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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"

26055 results found.

  1. GRB 251024A: Enhanced Swift-XRT position
  2. GRB 251023C: Glowbug gamma-ray detection
  3. GRB 251024A: LCOGT Optical Afterglow Detection
  4. GRB 251022A: KAIT optical observations
  5. GRB 251024A: Swift detection of a burst
  6. Swift GRB 251024A: Global MASTER-Net observations report
  7. EP251023a: MAO/AZT-22 optical observations
  8. EP251023a: OHP/T193 optical observations
  9. GRB 251023C: AstroSat CZTI detection
  10. GRB 251022A: Swift-XRT detection of GOTO25iym
  11. GRB 251023C: CALET Gamma-Ray Burst Monitor detection
  12. GRB 251023C: Swift/BAT-GUANO localization skymap of a burst
  13. EP251023a: GROWTH-India Telescope optical observations
  14. GRB 251022A: Fermi GBM Observation
  15. GRB 251022A: Swift/BAT-GUANO localization skymap of a burst
  16. EP251023a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at Teide Observatory
  17. GRB 251023B / EP#01709247298: COLIBRÍ optical counterpart candidate
  18. IPN triangulation of GRB 251016B
  19. EP#01709247298: Swift-XRT counterpart detection
  20. GRB 251013C: further SAO RAS optical observations
  21. EP251023a: Keck/LRIS spectroscopic redshift z=2.232
  22. GRB 251013C: ISON-Castelgrande observatory optical observations
  23. GRB 251022A: MASTER OT detection
  24. EP/WXT 01709247295: GOTO optical afterglow candidate.
  25. GRB 251022A: GOTO optical counterpart detection
  26. GRB 251022A: Fermi-LAT detection
  27. GRB 251022A: Tiled Swift observations
  28. GRB 250911A: MAXI/GSC detection
  29. GRB 251017A : RAPAS follow-up observations
  30. GRB 251017A: COLIBRÍ optical observations of a late plateau
  31. GRB 251017A: Swift-BAT refined analysis
  32. GRB 251018A: Fermi GBM Observation
  33. GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
  34. GRB 251018A: Swift-XRT refined Analysis
  35. GRB 251018A: Enhanced Swift-XRT position
  36. GRB 251016A: Swift-XRT afterglow detection
  37. GRB 251017A: Swift/UVOT Detection
  38. GRB 251016A: Swift/UVOT Detection
  39. GRB 251018A: Swift/UVOT Detection
  40. GRB 251017A: VLT/MUSE spectroscopic redshift z = 4.327
  41. GRB 251016A: VLT/FORS2 Optical Observation
  42. GRB 251017A: COLIBRÍ photometric redshift
  43. GRB 251017A: Swift-XRT refined Analysis
  44. GRB 251018A: MASTER OT detection
  45. GRB 251018A: TRT optical afterglow detection
  46. Swift GRB 251018A: Global MASTER-Net observations report
  47. GRB 251018A: Swift detection of a burst with an optical counterpart
  48. GRB 251017A: SVOM/VT optical observation
  49. GRB 251011A: Fermi GBM Observation
  50. GRB 251017A: OHP/T193 i-band observations
  51. GRB 251013C: OHP/T193 third epoch optical observations and detected rebrightening
  52. GRB 251017A: Glowbug gamma-ray detection
  53. GRB 251013C: Liverpool Telescope observations
  54. GRB 251013C: Leavitt Observatory optical photometry
  55. GRB 251017A: JinShan observations of the optical afterglow
  56. Swift GRB 251017A: Global MASTER-Net observations report
  57. GRB 251017A : MITSuME Akeno optical afterglow candidate detection
  58. Swift Trigger 1404295 is not a GRB
  59. GRB 251017A: Enhanced Swift-XRT position
  60. GRB 251017A: COLIBRÍ Early Afterglow Detection
  61. GRB 251017A: BOOTES-5/JGT early optical afterglow detection
  62. GRB 251017A: Swift detection of a burst with an optical counterpart
  63. GRB 251007B: Swift-BAT refined analysis
  64. GRB 251014D: Swift-BAT refined analysis
  65. GRB 251016A: BOOTES-6/DPRT optical upper limit
  66. sb25101602: Swift-XRT counterpart detection
  67. GRB 251014A: Swift-XRT observations
  68. GRB 251014B: PRIME J-band upper limit
  69. Swift GRB251015.60: Global MASTER-Net observations report
  70. GRB 251013C: Kilonova-Catcher optical afterglow detection
  71. GRB 251013D: Swift/UVOT Observations
  72. GRB 251013C: Swift/UVOT Detection
  73. Konus-Wind detection of GRB 251007A
  74. GRB 251013C: detection of a radio counterpart at 15.5GHz
  75. GRB 251013D: Swift-XRT observations
  76. Swift Trigger 1404295: possible GRB 251015A
  77. GRB 251014B: Swift-XRT observations
  78. GRB 251014B: Swift/UVOT Upper Limits
  79. GRB 251014B: VLT/FORS2 Optical Observation
  80. GRB 251014D: Swift/UVOT Upper Limits
  81. GRB 251014D: BOOTES-6/DPRT optical upper limit
  82. GRB 251014D: Swift-XRT afterglow detection
  83. GRB 251011B: SVOM/VT optical upper limit
  84. GRB 251013C: Swift ToO observations
  85. GRB 251013D: Fermi GBM Observation
  86. GRB 251014A: Swift-BAT refined analysis
  87. GRB 251013C: OHP/T193 further optical observations and possible color evolution
  88. GRB 251014D: Swift detection of a burst
  89. GRB 251014A: PRIME near-infrared upper limits
  90. GRB 251014A: Glowbug gamma-ray detection of a likely short burst
  91. GRB 251014A: VLT/FORS2 Optical Observation
  92. GRB 251013C: MarSEC, optical afterglow photometry
  93. GRB 251013C: OHP/T193 optical afterglow photometry and spectroscopy
  94. GRB 251014B: Swift ToO observations
  95. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  96. GRB 251014B: Swift/BAT-GUANO arcminute localization of a short burst
  97. GRB 251013C: Bassano Bresciano Observatory optical observations
  98. GRB 251013C: Fermi GBM Observation
  99. GRB 251013D: Swift ToO observations
  100. GRB 251014A: DDOTI Upper Limit

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