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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"

45700 results found.

  1. GRB 250812A: SVOM detection of a faint long burst
  2. GRB 250809A: Swift-BAT refined analysis
  3. Fermi Gamma-ray Burst Monitor trigger 776620220/250811660 is not a GRB
  4. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  5. GRB 250807A: Swift-BAT refined analysis
  6. LIGO/Virgo/KAGRA S250810ck: Updated Sky localization and EM Bright Classification
  7. GRB 250809A: Swift/UVOT Detection
  8. LIGO/Virgo/KAGRA S250810ck: Identification of a GW compact binary merger candidate
  9. Corrected Swift-XRT Refined Analysis of GRB 250809A
  10. GRB 250809A: Swift-XRT refined Analysis
  11. GRB 250807B: SVOM/VT optical observation
  12. EP250807a: EP-FXT follow-up observation upper limit
  13. GRB 250809A: LCOGT Optical Upper Limits
  14. GRB 250702B: Chandra X-ray Detection
  15. EP250807a: Global MASTER-Net observations report
  16. Fermi GRB 250808A: Global MASTER-Net observations report
  17. Fermi Gamma-ray Burst Monitor trigger 776449964/250809689 is not a GRB
  18. GRB 250808A: VLT X-shooter candidate counterpart
  19. GRB 250809A: Prompt enhanced Swift-XRT position
  20. GRB 250809A: Swift detection of a gamma ray burst
  21. GRB 250808A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  22. GRB 250808A: Fermi GBM Observation
  23. GRB 250808A: Swift-XRT candidate counterpart detection
  24. GRB 250807A: SVOM/VT optical continued observation
  25. EP-WXT trigger 01709195487: KAIT confirmation of the stellar flare
  26. GRB 250808A: SVOM detection of a long burst
  27. GRB 250808A: Fermi GBM Final Real-time Localization
  28. Konus-Wind detection of GRB 250807A
  29. GRB 250807B: Swift/UVOT Detection
  30. GRB 250807B: Kilonova-Catcher optical afterglow detection
  31. IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
  32. GRB 250807A: Swift/UVOT Detection
  33. GRB 250807A: Swift-XRT refined Analysis
  34. GRB 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
  35. GRB 250806A: SVOM/MXT refined analysis
  36. GRB 250806A: SVOM/ECLAIRs refined analysis
  37. EP250807a: NTT z-band optical upper limit
  38. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  39. GRB 250804B: Insight-HXMT detection
  40. GRB 250807A: SVOM/GRM observation
  41. Swift GRB250807.45: Global MASTER-Net observations report
  42. GRB 250807A: AstroSat CZTI detection of bright long burst
  43. GRB 250807B: Swift-XRT refined Analysis
  44. GRB 250806A: NOT z-band upper limit and host galaxy candidate
  45. GRB 250807B: NTT optical observations
  46. EP250807a: EP-WXT detection of a fast X-ray transient
  47. EP 250807.979: GOTO optical upper limit
  48. EP250807a: COLIBRÍ optical upper limit
  49. GRB 250807A: SVOM/VT optical observation
  50. EP250806a: Upper limit from Fermi-GBM Observations
  51. GRB 250807B: Enhanced Swift-XRT position
  52. Swift GRB250807.65: Global MASTER-Net observations report
  53. GRB 250807A: Enhanced Swift-XRT position
  54. IceCube-Cascade 250804A: Upper limits from a search for additional neutrino events in IceCube
  55. GRB 250807B: Swift detection of a burst with an optical counterpart.
  56. GRB 250805A: Kilonova-Catcher optical upper limits
  57. EP250806a:SVOM/VT refined analysis
  58. GRB 250805A: Swift/UVOT Upper Limits
  59. GRB 250806A: Swift/UVOT U-band detection
  60. EP250806a: Liverpool telescope optical upper limit
  61. GRB 250807A: Swift detection of a burst with an optical counterpart
  62. IceCube Alert 250804.84: Global MASTER-Net observations report
  63. GRB 250806A: EP-FXT observation
  64. EP#01709198415/EP250806a: Swift-XRT observations
  65. EP250806a: Global MASTER-Net observations report
  66. EP250802a: EP-FXT follow-up observation
  67. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  68. EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
  69. EP250806a: SVOM /VT optical candidate
  70. GRB 250806A: J-band upper limit from WINTER
  71. GRB 250805A: Swift-BAT refined analysis
  72. GRB 250806A: KAIT optical upper limit
  73. GRB 250806A: SVOM/VT refined analysis
  74. GRB 250806A: Swift-XRT counterpart detection
  75. EP250806a: COLIBRÍ optical upper limit
  76. GRB 250806A: Kilonova-Catcher optical upper limits
  77. EP250806a: Einstein Probe detection of an X-ray transient
  78. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  79. GRB 250806A: SVOM/VT optical upper limit
  80. GRB 250806A: SVOM detection of a soft burst
  81. GRB 250805A: SVOM/VT optical counterpart
  82. GRB 250805A: ESO/VLT observations
  83. GRB 250805A: Swift-XRT refined Analysis
  84. GRB 250804B: Swift-XRT observations
  85. GRB 250805A: Enhanced Swift-XRT position
  86. GRB 250804C: AstroSat CZTI detection of a long burst
  87. GRB 250805A: TRT optical upper limits
  88. IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
  89. GRB 250805A: Swift-XRT observations
  90. GRB 250805A: Swift detection of a burst
  91. Swift GRB250805.26: Global MASTER-Net observations report
  92. GRB 250804B: Tiled Swift observations
  93. Fermi trigger No 776041355: Global MASTER-Net observations report
  94. GRB 250804B: SVOM/GRM observation of a short burst
  95. GRB 250804A: Fermi GBM Final Localization
  96. EP250802a: additional Liverpool Telescope upper limits
  97. EP250730a: SVOM/VT optical upper limit
  98. Fermi Gamma-ray Burst Monitor trigger 775945985/250803856 is not a GRB
  99. EP250802a: Liverpool Telescope optical upper limits
  100. EP250802a: Global MASTER-Net observations report

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