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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"

32752 results found.

  1. EP260105a: GTC/HiPERCAM optical observations
  2. GRB 260120B: Swift/UVOT Detection
  3. GRB 260120B: COLIBRÍ optical upper limits
  4. GRB 260120B: SVOM/C-GFT optical counterpart detection
  5. GRB 260101A: 239Alferov CubeSat detection
  6. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  7. EP260119A: Mondy I-Band Observations
  8. GRB 260114A: Swift/UVOT Upper Limits
  9. EP260119a: Liverpool Telescope optical follow-up observations
  10. GRB 251202A: further radio observations with the VLA
  11. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  12. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  13. EP260119a: KAIT optical observations
  14. EP260119a: SVOM/VT optical observation
  15. EP260119a: update of EP-FXT follow-up observation
  16. EP260119a: NOT optical observations
  17. EP260119a: SAO RAS optical observations
  18. EP260116a: COLIBRÍ detection of a fading optical source
  19. GRB 251208D: SVOM/ECLAIRs refined analysis
  20. GRB 251208D: SVOM/ECLAIRs refined analysis
  21. GRB 260117A: Swift-XRT afterglow detection
  22. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  23. EP260119a: Global MASTER-Net observations report
  24. GRB 260115A: AstroSat CZTI detection
  25. EP260119a: LCO optical observations
  26. GRB 260117A: ZTSh optical upper limit
  27. EP260119a: COLIBRÍ optical counterpart candidate
  28. EP260119a: preliminary result from the EP-FXT observation
  29. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  30. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  31. Swift trigger on the HMXB 1A 1118-61
  32. GRB 260117A: SVOM/VT optical candidate
  33. GRB 260117A: SVOM/C-GFT upper limit
  34. GRB 260117A: Swift ToO observations
  35. EP 260116a: COLIBRÍ optical upper limit
  36. GRB 260115A: GECAM-B observation
  37. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  38. EP260116a: Liverpool Telescope upper limits
  39. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  40. EP260116A: 1.3m DFOT optical upper limit
  41. GRB 260114A: VLT/MUSE spectroscopic observations
  42. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  43. EP260116a: Global MASTER-Net observations report
  44. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  45. EP260116a: Xinglong optical upper limit
  46. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  47. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  48. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  49. Fermi GRB 260115A: Global MASTER-Net observations report
  50. GRB260114A: STEP/T80S optical limits
  51. GRB 251222A: radio detection with the VLA
  52. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  53. Konus-Wind detection of GRB 260114A
  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. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  70. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  71. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  72. EP260110a: TRT optical upper limits
  73. Konus-Wind detection of GRB 260101A
  74. GRB 260111A: Swift-XRT observations
  75. GRB 260111A: COLIBRÍ optical afterglow candidate
  76. GRB 260111A: GECAM-B observation of a burst
  77. GRB 260111A: Fermi GBM Observation
  78. Swift Trigger 1434591 is not a GRB
  79. GRB 260111A: GOTO optical upper limits
  80. GRB 260111A: Swift ToO observations
  81. GRB 251230A: Mondy Optical Observations
  82. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  83. EP260110a: SVOM/VT optical upper limits
  84. EP260110a: Global MASTER-Net observations report
  85. Fermi GRB 260111A: Global MASTER-Net observations report
  86. EP260110a: KAIT optical upper limit
  87. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  88. EP 260110a: COLIBRÍ optical observations
  89. EP260110a: SVOM/C-GFT upper limit
  90. EP260110a: BOOTES-5/JGU optical upper limit
  91. GRB 260109C: LCO optical upper limits
  92. GRB 260109C: Kilonova-Catcher optical upper limit
  93. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  94. GRB 260104A: Swift-BAT refined analysis
  95. GRB 260101A: Swift-BAT refined analysis
  96. Swift GRB 251230A: Global MASTER-Net OT detection
  97. Fermi GRB 260107A: Global MASTER-Net observations report
  98. GRB 260102A: AbAO optical observations
  99. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  100. Fermi GRB 260105A: Global MASTER-Net observations report

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