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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"

45721 results found.

  1. GRB 250813A: Fermi GBM Final Localization
  2. EP250812a: COLIBRÍ detection of the VT candidate and evidence of flattening
  3. EP250812a: Liverpool Telescope upper limits
  4. EP250812a: SVOM/VT optical counterpart
  5. EP250812a: refined analysis of the EP-WXT and EP-FXT observations
  6. IceCube-250813A - IceCube observation of a high-energy neutrino candidate track-like event
  7. IceCube Alert 250813.14: Global MASTER-Net observations report
  8. LIGO/Virgo/KAGRA S250813k: Identification of a GW compact binary merger candidate
  9. GRB 250812A: EP-FXT counterpart detection
  10. GRB 250812A: Swift ToO observations
  11. GRB 250807B: Swift-BAT refined analysis
  12. EP 250812a: GOTO optical upper limit
  13. GRB 250812A: Kilonova-Catcher optical afterglow detection
  14. EP250812a: Swift-XRT counterpart detection
  15. Fermi Gamma-ray Burst Monitor trigger 776705265/250812644 is not a GRB
  16. GRB 250812A: SVOM/COLIBRÍ (FM-GFT) optical observations
  17. EP250812a: Einstein Probe detection of an X-ray transient
  18. GRB 250812A: SVOM/VT optical afterglow confirmation
  19. GRB 250812A: Swift-XRT afterglow detection
  20. GRB 250812A: TRT likely optical counterpart detection
  21. IceCube-Cascade 250809A: Upper limits from a search for additional neutrino events in IceCube
  22. GRB 250812A: SVOM detection of a faint long burst
  23. GRB 250809A: Swift-BAT refined analysis
  24. Fermi Gamma-ray Burst Monitor trigger 776620220/250811660 is not a GRB
  25. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  26. GRB 250807A: Swift-BAT refined analysis
  27. LIGO/Virgo/KAGRA S250810ck: Updated Sky localization and EM Bright Classification
  28. GRB 250809A: Swift/UVOT Detection
  29. LIGO/Virgo/KAGRA S250810ck: Identification of a GW compact binary merger candidate
  30. Corrected Swift-XRT Refined Analysis of GRB 250809A
  31. GRB 250809A: Swift-XRT refined Analysis
  32. GRB 250807B: SVOM/VT optical observation
  33. EP250807a: EP-FXT follow-up observation upper limit
  34. GRB 250809A: LCOGT Optical Upper Limits
  35. GRB 250702B: Chandra X-ray Detection
  36. EP250807a: Global MASTER-Net observations report
  37. Fermi GRB 250808A: Global MASTER-Net observations report
  38. Fermi Gamma-ray Burst Monitor trigger 776449964/250809689 is not a GRB
  39. GRB 250808A: VLT X-shooter candidate counterpart
  40. GRB 250809A: Prompt enhanced Swift-XRT position
  41. GRB 250809A: Swift detection of a gamma ray burst
  42. GRB 250808A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  43. GRB 250808A: Fermi GBM Observation
  44. GRB 250808A: Swift-XRT candidate counterpart detection
  45. GRB 250807A: SVOM/VT optical continued observation
  46. EP-WXT trigger 01709195487: KAIT confirmation of the stellar flare
  47. GRB 250808A: SVOM detection of a long burst
  48. GRB 250808A: Fermi GBM Final Real-time Localization
  49. Konus-Wind detection of GRB 250807A
  50. GRB 250807B: Swift/UVOT Detection
  51. GRB 250807B: Kilonova-Catcher optical afterglow detection
  52. IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 250807A: Swift/UVOT Detection
  54. GRB 250807A: Swift-XRT refined Analysis
  55. GRB 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
  56. GRB 250806A: SVOM/MXT refined analysis
  57. GRB 250806A: SVOM/ECLAIRs refined analysis
  58. EP250807a: NTT z-band optical upper limit
  59. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  60. GRB 250804B: Insight-HXMT detection
  61. GRB 250807A: SVOM/GRM observation
  62. Swift GRB250807.45: Global MASTER-Net observations report
  63. GRB 250807A: AstroSat CZTI detection of bright long burst
  64. GRB 250807B: Swift-XRT refined Analysis
  65. GRB 250806A: NOT z-band upper limit and host galaxy candidate
  66. GRB 250807B: NTT optical observations
  67. EP250807a: EP-WXT detection of a fast X-ray transient
  68. EP 250807.979: GOTO optical upper limit
  69. EP250807a: COLIBRÍ optical upper limit
  70. GRB 250807A: SVOM/VT optical observation
  71. EP250806a: Upper limit from Fermi-GBM Observations
  72. GRB 250807B: Enhanced Swift-XRT position
  73. Swift GRB250807.65: Global MASTER-Net observations report
  74. GRB 250807A: Enhanced Swift-XRT position
  75. IceCube-Cascade 250804A: Upper limits from a search for additional neutrino events in IceCube
  76. GRB 250807B: Swift detection of a burst with an optical counterpart.
  77. GRB 250805A: Kilonova-Catcher optical upper limits
  78. EP250806a:SVOM/VT refined analysis
  79. GRB 250805A: Swift/UVOT Upper Limits
  80. GRB 250806A: Swift/UVOT U-band detection
  81. EP250806a: Liverpool telescope optical upper limit
  82. GRB 250807A: Swift detection of a burst with an optical counterpart
  83. IceCube Alert 250804.84: Global MASTER-Net observations report
  84. GRB 250806A: EP-FXT observation
  85. EP#01709198415/EP250806a: Swift-XRT observations
  86. EP250806a: Global MASTER-Net observations report
  87. EP250802a: EP-FXT follow-up observation
  88. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  89. EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
  90. EP250806a: SVOM /VT optical candidate
  91. GRB 250806A: J-band upper limit from WINTER
  92. GRB 250805A: Swift-BAT refined analysis
  93. GRB 250806A: KAIT optical upper limit
  94. GRB 250806A: SVOM/VT refined analysis
  95. GRB 250806A: Swift-XRT counterpart detection
  96. EP250806a: COLIBRÍ optical upper limit
  97. GRB 250806A: Kilonova-Catcher optical upper limits
  98. EP250806a: Einstein Probe detection of an X-ray transient
  99. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  100. GRB 250806A: SVOM/VT optical upper limit

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