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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"

24475 results found.

  1. GRB 261010A: Glowbug gamma-ray detection
  2. GRB 261008A: SVOM/GRM observation
  3. GRB 261009A: GECAM-B detection of a burst
  4. IceCube-261012A: Upper limits from a search for additional neutrino events in IceCube
  5. GRB 261010A: a short minimum variability timescale and a distinct pulse evolution compatible with a merger origin
  6. GRB 261013A: Fermi GBM Final Real-time Localization
  7. Fermi-LAT Gamma-ray Observations of IceCube-261012A
  8. GRID detection of GRB 261010A
  9. IceCube-260919A: No transient candidates from the Zwicky Transient Facility
  10. GRB 261010A: a Type I-L (merger-driven) GRB candidate
  11. GRB 261011A: Swift-BAT refined analysis
  12. IceCube-261012A - IceCube observation of a high-energy neutrino candidate track-like event
  13. MAXI GRB261012.23: Global MASTER-Net observations report
  14. GRB 261011A: REM optical/NIR observations
  15. Konus-Wind detection of GRB 261011A
  16. Konus-Wind detection of GRB 261007A/EP261007a
  17. EP261006a: 10 GHz VLA observations
  18. GRB 261010A: Swift-BAT refined analysis
  19. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  20. GRB 261011A: Optical followup from Sichuan South Observatory
  21. GRB 261011A: GMG Optical Observation
  22. GRB 261010A: Fermi GBM Observation
  23. GRB 261011B: Fermi GBM Final Localization
  24. EP261007b: Global MASTER-Net observations report
  25. GRB 261011A: GROWTH-India Telescope optical observations
  26. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  27. Swift GRB 261011A: Global MASTER-Net observations report
  28. GRB 261011A: SVOM/C-GFT optical observations
  29. GRB 261011A: LCO optical observations
  30. GRB 261011A: SVOM/VT optical observation from VHF data
  31. GRB 261011A: TRT optical afterglow detection
  32. GRB 261011A: GOTO optical counterpart detection
  33. GRB 261011A: SVOM detection of a long bright burst
  34. EP261010a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  35. GRB 261010A: Swift detection of a burst
  36. GRB 261010A: Fermi GBM Final Real-time Localization
  37. EP261006a / AT 2026aetp: Multiband optical follow-up with the PKU 60cm Telescope
  38. EP261010a: SVOM/VT optical upper limits
  39. EP261010a: Global MASTER-Net observations report
  40. GRB 261009A: Fermi GBM Final Real-time Localization
  41. EP261006a: Xinglong 2.16m/BFOSC optical follow-up observations
  42. EP261007b: J-band upper limit by SYSU 80cm infrared telescope
  43. EP261007b: Refined analysis of the EP-WXT and autonomous EP-FXT observations
  44. GRB 261007A: SVOM/ECLAIRs refined analysis
  45. EP261007b: SVOM/VT optical detection of the NOT transient
  46. GRB 261007A / EP261007a: SVOM/GWAC-F60A/B observations
  47. EP261006a / AT 2026aetp: VLT/X-shooter spectroscopic redshift z = 0.1853
  48. GRB 261008A: Fermi GBM Final Real-time Localization
  49. EP261007b: NOT optical observations, variable source outside the FXT region
  50. GRB 261007A: SVOM/GRM observation
  51. EP261007b: SVOM/C-GFT optical upper limits
  52. EP261007b: J-band upper limit with WINTER
  53. The EP-WXT trigger 01709321008/EP261007b：Xinglong optical upper limit
  54. EP261006a: Swift/XRT detection of the fading X-ray counterpart
  55. EP261007a/GRB 261007A：Xinglong optical observation
  56. EP261006a: Early Optical Observations by WFST
  57. GRB 261007A / EP261007a: SVOM/VT optical observations
  58. EP261007b: SVOM/VT optical upper limits
  59. GRB 261007A / EP261007a: NuSTAR detection of prompt emission
  60. EP Alert 261007.63: Global MASTER-Net observations report
  61. GRB 261007A / EP261007a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at McDonald Observatory
  62. GRB 261007A: Autonomous identification and follow-up of the counterpart to GRB 261007A by BTSbot with ZTF and P60/SEDM
  63. SVOM GRB261007.27: Global MASTER-Net observations report
  64. GRB 261007A: GROWTH-India Telescope optical observations
  65. GRB 261007A / EP261007a: TRT optical observations
  66. GRB 261007A: SVOM/C-GFT optical observations
  67. GRB 261007A / EP261007a: LCO optical observations
  68. GRB 261007B: Fermi GBM Final Real-time Localization
  69. SVOM GRB261007.23: Global MASTER-Net observations report
  70. GRB 261005B: Swift-BAT refined analysis
  71. EP261006a: LT and NOT discovery of an optical counterpart
  72. GRB 261007A: Fermi GBM observation
  73. GRB 261007A / EP261007a: VLT/X-shooter spectroscopic redshift z = 2.101
  74. EP261006a: SVOM/VT optical upper limits
  75. EP261006a: Einstein Probe detection of an X-ray transient
  76. GRB 261007A: SVOM detection of a burst
  77. EP trigger 01709320985: SVOM/C-GFT optical upper limits
  78. GRB 261005B: Fermi GBM Observation
  79. The EP-WXT trigger 01709320908 is likely a flaring star
  80. GRB 261005B: Swift detection of a burst
  81. GRB 261005A: Fermi GBM Final Real-time Localization
  82. GRB 261002A: Fermi GBM Final Localization
  83. GRB 260930B: SVOM/GRM observation
  84. Konus-Wind detection of GRB 260919A / EP 260920a
  85. EP261003a: J-band upper limit with WINTER
  86. GRB 260930B: GECAM-B detection of a burst
  87. Fermi GRB 261003A: Global MASTER-Net observations report
  88. GRB 261003A: Fermi GBM Final Real-time Localization
  89. EP Alert 261003.01: Global MASTER-Net observations report
  90. Fermi-LAT Gamma-ray Observations of IceCube-260930A
  91. Fermi GBM Detection of GRB 260919A / EP260920a
  92. IceCube-260930A: Upper limits from a search for additional neutrino events in IceCube
  93. IPN triangulation of GRB 260919A / EP260920a
  94. Fermi GRB 260930B: Global MASTER-Net observations report
  95. GRB 260926C: SVOM/GRM observation
  96. GRB 260930B: Fermi GBM Final Real-time Localization
  97. GRB 260930A: Fermi GBM Final Real-time Localization
  98. IceCube-260930A - IceCube observation of a high-energy neutrino candidate track-like event
  99. IceCube Alert 260930A: Global MASTER-Net observations report
  100. The EP-WXT trigger 01709320790 is likely a flaring star

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