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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"

41971 results found.

  1. EP 250812a: GOTO optical upper limit
  2. GRB 250812A: Kilonova-Catcher optical afterglow detection
  3. EP250812a: Swift-XRT counterpart detection
  4. GRB 250812A: SVOM/COLIBRÍ (FM-GFT) optical observations
  5. EP250812a: Einstein Probe detection of an X-ray transient
  6. GRB 250812A: SVOM/VT optical afterglow confirmation
  7. GRB 250812A: Swift-XRT afterglow detection
  8. GRB 250812A: TRT likely optical counterpart detection
  9. IceCube-Cascade 250809A: Upper limits from a search for additional neutrino events in IceCube
  10. GRB 250812A: SVOM detection of a faint long burst
  11. GRB 250809A: Swift-BAT refined analysis
  12. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  13. GRB 250807A: Swift-BAT refined analysis
  14. LIGO/Virgo/KAGRA S250810ck: Updated Sky localization and EM Bright Classification
  15. GRB 250809A: Swift/UVOT Detection
  16. LIGO/Virgo/KAGRA S250810ck: Identification of a GW compact binary merger candidate
  17. Corrected Swift-XRT Refined Analysis of GRB 250809A
  18. GRB 250809A: Swift-XRT refined Analysis
  19. EP250807a: EP-FXT follow-up observation upper limit
  20. GRB 250809A: LCOGT Optical Upper Limits
  21. GRB 250702B: Chandra X-ray Detection
  22. EP250807a: Global MASTER-Net observations report
  23. Fermi GRB 250808A: Global MASTER-Net observations report
  24. GRB 250808A: VLT X-shooter candidate counterpart
  25. GRB 250809A: Prompt enhanced Swift-XRT position
  26. GRB 250809A: Swift detection of a gamma ray burst
  27. GRB 250808A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  28. GRB 250808A: Fermi GBM Observation
  29. GRB 250808A: Swift-XRT candidate counterpart detection
  30. GRB 250807A: SVOM/VT optical continued observation
  31. EP-WXT trigger 01709195487: KAIT confirmation of the stellar flare
  32. GRB 250808A: SVOM detection of a long burst
  33. GRB 250808A: Fermi GBM Final Real-time Localization
  34. Konus-Wind detection of GRB 250807A
  35. GRB 250807B: Swift/UVOT Detection
  36. GRB 250807B: Kilonova-Catcher optical afterglow detection
  37. IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
  38. GRB 250807A: Swift/UVOT Detection
  39. GRB 250807A: Swift-XRT refined Analysis
  40. GRB 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
  41. GRB 250806A: SVOM/MXT refined analysis
  42. GRB 250806A: SVOM/ECLAIRs refined analysis
  43. EP250807a: NTT z-band optical upper limit
  44. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  45. GRB 250804B: Insight-HXMT detection
  46. GRB 250807A: SVOM/GRM observation
  47. Swift GRB250807.45: Global MASTER-Net observations report
  48. GRB 250807A: AstroSat CZTI detection of bright long burst
  49. GRB 250807B: Swift-XRT refined Analysis
  50. GRB 250806A: NOT z-band upper limit and host galaxy candidate
  51. GRB 250807B: NTT optical observations
  52. EP250807a: EP-WXT detection of a fast X-ray transient
  53. EP 250807.979: GOTO optical upper limit
  54. EP250807a: COLIBRÍ optical upper limit
  55. GRB 250807A: SVOM/VT optical observation
  56. EP250806a: Upper limit from Fermi-GBM Observations
  57. GRB 250807B: Enhanced Swift-XRT position
  58. Swift GRB250807.65: Global MASTER-Net observations report
  59. GRB 250807A: Enhanced Swift-XRT position
  60. IceCube-Cascade 250804A: Upper limits from a search for additional neutrino events in IceCube
  61. GRB 250807B: Swift detection of a burst with an optical counterpart.
  62. GRB 250805A: Kilonova-Catcher optical upper limits
  63. EP250806a:SVOM/VT refined analysis
  64. GRB 250805A: Swift/UVOT Upper Limits
  65. GRB 250806A: Swift/UVOT U-band detection
  66. EP250806a: Liverpool telescope optical upper limit
  67. GRB 250807A: Swift detection of a burst with an optical counterpart
  68. IceCube Alert 250804.84: Global MASTER-Net observations report
  69. GRB 250806A: EP-FXT observation
  70. EP#01709198415/EP250806a: Swift-XRT observations
  71. EP250806a: Global MASTER-Net observations report
  72. EP250802a: EP-FXT follow-up observation
  73. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  74. EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
  75. EP250806a: SVOM /VT optical candidate
  76. GRB 250806A: J-band upper limit from WINTER
  77. GRB 250805A: Swift-BAT refined analysis
  78. GRB 250806A: KAIT optical upper limit
  79. GRB 250806A: SVOM/VT refined analysis
  80. GRB 250806A: Swift-XRT counterpart detection
  81. EP250806a: COLIBRÍ optical upper limit
  82. GRB 250806A: Kilonova-Catcher optical upper limits
  83. EP250806a: Einstein Probe detection of an X-ray transient
  84. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  85. GRB 250806A: SVOM/VT optical upper limit
  86. GRB 250806A: SVOM detection of a soft burst
  87. GRB 250805A: SVOM/VT optical counterpart
  88. GRB 250805A: ESO/VLT observations
  89. GRB 250805A: Swift-XRT refined Analysis
  90. GRB 250804B: Swift-XRT observations
  91. GRB 250805A: Enhanced Swift-XRT position
  92. GRB 250804C: AstroSat CZTI detection of a long burst
  93. GRB 250805A: TRT optical upper limits
  94. IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
  95. GRB 250805A: Swift-XRT observations
  96. GRB 250805A: Swift detection of a burst
  97. Swift GRB250805.26: Global MASTER-Net observations report
  98. GRB 250804B: Tiled Swift observations
  99. Fermi trigger No 776041355: Global MASTER-Net observations report
  100. GRB 250804B: SVOM/GRM observation of a short burst

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