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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

27039 results found.

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

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