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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"

32551 results found.

  1. GRB 260120B: Swift/UVOT Detection
  2. GRB 260120B: COLIBRÍ optical upper limits
  3. GRB 260120B: SVOM/C-GFT optical counterpart detection
  4. GRB 260101A: 239Alferov CubeSat detection
  5. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  6. EP260119A: Mondy I-Band Observations
  7. GRB 260114A: Swift/UVOT Upper Limits
  8. EP260119a: Liverpool Telescope optical follow-up observations
  9. GRB 251202A: further radio observations with the VLA
  10. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  11. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  12. EP260119a: KAIT optical observations
  13. EP260119a: SVOM/VT optical observation
  14. EP260119a: update of EP-FXT follow-up observation
  15. EP260119a: NOT optical observations
  16. EP260119a: SAO RAS optical observations
  17. EP260116a: COLIBRÍ detection of a fading optical source
  18. GRB 251208D: SVOM/ECLAIRs refined analysis
  19. GRB 251208D: SVOM/ECLAIRs refined analysis
  20. GRB 260117A: Swift-XRT afterglow detection
  21. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  22. EP260119a: Global MASTER-Net observations report
  23. GRB 260115A: AstroSat CZTI detection
  24. EP260119a: LCO optical observations
  25. GRB 260117A: ZTSh optical upper limit
  26. EP260119a: COLIBRÍ optical counterpart candidate
  27. EP260119a: preliminary result from the EP-FXT observation
  28. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  29. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  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 ToO observations
  34. EP 260116a: COLIBRÍ optical upper limit
  35. GRB 260115A: GECAM-B observation
  36. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  37. EP260116a: Liverpool Telescope upper limits
  38. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  39. EP260116A: 1.3m DFOT optical upper limit
  40. GRB 260114A: VLT/MUSE spectroscopic observations
  41. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  42. EP260116a: Global MASTER-Net observations report
  43. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  44. EP260116a: Xinglong optical upper limit
  45. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  46. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  47. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  48. Fermi GRB 260115A: Global MASTER-Net observations report
  49. GRB260114A: STEP/T80S optical limits
  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: 6 GHz VLA observations
  54. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  55. GRB 260114A : MITSuME Akeno optical upper limits
  56. GRB 260114A: COLIBRÍ optical upper limits
  57. GRB 260114A: TNG NIR upper limit
  58. GRB 260114A: NOT optical observations
  59. Konus-Wind detection of GRB 251230A / EP251230a
  60. GRB 260114A: SVOM/GRM observation of a short burst
  61. Swift GRB 260114A: Global MASTER-Net observations report
  62. GRB 260114A: GECAM-B observation of a short burst
  63. GRB 260114A: Mondy optical observations
  64. GRB 260114A: Fermi GBM observation
  65. GRB 260112B: GECAM-B observation
  66. GRB 260114A: GMG Optical Observation
  67. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  68. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  69. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  70. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  71. EP260110a: TRT optical upper limits
  72. Konus-Wind detection of GRB 260101A
  73. GRB 260111A: Swift-XRT observations
  74. GRB 260111A: COLIBRÍ optical afterglow candidate
  75. GRB 260111A: GECAM-B observation of a burst
  76. GRB 260111A: Fermi GBM Observation
  77. Swift Trigger 1434591 is not a GRB
  78. GRB 260111A: GOTO optical upper limits
  79. GRB 260111A: Swift ToO observations
  80. GRB 251230A: Mondy Optical Observations
  81. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  82. EP260110a: SVOM/VT optical upper limits
  83. EP260110a: Global MASTER-Net observations report
  84. Fermi GRB 260111A: Global MASTER-Net observations report
  85. EP260110a: KAIT optical upper limit
  86. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  87. EP 260110a: COLIBRÍ optical observations
  88. EP260110a: SVOM/C-GFT upper limit
  89. EP260110a: BOOTES-5/JGU optical upper limit
  90. GRB 260109C: LCO optical upper limits
  91. GRB 260109C: Kilonova-Catcher optical upper limit
  92. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  93. GRB 260104A: Swift-BAT refined analysis
  94. GRB 260101A: Swift-BAT refined analysis
  95. Swift GRB 251230A: Global MASTER-Net OT detection
  96. Fermi GRB 260107A: Global MASTER-Net observations report
  97. GRB 260102A: AbAO optical observations
  98. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  99. Fermi GRB 260105A: Global MASTER-Net observations report
  100. EP260105a: FTW optical observations

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