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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

19670 results found.

  1. IPN triangulation of GRB 250119B
  2. Improved IPN triangulation of GRB 250107C
  3. GRB 250114A: Swift-BAT refined analysis
  4. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  5. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  6. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  7. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  8. Konus-Wind detection of GRB 250117A
  9. IPN triangulation of GRB 250117A (short)
  10. GRB 250117A: SVOM/GRM observation of a short burst
  11. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  12. Swift Trigger 1282245 is not a GRB
  13. GRB 250114B: Swift-XRT afterglow detection
  14. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  15. IPN triangulation of GRB 250113A
  16. GRB 250114B: Swift-XRT observations
  17. GRB 250114A: LCO optical counterpart detection.
  18. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  19. GRB 250114A: Swift-XRT refined Analysis
  20. GRB 250114A: LCOGT optical afterglow i-band detection
  21. GRB 250114B: Swift ToO observations
  22. EP250111a: SAO RAS optical upper limit
  23. GRB 250114A: Enhanced Swift-XRT position
  24. GRB 250114A: REM detection of the optical and NIR counterpart
  25. Swift GRB250114A: Global MASTER-Net OT detection
  26. GRB 250114A: LCO optical observations
  27. GRB 250114A: TRT optical observations
  28. Swift GRB 250114A: Global MASTER-Net observations report
  29. GRB 250114A: Swift detection of a burst with an optical counterpart
  30. GRB 250107A: VZLUSAT-2 detection
  31. GRB 250109A / EP250109a: GRBAlpha detection
  32. GRB 250106A: Swift-XRT afterglow detection
  33. GRB 250109A / EP250109a: Mephisto optical upper limits
  34. EP250111a: Swift/XRT detection and fading
  35. EP250108a / AT 2025kg: Swift UVOT detections
  36. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  37. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  38. GRB 250108A: Swift/XRT afterglow fading
  39. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  40. EP250109a: Swift/UVOT non-detection
  41. IPN triangulation of GRB 250107D (short/hard)
  42. IPN triangulation of GRB 250107C
  43. GRB 250108B: Swift-BAT refined analysis
  44. GRB 250108B: 1.3m DFOT upper limit
  45. GRB 250108B: REM optical/NIR upper limits
  46. EP250109a: GOTO optical upper limits
  47. EP250109a: Swift/XRT non-detection
  48. GRB 250108A: Swift/UVOT Upper Limits
  49. GRB 250108A: NOT optical upper limit
  50. GRB 250108B: Swift-XRT refined Analysis
  51. Swift GRB 250108B: Global MASTER-Net observations report
  52. GRB 250108A: Swift-XRT afterglow detection
  53. GRB 250108B: Swift/UVOT Upper Limits
  54. GRB 250103A: Swift-XRT afterglow detection
  55. GRB 250108B: Enhanced Swift-XRT position
  56. GRB 250108B: Swift detection of a burst
  57. GRB 250108A: Swift ToO observations
  58. GRB 250107A: Fermi GBM Observation
  59. GRB 241228B: Fermi-LAT detection
  60. GRB 250107A: Swift ToO observations
  61. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  62. GRB 250106A: NOT optical observations
  63. GRB 250103B: REM optical/NIR upper limits
  64. GRB 250101A: REM optical/NIR counterpart detection
  65. GRB 250106A: Swift-XRT observations
  66. GRB 250106A: Swift ToO observations
  67. GRB 241229A: SVOM/VT optical upperlimit
  68. GRB 250103B: Swift-XRT refined Analysis
  69. GRB 250103B: LCO/1m optical afterglow candidate detection
  70. GRB 250103A: Swift-XRT observations
  71. GRB 250101A: 1.3m DFOT optical afterglow detection
  72. GRB 241229A: 1.3m DFOT upper limit
  73. GRB 241228A: 1.3m DFOT upper limit
  74. GRB 250103B：SVOM/VT optical counterpart
  75. GRB 250101A: further LCOGT optical afterglow observations
  76. GRB 250103B: LCOGT Optical Upper Limit
  77. Swift GRB 250103B: Global MASTER-Net observations report
  78. GRB 250103A: Swift ToO observations
  79. GRB 250101a: Liverpool Telescope optical follow-up
  80. GRB 250103B: SVOM detection of a long burst
  81. GRB 250103B: Swift detection of a burst
  82. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO
  83. GRB 250101A: Swift-BAT refined analysis
  84. GRB 250101A: further SAO RAS optical observations
  85. GRB 250101A: LCO optical counterpart detection
  86. GRB 250101A: GMG spectroscopic redshift at z ~ 2.481
  87. GRB 250101A: Swift/UVOT Detection
  88. GRB 250101A: 1.6m Mephisto multi-band optical followup
  89. GRB 250101A: Swift-XRT refined Analysis
  90. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  91. GRB 250101A: LCOGT optical afterglow detection
  92. GRB 250101A: OASDG optical observations
  93. GRB 250101A: BOOTES-4/MET optical afterglow detection
  94. GRB 250101A: SAO RAS optical observations
  95. GRB 250101A: Enhanced Swift-XRT position
  96. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  97. GRB 250101A: SVOM/C-GFT early optical observations
  98. GRB 250101A: MASTER earlier OT observations with SOSS emission features
  99. GRB 250101A: Nanshan/HMT optical observations
  100. GRB 250101A : GIT optical detection

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