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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"

29126 results found.

  1. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  2. GRB 251026B: Fermi GBM Final Localization
  3. GRB 251026A: SVOM detection of a long burst
  4. GRB 251025B: SVOM/VT optical bump
  5. GRB 251025B: SVOM/COLIBRÍ (FM-GFT) strong rebrightening of the optical counterpart
  6. GRB 251023A: SVOM/GRM observation
  7. GRB 251025B: ULL-ASTRO-MASTER optical counterpart detection with IAC80 telescope at Teide Observatory
  8. GRB 251025C: Fermi GBM Final Real-time Localization
  9. Konus-Wind detection of GRB 251016B
  10. GRB 251025B: GROWTH-India Telescope optical observations
  11. GRB 251024A: Swift/UVOT Upper Limits
  12. GRB 251024A: Swift-BAT refined analysis
  13. IceCube Alert 251025.57: Global MASTER-Net observations report
  14. GRB 251024A: Swift-XRT refined Analysis
  15. GRB 251025A (sb25102501): stellar flare confirmed
  16. GRB 251025B: SVOM/C-GFT optical counterpart detection
  17. GRB 251025B: SVOM detection of a burst
  18. IceCube-251025A - IceCube observation of a high-energy neutrino candidate track-like event
  19. GRB 251025A (sb25102501): Likely a stellar flare by SVOM/VT
  20. GRB 251025A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  21. GRB 251025A: SVOM/VT VHF optical upper limit
  22. GRB 251025A: SVOM detection of a faint burst
  23. GRB 251003A: VLA Detection
  24. GRB 251024A: LCOGT Optical Afterglow Detection
  25. GRB 251022A: KAIT optical observations
  26. GRB 251024A: Swift detection of a burst
  27. Swift GRB 251024A: Global MASTER-Net observations report
  28. GRB 251023B / EP251023b: COLIBRÍ Confirmation of the Fading Nature of the Optical Candidate
  29. GRB 251022A: COLIBRÍ Further Multi-frequency Optical Observations
  30. EP251023a: MAO/AZT-22 optical observations
  31. EP251023b/GRB 251023B: JinShan optical observation
  32. GRB 251022A: Swift-XRT detection of GOTO25iym
  33. EP251023b: Global MASTER-Net observations report
  34. GRB 251022A: GROWTH-India Telescope optical observations
  35. GRB 251023C: Swift/BAT-GUANO localization skymap of a burst
  36. EP251023a: GROWTH-India Telescope optical observations
  37. GRB 251022A: Fermi GBM Observation
  38. GRB 251022A: Swift/BAT-GUANO localization skymap of a burst
  39. GRB 251023A: Glowbug gamma-ray detection
  40. EP251023a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at Teide Observatory
  41. EP251023a: Global MASTER-Net observations report
  42. GRB 251023B / EP#01709247298: COLIBRÍ optical counterpart candidate
  43. IPN triangulation of GRB 251016B
  44. EP#01709247298: Swift-XRT counterpart detection
  45. EP251023a: COLIBRÍ optical observations
  46. GRB 251013C: further SAO RAS optical observations
  47. EP251023a: Keck/LRIS spectroscopic redshift z=2.232
  48. GRB 251022A: COLIBRÍ optical observations
  49. GRB 251013C: ISON-Castelgrande observatory optical observations
  50. GRB 251022A: MASTER OT detection
  51. GRB 251022A: DDOTI Optical Detection
  52. EP251021b/GRB 251021A: SVOM/VT optical candidate
  53. EP251023a: NOT optical counterpart detection
  54. Fermi GRB 251023A: Global MASTER-Net observations report
  55. EP251023a: GSP Optical Counterpart Detection
  56. EP/WXT 01709247295: GOTO optical afterglow candidate.
  57. GRB 251022A: GOTO optical counterpart detection
  58. GRB 251023A: Fermi GBM Final Localization Correction
  59. GRB 251022A: Fermi-LAT detection
  60. GRB 251016B: Fermi GBM Detection
  61. GRB 251022A: Tiled Swift observations
  62. LAT GRB251022A: Global MASTER-Net observations report
  63. GRB 251022A: Fermi GBM Final Real-time Localization
  64. GRB 251021A/EP251021b: Fermi-GBM Sub-Threshold Detection
  65. EP251021b: BOOTES-7 optical upper limit
  66. EP251021b: Einstein Probe detection of a fast X-ray transient
  67. GRB 251016A: SVOM/ECLAIRs refined analysis
  68. Fermi-LAT gamma-ray observations of IceCube-251018A
  69. GRB 251017A: COLIBRÍ optical observations of a late plateau
  70. IceCube-251018A: DDOTI Optical Upper Limit
  71. GRB 251017A: Swift-BAT refined analysis
  72. GRB 251016A: Fermi GBM Observation
  73. GRB 251018A: Fermi GBM Observation
  74. GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
  75. GRB 251018A: Swift-XRT refined Analysis
  76. Fermi trigger No 782500909: Global MASTER-Net observations report
  77. GRB 251016A: HXMT/HE detection
  78. IceCube-251018A: Global MASTER-Net observations report
  79. GRB 251017A: Swift/UVOT Detection
  80. GRB 251016A: Swift/UVOT Detection
  81. GRB 251018A: Swift/UVOT Detection
  82. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event
  83. GRB 251017A: VLT/MUSE spectroscopic redshift z = 4.327
  84. GRB 251016A: VLT/FORS2 Optical Observation
  85. GRB 251017A: COLIBRÍ photometric redshift
  86. GRB 251017A: Swift-XRT refined Analysis
  87. GRB 251018A: MASTER OT detection
  88. GRB 251018A: TRT optical afterglow detection
  89. Swift GRB 251018A: Global MASTER-Net observations report
  90. GRB 251018A: Swift detection of a burst with an optical counterpart
  91. GRB 251018A: Fermi GBM Final Real-time Localization
  92. GRB 251017A: SVOM/VT optical observation
  93. GRB 251011A: Fermi GBM Observation
  94. LIGO/Virgo/KAGRA S251017di: Retraction of GW compact binary merger candidate
  95. GRB 251017A: J-band detection with WINTER
  96. GRB 251013C: Liverpool Telescope observations
  97. GRB 251013C: Leavitt Observatory optical photometry
  98. Fermi GRB 251016B: Global MASTER-Net observations report
  99. GRB 251017A: JinShan observations of the optical afterglow
  100. Swift GRB 251017A: Global MASTER-Net observations report

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