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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"

14824 results found.

  1. GRB 251023B / EP251023b: COLIBRÍ Confirmation of the Fading Nature of the Optical Candidate
  2. GRB 251022A: COLIBRÍ Further Multi-frequency Optical Observations
  3. GRB 251023C: AstroSat CZTI detection
  4. EP251023b/GRB 251023B: JinShan optical observation
  5. GRB 251022A: Swift-XRT detection of GOTO25iym
  6. EP251023b/GRB 251023B : Einstein Probe detection of a fast X-ray transient
  7. GRB 251023C: CALET Gamma-Ray Burst Monitor detection
  8. GRB 251023A: Glowbug gamma-ray detection
  9. GRB 251023B: Glowbug gamma-ray detection
  10. EP251023a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at Teide Observatory
  11. IPN triangulation of GRB 251016B
  12. GRB 251023B: CALET Gamma-Ray Burst Monitor detection
  13. EP#01709247298: Swift-XRT counterpart detection
  14. GRB 251013C: further SAO RAS optical observations
  15. GRB 251013C: ISON-Castelgrande observatory optical observations
  16. GRB 251022A: MASTER OT detection
  17. GRB 251022A: DDOTI Optical Detection
  18. GRB 251023B / MAXI J0451+122: MAXI/GSC detection
  19. EP251023a: NOT optical counterpart detection
  20. EP251023a: GSP Optical Counterpart Detection
  21. EP251023a: Einstein Probe detection of an X-ray transient
  22. GRB 251022A: GOTO optical counterpart detection
  23. GRB 251023A: Fermi GBM Final Localization Correction
  24. GRB 251022A: Fermi-LAT detection
  25. GRB 251016B: Fermi GBM Detection
  26. GRB 251022A: Fermi GBM Final Real-time Localization
  27. GRB 251021A/EP251021b: Fermi-GBM Sub-Threshold Detection
  28. EP251021b: BOOTES-7 optical upper limit
  29. EP251021b: Einstein Probe detection of a fast X-ray transient
  30. GRB 250911A: MAXI/GSC detection
  31. GRB 251016A: SVOM/ECLAIRs refined analysis
  32. GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
  33. GRB 251016A: HXMT/HE detection
  34. GRB 251016A: Swift-XRT afterglow detection
  35. GRB 251017A: Swift/UVOT Detection
  36. GRB 251016A: Swift/UVOT Detection
  37. GRB 251018A: Swift/UVOT Detection
  38. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event
  39. GRB 251018A: MASTER OT detection
  40. GRB 251018A: TRT optical afterglow detection
  41. GRB 251018A: Swift detection of a burst with an optical counterpart
  42. GRB 251018A: Fermi GBM Final Real-time Localization
  43. GRB 251013C: OHP/T193 third epoch optical observations and detected rebrightening
  44. LIGO/Virgo/KAGRA S251017di: Retraction of GW compact binary merger candidate
  45. GRB 251017A: J-band detection with WINTER
  46. GRB 251017A: Glowbug gamma-ray detection
  47. GRB 251017A: JinShan observations of the optical afterglow
  48. GRB 251017A : MITSuME Akeno optical afterglow candidate detection
  49. GRB 251016A: AstroSat CZTI detection of a short burst
  50. GRB 251017A: COLIBRÍ Early Afterglow Detection
  51. GRB 251016B: AstroSat CZTI detection
  52. GRB 251017A: BOOTES-5/JGT early optical afterglow detection
  53. GRB 251017A: Swift detection of a burst with an optical counterpart
  54. GRB 251016A: CALET Gamma-Ray Burst Monitor detection
  55. GRB 251016B: CALET Gamma-Ray Burst Monitor detection
  56. GRB 251013C: JinShan observations of the non-thermal rebrightening of the optical counterpart
  57. GRB 251016B: Fermi GBM Final Real-time Localization
  58. GRB 251016A: BOOTES-6/DPRT optical upper limit
  59. GRB 251016A: Glowbug gamma-ray detection of a short burst
  60. GRB 251013C: VLA detection
  61. sb25101602: Swift-XRT counterpart detection
  62. GRB 251016A: Fermi GBM Final Localization
  63. GRB 251016A: SVOM detection of a short burst
  64. GRB 251014B: PRIME J-band upper limit
  65. GRB 251013C: Kilonova-Catcher optical afterglow detection
  66. GRB 251013C: Swift/UVOT Detection
  67. Konus-Wind detection of GRB 251007A
  68. GRB 251013C: detection of a radio counterpart at 15.5GHz
  69. GRB 251015A: Fermi GBM Final Real-time Localization
  70. Swift Trigger 1404295: possible GRB 251015A
  71. GRB 251014D: BOOTES-6/DPRT optical upper limit
  72. GRB 251014D: Swift-XRT afterglow detection
  73. IceCube-251014A - IceCube observation of a high-energy neutrino candidate track-like event
  74. GRB 251014D: Swift detection of a burst
  75. GRB 251014A: PRIME near-infrared upper limits
  76. GRB 251014C: Fermi GBM Final Localization
  77. GRB 251014A: Glowbug gamma-ray detection of a likely short burst
  78. GRB 251013C: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an bright optical counterpart
  79. GRB 251012A: Glowbug gamma-ray detection of a likely short burst
  80. GRB 251014B: Swift/BAT-GUANO arcminute localization of a short burst
  81. GRB 251013C: Early and late-time optical counterpart detection by LCO
  82. GRB 251013C: ULL-ASTRO-MASTER detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  83. GRB 251013A: CALET Gamma-Ray Burst Monitor detection
  84. GRB 251013C: J band observations by SYSU 80cm infrared telescope
  85. GRB 251013C: EP-FXT counterpart detection
  86. GRB 251013C: AstroSat CZTI detection
  87. GRB 251011A: Swift/BAT-GUANO arcminute localization of a burst
  88. GRB 251013C: ALMA detection
  89. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
  90. GRB 251013C: DDOTI detection of the optical afterglow
  91. GRB 251014A: Swift detection of a possibly-short burst
  92. GRB 251014A: Fermi GBM Final Real-time Localization
  93. GRB 251013C: Swift-XRT counterpart detection
  94. GRB 251013C: GOTO optical afterglow detection
  95. GRB 251013C: LCO optical afterglow detection
  96. GRB 251013C: NOT spectroscopic redshift z = 0.572
  97. GRB 251013C: LAST detection of optical counterpart
  98. GRB 251013C: BOOTES-6 early optical detection
  99. GRB 251013D: Fermi GBM Final Real-time Localization
  100. GRB 251013C: SVOM detection of a burst

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