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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 / EP261007a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at McDonald Observatory
  2. GRB 261007A: Autonomous identification and follow-up of the counterpart to GRB 261007A by BTSbot with ZTF and P60/SEDM
  3. SVOM GRB261007.27: Global MASTER-Net observations report
  4. GRB 261007A: GROWTH-India Telescope optical observations
  5. GRB 261007A / EP261007a: TRT optical observations
  6. GRB 261007A: Swift ToO observations
  7. GRB 261007A: SVOM/C-GFT optical observations
  8. GRB 261007A / EP261007a: LCO optical observations
  9. GRB 261007B: Fermi GBM Final Real-time Localization
  10. SVOM GRB261007.23: Global MASTER-Net observations report
  11. GRB 261005B: Swift-BAT refined analysis
  12. EP261006a: NOT spectroscopy of a blue continuum
  13. GRB 261007A: WINTER J-band observations
  14. EP261006a: LT and NOT discovery of an optical counterpart
  15. GRB 261007A: Fermi GBM observation
  16. GRB 261007A / EP261007a: VLT/X-shooter spectroscopic redshift z = 2.101
  17. EP261007a/GRB 261007A: Einstein Probe detection of an X-ray transient
  18. EP261006a: SVOM/VT optical upper limits
  19. EP261006a: Einstein Probe detection of an X-ray transient
  20. GRB 261007A: KAIT optical counterpart candidate
  21. GRB 261007A: SVOM detection of a burst
  22. EP trigger 01709320985: SVOM/C-GFT optical upper limits
  23. GRB 261005B: Swift-XRT refined Analysis
  24. EP trigger 01709320985: Ondrejov D50 optical upper limits
  25. GRB 261005A: Glowbug gamma-ray detection
  26. GRB 261005B: Swift/UVOT Upper Limits
  27. GRB 261005B: J-band upper limit with WINTER
  28. GRB 261001A: GECAM-B observation of a likely long GRB
  29. GRB 261005B: Fermi GBM Observation
  30. GRB 261005B: Enhanced Swift-XRT position
  31. The EP-WXT trigger 01709320908 is likely a flaring star
  32. EP trigger 01709320908: Ondrejov D50 observation, fading star suggests stellar flare
  33. GRB 261005B: Swift detection of a burst
  34. GRB 261005A: Fermi GBM Final Real-time Localization
  35. GRB 261003A: Glowbug gamma-ray detection of a likely short burst
  36. GRB 261002A: Fermi GBM Final Localization
  37. EP#01709320865: Swift-XRT observations
  38. GRB 260930B: SVOM/GRM observation
  39. Konus-Wind detection of GRB 260919A / EP 260920a
  40. GRB 260921B: GECAM-B observation
  41. EP261003a: J-band upper limit with WINTER
  42. EP261003a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  43. GRB 260930B: GECAM-B detection of a burst
  44. EP261003a: COLIBRÍ optical upper limits
  45. Trigger_21915: Swift ToO observations (retracted)
  46. Fermi GRB 261003A: Global MASTER-Net observations report
  47. EP261003a: Einstein Probe detection of an X-ray transient
  48. GRB 261003A: Fermi GBM Final Real-time Localization
  49. EP Alert 261003.01: Global MASTER-Net observations report
  50. Fermi-LAT Gamma-ray Observations of IceCube-260930A
  51. Fermi GBM Detection of GRB 260919A / EP260920a
  52. IceCube-260930A: Upper limits from a search for additional neutrino events in IceCube
  53. IPN triangulation of GRB 260919A / EP260920a
  54. Fermi GRB 260930B: Global MASTER-Net observations report
  55. GRB 260926C: SVOM/GRM observation
  56. GRB 260930B: Fermi GBM Final Real-time Localization
  57. GRB 260930A: Fermi GBM Final Real-time Localization
  58. IceCube-260930A - IceCube observation of a high-energy neutrino candidate track-like event
  59. IceCube Alert 260930A: Global MASTER-Net observations report
  60. The EP-WXT trigger 01709320790 is likely a flaring star
  61. EP260927a: SVOM/ECLAIRs Upper Limit
  62. GRB 260926C: AstroSat CZTI detection
  63. GRB 260926C: GECAM-B observation
  64. GRB 260926A: GECAM-B observation
  65. EP260927a: Global MASTER-Net observations report
  66. EP260927a: Einstein Probe detection of a fast X-ray transient
  67. GRB 260926B: Glowbug gamma-ray detection of a likely short burst
  68. GRB 260926A: Glowbug gamma-ray detection
  69. GRB 260924A: VLA detection
  70. GRB 260924A: Swift/UVOT UV grism spectrum results
  71. GRB 260924A: AbAO optical observations
  72. Fermi GRB 260928A: Global MASTER-Net observations report
  73. GRB 260928A: Fermi GBM Final Real-time Localization
  74. EP260924a: Global MASTER-Net observations report
  75. GRB 260925A: Swift-BAT refined analysis
  76. Swift Trigger 1513439: consistent with noise and not astrophysical
  77. GRB 260924A: Upper limits from a neutrino search with IceCube
  78. Fermi GRB 260926C: Global MASTER-Net observations report
  79. GRB 260926C: Fermi GBM Final Real-time Localization
  80. GRB260914A: MAO/AZT-22 optical observations
  81. GRB 260926B: Fermi GBM Final Real-time Localization
  82. Fermi GRB 260926A: Global MASTER-Net observations report
  83. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  84. GRB 260926A: Fermi GBM Final Real-time Localization
  85. The EP-WXT trigger 01709320726 is likely a flaring star
  86. GRB 260924A: COLIBRÍ optical observations
  87. GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  88. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  89. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  90. GRB 260925A: Swift-XRT refined Analysis
  91. EP260924a: EP-FXT follow-up observation
  92. Swift Trigger 1513439 is probably not a GRB
  93. GRB 260925A: Swift/UVOT Upper Limits
  94. Konus-Wind detection of GRB 260924A
  95. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  96. GRB 260923A: Glowbug gamma-ray detection
  97. GRB 260924A: Optical follow-up observations with Kinder
  98. GRB 260922A: Glowbug gamma-ray detection
  99. GRB 260925A: Enhanced Swift-XRT position
  100. GRB 260925A: COLIBRÍ optical upper limits

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