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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').
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.

Lucene Examples (click to copy):

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

32080 results found.

  1. GRB 231129A: VZLUSAT-2 detection
  2. GRB 231129B: Swift-XRT observations
  3. GRB 231128A: VZLUSAT-2 detection
  4. GRB 231129C: AGILE detection
  5. GRB 231129A : MITSuME Akeno optical upper limits
  6. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  7. GRB 231129A: Swift-BAT refined analysis
  8. GRB 231129C: MASTER OT detection
  9. GRB 231129A: BOOTES-5/JGT optical upper limit
  10. GRB 231129C: Fermi-LAT detection
  11. GRB 231129A: JinShan optical upper limit
  12. GRB 231129C: GRBAlpha detection
  13. GRB 231129C: Glowbug gamma-ray detection
  14. GRB 231129C: Swift-XRT observations
  15. GRB 231129A: Swift/UVOT Upper Limits
  16. GRB 231129A: optical upper limit in Mondy observatory
  17. GRB 231129C: GECAM-B detection of a bright burst
  18. GRB 231129C: AstroSat CZTI detection
  19. GRB 231129C: iTelescope OT retraction
  20. GRB 231129C: CALET Gamma-Ray Burst Monitor detection
  21. GRB 231129C: Fermi GBM Observation of a very bright GRB
  22. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  23. GRB 231129C: Tiled Swift observations
  24. GRB 231127A: GRBAlpha detection
  25. GRB 231129C: MAXI/GSC detection
  26. GRB 231129C: BALROG localization (Fermi Trigger / GRB 231129799)
  27. GRB 231129C: Fermi GBM detection of a very bright burst
  28. GRB 231129A: Enhanced Swift-XRT position
  29. GRB 231129A: Swift-XRT refined Analysis
  30. GRB 231129C: Fermi GBM Final Real-time Localization
  31. GRB 231129B: Tiled Swift observations
  32. GRB 231129B: MAXI/GSC detection
  33. GRB 231129A: GECAM-C detection of a long burst
  34. GRB 231129A: INTEGRAL detection of a long GRB
  35. GRB 231129A: Swift detection of a burst
  36. GRB 231128A: Fermi GBM Final Real-time Localization
  37. GRB 231123C: Fermi GBM Observation
  38. GRB 231123B: Fermi GBM Observation
  39. GRB 231117A: MeerKAT 1.3GHz detection
  40. GRB 231127A: CALET Gamma-Ray Burst Monitor detection
  41. GRB 231125A: GRBAlpha detection
  42. GRB 231125A: CALET Gamma-Ray Burst Monitor detection
  43. GRB 231127A: AstroSat CZTI detection
  44. GRB 231125A (short): Glowbug gamma-ray detection
  45. GRB 231123B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  46. GRB 231124A: GRBAlpha detection
  47. GRB 231125A: AstroSat CZTI detection of a short burst
  48. GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
  49. GRB 231126A: Fermi GBM Final Real-time Localization
  50. GRB 231123C: Insight-HXMT/HE detection
  51. GRB 231123C (short): Glowbug gamma-ray detection
  52. GRB 231124A: Glowbug gamma-ray detection
  53. GRB 231123C: Swift/BAT-GUANO detection of a short burst likely outside the coded FOV
  54. GRB 231124A: CALET Gamma-Ray Burst Monitor detection
  55. GRB 231115A: XMM-Newton observation
  56. GRB 231124A: Fermi GBM Final Real-time Localization
  57. GRB 231123A: AstroSat CZTI detection
  58. GRB 231117A: Mondy optical observations
  59. GRB 231123C: Fermi GBM Final Real-time Localization
  60. GRB 231123B: Fermi GBM Final Real-time Localization
  61. GRB 231118A: REM optical afterglow detection
  62. GRB 231122B: AstroSat CZTI detection
  63. GRB 231122B: CALET Gamma-Ray Burst Monitor detection
  64. GRB 231122B: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  65. GRB 231117A: Chandra afterglow detection
  66. GRB 231123A: Fermi GBM Final Real-time Localization
  67. GRB 231122B: Glowbug gamma-ray detection
  68. GRB 231117A: Continued GTC Observations
  69. GRB 231122A: GECAM detection
  70. GRB 231122B: GECAM detection
  71. GRB 231122A: Fermi GBM Final Real-time Localization
  72. GRB 231118A: ATCA detection of radio counterpart
  73. GRB 231117A: Swift/UVOT late time observations
  74. GRB 231117A: GTC Near-Infrared Observations
  75. GRB 231117A: Swift-BAT refined analysis
  76. GRB 231118A: GRBAlpha detection
  77. LIGO/Virgo/KAGRA S231118d: Upper limits from Swift/BAT-GUANO
  78. LIGO/Virgo/KAGRA S231118an: Upper limits from Swift/BAT-GUANO
  79. LIGO/Virgo/KAGRA S231114n: Upper limits from Swift/BAT-GUANO
  80. LIGO/Virgo/KAGRA S231113bb: Upper limits from Swift/BAT-GUANO
  81. GRB 231118A: VZLUSAT-2 detection
  82. GRB 231117A: AMI-LA radio observations
  83. GRB 231118A: Swift-BAT refined analysis
  84. Konus-Wind detection of GRB 231020A
  85. GRB 231117A: LDT Confirmation of Optical Fading
  86. GRB 231117A: Wendelstein Confirmation of Fading of the Optical Afterglow
  87. GRB 231118B: CALET Gamma-Ray Burst Monitor detection
  88. GRB 231117A: CALET Gamma-Ray Burst Monitor detection
  89. 231118A: Swift-UVOT Detection
  90. GRB231117A: Swift-UVOT detection
  91. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  92. GRB 231118B: Fermi GBM observation
  93. GRB 231118A: Fermi GBM observation
  94. GRB 231120A: Fermi GBM Final Real-time Localization
  95. GRB 231117A: Swift-XRT refined Analysis
  96. GRB 231118A: Swift-XRT refined Analysis
  97. GRB 231118A: MeerLICHT afterglow detection
  98. GRB 231117A: OHP/T120 optical observations
  99. GRB 231118A: VLT/X-shooter redshift
  100. GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading

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