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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"

45749 results found.

  1. Fermi GRB 260120C: Global MASTER-Net observations report
  2. GRB 260120B: Swift-BAT refined analysis
  3. GRB 260120B: Swift-XRT refined Analysis
  4. EP260116a: COLIBRÍ further observations
  5. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  6. GRB 260120B: Fermi GBM Observation
  7. EP260105a: GTC/HiPERCAM optical observations
  8. GRB 260120B: Swift/UVOT Detection
  9. GRB 260120B: COLIBRÍ optical upper limits
  10. SVOM GRB260121.06: Global MASTER-Net observations report
  11. GRB 260120B: Enhanced Swift-XRT position
  12. GRB 260120B: SVOM/C-GFT optical counterpart detection
  13. GRB 260120C: Fermi GBM Final Real-time Localization
  14. GRB 260101A: 239Alferov CubeSat detection
  15. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  16. GRB 260120B: Swift detection of a burst
  17. Swift GRB260120B: Global MASTER-Net observations report
  18. GRB 260120B: Fermi GBM Final Real-time Localization
  19. EP260119A: Mondy I-Band Observations
  20. Fermi trigger No 790601190: Global MASTER-Net observations report
  21. Fermi trigger No 790570272: Global MASTER-Net observations report
  22. GRB 260114A: Swift/UVOT Upper Limits
  23. EP260119a: Liverpool Telescope optical follow-up observations
  24. GRB 251202A: further radio observations with the VLA
  25. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  26. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  27. EP260119a: KAIT optical observations
  28. GRB 260120A: Fermi GBM Final Real-time Localization
  29. EP260119a: SVOM/VT optical observation
  30. EP260119a: update of EP-FXT follow-up observation
  31. EP260119a: NOT optical observations
  32. EP260119a: SAO RAS optical observations
  33. SVOM GRB260119.92: Global MASTER-Net observations report
  34. SVOM GRB260119.92: Global MASTER-Net observations report
  35. SVOM GRB260119.90: Global MASTER-Net observations report
  36. EP260116a: COLIBRÍ detection of a fading optical source
  37. GRB 251208D: SVOM/ECLAIRs refined analysis
  38. GRB 251208D: SVOM/ECLAIRs refined analysis
  39. GRB 260117A: Swift-XRT afterglow detection
  40. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  41. EP260119a: Global MASTER-Net observations report
  42. GRB 260115A: AstroSat CZTI detection
  43. EP260119a: LCO optical observations
  44. GRB 260117A: ZTSh optical upper limit
  45. EP260119a: COLIBRÍ optical counterpart candidate
  46. EP260119a: preliminary result from the EP-FXT observation
  47. GRB 260110A: SVOM detection of a burst through offline search
  48. EP260119a: EP-WXT detection of a fast X-ray transient
  49. Swift GRB260118.48: Global MASTER-Net observations report
  50. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  51. SVOM GRB260117.82: Global MASTER-Net observations report
  52. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  53. Swift trigger on the HMXB 1A 1118-61
  54. GRB 260117A: SVOM/VT optical candidate
  55. GRB 260117A: SVOM/C-GFT upper limit
  56. GRB 260117A: Swift-XRT observations
  57. GRB 260117A: Swift ToO observations
  58. GRB 260117A: SVOM detection of a long faint burst
  59. EP 260116a: COLIBRÍ optical upper limit
  60. Swift triggered on the HMXB 1A 1118-61
  61. GRB 260115A: GECAM-B observation
  62. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  63. EP260116a: Liverpool Telescope upper limits
  64. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  65. EP260116A: 1.3m DFOT optical upper limit
  66. GRB 260114A: VLT/MUSE spectroscopic observations
  67. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  68. EP260116a: Global MASTER-Net observations report
  69. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  70. EP260116a: Xinglong optical upper limit
  71. EP260116a: Einstein Probe detection of an X-ray transient
  72. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  73. IceCube Alert 260115.73: Global MASTER-Net observations report
  74. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  75. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  76. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  77. Fermi GRB 260115A: Global MASTER-Net observations report
  78. GRB 260115A: Fermi GBM Final Real-time Localization
  79. GRB260114A: STEP/T80S optical limits
  80. GRB 251222A: radio detection with the VLA
  81. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  82. Konus-Wind detection of GRB 260114A
  83. GRB 260114A: Swift-XRT refined Analysis
  84. GRB 260114A: 6 GHz VLA observations
  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. Konus-Wind detection of GRB 251230A / EP251230a
  91. GRB 260114A: SVOM/GRM observation of a short burst
  92. Swift GRB 260114A: Global MASTER-Net observations report
  93. GRB 260114A: GECAM-B observation of a short burst
  94. GRB 260114A: Mondy optical observations
  95. GRB 260114A: Fermi GBM observation
  96. GRB 260112B: GECAM-B observation
  97. GRB 260114A: GMG Optical Observation
  98. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  99. GRB 260114A: Swift detection of a short burst
  100. GRB 260114A: Fermi GBM Final Real-time Localization

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