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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"

28233 results found.

  1. GRB 260125A: Swift-XRT observations
  2. EP260126a: Optical upper limit with Kinder observations
  3. EP260126a: Liverpool Telescope optical upper limits
  4. EP260126a: Further NOT optical upper limits
  5. EP260126a: COLIBRÍ optical upper limits
  6. EP260126a: NOT optical observations
  7. EP260126a: Einstein Probe detection of a fast X-ray transient
  8. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  9. GRB 251222A: SVOM/ECLAIRs refined analysis
  10. GRB 260125A: GOTO candidate optical counterpart
  11. Fermi GRB 260125B: Global MASTER-Net observations report
  12. GRB 260114A: SVOM/VT optical upper limits
  13. GRB 260122B: Swift-BAT refined analysis
  14. GRB 260120B: SVOM/GRM observation
  15. Swift GRB260122.97: Global MASTER-Net observations report
  16. EP260119a: Assy AZT-20 optical observations
  17. EP260119a: Mondy and SAO RAS optical upper limits
  18. EP260119a: Xinglong optical upper limit
  19. Fermi GRB 260120C: Global MASTER-Net observations report
  20. GRB 260120B: Swift-BAT refined analysis
  21. GRB 260120B: Swift-XRT refined Analysis
  22. EP260116a: COLIBRÍ further observations
  23. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  24. GRB 260120B: Fermi GBM Observation
  25. EP260105a: GTC/HiPERCAM optical observations
  26. GRB 260120B: Swift/UVOT Detection
  27. GRB 260120B: COLIBRÍ optical upper limits
  28. SVOM GRB260121.06: Global MASTER-Net observations report
  29. GRB 260120B: Enhanced Swift-XRT position
  30. GRB 260120B: SVOM/C-GFT optical counterpart detection
  31. GRB 260101A: 239Alferov CubeSat detection
  32. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  33. GRB 260120B: Swift detection of a burst
  34. Swift GRB260120B: Global MASTER-Net observations report
  35. EP260119A: Mondy I-Band Observations
  36. Fermi trigger No 790601190: Global MASTER-Net observations report
  37. Fermi trigger No 790570272: Global MASTER-Net observations report
  38. GRB 260114A: Swift/UVOT Upper Limits
  39. EP260119a: Liverpool Telescope optical follow-up observations
  40. GRB 251202A: further radio observations with the VLA
  41. EP260119a: KAIT optical observations
  42. EP260119a: SVOM/VT optical observation
  43. EP260119a: NOT optical observations
  44. EP260119a: SAO RAS optical observations
  45. SVOM GRB260119.92: Global MASTER-Net observations report
  46. SVOM GRB260119.92: Global MASTER-Net observations report
  47. SVOM GRB260119.90: Global MASTER-Net observations report
  48. EP260116a: COLIBRÍ detection of a fading optical source
  49. GRB 260117A: Swift-XRT afterglow detection
  50. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  51. EP260119a: Global MASTER-Net observations report
  52. EP260119a: LCO optical observations
  53. GRB 260117A: ZTSh optical upper limit
  54. EP260119a: COLIBRÍ optical counterpart candidate
  55. EP260119a: EP-WXT detection of a fast X-ray transient
  56. Swift GRB260118.48: Global MASTER-Net observations report
  57. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  58. SVOM GRB260117.82: Global MASTER-Net observations report
  59. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  60. Swift trigger on the HMXB 1A 1118-61
  61. GRB 260117A: SVOM/VT optical candidate
  62. GRB 260117A: SVOM/C-GFT upper limit
  63. GRB 260117A: Swift-XRT observations
  64. GRB 260117A: SVOM detection of a long faint burst
  65. EP 260116a: COLIBRÍ optical upper limit
  66. Swift triggered on the HMXB 1A 1118-61
  67. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  68. EP260116a: Liverpool Telescope upper limits
  69. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  70. EP260116A: 1.3m DFOT optical upper limit
  71. GRB 260114A: VLT/MUSE spectroscopic observations
  72. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  73. EP260116a: Global MASTER-Net observations report
  74. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  75. EP260116a: Xinglong optical upper limit
  76. EP260116a: Einstein Probe detection of an X-ray transient
  77. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  78. IceCube Alert 260115.73: Global MASTER-Net observations report
  79. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  80. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  81. Fermi GRB 260115A: Global MASTER-Net observations report
  82. GRB 251222A: radio detection with the VLA
  83. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  84. GRB 260114A: Swift-XRT refined Analysis
  85. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  86. GRB 260114A : MITSuME Akeno optical upper limits
  87. GRB 260114A: COLIBRÍ optical upper limits
  88. GRB 260114A: TNG NIR upper limit
  89. GRB 260114A: NOT optical observations
  90. GRB 260114A: SVOM/GRM observation of a short burst
  91. Swift GRB 260114A: Global MASTER-Net observations report
  92. GRB 260114A: Mondy optical observations
  93. GRB 260114A: GMG Optical Observation
  94. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  95. GRB 260114A: Swift detection of a short burst
  96. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  97. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  98. Swift GRB260113.43: Global MASTER-Net observations report
  99. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  100. EP260110a: TRT optical upper limits

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