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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"

41979 results found.

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

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