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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"
  1. GRB 261007A: SVOM/GRM observation
  2. EP261007b: SVOM/C-GFT optical upper limits
  3. EP261007b: J-band upper limit with WINTER
  4. The EP-WXT trigger 01709321008/EP261007b：Xinglong optical upper limit
  5. GRB 261007A / EP261007a: AstroSat CZTI detection
  6. GRB 261005A: GECAM-B observation
  7. EP261006a: Swift/XRT detection of the fading X-ray counterpart
  8. EP261007a/GRB 261007A：Xinglong optical observation
  9. GRB 261007A/EP261007a: Optical follow-up observations with Kinder
  10. EP261006a: Optical follow-up observations with Kinder
  11. EP261006a: Liverpool Telescope optical observations
  12. EP261006a: Early Optical Observations by WFST
  13. GRB 261007A / EP261007a: SVOM/VT optical observations
  14. GRB 261007A: Swift-XRT afterglow detection
  15. EP261007b: SVOM/VT optical upper limits
  16. GRB 261007A: SVOM/COLIBRÍ (FM-GFT) optical observations
  17. EP261007b: Einstein Probe detection of an X-ray transient
  18. GRB 261007A / EP261007a: NuSTAR detection of prompt emission
  19. EP Alert 261007.63: Global MASTER-Net observations report
  20. GRB 261007A / EP261007a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at McDonald Observatory
  21. GRB 261007A: Autonomous identification and follow-up of the counterpart to GRB 261007A by BTSbot with ZTF and P60/SEDM
  22. SVOM GRB261007.27: Global MASTER-Net observations report
  23. GRB 261007A: GROWTH-India Telescope optical observations
  24. GRB 261007A / EP261007a: TRT optical observations
  25. GRB 261007A: Swift ToO observations
  26. GRB 261007A: SVOM/C-GFT optical observations
  27. GRB 261007A / EP261007a: LCO optical observations
  28. GRB 261007B: Fermi GBM Final Real-time Localization
  29. SVOM GRB261007.23: Global MASTER-Net observations report
  30. GRB 261005B: Swift-BAT refined analysis
  31. EP261006a: NOT spectroscopy of a blue continuum
  32. GRB 261007A: WINTER J-band observations
  33. EP261006a: LT and NOT discovery of an optical counterpart
  34. GRB 261007A: Fermi GBM observation
  35. GRB 261007A / EP261007a: VLT/X-shooter spectroscopic redshift z = 2.101
  36. EP261007a/GRB 261007A: Einstein Probe detection of an X-ray transient
  37. EP261006a: SVOM/VT optical upper limits
  38. EP261006a: Einstein Probe detection of an X-ray transient
  39. GRB 261007A: KAIT optical counterpart candidate
  40. GRB 261007A: SVOM detection of a burst
  41. EP trigger 01709320985: SVOM/C-GFT optical upper limits
  42. GRB 261005B: Swift-XRT refined Analysis
  43. EP trigger 01709320985: Ondrejov D50 optical upper limits
  44. GRB 261005A: Glowbug gamma-ray detection
  45. GRB 261005B: Swift/UVOT Upper Limits
  46. GRB 261005B: J-band upper limit with WINTER
  47. GRB 261001A: GECAM-B observation of a likely long GRB
  48. GRB 261005B: Fermi GBM Observation
  49. GRB 261005B: Enhanced Swift-XRT position
  50. The EP-WXT trigger 01709320908 is likely a flaring star
  51. EP trigger 01709320908: Ondrejov D50 observation, fading star suggests stellar flare
  52. GRB 261005B: Swift detection of a burst
  53. GRB 261005A: Fermi GBM Final Real-time Localization
  54. GRB 261003A: Glowbug gamma-ray detection of a likely short burst
  55. GRB 261002A: Fermi GBM Final Localization
  56. EP#01709320865: Swift-XRT observations
  57. GRB 260930B: SVOM/GRM observation
  58. Konus-Wind detection of GRB 260919A / EP 260920a
  59. GRB 260921B: GECAM-B observation
  60. EP261003a: J-band upper limit with WINTER
  61. EP261003a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  62. GRB 260930B: GECAM-B detection of a burst
  63. EP261003a: COLIBRÍ optical upper limits
  64. Trigger_21915: Swift ToO observations (retracted)
  65. Fermi GRB 261003A: Global MASTER-Net observations report
  66. EP261003a: Einstein Probe detection of an X-ray transient
  67. GRB 261003A: Fermi GBM Final Real-time Localization
  68. EP Alert 261003.01: Global MASTER-Net observations report
  69. Fermi-LAT Gamma-ray Observations of IceCube-260930A
  70. Fermi GBM Detection of GRB 260919A / EP260920a
  71. IceCube-260930A: Upper limits from a search for additional neutrino events in IceCube
  72. IPN triangulation of GRB 260919A / EP260920a
  73. Fermi GRB 260930B: Global MASTER-Net observations report
  74. GRB 260926C: SVOM/GRM observation
  75. GRB 260930B: Fermi GBM Final Real-time Localization
  76. GRB 260930A: Fermi GBM Final Real-time Localization
  77. IceCube-260930A - IceCube observation of a high-energy neutrino candidate track-like event
  78. IceCube Alert 260930A: Global MASTER-Net observations report
  79. The EP-WXT trigger 01709320790 is likely a flaring star
  80. EP260927a: SVOM/ECLAIRs Upper Limit
  81. GRB 260926C: AstroSat CZTI detection
  82. GRB 260926C: GECAM-B observation
  83. GRB 260926A: GECAM-B observation
  84. EP260927a: Global MASTER-Net observations report
  85. EP260927a: Einstein Probe detection of a fast X-ray transient
  86. GRB 260926B: Glowbug gamma-ray detection of a likely short burst
  87. GRB 260926A: Glowbug gamma-ray detection
  88. GRB 260924A: VLA detection
  89. GRB 260924A: Swift/UVOT UV grism spectrum results
  90. GRB 260924A: AbAO optical observations
  91. Fermi GRB 260928A: Global MASTER-Net observations report
  92. GRB 260928A: Fermi GBM Final Real-time Localization
  93. EP260924a: Global MASTER-Net observations report
  94. GRB 260925A: Swift-BAT refined analysis
  95. Swift Trigger 1513439: consistent with noise and not astrophysical
  96. GRB 260924A: Upper limits from a neutrino search with IceCube
  97. Fermi GRB 260926C: Global MASTER-Net observations report
  98. GRB 260926C: Fermi GBM Final Real-time Localization
  99. GRB260914A: MAO/AZT-22 optical observations
  100. GRB 260926B: Fermi GBM Final Real-time Localization

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