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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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.

Advanced Search Examples (click to copy):

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

42942 results found.

  1. GRB 261010A: LBT tentative near-infrared detection
  2. GRB 261011A: SAO RAS and AbAO optical observations
  3. GRB 261010A: Glowbug gamma-ray detection
  4. GRB 261008A: SVOM/GRM observation
  5. GRB 261009A: GECAM-B detection of a burst
  6. EP261006a : MeerKAT radio observations.
  7. IceCube-261012A: Upper limits from a search for additional neutrino events in IceCube
  8. GRB 261010A: initial pulse rest-frame energetics from Konus-Wind detection
  9. GRB 261010A: a short minimum variability timescale and a distinct pulse evolution compatible with a merger origin
  10. GRB 261013A: Fermi GBM Final Real-time Localization
  11. GRB 261011A: Later-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  12. Fermi-LAT Gamma-ray Observations of IceCube-261012A
  13. GRID detection of GRB 261010A
  14. GRB 261011A: GECAM-B observation
  15. GRB 261011B: GECAM-B observation
  16. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  17. IceCube-260919A: No transient candidates from the Zwicky Transient Facility
  18. GRB 261010A: Swift-XRT refined Analysis
  19. GRB 261011A: Swift-XRT refined Analysis
  20. GRB 261011A: Enhanced Swift-XRT position
  21. GRB 261010A: a Type I-L (merger-driven) GRB candidate
  22. GRB 261011A: 10.4m GTC spectroscopic redshift (z = 2.407)
  23. GRB 261011A: Swift-BAT refined analysis
  24. IceCube-261012A - IceCube observation of a high-energy neutrino candidate track-like event
  25. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  26. MAXI GRB261012.23: Global MASTER-Net observations report
  27. GRB 261011A: REM optical/NIR observations
  28. Konus-Wind detection of GRB 261010A
  29. Konus-Wind detection of GRB 261011A
  30. Konus-Wind detection of GRB 261007A/EP261007a
  31. GRB 261011A: SOAR optical afterglow observations at ~17 hours
  32. EP261006a: 10 GHz VLA observations
  33. GRB 261011A: VLT/X-shooter redshift constraints
  34. GRB 261012A: MAXI GSC detection
  35. GRB 261010A: Swift-BAT refined analysis
  36. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  37. GRB 261011A: Optical followup from Sichuan South Observatory
  38. GRB 261011A: GMG Optical Observation
  39. GRB 261011A: Liverpool Telescope optical observations
  40. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  41. GRB 261010A: NOT confirmation of the optical afterglow
  42. GRB 261010A: Fermi GBM Observation
  43. GRB 261011B: Fermi GBM Final Localization
  44. GRB 261011A: continued LCO optical observations
  45. EP261007b: Global MASTER-Net observations report
  46. GRB 261011A: GROWTH-India Telescope optical observations
  47. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  48. Swift GRB 261011A: Global MASTER-Net observations report
  49. GRB 261011A: Optical follow-up observations with Kinder
  50. GRB 261011A: SVOM/C-GFT optical observations
  51. EP261007b: Second EP-FXT follow-up observation and a possible X-ray counterpart to the optical transient
  52. GRB 261011A: LCO optical observations
  53. GRB 261011A: SVOM/VT optical observation from VHF data
  54. GRB 261011A: LCO optical observations
  55. GRB 261011A: TRT optical afterglow detection
  56. GRB 261011A: GOTO optical counterpart detection
  57. GRB 261011A: Swift detection of an unusual burst
  58. GRB 261011A: SVOM detection of a long bright burst
  59. GRB 261010A: Enhanced Swift-XRT position
  60. EP261010a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  61. EP261006a / AT 2026aetp: Luminance-band optical follow-up with small-aperture telescopes
  62. GRB 261010A: possible optical afterglow detected with the 1.5m OSN
  63. GRB 261010A: NOT possible optical counterpart
  64. GRB 261010A: Swift detection of a burst
  65. GRB 261010A: Fermi GBM Final Real-time Localization
  66. EP261006a: Kilonova-Catcher optical follow-up and detection
  67. GRB 261001A: SVOM/GRM observation
  68. EP261006a / AT 2026aetp: Multiband optical follow-up with the PKU 60cm Telescope
  69. EP261010a: SVOM/VT optical upper limits
  70. EP261006a: Liverpool Telescope optical follow-up
  71. EP261010a: NOT optical upper limits
  72. EP261010a: Global MASTER-Net observations report
  73. EP261010a Einstein Probe detection of an X-ray transient
  74. GRB 261009A: Fermi GBM Final Real-time Localization
  75. GRB261007A: Lesedi optical afterglow detection
  76. EP261006a: Xinglong 2.16m/BFOSC optical follow-up observations
  77. EP261007b: SVOM/ECLAIRs Upper Limit
  78. GRB 261008A: GECAM-B observation
  79. EP261006a: Optical follow-up observations with MATCH
  80. EP261007b: J-band upper limit by SYSU 80cm infrared telescope
  81. EP261007b: Refined analysis of the EP-WXT and autonomous EP-FXT observations
  82. GRB 261007A: SVOM/ECLAIRs refined analysis
  83. EP261007b: SVOM/VT optical detection of the NOT transient
  84. GRB 261007A / EP261007a: SVOM/GWAC-F60A/B observations
  85. EP261006a / AT 2026aetp: VLT/X-shooter spectroscopic redshift z = 0.1853
  86. GRB 261007A: Glowbug gamma-ray detection
  87. GRB 261008A: Fermi GBM Final Real-time Localization
  88. GRB 261007A: NOT optical observations
  89. EP261007b: NOT optical observations, variable source outside the FXT region
  90. GRB 261007A: SVOM/GRM observation
  91. EP261007b: SVOM/C-GFT optical upper limits
  92. EP261007b: J-band upper limit with WINTER
  93. The EP-WXT trigger 01709321008/EP261007b：Xinglong optical upper limit
  94. GRB 261007A / EP261007a: AstroSat CZTI detection
  95. GRB 261005A: GECAM-B observation
  96. EP261006a: Swift/XRT detection of the fading X-ray counterpart
  97. EP261007a/GRB 261007A：Xinglong optical observation
  98. GRB 261007A/EP261007a: Optical follow-up observations with Kinder
  99. EP261006a: Optical follow-up observations with Kinder
  100. EP261006a: Liverpool Telescope optical observations

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