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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"

45590 results found.

  1. GRB 250402A: REM optical/NIR upper limits
  2. GRB 250402A: LCO optical counterpart detection
  3. GRB 250402A: refined SVOM/MXT data analysis
  4. The EP-WXT trigger 01709133862 is a flaring star
  5. EP250402a: Einstein Probe detection of a fast X-ray transient
  6. GRB 250402B: AstroSat CZTI detection of a short burst
  7. GRB 250402A: SVOM/VT optical counterpart
  8. GRB 250402A: SVOM detection of a burst
  9. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  10. GRB 250314A: ALMA detection
  11. GRB 250329B: Swift/UVOT Upper Limit
  12. GRB 250329A: Swift/UVOT Upper Limit
  13. GRB 250327B: Swift/UVOT Detection
  14. GRB 250327A: Swift/UVOT Upper Limits
  15. GRB 250331E: SVOM/GRM observation
  16. GRB 250327B: Kilonova-Catcher Observations
  17. GRB250331D: AbAO optical observations
  18. GRB 250331D: Fermi GBM observation
  19. GRB 250331C: Swift/UVOT Upper Limits
  20. GRB 250331B: Swift/UVOT Upper Limits
  21. GRB 250328A: AbAO AS-32 Optical Observations
  22. GRB 250219A: NOT candidate host galaxy detection
  23. GRB 250322B: GRBAlpha detection
  24. GRB 250331D: Swift-XRT observations
  25. GRB 250331C: Swift-XRT refined Analysis
  26. GRB 250331B: Swift-XRT refined Analysis
  27. GRB 250331B: Swift-XRT refined Analysis
  28. GRB 250322B possible detection by the AstroSat Satellite
  29. GRB 250330B: SVOM/GRM observation of a short burst
  30. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 2)
  31. Fermi GRB 250331E: Global MASTER-Net observations report
  32. Fermi GRB 250331D: Global MASTER-Net observations report
  33. GRB 250330B: EIRSAT-1 GMOD Detection
  34. GRB 250331E: Fermi GBM Final Real-time Localization
  35. GRB 250327A Swift-BAT refined analysis
  36. LIGO/Virgo/KAGRA S250331o: Updated Sky localization
  37. GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
  38. Fermi trigger No 765078057: Global MASTER-Net observations report
  39. GRB 250329B: CAHA 2.2m telescope optical limit
  40. GRB 250331D: Swift ToO observations
  41. Swift GRB 250331C: Global MASTER-Net observations report
  42. Swift GRB 250331B: Global MASTER-Net observations report
  43. GRB 250331D: Swift/BAT-GUANO arcminute localization of a burst during slew
  44. Konus-Wind detection of GRB 250327B
  45. GRB 250331C: Enhanced Swift-XRT position
  46. IceCube-250330A: Upper limits from a search for additional neutrino events in IceCube
  47. LIGO/Virgo/KAGRA S250331o: NED Galaxies in the 3-Initial Localization Volume
  48. GRB 250331B: Enhanced Swift-XRT position
  49. GRB 250320C : SVOM detection of a burst through offline search
  50. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  51. GRB 250329B: Swift-XRT confirmation of fading
  52. GRB 250330A: VLT/FORS2 Afterglow Detection
  53. GRB20250327B: 45th Parallel Observatory upper limit
  54. GRB 250328A: Swift/UVOT Detection
  55. GRB 250328A: Swift-XRT refined Analysis
  56. Fermi-LAT gamma-ray observations of IceCube-250330A
  57. SVOM/sb25033102 is a false trigger
  58. GRB 250330A: Fermi GBM Observation
  59. GRB 250331C: COLIBRÍ/DDRAGO optical upper limit
  60. GRB 250331B: COLIBRÍ/DDRAGO optical upper limit
  61. GRB 250331D: Fermi GBM Final Real-time Localization
  62. GRB 250331C: Prompt enhanced Swift-XRT position
  63. GRB 250331C: Swift detection of a burst
  64. GRB 250331B: Swift detection of a burst
  65. GRB 250330A: SVOM/VT optical upper limit
  66. GRB 250331A: MAXI/GSC detection
  67. SVOM/sb25033102: SVOM detection of an X-ray transient
  68. GRB 250314A: VLA detection
  69. LIGO/Virgo/KAGRA S250331o: Identification of a GW compact binary merger candidate
  70. Fermi GRB 250330B: Global MASTER-Net observations report
  71. GRB 250330B: Fermi GBM Final Real-time Localization
  72. Fermi GRB 250330A: Global MASTER-Net observations report
  73. GRB 250330A: BOOTES-7 early optical upper limit
  74. GRB 250330A: Swift/UVOT Upper Limits
  75. GRB 250330A: Swift-XRT afterglow detection
  76. GRB 250328A: 1.6m Mephisto optical observations
  77. GRB 250329B: SVOM/COLIBRÍ (F-GFT) optical upper limit
  78. GRB 250330A: Fermi GBM Final Localization
  79. IceCube-250330A - IceCube observation of a high-energy neutrino candidate track-like event
  80. IceCube Alert 250330.35: Global MASTER-Net observations report
  81. GRB 250330A: VLT/FORS2 Optical Observations
  82. GRB 250330A: Prompt Swift-XRT position
  83. GRB 250329B: Swift-XRT afterglow detection
  84. GRB 250330A: Swift detection of a burst
  85. Swift GRB250330.26: Global MASTER-Net observations report
  86. GRB 250328A: A fading optical afterglow confirmed by SVOM/VT
  87. GRB 250329B: SVOM/C-GFT optical upper limit
  88. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 1)
  89. GRB 250327B: ALMA detection
  90. GRB 250327B: VLA detection
  91. GRB 250329B: SVOM/VT optical upper limit
  92. GRB 250327B: SVOM/COLIBRÍ (F-GFT) Further Observations
  93. GRB 250329B: 1.6m Mephisto Optical Upper Limits
  94. LIGO/Virgo/KAGRA S250329fl: 2 counterpart neutrino candidate events from an IceCube neutrino search
  95. GRB250329A: REM optical afterglow detection
  96. GRB 250329B: GWAC-F50A optical upper limit
  97. GRB 250329B: SVOM detection of a faint transient
  98. GRB 250329A: Swift-XRT afterglow detection
  99. GRB 250328A: SVOM/VT optical observation
  100. GRB 250329A: Fading optical counterpart detection by LCO.

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