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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"

43941 results found.

  1. GRB 250402A: Fermi GBM Observation
  2. GRB 250403A: SVOM/C-GFT optical observations
  3. GRB 250403A: GOTO detection of the optical afterglow
  4. GRB 250402A: Swift-XRT observations
  5. GRB 250403A : SVOM detection of a burst
  6. GRB 250403A: Fermi GBM Final Real-time Localization
  7. GRB 250225B: VLT host galaxy redshift z = 0.950
  8. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  9. GRB 250402A: VLT/FORS2 spectroscopic redshift z = 2.823
  10. GRB 250402A: REM optical/NIR upper limits
  11. GRB 250402A: LCO optical counterpart detection
  12. GRB 250402A: refined SVOM/MXT data analysis
  13. The EP-WXT trigger 01709133862 is a flaring star
  14. EP250402a: Einstein Probe detection of a fast X-ray transient
  15. GRB 250402B: AstroSat CZTI detection of a short burst
  16. GRB 250402A: SVOM/VT optical counterpart
  17. GRB 250402A: SVOM detection of a burst
  18. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  19. GRB 250314A: ALMA detection
  20. GRB 250327B: Swift/UVOT Detection
  21. GRB 250331E: SVOM/GRM observation
  22. GRB 250327B: Kilonova-Catcher Observations
  23. GRB250331D: AbAO optical observations
  24. GRB 250331D: Fermi GBM observation
  25. GRB 250328A: AbAO AS-32 Optical Observations
  26. GRB 250219A: NOT candidate host galaxy detection
  27. GRB 250322B: GRBAlpha detection
  28. GRB 250331D: Swift-XRT observations
  29. GRB 250331C: Swift-XRT refined Analysis
  30. GRB 250331B: Swift-XRT refined Analysis
  31. GRB 250331B: Swift-XRT refined Analysis
  32. GRB 250322B possible detection by the AstroSat Satellite
  33. GRB 250330B: SVOM/GRM observation of a short burst
  34. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 2)
  35. Fermi GRB 250331E: Global MASTER-Net observations report
  36. Fermi GRB 250331D: Global MASTER-Net observations report
  37. GRB 250330B: EIRSAT-1 GMOD Detection
  38. GRB 250331E: Fermi GBM Final Real-time Localization
  39. GRB 250327A Swift-BAT refined analysis
  40. LIGO/Virgo/KAGRA S250331o: Updated Sky localization
  41. GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
  42. Fermi trigger No 765078057: Global MASTER-Net observations report
  43. GRB 250329B: CAHA 2.2m telescope optical limit
  44. GRB 250331D: Swift ToO observations
  45. Swift GRB 250331C: Global MASTER-Net observations report
  46. Swift GRB 250331B: Global MASTER-Net observations report
  47. GRB 250331D: Swift/BAT-GUANO arcminute localization of a burst during slew
  48. Konus-Wind detection of GRB 250327B
  49. GRB 250331C: Enhanced Swift-XRT position
  50. IceCube-250330A: Upper limits from a search for additional neutrino events in IceCube
  51. LIGO/Virgo/KAGRA S250331o: NED Galaxies in the 3-Initial Localization Volume
  52. GRB 250331B: Enhanced Swift-XRT position
  53. GRB 250320C : SVOM detection of a burst through offline search
  54. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  55. GRB 250329B: Swift-XRT confirmation of fading
  56. GRB 250330A: VLT/FORS2 Afterglow Detection
  57. GRB20250327B: 45th Parallel Observatory upper limit
  58. GRB 250328A: Swift/UVOT Detection
  59. GRB 250328A: Swift-XRT refined Analysis
  60. Fermi-LAT gamma-ray observations of IceCube-250330A
  61. SVOM/sb25033102 is a false trigger
  62. GRB 250330A: Fermi GBM Observation
  63. GRB 250331C: COLIBRÍ/DDRAGO optical upper limit
  64. GRB 250331B: COLIBRÍ/DDRAGO optical upper limit
  65. GRB 250331D: Fermi GBM Final Real-time Localization
  66. GRB 250331C: Prompt enhanced Swift-XRT position
  67. GRB 250331C: Swift detection of a burst
  68. GRB 250331B: Swift detection of a burst
  69. GRB 250330A: SVOM/VT optical upper limit
  70. GRB 250331A: MAXI/GSC detection
  71. SVOM/sb25033102: SVOM detection of an X-ray transient
  72. GRB 250314A: VLA detection
  73. LIGO/Virgo/KAGRA S250331o: Identification of a GW compact binary merger candidate
  74. Fermi GRB 250330B: Global MASTER-Net observations report
  75. GRB 250330B: Fermi GBM Final Real-time Localization
  76. Fermi GRB 250330A: Global MASTER-Net observations report
  77. GRB 250330A: BOOTES-7 early optical upper limit
  78. GRB 250330A: Swift-XRT afterglow detection
  79. GRB 250328A: 1.6m Mephisto optical observations
  80. GRB 250329B: SVOM/COLIBRÍ (F-GFT) optical upper limit
  81. GRB 250330A: Fermi GBM Final Localization
  82. IceCube-250330A - IceCube observation of a high-energy neutrino candidate track-like event
  83. IceCube Alert 250330.35: Global MASTER-Net observations report
  84. GRB 250330A: Prompt Swift-XRT position
  85. GRB 250329B: Swift-XRT afterglow detection
  86. GRB 250330A: Swift detection of a burst
  87. Swift GRB250330.26: Global MASTER-Net observations report
  88. GRB 250328A: A fading optical afterglow confirmed by SVOM/VT
  89. GRB 250329B: SVOM/C-GFT optical upper limit
  90. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 1)
  91. GRB 250327B: ALMA detection
  92. GRB 250327B: VLA detection
  93. GRB 250329B: SVOM/VT optical upper limit
  94. GRB 250327B: SVOM/COLIBRÍ (F-GFT) Further Observations
  95. GRB 250329B: 1.6m Mephisto Optical Upper Limits
  96. LIGO/Virgo/KAGRA S250329fl: 2 counterpart neutrino candidate events from an IceCube neutrino search
  97. GRB250329A: REM optical afterglow detection
  98. GRB 250329B: GWAC-F50A optical upper limit
  99. GRB 250329B: SVOM detection of a faint transient
  100. GRB 250329A: Swift-XRT afterglow detection

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