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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"

2407 results found.

  1. SVOM GRB260119.92: Global MASTER-Net observations report
  2. SVOM GRB260119.90: Global MASTER-Net observations report
  3. EP260116a: COLIBRÍ detection of a fading optical source
  4. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  5. EP260119a: Global MASTER-Net observations report
  6. GRB 260115A: AstroSat CZTI detection
  7. EP260119a: LCO optical observations
  8. GRB 260117A: ZTSh optical upper limit
  9. EP260119a: COLIBRÍ optical counterpart candidate
  10. EP260119a: preliminary result from the EP-FXT observation
  11. GRB 260110A: SVOM detection of a burst through offline search
  12. EP260119a: EP-WXT detection of a fast X-ray transient
  13. Swift GRB260118.48: Global MASTER-Net observations report
  14. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  15. SVOM GRB260117.82: Global MASTER-Net observations report
  16. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  17. GRB 260117A: SVOM/VT optical candidate
  18. GRB 260117A: SVOM/C-GFT upper limit
  19. GRB 260117A: SVOM detection of a long faint burst
  20. EP 260116a: COLIBRÍ optical upper limit
  21. GRB 260115A: GECAM-B observation
  22. EP260116a: Liverpool Telescope upper limits
  23. EP260116A: 1.3m DFOT optical upper limit
  24. GRB 260114A: VLT/MUSE spectroscopic observations
  25. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  26. EP260116a: Global MASTER-Net observations report
  27. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  28. EP260116a: Xinglong optical upper limit
  29. EP260116a: Einstein Probe detection of an X-ray transient
  30. IceCube Alert 260115.73: Global MASTER-Net observations report
  31. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  32. Fermi GRB 260115A: Global MASTER-Net observations report
  33. GRB 260115A: Fermi GBM Final Real-time Localization
  34. GRB 260114A : MITSuME Akeno optical upper limits
  35. GRB 260114A: COLIBRÍ optical upper limits
  36. GRB 260114A: TNG NIR upper limit
  37. GRB 260114A: NOT optical observations
  38. GRB 260114A: SVOM/GRM observation of a short burst
  39. Swift GRB 260114A: Global MASTER-Net observations report
  40. GRB 260114A: GECAM-B observation of a short burst
  41. GRB 260114A: Mondy optical observations
  42. GRB 260114A: Fermi GBM observation
  43. GRB 260112B: GECAM-B observation
  44. GRB 260114A: GMG Optical Observation
  45. GRB 260114A: Fermi GBM Final Real-time Localization
  46. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  47. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  48. Swift GRB260113.43: Global MASTER-Net observations report
  49. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  50. EP260110a: TRT optical upper limits
  51. GRB 260111A: COLIBRÍ optical afterglow candidate
  52. GRB 260111A: GECAM-B observation of a burst
  53. GRB 260111A: Fermi GBM Observation
  54. The EP-WXT trigger 01709251266 is likely a flaring star
  55. GRB 260111A: GOTO optical upper limits
  56. GRB 260112B: Fermi GBM Final Real-time Localization
  57. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  58. GRB 260112A: Fermi GBM Final Real-time Localization
  59. EP260110a: SVOM/VT optical upper limits
  60. IceCube Alert 260111A: Global MASTER-Net observations report
  61. EP260110a: Global MASTER-Net observations report
  62. Fermi GRB 260111A: Global MASTER-Net observations report
  63. GRB 260111A: Fermi GBM Final Real-time Localization
  64. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  65. EP 260110a: COLIBRÍ optical observations
  66. EP260110a: SVOM/C-GFT upper limit
  67. EP260110a: Einstein Probe detection of an X-ray transient
  68. GRB 260109C: LCO optical upper limits
  69. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  70. GRB 260109B: Fermi GBM Final Real-time Localization
  71. GRB 260109A: Fermi GBM Final Real-time Localization
  72. Fermi GRB 260107A: Global MASTER-Net observations report
  73. GRB 260102A: AbAO optical observations
  74. GRB 260107A: Fermi GBM Final Real-time Localization
  75. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  76. The EP-WXT trigger 01709251112 is likely a flaring star
  77. Fermi GRB 260105A: Global MASTER-Net observations report
  78. GRB 260105B: Fermi GBM Detection
  79. EP260105a: FTW optical observations
  80. EP260104a: FTW optical observations
  81. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  82. GRB 260105A: SVOM/GRM observation
  83. GRB 260105B: SVOM/GRM observation
  84. The EP-WXT trigger 01709251028 is likely a flaring star
  85. FRB 20251229A: COLIBRÍ optical upper limits
  86. Fermi GRB 260105B: Global MASTER-Net observations report
  87. EP260105a: SVOM/VT optical upperlimit
  88. GRB 260105B: Fermi GBM Final Real-time Localization
  89. GRB 260105A: Fermi GBM Final Real-time Localization
  90. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  91. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  92. EP260105a: LCO Optical Upper limit
  93. EP260104a: Global MASTER-Net observations report
  94. EP260104a: Einstein Probe detection of a fast X-ray transient
  95. GRB 260101A: COLIBRÍ optical upper limits
  96. EP260105a: Global MASTER-Net observations report
  97. EP260105a: Einstein Probe detection of an X-ray transient
  98. GRB 260103A: Insight-HXMT/HE detection
  99. GRB 260104A: COLIBRÍ optical upper limits
  100. GRB 260104C: Fermi GBM Final Real-time Localization

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