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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"

27932 results found.

  1. GRB 250725A: Swift detection of a burst
  2. Swift GRB 250725A: Global MASTER-Net OT detection
  3. GRB 250725A: Fermi GBM Final Real-time Localization
  4. Swift GRB 250725A: Global MASTER-Net observations report
  5. EP250702a/GRB250702 B,E,D: MeerKAT radio observations at 3.06 GHz
  6. EP250702a/GRB250702 B,D,E: uGMRT Radio detection in 1.26 GHz
  7. SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
  8. GRB 250723B: Fermi GBM Final Real-time Localization
  9. GRB 250723A: Fermi GBM Final Real-time Localization
  10. SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits
  11. Swift-BAT trigger 1334535 is not a GRB
  12. GRB 250721A: Swift-XRT observations
  13. GRB 250722A: Fermi GBM Final Real-time Localization
  14. GRB 250717B: SVOM/GRM observation
  15. GRB 250721A: Tiled Swift observations
  16. GRB 250721A: MAXI/GSC detection
  17. GRB 250721A: Fermi GBM Final Localization
  18. GRB 250720B: Fermi GBM Final Localization Correction
  19. GRB 250720A: Fermi GBM Final Localization
  20. GRB 250717B: COLIBRÍ optical upper limit
  21. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  22. GRB 250717B: Swift-XRT observations
  23. GRB 250718B: Fermi GBM Final Localization Correction
  24. GRB 250718B: Fermi GBM Final Real-time Localization
  25. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  26. Swift Trigger 1334535: a possible GRB 250718A
  27. Swift GRB250718.01: Global MASTER-Net observations report
  28. GRB 250717B: Swift ToO observations
  29. GRB 270713A: Kitab and AbAO Optical Observations
  30. GRB 250717B: Fermi GBM Observation
  31. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  32. Konus-Wind detection of GRB 250716A
  33. GRB 250716A: Swift-XRT afterglow detection
  34. GRB 250717B: Fermi GBM Final Real-time Localization
  35. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  36. GRB 250717A: Fermi GBM Final Real-time Localization
  37. GRB 250716A: Swift ToO observations
  38. GRB 250716A: Fermi GBM Final Real-time Localization
  39. GRB 250715A: Fermi GBM Final Real-time Localization
  40. GRB 250702B,D,E / EP250702a: H.E.S.S. very-high-energy gamma-ray observations
  41. GRB 250713A: SVOM/C-GFT upper limit
  42. GRB 250714A: Fermi GBM Final Real-time Localization
  43. GRB 250706B/C: 7DT Follow-up Observations
  44. GRB 250713A: Swift-XRT observations
  45. GRB 250713A: EP-FXT counterpart detection
  46. GRB 250706A: Swift-BAT refined analysis
  47. GRB 250702F: Swift-BAT refined analysis
  48. GRB 250628A: Swift-BAT refined analysis
  49. GRB 250713A: SVOM detection of a long burst
  50. EP250711a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  51. GRB 250711A: Fermi GBM Final Real-time Localization
  52. GRB 250702B,D,E/EP250702A: JCMT sub-mm observations at 350 GHz
  53. GRB 250704B / EP250704a: 1.3 GHz MeerKAT Detection
  54. GRB 250702B,D,E / EP250702a: ALMA detection
  55. LIGO/Virgo/KAGRA S250629bs: Upper limits from Swift/BAT-GUANO
  56. LIGO/Virgo/KAGRA S250629ae: Upper limits from Swift/BAT-GUANO
  57. GRB 250702B,D,E/EP250702A: MeerKAT radio observations at 1.28GHz
  58. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  59. GRB 250709A: Fermi GBM Final Localization
  60. IPN triangulation of GRB 250704B (short/hard, consistent with EP 250704a)
  61. GRB 250706B/C: Insight-HXMT detection
  62. EP-WXT trigger 01709181970. confirmation of a stellar flare by BOOTES-6
  63. EP250704a/GRB 250704B: 10 GHz VLA detection
  64. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  65. IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
  66. IceCube-250708A - IceCube observation of a high-energy neutrino candidate track-like event
  67. GRB 250704B / EP250704a: VLA radio detection
  68. GRB 250708A: Fermi GBM Final Real-time Localization
  69. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  70. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  71. GRB 250704B: CALET Gamma-Ray Burst Monitor detection
  72. GRB 250702F: radio detection with the VLA
  73. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  74. GRB 250706B/C: Fermi-LAT detection
  75. GRB 250706B: Swift/UVOT Detection
  76. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  77. GRB 250706C: Konus-Wind detection of a very bright GRB ~1200 s before GRB 250706B
  78. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  79. GRB 250702F: GRANDMA observations
  80. GRB 250706A: Swift-XRT refined Analysis
  81. GRB 250706A: Swift/UVOT Upper Limits
  82. GRB 250706A: REM optical/NIR observations
  83. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  84. IceCube-250416A: DDOTI Optical Upper Limit
  85. Swift GRB 250706A: Global MASTER-Net observations report
  86. GRB 250706A: JinShan optical upper limits
  87. GRB 250706A: SAO RAS optical observations
  88. EP250704A: NOWT Detection
  89. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  90. GRB250706B: Swift-XRT counterpart detection
  91. IceCube-250706A - IceCube observation of a high-energy neutrino candidate track-like event
  92. GRB 250706B: TRT bright optical counterpart detection
  93. GRB 250706A: GROWTH-India Telescope optical upper limit
  94. GRB 250706B: SVOM detection of a long burst
  95. GRB 250706A: Swift detection of a burst
  96. GRB 250704B: Swift-XRT refined Analysis
  97. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  98. EP250702a/GRB250702 B,E,D: MeerKAT radio counterpart
  99. GRB 250703A: EIRSAT-1 GMOD Detection
  100. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST

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