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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.

Advanced Search Examples (click to copy):

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

36180 results found.

  1. GRB 231111A: Swift-BAT refined analysis
  2. Fermi GRB 231114A: Global MASTER-Net observations report
  3. GRB 231113A (short): Glowbug gamma-ray detection
  4. GRB 231114A (short): Glowbug gamma-ray detection
  5. GRB 231114A: Fermi GBM Final Localization
  6. SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare
  7. LIGO/Virgo/KAGRA S231113bw: Upper limits from Fermi-GBM Observations
  8. GRB 231110A: CALET Gamma-Ray Burst Monitor detection
  9. GRB 231110A: Swift-BAT refined analysis
  10. GRB231111A: MDM 2.4m Hiltner Telescope Observation
  11. GRB 231106A: Glowbug gamma-ray detection
  12. GRB 231111A: Xinglong-2.16m optical observations
  13. GRB 231110A: Swift-UVOT Upper Limits
  14. GRB 231111A: Afterglow redshift from OSIRIS+/GTC
  15. GRB 231104A: VZLUSAT-2 detection
  16. GRB 231111A: TNG tentative redshift
  17. GRB 231110A: Glowbug gamma-ray detection
  18. GRB 231110A: AstroSat CZTI detection
  19. GRB 231111A NUTTelA-TAO / BSTI Early Measurements
  20. GRB 231111A: Leavitt Observatory optical observations
  21. GRB231111A: Optical follow-up observations with Mephisto
  22. GRB 231111A: GMG observation (correction)
  23. GRB 231111A: GMG observation upper limit
  24. GRB 231106B: GRBAlpha detection
  25. GRB 231111A: Osservatorio Astronomico "Nastro Verde" optical observations with detection of an optical counterpart
  26. GRB 231110A: Terskol Zeiss-2000 optical upper limit
  27. GRB 231111A: Swift-XRT refined Analysis
  28. GRB 231111A: Mondy optical observations
  29. GRB 231111A: GECAM-C detection of a long burst (correction)
  30. GRB 231110A: GECAM-B detection (correction)
  31. GRB 231111A: Enhanced Swift-XRT position
  32. GRB 231111A: GECAM-C detection of a long burst
  33. GRB 231110A: GECAM detection
  34. GRB 231110A: GOTO optical upper limits
  35. GRB 231110A: SAO RAS optical observations
  36. GRB 231110A: Swift-XRT afterglow detection
  37. GRB231111A: YAHPT Observations
  38. GRB231111A: GIT confirmation of the optical afterglow
  39. GRB 231111A: MASTER OT earlier detection
  40. GRB 231111A: Nanshan/HMT optical observations
  41. GRB 231111A: Swift detection of a burst with an optical counterpart
  42. GRB231110A: WFST Observation and upper limits
  43. GRB 231110A: Swift detection of a burst
  44. GRB 231109A: Fermi GBM Final Localization
  45. Fermi GRB 231108A: Global MASTER-Net observations report
  46. GRB 231108A: Fermi GBM Final Real-time Localization
  47. GRB 231106A: AstroSat CZTI detection
  48. GRB 231106A: CALET Gamma-Ray Burst Monitor detection
  49. GRB 231104A: Swift-BAT refined analysis
  50. Fermi Gamma-ray Burst Monitor trigger 231107654 / 721064512 is not a GRB
  51. GRB 231104A: FRAM-ORM optical limit
  52. LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
  53. Fermi GRB 231106A: Global MASTER-Net observations report
  54. GRB 231104A: Wendelstein Optical/Infrared Observations
  55. GRB 231104A: NuSTAR Observation of the prompt emission
  56. GRB 231106A: Fermi GBM Final Real-time Localization
  57. GRB 231104A: 3.6m DOT optical upper limit
  58. IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
  59. GRB 231104A: NOT upper limit
  60. GRB 231104A: Fermi GBM Observation
  61. GRB 231104B: Fermi GBM Final Real-time Localization
  62. Fermi GRB 231103A: Global MASTER-Net observations report
  63. GRB 231104A: AKO Upper Limit
  64. GRB 231104A: AstroSat CZTI detection
  65. GRB 231104A: Swift-XRT refined Analysis
  66. GRB 231104A: Fermi-LAT detection
  67. GRB 231104A: Swift/UVOT Upper Limits
  68. GRB 231104A: Enhanced Swift-XRT position
  69. GRB231104A: LCOGT Optical Upper Limits
  70. GRB 231104A: Swift detection of a bright burst
  71. GRB 231104A: Fermi GBM Final Real-time Localization
  72. GRB 231103A: Fermi GBM Final Real-time Localization
  73. GRB 231101A: Glowbug gamma-ray detection
  74. GRB 231024A: GRANDMA observations of AT2023vuc/GOTO23baj candidate
  75. GRB 231101A: Fermi GBM Final Real-time Localization
  76. GRB 231030B: GRBAlpha detection
  77. GRB 231028B: VZLUSAT-2 detection
  78. GRB 231030B: Fermi GBM Detection
  79. GRB 231030B: AstroSat CZTI detection
  80. Fermi GRB 231030B: Global MASTER-Net observations report
  81. IPN triangulation of GRB 231020A
  82. GRB 231030B: BALROG localization (Fermi Trigger 720388704 / GRB 231030832)
  83. GRB 231030B: Fermi GBM Final Real-time Localization
  84. GRB 231028A: Swift-BAT refined analysis
  85. IceCube-231027A: Upper limits from a search for additional neutrino events in IceCube
  86. LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
  87. GRB 231024A: AKO Optical Counterpart Candidate
  88. GRB 231028A: CALET Gamma-Ray Burst Monitor detection
  89. Fermi GRB 231030A: Global MASTER-Net observations report
  90. GRB 231030A: Fermi GBM Final Real-time Localization
  91. GRID detection of GRB 231020A
  92. GRB 231028A: AstroSat CZTI detection
  93. GRB 231028A: Glowbug gamma-ray detection
  94. GRB 231028A: Fermi GBM Detection
  95. Swift GRB 231028A: Global MASTER-Net observations report
  96. GRB 231028A: Swift detection of a burst
  97. GRB 231028A: Fermi GBM Final Real-time Localization
  98. GRB 231019A: Glowbug gamma-ray detection
  99. GRB 231025A: Fermi GBM Observation
  100. GRB 231024A: Fermi GBM Observation

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