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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"

42438 results found.

  1. The EP-WXT trigger 01709250662 is likely a flaring star
  2. GRB 251228A: Fermi GBM Final Real-time Localization
  3. GRB 251226A: SVOM/GRM observation
  4. GRB 251226A: GECAM-B detection
  5. SVOM GRB251227.07: Global MASTER-Net observations report
  6. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  7. The EP-WXT trigger 01709250617 is likely a flaring star
  8. IceCube Alert 251225.84: Global MASTER-Net observations report
  9. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  10. GRB 251222A: NUTTelA-TAO Early Measurements
  11. GRB 251222A/EP251222b: Optical detection with Kinder observations
  12. EP251222a: Optical upper limit with Kinder observations
  13. GRB 251221A: Swift-BAT refined analysis
  14. GRB 251222A/EP251222b: FTW optical and NIR observations
  15. EP251222a: FTW optical and NIR observations
  16. GRB 251205A: Kilonova-Catcher optical afterglow detection
  17. GRB 251222A: AbAO optical observations
  18. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  19. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  20. EP251222a: VLT/FORS2 spectroscopic redshift z = 0.505
  21. GRB 251222A: ZTSH BVRI optical observations
  22. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  23. GRB 251222A: Continued 1.3m DFOT optical observation
  24. EP251220a: 3.6m DOT optical afterglow detection
  25. GRB 251222A: Fermi GBM Observation
  26. EP251220a: CrAO ZTSh optical observations
  27. EP251221a: PRIME upper limit
  28. EP251222a: Global MASTER-Net observations report
  29. GRB 251222A / EP251222b: GECAM-B observation
  30. EP251221a: Liverpool Telescope upper limits
  31. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  32. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  33. Konus-Wind detection of GRB 251222A / EP251222b
  34. GRB 251222A: Swift-XRT afterglow detection
  35. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  36. EP251222a: NTT/ULTRACAM optical observations
  37. EP251222a: GOTO optical upper limit
  38. GRB 251222A / EP251222b: GOTO optical counterpart detection
  39. GRB 251222A / EP251222b: LCO optical observations
  40. GRB 251222A: 1.3m DFOT optical detection
  41. GRB251221A: 7DT optical upper limits
  42. EP251222a: GSP Optical Counterpart Detection
  43. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  44. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  45. EP251222b/GRB 251222A: SVOM/GRM observation
  46. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  47. EP251222a: Einstein Probe detection of an X-ray transient
  48. The EP-WXT trigger 01709250397 is likely a flaring star
  49. EP251221a: Global MASTER-Net observations report
  50. GRB 251222A: PRIME near-infrared detection
  51. EP251221a: NOT optical upper limit
  52. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  53. GRB 251222A: NOT optical observations
  54. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  55. GRB 251222A: Swift ToO observations
  56. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  57. GRB 251222A: SVOM/VT optical candidate
  58. GRB 251222A: SVOM detection of a long burst
  59. SVOM GRB251222A: Global MASTER-Net observations report
  60. GRB 251222A: Fermi GBM Final Real-time Localization
  61. EP251220a: PRIME upper limit
  62. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  63. GRB 251221A: PRIME near-infrared observation
  64. EP251220a: NOT optical observations
  65. EP251220a: FTW optical and NIR observations
  66. GRB 251221A: UAFO and Mondy optical upper limit
  67. GRB 251221A: Swift-XRT refined Analysis
  68. EP251221a: Einstein Probe detection of a fast X-ray transient
  69. GRB 251221A: Swift/UVOT Upper Limits
  70. GRB 251221A: Enhanced Swift-XRT position
  71. GRB 251221A: Fermi GBM Observation
  72. GRB 251221B: Fermi GBM Final Real-time Localization
  73. EP251220a: EP-FXT follow-up observation
  74. GRB 251220B: SVOM/GRM observation of a short burst
  75. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  76. EP 251220a: GOTO optical counterpart detection
  77. GRB 251221A: COLIBRÍ detection of the optical counterpart
  78. EP 251220a: COLIBRÍ detection of the optical counterpart
  79. GRB 251221A: Swift detection of a burst
  80. Swift GRB251221A: Global MASTER-Net observations report
  81. GRB 251221A: Fermi GBM Final Real-time Localization
  82. EP251220a: Global MASTER-Net observations report
  83. EP251220a: EP detection of a fast X-ray transient
  84. SVOM GRB251220.98: Global MASTER-Net observations report
  85. GRB 251220B: Fermi GBM Final Real-time Localization
  86. GRB 251219A: SVOM/GRM observation of a short burst
  87. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  88. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  89. GRB 251220A: MAXI/GSC detection
  90. GRB 251215A: Swift-XRT afterglow detection
  91. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  92. IceCube-251218A: COLIBRÍ optical upper limits
  93. SVOM GRB251219.11: Global MASTER-Net observations report
  94. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  95. IceCube Alert 251218.85: Global MASTER-Net observations report
  96. GRB 251214B: VIRT Optical Upper Limit
  97. Fermi trigger No 787736968: Global MASTER-Net observations report
  98. Fermi GRB 251217A: Global MASTER-Net observations report
  99. GRB 251217A: Fermi GBM Final Real-time Localization
  100. GRB 251215A: Swift/UVOT Upper LImits

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