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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"

36140 results found.

  1. GRB 231215A: Enhanced Swift-XRT position
  2. GRB 231214A: REM optical/NIR upper limits
  3. GRB 231215A: GROWTH-India optical follow-up
  4. GRB 231215A : Nanshan/HMT optical observations
  5. GRB 231215A: AstroSat CZTI detection
  6. GRB 231215A : MITSuME Akeno optical afterglow candidate detection
  7. GRB 231214A: Swift-XRT refined Analysis
  8. GRB 231215A: Mondy optical bright afterglow detection
  9. GRB 231214A: AstroSat CZTI detection
  10. GRB 231215C: MASTER OT detection
  11. GRB 231215A: Swift-XRT observations
  12. GRB 231215B: Fermi GBM Final Real-time Localization
  13. GRB 231215A: Swift detection of a burst
  14. GRB 231214A: Fermi-LAT detection
  15. GRB 231214A: Enhanced Swift-XRT position
  16. GRB 231214B: Swift/BAT-GUANO detection of a burst
  17. GRB231214A: BOOTES-6/DPRT optical upper limit
  18. GRB 231214A: Swift detection of a burst
  19. GRB 231214A: Fermi GBM Final Real-time Localization
  20. GRB 231210B: REM optical/NIR upper limits
  21. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  22. LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
  23. LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
  24. GRB 231212A: GECAM-C detection of a likely short burst
  25. GRB 231210B: MeerLICHT afterglow observations
  26. GRB 231210B: Swift-BAT refined analysis
  27. GRB 231210B: Swift-XRT refined Analysis
  28. GRB 231210B: Enhanced Swift-XRT position
  29. GRB 231210B: VLT/X-shooter redshift
  30. GRB 231210B: detection of the optical counterpart with the LCOGT 40cm telescope at Sutherland Observatory
  31. GRB 231210B: Swift detection of a burst with optical counterpart
  32. IPN triangulation of GRB 231129C
  33. GRB 231210A: Fermi GBM Final Real-time Localization
  34. GRB 231208A: GRBAlpha detection
  35. GRB231205B: Swift/UVOT Upper Limits
  36. GRB 231208A: Glowbug gamma-ray detection
  37. GRB 231208A: AstroSat CZTI detection of a faint burst
  38. IPN triangulation of GRB 231205A
  39. GRB 231205B: Swift-BAT refined analysis
  40. GRB 231205B: 1.3m DFOT Optical upper limit
  41. GRB 231206A: joint location of multiple instruments by ETJASMIN
  42. GRB 231205B: optical upper limit in TSHAOand AbAO
  43. GRB231115A: TURBO Pre-Burst Optical Upper Limits
  44. GRB 231205B: AGILE detection
  45. GRB 231206B: Fermi GBM Final Real-time Localization
  46. GRB 231205B: Ondrejov D50 optical upper limit
  47. GRB 231205B: Swift-XRT refined Analysis
  48. GRB 231205B: REM optical/NIR upper limits
  49. GRB 231129C: ASIM MXGS observation and localization
  50. GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
  51. GRB 231205B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  52. GRB 231206A: GECAM-B detection of a short burst (correction)
  53. GRB 231205B : MITSuME Akeno optical upper limits
  54. GRB 231206A: GECAM-B detection of a short burst
  55. GRB 231205B: Zadko observatory - Gingin optical observations
  56. GRB 231205B: Gaoyazi/GOT optical upper limit
  57. GRB 231205B: Nanshan/HMT optical upper limit
  58. GRB 231205B: GECAM-B detection of a long burst
  59. GRB 231205B: LCOGT Optical Upper Limits
  60. GRB 231205A: DDOTI Upper Limits on the Afterglow
  61. GRB 231205B: Enhanced Swift-XRT position
  62. GRB 231204A: Glowbug gamma-ray detection
  63. GRB 231204A: CALET Gamma-Ray Burst Monitor detection
  64. GRB 231205B: AKO Optical Upper Limit
  65. GRB 231205B: Swift detection of a burst
  66. GRB 231205A: joint location of multiple instruments by ETJASMIN
  67. GRB 231204A: AstroSat CZTI detection
  68. GRB 231205A: GECAM-B detection of a short burst
  69. GRB 231205A: Fermi GBM Final Real-time Localization
  70. LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
  71. IceCube-231202A: Upper limits from a search for additional neutrino events in IceCube
  72. GRB 231203A: Fermi GBM Observation
  73. GRB 231204A: Fermi GBM Final Real-time Localization
  74. GRB 231203A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  75. Konus-Wind detection of GRB 231129C
  76. The Fermi GBM team reports the detection of a likely SHORT GRB
  77. GRB 231203A: Fermi GBM Final Real-time Localization
  78. GRB 231129C: Swift-XRT afterglow detection
  79. GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
  80. GRB 231129A: VZLUSAT-2 detection
  81. GRB 231129B: Swift-XRT observations
  82. GRB 231128A: VZLUSAT-2 detection
  83. GRB 231129C: AGILE detection
  84. GRB 231129A : MITSuME Akeno optical upper limits
  85. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  86. GRB 231129A: Swift-BAT refined analysis
  87. GRB 231129C: MASTER OT detection
  88. GRB 231129A: BOOTES-5/JGT optical upper limit
  89. GRB 231129C: Fermi-LAT detection
  90. GRB 231129A: JinShan optical upper limit
  91. GRB 231129C: GRBAlpha detection
  92. GRB 231129C: Glowbug gamma-ray detection
  93. GRB 231129C: Swift-XRT observations
  94. GRB 231129A: Swift/UVOT Upper Limits
  95. GRB 231129A: optical upper limit in Mondy observatory
  96. GRB 231129C: GECAM-B detection of a bright burst
  97. GRB 231129C: AstroSat CZTI detection
  98. GRB 231129C: iTelescope OT retraction
  99. GRB 231129C: CALET Gamma-Ray Burst Monitor detection
  100. GRB 231129C: Fermi GBM Observation of a very bright GRB

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