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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"

28230 results found.

  1. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  2. IceCube Alert 251225.84: Global MASTER-Net observations report
  3. GRB 251222A/EP251222b: Optical detection with Kinder observations
  4. EP251222a: Optical upper limit with Kinder observations
  5. GRB 251221A: Swift-BAT refined analysis
  6. GRB 251205A: Kilonova-Catcher optical afterglow detection
  7. GRB 251222A: AbAO optical observations
  8. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  9. GRB 251222A: ZTSH BVRI optical observations
  10. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  11. GRB 251222A: Continued 1.3m DFOT optical observation
  12. EP251220a: 3.6m DOT optical afterglow detection
  13. GRB 251222A: Fermi GBM Observation
  14. EP251220a: CrAO ZTSh optical observations
  15. EP251221a: PRIME upper limit
  16. EP251222a: Global MASTER-Net observations report
  17. EP251221a: Liverpool Telescope upper limits
  18. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  19. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  20. GRB 251222A: Swift-XRT afterglow detection
  21. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  22. EP251222a: NTT/ULTRACAM optical observations
  23. GRB 251222A / EP251222b: GOTO optical counterpart detection
  24. GRB 251222A / EP251222b: LCO optical observations
  25. GRB 251222A: 1.3m DFOT optical detection
  26. GRB251221A: 7DT optical upper limits
  27. EP251222a: GSP Optical Counterpart Detection
  28. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  29. EP251222a: Einstein Probe detection of an X-ray transient
  30. EP251221a: Global MASTER-Net observations report
  31. GRB 251222A: PRIME near-infrared detection
  32. EP251221a: NOT optical upper limit
  33. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  34. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  35. IPN triangulation of GRB 251220B (short)
  36. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  37. GRB 251222A: SVOM/VT optical candidate
  38. GRB 251222A: SVOM detection of a long burst
  39. SVOM GRB251222A: Global MASTER-Net observations report
  40. EP251220a: PRIME upper limit
  41. GRB 251221A: PRIME near-infrared observation
  42. GRB 251221A: UAFO and Mondy optical upper limit
  43. GRB 251221A: Swift-XRT refined Analysis
  44. EP251221a: Einstein Probe detection of a fast X-ray transient
  45. GRB 251221A: Swift/UVOT Upper Limits
  46. GRB 251221A: Enhanced Swift-XRT position
  47. GRB 251221A: Fermi GBM Observation
  48. GRB 251220B: SVOM/GRM observation of a short burst
  49. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  50. EP 251220a: GOTO optical counterpart detection
  51. GRB 251221A: COLIBRÍ detection of the optical counterpart
  52. EP 251220a: COLIBRÍ detection of the optical counterpart
  53. GRB 251221A: Swift detection of a burst
  54. Swift GRB251221A: Global MASTER-Net observations report
  55. EP251220a: Global MASTER-Net observations report
  56. EP251220a: EP detection of a fast X-ray transient
  57. SVOM GRB251220.98: Global MASTER-Net observations report
  58. GRB 251219A: SVOM/GRM observation of a short burst
  59. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  60. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  61. GRB 251220A: MAXI/GSC detection
  62. GRB 251215A: Swift-XRT afterglow detection
  63. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  64. IceCube-251218A: COLIBRÍ optical upper limits
  65. SVOM GRB251219.11: Global MASTER-Net observations report
  66. IceCube Alert 251218.85: Global MASTER-Net observations report
  67. GRB 251214B: VIRT Optical Upper Limit
  68. Fermi trigger No 787736968: Global MASTER-Net observations report
  69. Fermi GRB 251217A: Global MASTER-Net observations report
  70. GRB 251215A: Swift/UVOT Upper LImits
  71. GRB 251215A: Fermi GBM Observation
  72. Fermi GRB 251216A: Global MASTER-Net observations report
  73. GRB 251202A/EP251202a: Koshka optical upper limit
  74. GRB 251214B: Mondy optical upper limit
  75. GRB 251215A: COLIBRÍ optical upper limit
  76. EP251214b: KAIT optical upper limit
  77. GRB 251215A: Swift-XRT observations
  78. Fermi GRB 251215A: Global MASTER-Net observations report
  79. EP251214a: Optical upper limit with Kinder observations
  80. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  81. GRB 251215A: Glowbug gamma-ray detection
  82. GRB 251214B: UAFO optical upper limit
  83. GRB 251214B: VLT/X-shooter observations
  84. GRB 251214B: Swift-BAT refined analysis
  85. GRB 251202A: radio detection with the VLA
  86. EP251214b: Global MASTER-Net observations report
  87. EP251214b : Einstein Probe detection of a fast X-ray transient
  88. EP251214b : Einstein Probe detection of a fast X-ray transient
  89. GRB 251214B: AbAO optical observations
  90. GRB 251214B: LCO detection of the optical counterpart
  91. GRB 251214B: Fermi GBM Observation
  92. EP251214b (EP trigger 01709250023): LCO optical limits
  93. GRB 251203B: AbAO optical observations
  94. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  95. GRB 251214B: Swift-XRT refined Analysis
  96. GRB 251213A: SVOM/GRM observation
  97. EP251214a: KAIT optical upper limit
  98. GRB 251213A: AstroSat CZTI detection
  99. GRB 251214A: AstroSat CZTI detection
  100. GRB 251213A: GECAM-B detection

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