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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"

36790 results found.

  1. Fermi trigger No 785388351: Global MASTER-Net observations report
  2. GRB 251118A: Swift/UVOT Detection
  3. EP251118a / GRB 251118C: SAO RAS optical observations
  4. GRB 251118A: Glowbug gamma-ray detection
  5. GRB 251118A: Fermi GBM Observation
  6. GRB 251118A: Swift-XRT afterglow detection
  7. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  8. GRB 251118A: GECAM-B detection
  9. EP251118a / GRB 251118C: SVOM/VT optical observation
  10. GRB 251118A: NuSTAR detection of bright prompt emission
  11. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  12. GRB 251116C: NOT optical observations
  13. GRB 251118C: Glowbug gamma-ray detection of the fast X-ray transient EP251118A
  14. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  15. GRB 251018A: FRAM-Auger optical detection
  16. GRB 251117A: Swift-XRT observations
  17. EP251118A / GRB 251118C : MASTER optical counterpart observations
  18. GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
  19. Konus-Wind detection of GRB 251118C (EP251118a)
  20. GRB 251117A: Insight-HXMT/HE detection
  21. GRB 251119A: SVOM trigger sb25111901 is not a GRB
  22. GRB 251116D: SVOM/GRM observation of a long GRB
  23. GRB 251119A: SVOM detection of a possible burst
  24. EP251118a: NOT spectroscopic redshift of z = 1.216
  25. GRB 251118A: Fermi-LAT detection
  26. GRB 251118A: Swift ToO observations
  27. Fermi GRB 251118B: Global MASTER-Net observations report
  28. GRB 251118B: Fermi GBM Final Real-time Localization
  29. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  30. GRB 251118A: BALROG localization (Fermi Trigger 785190695 / GRB 251118855)
  31. GRB 251117A: FTW Observations of Swift candidate X-ray sources
  32. GRB 251118A: Fermi GBM Final Real-time Localization
  33. GRB 251116C: SVOM/ECLAIRs refined analysis
  34. GRB 251116B: SVOM/ECLAIRs refined analysis
  35. GRB 251117A: AstroSat CZTI detection
  36. GRB 251114B: Insight-HXMT/HE detection
  37. GRB 251114B: GECAM-B detection of a short burst
  38. GRB 251117A: Fermi GBM observation
  39. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  40. GRB 251116D: Insight-HXMT/HE detection
  41. GRB 251115A: Swift-XRT observations
  42. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  43. GRB 251117A: SVOM/GRM observation of a short burst
  44. GRB 251117A: Tiled Swift observations
  45. GRB 251117A: Fermi-LAT detection
  46. GRB 251116C: Swift/BAT arcminute localization of a burst
  47. GRB 251116B: SVOM/VT optical upper limit
  48. GRB 251116C: Swift-XRT observations
  49. GRB 251117A: Fermi GBM Final Localization Correction
  50. GRB 251116D: Glowbug gamma-ray detection
  51. EP251023a: Assy AZT-20 optical observations
  52. EP251023a: UAFO and AbAO optical observations
  53. GRB 251116D: AstroSat CZTI detection
  54. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  55. GRB 251116C: SVOM/VT optical upper limit
  56. GRB 251025B: further Mondy optical observations
  57. GRB 251111A: Mondy optical upper limit
  58. GRB 251116B: EP-FXT follow-up observation
  59. GRB 251116B: LCO optical upper limits
  60. GRB 251116C: LCO optical upper limits
  61. GRB 251116C: SVOM detection of a burst
  62. GRB 251116B: SVOM detection of a burst
  63. GRB 251116A: Fermi GBM Final Real-time Localization
  64. GRB 251115A: Tiled Swift observations
  65. GRB 251115A: Fermi-LAT detection
  66. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  67. Fermi GRB 251115A: Global MASTER-Net observations report
  68. GRB 251115A: Fermi GBM Final Real-time Localization
  69. GRB 251113A: Glowbug gamma-ray detection
  70. GRB 251113A: AstroSat CZTI detection
  71. GRB 251114B: Fermi GBM Final Real-time Localization
  72. GRB 251112A: Swift-BAT refined analysis
  73. Konus-Wind detection of GRB 251108C
  74. Fermi trigger No 784717756: Global MASTER-Net observations report
  75. Konus-Wind detection of GRB 251103A
  76. IPN triangulation of GRB 251108C
  77. Fermi GRB 251114A: Global MASTER-Net observations report
  78. GRB 251114A: Fermi GBM Final Real-time Localization
  79. Fermi GRB 251113A: Global MASTER-Net observations report
  80. GRB 251113A: BALROG localization (Fermi Trigger 784748255 / GRB 251113734)
  81. GRB 251113A: Fermi GBM Final Real-time Localization
  82. GRB 251111A: SVOM/ECLAIRs refined analysis
  83. GRB 251025B: SVOM/ECLAIRs refined analysis
  84. Fermi Gamma-ray Burst Monitor trigger 784717756/251113381 is not a GRB
  85. GRB 251112A: Swift/UVOT Upper Limits
  86. GRB 251112A: Swift-XRT refined Analysis
  87. GRB 251108C: AstroSat CZTI detection
  88. GRB 251112B: MAXI/GSC detection
  89. Fermi Gamma-ray Burst Monitor trigger 784687703/251113034 is not a GRB
  90. Fermi Gamma-ray Burst Monitor trigger 784687099/251113027 is not a GRB
  91. GRB 251108B: Glowbug gamma-ray detection
  92. Swift Trigger 1413695: a possible GRB 251112A
  93. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  94. Fermi trigger No 784621743: Global MASTER-Net observations report
  95. Fermi Gamma-ray Burst Monitor trigger 784653403/251112637 is not a GRB
  96. GRB 251106B: Glowbug gamma-ray detection of a likely short burst
  97. GRB 251111A: Swift-XRT afterglow detection
  98. GRB 251111A: SVOM/VT optical observations with X-band data
  99. GRB 251111A: Swift-XRT observations
  100. GRB 251111A: EP-FXT counterpart detection

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