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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. GRB 251202A: further radio observations with the VLA
  2. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  3. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  4. EP260119a: KAIT optical observations
  5. GRB 260120A: Fermi GBM Final Real-time Localization
  6. EP260119a: SVOM/VT optical observation
  7. EP260119a: update of EP-FXT follow-up observation
  8. EP260119a: NOT optical observations
  9. EP260119a: SAO RAS optical observations
  10. SVOM GRB260119.92: Global MASTER-Net observations report
  11. SVOM GRB260119.92: Global MASTER-Net observations report
  12. SVOM GRB260119.90: Global MASTER-Net observations report
  13. EP260116a: COLIBRÍ detection of a fading optical source
  14. GRB 251208D: SVOM/ECLAIRs refined analysis
  15. GRB 251208D: SVOM/ECLAIRs refined analysis
  16. GRB 260117A: Swift-XRT afterglow detection
  17. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  18. EP260119a: Global MASTER-Net observations report
  19. GRB 260115A: AstroSat CZTI detection
  20. EP260119a: LCO optical observations
  21. GRB 260117A: ZTSh optical upper limit
  22. EP260119a: COLIBRÍ optical counterpart candidate
  23. EP260119a: preliminary result from the EP-FXT observation
  24. GRB 260110A: SVOM detection of a burst through offline search
  25. EP260119a: EP-WXT detection of a fast X-ray transient
  26. Swift GRB260118.48: Global MASTER-Net observations report
  27. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  28. SVOM GRB260117.82: Global MASTER-Net observations report
  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-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: Liverpool Telescope upper limits
  41. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  42. EP260116A: 1.3m DFOT optical upper limit
  43. GRB 260114A: VLT/MUSE spectroscopic observations
  44. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  45. EP260116a: Global MASTER-Net observations report
  46. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  47. EP260116a: Xinglong optical upper limit
  48. EP260116a: Einstein Probe detection of an X-ray transient
  49. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  50. IceCube Alert 260115.73: Global MASTER-Net observations report
  51. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  52. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  53. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  54. Fermi GRB 260115A: Global MASTER-Net observations report
  55. GRB 260115A: Fermi GBM Final Real-time Localization
  56. GRB260114A: STEP/T80S optical limits
  57. GRB 251222A: radio detection with the VLA
  58. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  59. Konus-Wind detection of GRB 260114A
  60. GRB 260114A: Swift-XRT refined Analysis
  61. GRB 260114A: 6 GHz VLA observations
  62. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  63. GRB 260114A : MITSuME Akeno optical upper limits
  64. GRB 260114A: COLIBRÍ optical upper limits
  65. GRB 260114A: TNG NIR upper limit
  66. GRB 260114A: NOT optical observations
  67. Konus-Wind detection of GRB 251230A / EP251230a
  68. GRB 260114A: SVOM/GRM observation of a short burst
  69. Swift GRB 260114A: Global MASTER-Net observations report
  70. GRB 260114A: GECAM-B observation of a short burst
  71. GRB 260114A: Mondy optical observations
  72. GRB 260114A: Fermi GBM observation
  73. GRB 260112B: GECAM-B observation
  74. GRB 260114A: GMG Optical Observation
  75. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  76. GRB 260114A: Swift detection of a short burst
  77. GRB 260114A: Fermi GBM Final Real-time Localization
  78. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  79. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  80. Swift GRB260113.43: Global MASTER-Net observations report
  81. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  82. EP260110a: TRT optical upper limits
  83. Konus-Wind detection of GRB 260101A
  84. GRB 260111A: Swift-XRT observations
  85. Swift Trigger 1439093: is probably not GRB 260113A
  86. GRB 260111A: COLIBRÍ optical afterglow candidate
  87. GRB 260111A: GECAM-B observation of a burst
  88. GRB 260111A: Fermi GBM Observation
  89. The EP-WXT trigger 01709251266 is likely a flaring star
  90. Swift Trigger 1434591 is not a GRB
  91. GRB 260111A: GOTO optical upper limits
  92. GRB 260112B: Fermi GBM Final Real-time Localization
  93. GRB 260111A: Swift ToO observations
  94. GRB 251230A: Mondy Optical Observations
  95. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  96. GRB 260112A: Fermi GBM Final Real-time Localization
  97. EP260110a: SVOM/VT optical upper limits
  98. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  99. IceCube Alert 260111A: Global MASTER-Net observations report
  100. EP260110a: Global MASTER-Net observations report

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