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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"

39266 results found.

  1. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  2. GRB 260120B: Swift detection of a burst
  3. Swift GRB260120B: Global MASTER-Net observations report
  4. GRB 260120B: Fermi GBM Final Real-time Localization
  5. EP260119A: Mondy I-Band Observations
  6. Fermi trigger No 790601190: Global MASTER-Net observations report
  7. Fermi trigger No 790570272: Global MASTER-Net observations report
  8. GRB 260114A: Swift/UVOT Upper Limits
  9. GRB 251202A: further radio observations with the VLA
  10. EP260119a: KAIT optical observations
  11. GRB 260120A: Fermi GBM Final Real-time Localization
  12. EP260119a: SAO RAS optical observations
  13. SVOM GRB260119.92: Global MASTER-Net observations report
  14. SVOM GRB260119.92: Global MASTER-Net observations report
  15. SVOM GRB260119.90: Global MASTER-Net observations report
  16. EP260116a: COLIBRÍ detection of a fading optical source
  17. GRB 251208D: SVOM/ECLAIRs refined analysis
  18. GRB 251208D: SVOM/ECLAIRs refined analysis
  19. GRB 260117A: Swift-XRT afterglow detection
  20. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  21. EP260119a: Global MASTER-Net observations report
  22. GRB 260115A: AstroSat CZTI detection
  23. EP260119a: LCO optical observations
  24. GRB 260117A: ZTSh optical upper limit
  25. EP260119a: COLIBRÍ optical counterpart candidate
  26. GRB 260110A: SVOM detection of a burst through offline search
  27. Swift GRB260118.48: Global MASTER-Net observations report
  28. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  29. SVOM GRB260117.82: Global MASTER-Net observations report
  30. Swift trigger on the HMXB 1A 1118-61
  31. GRB 260117A: SVOM/VT optical candidate
  32. GRB 260117A: SVOM/C-GFT upper limit
  33. GRB 260117A: Swift-XRT observations
  34. GRB 260117A: Swift ToO observations
  35. GRB 260117A: SVOM detection of a long faint burst
  36. EP 260116a: COLIBRÍ optical upper limit
  37. Swift triggered on the HMXB 1A 1118-61
  38. GRB 260115A: GECAM-B observation
  39. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  40. EP260116A: 1.3m DFOT optical upper limit
  41. GRB 260114A: VLT/MUSE spectroscopic observations
  42. EP260116a: Global MASTER-Net observations report
  43. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  44. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  45. IceCube Alert 260115.73: Global MASTER-Net observations report
  46. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  47. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  48. Fermi GRB 260115A: Global MASTER-Net observations report
  49. GRB 260115A: Fermi GBM Final Real-time Localization
  50. GRB 251222A: radio detection with the VLA
  51. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  52. Konus-Wind detection of GRB 260114A
  53. GRB 260114A: Swift-XRT refined Analysis
  54. GRB 260114A: 6 GHz VLA observations
  55. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  56. GRB 260114A : MITSuME Akeno optical upper limits
  57. GRB 260114A: COLIBRÍ optical upper limits
  58. GRB 260114A: TNG NIR upper limit
  59. GRB 260114A: NOT optical observations
  60. Konus-Wind detection of GRB 251230A / EP251230a
  61. GRB 260114A: SVOM/GRM observation of a short burst
  62. Swift GRB 260114A: Global MASTER-Net observations report
  63. GRB 260114A: GECAM-B observation of a short burst
  64. GRB 260114A: Mondy optical observations
  65. GRB 260114A: Fermi GBM observation
  66. GRB 260112B: GECAM-B observation
  67. GRB 260114A: GMG Optical Observation
  68. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  69. GRB 260114A: Swift detection of a short burst
  70. GRB 260114A: Fermi GBM Final Real-time Localization
  71. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  72. Swift GRB260113.43: Global MASTER-Net observations report
  73. EP260110a: TRT optical upper limits
  74. Konus-Wind detection of GRB 260101A
  75. GRB 260111A: Swift-XRT observations
  76. Swift Trigger 1439093: is probably not GRB 260113A
  77. GRB 260111A: COLIBRÍ optical afterglow candidate
  78. GRB 260111A: GECAM-B observation of a burst
  79. GRB 260111A: Fermi GBM Observation
  80. Swift Trigger 1434591 is not a GRB
  81. GRB 260111A: GOTO optical upper limits
  82. GRB 260112B: Fermi GBM Final Real-time Localization
  83. GRB 260111A: Swift ToO observations
  84. GRB 251230A: Mondy Optical Observations
  85. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  86. GRB 260112A: Fermi GBM Final Real-time Localization
  87. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  88. IceCube Alert 260111A: Global MASTER-Net observations report
  89. EP260110a: Global MASTER-Net observations report
  90. Fermi GRB 260111A: Global MASTER-Net observations report
  91. GRB 260111A: Fermi GBM Final Real-time Localization
  92. EP260110a: KAIT optical upper limit
  93. EP 260110a: COLIBRÍ optical observations
  94. EP260110a: SVOM/C-GFT upper limit
  95. GRB 260109C: LCO optical upper limits
  96. GRB 260109C: Kilonova-Catcher optical upper limit
  97. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  98. Swift Trigger 1434591: possible GRB 260109C
  99. GRB 260109B: Fermi GBM Final Real-time Localization
  100. GRB 260102A: Swift-XRT afterglow detection

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