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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

2034 results found.

  1. GRB 250308A: CALET Gamma-Ray Burst Monitor detection
  2. GRB 250311B: SVOM detection of a burst
  3. GRB 250309B: SVOM/VT optical observation
  4. IPN triangulation of GRB 250308A (short)
  5. GRB 250308A: SVOM/GRM detection of QPO in the tail emission
  6. GRB 250308A: SVOM/GRM observation of a bright short burst
  7. GRB 250305A: AstroSat CZTI detection
  8. GRB 250305A: SVOM/GRM observation of a burst
  9. GRB 250219A: SVOM/C-GFT optical upper limit at early phase
  10. Konus-Wind detection of GRB 250222A
  11. IPN triangulation of GRB 250222A
  12. EP250302a: SVOM/VT optical observation
  13. EP250302a: Xinglong F60B optical observation
  14. EP250302a: SVOM/C-GFT optical observations
  15. GRB 250225B: EIRSAT-1 GMOD Detection
  16. GRB 250226A: Fermi GBM Observation
  17. GRB 250225B: INTEGRAL SPI-ACS detection
  18. EP250226a / GRB 250226A: SVOM/VT optical observations
  19. LIGO/Virgo/KAGRA S250206dm: Upper limits from SVOM/GRM Observations
  20. GRB 250225B: REM NIR upper limits
  21. Konus-Wind detection of GRB 250225B
  22. GRB 250225B: SVOM/GRM observation of a long burst
  23. GRB 250214A: SVOM/GRM observation
  24. GRB 250223C: SVOM/GRM observation of a long burst
  25. GRB 250219A: EP-FXT afterglow detection
  26. GRB 250222A: SVOM/GRM observation of a burst
  27. GRB 250210A: VZLUSAT-2 detection
  28. EP250223a: SVOM/VT optical observation
  29. GRB 250219A: NUTTelA-TAO / BSTI Optical Limits
  30. GRB 250219A: GRANDMA/Kilonova-Catcher upper limits
  31. SVOM trigger sb25022102 is not an astrophysical event
  32. SVOM/sb25022102: SVOM detection of an X-ray transient
  33. Konus-Wind detection of GRB 250217C (short)
  34. GRB 250219A: Swift/UVOT Upper Limits
  35. GRB 250219A: NOT optical observations
  36. GRB 250219A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  37. GRB 250219A: 1.6m Mephisto optical upper limits
  38. GRB 250219A: SVOM/VT optical counterpart
  39. GRB 250219A: Swift-XRT observations
  40. GRB 250219A: Swift ToO observations
  41. GRB 250219A: SVOM detection of a burst
  42. Konus-Wind detection of GRB 250215A / EP250215a
  43. SVOM/sb25021804: COLIBRÍ/DDRAGO Confirmation of Variability
  44. SVOM/sb25021804: QSO variability in Liverpool Telescope observations
  45. GRB 250217C: SVOM/GRM observation
  46. GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61
  47. Transient SVOM/sb25021804: COLIBRÍ/DDRAGO Optical Upper Limits on the Optical Counterpart
  48. SVOM/sb25021804: SVOM detection of a long X-ray transient
  49. GRB 250213A: Swift-XRT observations
  50. GRB 250215A / EP250215a: LCO detection of the afterglow
  51. EP250215a / GRB 250215A : GTC redshift z = 4.61
  52. GRB 250215A: Fermi GBM Observation
  53. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  54. GRB 250215A: SVOM/GRM observation
  55. GRB 250215A / EP250215a: SVOM/VT optical candidate comfirmation
  56. GRB 250213A：SVOM/VT optical candidate
  57. GRB 250213A: Swift ToO observations
  58. GRB 250213A: SVOM detection of a burst
  59. GRB 250205A: Leavitt Observatory optical upper limit
  60. GRB 250210A: GRBAlpha detection
  61. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  62. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  63. GRB 250211A: Swift ToO observations
  64. GRB 250210A: SVOM/GRM observation of a long burst
  65. GRB 250204B: GRBAlpha detection
  66. GRB 250205A: 1.3m DFOT optical upper limit
  67. Konus-Wind detection of GRB 250204B
  68. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  69. GRB 250205A: Fermi GBM Observation
  70. GRB 250205A: REM NIR upper limit
  71. GRB 250205A: Swift/UVOT Upper Limits
  72. EP250205a/GRB 250205A: Einstein Probe observation
  73. GRB 250127C: SVOM/GRM observation of a burst
  74. GRB 250204B: SVOM/GRM observation of a likely short burst
  75. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  76. GRB 250205A: Swift/XRT detection
  77. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  78. GRB250205A: SVOM/VT optical afterglow detection
  79. GRB 250205A: GOTO optical upper limits
  80. GRB 250205A: SVOM detection of a burst
  81. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  82. GRB 250129A: SVOM/C-GFT optical observations
  83. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  84. GRB 250129A: COLIBRÍ Optical Observations
  85. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  86. GRB 250127A: CrAO and Terskol optical upper limits
  87. GRB 250127A: Swift-XRT observations
  88. GRB 250127A: EP-FXT afterglow detection
  89. GRB 250117A: Fermi GBM Observation
  90. GRB 250127A: SVOM/VT upper limit
  91. GRB 250127A: Swift ToO observations
  92. GRB 250127A: LCO optical upper limit
  93. GRB 250127A: SVOM detection of a long burst
  94. GECAM-A detection of a bright burst from SGR 1E1841-045
  95. IPN triangulation of a bright burst from SGR 1E1841-045
  96. Improved IPN triangulation of GRB 250107C
  97. Konus-Wind detection of GRB 250117A
  98. IPN triangulation of GRB 250117A (short)
  99. GRB 250117A: SVOM/GRM observation of a short burst
  100. GRB 250114B: SVOM/VT upper limit

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