical upper limits
  14. GRB 241218A: Swift-BAT refined analysis
  15. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  16. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  17. GRB 241218A: REM optical upper limit
  18. GRB 241217A/EP241217b: REM optical/NIR upper limits
  19. EP241217a: REM optical/NIR upper limits
  20. GRB 241218a: Liverpool Telescope optical follow-up
  21. GRB 241217a: Liverpool Telescope optical follow-up
  22. GRB 241218A: Swift-XRT refined Analysis
  23. GRB 241209A: ATCA radio follow-up observations
  24. GRB 241218A: LCOGT Optical Upper Limit
  25. GRB 241218A: Enhanced Swift-XRT position
  26. GRB 241218A: Swift detection of a burst
  27. GRB 241217A : SVOM/VT optical afterglow detection
  28. GRB 241217A: Swift-XRT afterglow detection
  29. EP241217a: Swift-XRT Detection
  30. GRB 241214A: GRBAlpha detection
  31. GRB 241213A (EP241213a): GRBAlpha detection
  32. GRB 241209D: GRBAlpha detection
  33. GRB 241213A: Swift-BAT refined analysis
  34. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  35. Konus-Wind detection of GRB 241213A (EP 241213a)
  36. GRB 241212A: Swift-XRT observations
  37. GRB 241213B: Swift-XRT observations
  38. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  39. GRB 241213A: SVOM/VT optical candidate
  40. GRB 241213B: Tiled Swift observations
  41. GRB 241213A: Swift/UVOT Upper Limits
  42. GRB 241213A: Swift-XRT refined Analysis
  43. GRB 241212A: Swift ToO observations
  44. GRB 241213A: LCOGT Optical Upper Limits
  45. EP241213a: EP detection of An X-ray Transient
  46. GRB 241213A: REM optical/NIR upper limits
  47. GRB 241213A: Enhanced Swift-XRT position
  48. Swift GRB 241213A: Global MASTER-Net observations report
  49. GRB 241213A: Swift detection of a burst
  50. GRB 241209A: Chandra X-ray Detection
  51. Konus-Wind detection of GRB 241209B
  52. GRB 241209B: GRBAlpha detection
  53. GRB 241129A: Fermi GBM Observation
  54. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  55. GRB 241209D: REM optical/NIR upper limits
  56. Konus-Wind detection of GRB 241209D
  57. GRB 241209B: Swift-XRT afterglow detection
  58. GRB 241209C: Fermi GBM Observation
  59. GRB 241209A: Swift-XRT refined Analysis
  60. GRB 241209D: AstroSat CZTI detection
  61. GRB 241209A: EP-FXT follow-up observations
  62. GRB 241209B: SVOM/VT afterglow detection
  63. GRB 241207B: Fermi GBM Observation
  64. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  65. GRB 241209D: Swift-XRT refined Analysis
  66. GRB 241209D: Fermi GBM Observation
  67. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  68. GRB 241209D: COLIBRÍ detection of the afterglow
  69. GRB 241209A: COLIBRÍ Optical Upper Limit
  70. GRB 241209A: Fermi GBM Observation
  71. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  72. GRB 241209A: GRANDMA/TAROT upper limit
  73. Swift GRB 241209D: Global MASTER-Net observations report
  74. GRB 241209B: Swift ToO observations
  75. GRB 241209A: REM optical/NIR observations
  76. GRB 241209D: Enhanced Swift-XRT position
  77. GRB 241209D: Swift detection of a burst
  78. GRB 241209A: Enhanced Swift-XRT position
  79. GRB 241209A: GOTO optical upper limits
  80. GRB 241209A: Prompt enhanced Swift-XRT position
  81. GRB 241209A: Swift detection of a short burst
  82. Swift GRB241209.23: Global MASTER-Net observations report
  83. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  84. GRB 241206A: DDOTI Upper Limit on the Afterglow
  85. GRB 241207C: Tiled Swift observations
  86. GRB 241206A: Fermi GBM observation
  87. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  88. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  89. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  90. GRB 241128A: Swift/UVOT Upper Limits
  91. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  92. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  93. SVOM/GRM observation of a short burst from soft gamma repeater Kes 73
  94. GRB 241128A: Swift-BAT refined analysis
  95. GRB 241127A: Swift-BAT refined analysis
  96. GRB 241127A: PRIME near-infrared detection
  97. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  98. Swift-XRT observations of IceCube -241127A
  99. Swift GRB 241128A: Global MASTER-Net observations report
  100. GRB 241128A: Swift-XRT refined Analysis

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