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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"

588 results found.

  1. Fermi-LAT gamma-ray observations of IceCube-250421A
  2. GRB 250327A: Swift-XRT refined Analysis
  3. GRB 250327A: SVOM/VT optical candidate
  4. GRB 250322A: AstroSat CZTI detection of a short burst
  5. Fermi trigger No 763509110: Global MASTER-Net observations report
  6. Fermi GRB 250309B: Global MASTER-Net observations report
  7. GRB 250226A: Fermi GBM Observation
  8. Fermi GRB 250223A: Global MASTER-Net observations report
  9. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  10. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  11. LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
  12. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  13. GRB 250207A: REM IR afterglow detection
  14. GRB 250207A: REM optical afterglow detection
  15. GRB 250114B: OHP/T193 optical upper limit
  16. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  17. GRB 241207C: MASTER optical observations
  18. Fermi trigger No 755225799: Global MASTER-Net observations report
  19. Swift GRB 241128A: Global MASTER-Net observations report
  20. Swift GRB241127.91: Global MASTER-Net observations report
  21. GRB 241113A: Swift/UVOT Detection
  22. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  23. Fermi GRB 240918A: Global MASTER-Net observations report
  24. EP EP240913a: Global MASTER-Net observations report
  25. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  26. GRB 240829A: Swift-BAT refined analysis
  27. LAT GRB240828.62: Global MASTER-Net observations report
  28. Fermi trigger No 745866488: Global MASTER-Net observations report
  29. Fermi trigger No 745057312: Global MASTER-Net observations report
  30. Swift GRB 240811A: Global MASTER-Net observations report
  31. GRB 240727C: AstroSat CZTI detection of a long burst
  32. Konus-Wind detection of GRB 240627A
  33. Fermi GRB 240702A: Global MASTER-Net observations report
  34. Fermi trigger No 741211696: Global MASTER-Net observations report
  35. Swift Trigger 1232465: consistent with noise
  36. Konus-Wind detection of GRB 240529A
  37. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  38. GRB 240419B: Swift-BAT refined analysis
  39. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  40. LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
  41. LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
  42. Swift GRB 240419B: Global MASTER-Net observations report
  43. GRB 240414A: Swift-BAT refined analysis
  44. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  45. Swift Trigger 1220736: detection of 4U 1543-62.
  46. Fermi GRB 240408A: Global MASTER-Net observations report
  47. Konus-Wind detection of LXT 240402A/GRB 240402B
  48. Konus-Wind detection of GRB 240303B
  49. GRB 240109A: Swift-BAT refined analysis
  50. GRB 231215A: radio detection with the VLA
  51. GRB 231129A: Swift-BAT refined analysis
  52. GRB 231129A: BOOTES-5/JGT optical upper limit
  53. GRB 231118A: Swift-BAT refined analysis
  54. GRB 231111A: Swift-BAT refined analysis
  55. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  56. IceCube Alert 231027.18: Global MASTER-Net observations report
  57. GRB 230911C: Swift-BAT refined analysis
  58. GRB 230826A: Swift-BAT refined analysis
  59. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  60. Fermi GRB 230827A: Global MASTER-Net observations report
  61. Swift GRB230825.75: Global MASTER-Net observations report
  62. Fermi GRB 230814A: Global MASTER-Net observations report
  63. Swift GRB230728.12: Global MASTER-Net observations report
  64. LIGO/Virgo S230622e: Global MASTER-Net observations report
  65. LIGO/Virgo S230615be: Global MASTER-Net observations report
  66. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  67. GRB 230430A: AstroSat CZTI detection
  68. IPN triangulation of GRB 230418A (short)
  69. Fermi GRB 230402A: Global MASTER-Net observations report
  70. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  71. Fermi GRB 230227A: Global MASTER-Net observations report
  72. Fermi GRB 230215A: Global MASTER-Net observations report
  73. GRB 221231A: Fermi GBM Observation
  74. GRB 230101A: AstroSat CZTI detection
  75. Fermi GRB 221223A: Global MASTER-Net observations report
  76. GRB 221216A: Swift-XRT refined Analysis
  77. Fermi trigger No 687190301: Global MASTER-Net observations report
  78. GRB 220831A: ATCA 5/9 GHz radio observations
  79. GRB 220711B: Fermi GBM Detection
  80. GRB 220624A: Fermi GBM Detection
  81. Fermi GRB 220623B: Global MASTER-Net observations report
  82. GRB 220623A: Swift-XRT observations
  83. Konus-Wind detection of an intermediate flare from SGR 1935+2154 on June 16
  84. Swift GRB220521.97: Global MASTER-Net observations report
  85. GRB 220514B: MAXI/GSC detection
  86. Fermi-LAT Gamma-ray Observations of IceCube-220509A
  87. MAXI GRB220506.27: Global MASTER-Net observations report
  88. IceCube Alert 220501.95: Global MASTER-Net observations report
  89. GRB 220319A: Mondy optical uper limit
  90. GRB 220315A: MASTER Global Robotic Net optical observations
  91. Konus-Wind detection of GRB 220310A
  92. Fermi trigger No 668410535: Global MASTER-Net observations report
  93. Swift GRB 220306B: Global MASTER-Net observations report
  94. Konus-Wind observation of GRB 220219B
  95. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  96. GRB 220130A: Fermi GBM Observation
  97. Konus-Wind detection of GRB 220107A
  98. Konus-Wind detection of GRB 210928A
  99. Swift GRB 210919A: Global MASTER-Net observations report
  100. Konus-Wind detection of GRB 210905A

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