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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"

24479 results found.

  1. EP261015c: Einstein Probe detection of a fast X-ray transient
  2. GRB261010A: Keck/MOSFIRE detection of a near-IR source
  3. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  4. The EP-WXT trigger 01709321333 is likely a flaring star
  5. GRB 261010A: Glowbug gamma-ray detection
  6. GRB 261008A: SVOM/GRM observation
  7. GRB 261009A: GECAM-B detection of a burst
  8. IceCube-261012A: Upper limits from a search for additional neutrino events in IceCube
  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. Fermi-LAT Gamma-ray Observations of IceCube-261012A
  12. GRID detection of GRB 261010A
  13. IceCube-260919A: No transient candidates from the Zwicky Transient Facility
  14. GRB 261010A: a Type I-L (merger-driven) GRB candidate
  15. GRB 261011A: Swift-BAT refined analysis
  16. IceCube-261012A - IceCube observation of a high-energy neutrino candidate track-like event
  17. MAXI GRB261012.23: Global MASTER-Net observations report
  18. GRB 261011A: REM optical/NIR observations
  19. Konus-Wind detection of GRB 261011A
  20. Konus-Wind detection of GRB 261007A/EP261007a
  21. EP261006a: 10 GHz VLA observations
  22. GRB 261010A: Swift-BAT refined analysis
  23. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  24. GRB 261011A: Optical followup from Sichuan South Observatory
  25. GRB 261011A: GMG Optical Observation
  26. GRB 261010A: Fermi GBM Observation
  27. GRB 261011B: Fermi GBM Final Localization
  28. EP261007b: Global MASTER-Net observations report
  29. GRB 261011A: GROWTH-India Telescope optical observations
  30. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  31. Swift GRB 261011A: Global MASTER-Net observations report
  32. GRB 261011A: SVOM/C-GFT optical observations
  33. GRB 261011A: LCO optical observations
  34. GRB 261011A: SVOM/VT optical observation from VHF data
  35. GRB 261011A: TRT optical afterglow detection
  36. GRB 261011A: GOTO optical counterpart detection
  37. GRB 261011A: SVOM detection of a long bright burst
  38. EP261010a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  39. GRB 261010A: Swift detection of a burst
  40. GRB 261010A: Fermi GBM Final Real-time Localization
  41. EP261006a / AT 2026aetp: Multiband optical follow-up with the PKU 60cm Telescope
  42. EP261010a: SVOM/VT optical upper limits
  43. EP261010a: Global MASTER-Net observations report
  44. GRB 261009A: Fermi GBM Final Real-time Localization
  45. EP261006a: Xinglong 2.16m/BFOSC optical follow-up observations
  46. EP261007b: J-band upper limit by SYSU 80cm infrared telescope
  47. EP261007b: Refined analysis of the EP-WXT and autonomous EP-FXT observations
  48. GRB 261007A: SVOM/ECLAIRs refined analysis
  49. EP261007b: SVOM/VT optical detection of the NOT transient
  50. GRB 261007A / EP261007a: SVOM/GWAC-F60A/B observations
  51. EP261006a / AT 2026aetp: VLT/X-shooter spectroscopic redshift z = 0.1853
  52. GRB 261008A: Fermi GBM Final Real-time Localization
  53. EP261007b: NOT optical observations, variable source outside the FXT region
  54. GRB 261007A: SVOM/GRM observation
  55. EP261007b: SVOM/C-GFT optical upper limits
  56. EP261007b: J-band upper limit with WINTER
  57. The EP-WXT trigger 01709321008/EP261007b：Xinglong optical upper limit
  58. EP261006a: Swift/XRT detection of the fading X-ray counterpart
  59. EP261007a/GRB 261007A：Xinglong optical observation
  60. EP261006a: Early Optical Observations by WFST
  61. GRB 261007A / EP261007a: SVOM/VT optical observations
  62. EP261007b: SVOM/VT optical upper limits
  63. GRB 261007A / EP261007a: NuSTAR detection of prompt emission
  64. EP Alert 261007.63: Global MASTER-Net observations report
  65. GRB 261007A / EP261007a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at McDonald Observatory
  66. GRB 261007A: Autonomous identification and follow-up of the counterpart to GRB 261007A by BTSbot with ZTF and P60/SEDM
  67. SVOM GRB261007.27: Global MASTER-Net observations report
  68. GRB 261007A: GROWTH-India Telescope optical observations
  69. GRB 261007A / EP261007a: TRT optical observations
  70. GRB 261007A: SVOM/C-GFT optical observations
  71. GRB 261007A / EP261007a: LCO optical observations
  72. GRB 261007B: Fermi GBM Final Real-time Localization
  73. SVOM GRB261007.23: Global MASTER-Net observations report
  74. GRB 261005B: Swift-BAT refined analysis
  75. EP261006a: LT and NOT discovery of an optical counterpart
  76. GRB 261007A: Fermi GBM observation
  77. GRB 261007A / EP261007a: VLT/X-shooter spectroscopic redshift z = 2.101
  78. EP261006a: SVOM/VT optical upper limits
  79. EP261006a: Einstein Probe detection of an X-ray transient
  80. GRB 261007A: SVOM detection of a burst
  81. EP trigger 01709320985: SVOM/C-GFT optical upper limits
  82. GRB 261005B: Fermi GBM Observation
  83. The EP-WXT trigger 01709320908 is likely a flaring star
  84. GRB 261005B: Swift detection of a burst
  85. GRB 261005A: Fermi GBM Final Real-time Localization
  86. GRB 261002A: Fermi GBM Final Localization
  87. GRB 260930B: SVOM/GRM observation
  88. Konus-Wind detection of GRB 260919A / EP 260920a
  89. EP261003a: J-band upper limit with WINTER
  90. GRB 260930B: GECAM-B detection of a burst
  91. Fermi GRB 261003A: Global MASTER-Net observations report
  92. GRB 261003A: Fermi GBM Final Real-time Localization
  93. EP Alert 261003.01: Global MASTER-Net observations report
  94. Fermi-LAT Gamma-ray Observations of IceCube-260930A
  95. Fermi GBM Detection of GRB 260919A / EP260920a
  96. IceCube-260930A: Upper limits from a search for additional neutrino events in IceCube
  97. IPN triangulation of GRB 260919A / EP260920a
  98. Fermi GRB 260930B: Global MASTER-Net observations report
  99. GRB 260926C: SVOM/GRM observation
  100. GRB 260930B: Fermi GBM Final Real-time Localization

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