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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. EP Alert 261007.63: Global MASTER-Net observations report
  2. GRB 261007A / EP261007a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at McDonald Observatory
  3. Autonomous identification and follow-up of the counterpart to GRB 261007A by BTSbot with ZTF and P60/SEDM
  4. SVOM GRB261007.27: Global MASTER-Net observations report
  5. GRB 261007A: GROWTH-India Telescope optical observations
  6. GRB 261007A / EP261007a: TRT optical observations
  7. GRB 261007A: Swift ToO observations
  8. GRB 261007A: SVOM/C-GFT optical observations
  9. GRB 261007A / EP261007a: LCO optical observations
  10. GRB 261007B: Fermi GBM Final Real-time Localization
  11. SVOM GRB261007.23: Global MASTER-Net observations report
  12. GRB 261005B: Swift-BAT refined analysis
  13. EP261006a: NOT spectroscopy of a blue continuum
  14. GRB 261007A: WINTER J-band observations
  15. EP261006a: LT and NOT discovery of an optical counterpart
  16. GRB 261007A: Fermi GBM observation
  17. GRB 261007A / EP261007a: VLT/X-shooter spectroscopic redshift z = 2.101
  18. EP261007a/GRB 261007A: Einstein Probe detection of an X-ray transient
  19. EP261006a: SVOM/VT optical upper limits
  20. EP261006a: Einstein Probe detection of an X-ray transient
  21. GRB 261007A: KAIT optical counterpart candidate
  22. GRB 261007A: SVOM detection of a burst
  23. EP trigger 01709320985: SVOM/C-GFT optical upper limits
  24. GRB 261005B: Swift-XRT refined Analysis
  25. EP trigger 01709320985: Ondrejov D50 optical upper limits
  26. GRB 261005A: Glowbug gamma-ray detection
  27. GRB 261005B: Swift/UVOT Upper Limits
  28. GRB 261005B: J-band upper limit with WINTER
  29. GRB 261001A: GECAM-B observation of a likely long GRB
  30. GRB 261005B: Fermi GBM Observation
  31. GRB 261005B: Enhanced Swift-XRT position
  32. The EP-WXT trigger 01709320908 is likely a flaring star
  33. EP trigger 01709320908: Ondrejov D50 observation, fading star suggests stellar flare
  34. GRB 261005B: Swift detection of a burst
  35. GRB 261005A: Fermi GBM Final Real-time Localization
  36. GRB 261003A: Glowbug gamma-ray detection of a likely short burst
  37. GRB 261002A: Fermi GBM Final Localization
  38. EP#01709320865: Swift-XRT observations
  39. GRB 260930B: SVOM/GRM observation
  40. Konus-Wind detection of GRB 260919A / EP 260920a
  41. GRB 260921B: GECAM-B observation
  42. EP261003a: J-band upper limit with WINTER
  43. EP261003a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  44. GRB 260930B: GECAM-B detection of a burst
  45. EP261003a: COLIBRÍ optical upper limits
  46. Trigger_21915: Swift ToO observations
  47. Fermi GRB 261003A: Global MASTER-Net observations report
  48. EP261003a: Einstein Probe detection of an X-ray transient
  49. GRB 261003A: Fermi GBM Final Real-time Localization
  50. EP Alert 261003.01: Global MASTER-Net observations report
  51. Fermi-LAT Gamma-ray Observations of IceCube-260930A
  52. Fermi GBM Detection of GRB 260919A / EP260920a
  53. IceCube-260930A: Upper limits from a search for additional neutrino events in IceCube
  54. IPN triangulation of GRB 260919A / EP260920a
  55. Fermi GRB 260930B: Global MASTER-Net observations report
  56. GRB 260926C: SVOM/GRM observation
  57. GRB 260930B: Fermi GBM Final Real-time Localization
  58. GRB 260930A: Fermi GBM Final Real-time Localization
  59. IceCube-260930A - IceCube observation of a high-energy neutrino candidate track-like event
  60. IceCube Alert 260930A: Global MASTER-Net observations report
  61. The EP-WXT trigger 01709320790 is likely a flaring star
  62. EP260927a: SVOM/ECLAIRs Upper Limit
  63. GRB 260926C: AstroSat CZTI detection
  64. GRB 260926C: GECAM-B observation
  65. GRB 260926A: GECAM-B observation
  66. EP260927a: Global MASTER-Net observations report
  67. EP260927a: Einstein Probe detection of a fast X-ray transient
  68. GRB 260926B: Glowbug gamma-ray detection of a likely short burst
  69. GRB 260926A: Glowbug gamma-ray detection
  70. GRB 260924A: VLA detection
  71. GRB 260924A: Swift/UVOT UV grism spectrum results
  72. GRB 260924A: AbAO optical observations
  73. Fermi GRB 260928A: Global MASTER-Net observations report
  74. GRB 260928A: Fermi GBM Final Real-time Localization
  75. EP260924a: Global MASTER-Net observations report
  76. GRB 260925A: Swift-BAT refined analysis
  77. Swift Trigger 1513439: consistent with noise and not astrophysical
  78. GRB 260924A: Upper limits from a neutrino search with IceCube
  79. Fermi GRB 260926C: Global MASTER-Net observations report
  80. GRB 260926C: Fermi GBM Final Real-time Localization
  81. GRB260914A: MAO/AZT-22 optical observations
  82. GRB 260926B: Fermi GBM Final Real-time Localization
  83. Fermi GRB 260926A: Global MASTER-Net observations report
  84. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  85. GRB 260926A: Fermi GBM Final Real-time Localization
  86. The EP-WXT trigger 01709320726 is likely a flaring star
  87. GRB 260924A: COLIBRÍ optical observations
  88. GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  89. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  90. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  91. GRB 260925A: Swift-XRT refined Analysis
  92. EP260924a: EP-FXT follow-up observation
  93. Swift Trigger 1513439 is probably not a GRB
  94. GRB 260925A: Swift/UVOT Upper Limits
  95. Konus-Wind detection of GRB 260924A
  96. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  97. GRB 260923A: Glowbug gamma-ray detection
  98. GRB 260924A: Optical follow-up observations with Kinder
  99. GRB 260922A: Glowbug gamma-ray detection
  100. GRB 260925A: Enhanced Swift-XRT position

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