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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"

11622 results found.

  1. GRB 250919A / EP250919a: MASTER bright afterglow detection 24h after GRB time
  2. GRB 250916A: Mondy R-band optical observations
  3. GRB 250919A: Glowbug gamma-ray detection
  4. GRB 250919A: Fermi GBM Observation
  5. Fermi GRB 250918A: Global MASTER-Net observations report
  6. GRB 250919A / EP250919a: NuSTAR detection of bright prompt emission
  7. GRB 250918A: SVOM/GRM observation
  8. GRB 250919A/EP250919A: Swift/UVOT afterglow detection
  9. GRB 250919A: Swift-XRT afterglow detection
  10. GRB 250919A: Fermi-LAT detection
  11. EP250919a/GRB 250919A: Gemini/GMOS-S spectroscopic redshift z = 1.145
  12. GRB 250919A: SVOM/GRM observation of a very bright GRB
  13. GRB 250919A: BALROG localization (Fermi Trigger 779934537 / GRB 250919020)
  14. GRB 250916A: Fermi GBM Observation
  15. Fermi GRB 250919A: Global MASTER-Net observations report
  16. GRB 250919A: Fermi GBM Final Real-time Localization
  17. GRB 250916A: KAIT optical observations
  18. GRB 250917B: VLT/HAWK-I near-infrared observations
  19. GRB 250916A: NuSTAR detection of the prompt emission
  20. GRB 250916A: further SAO RAS optical observations
  21. GRB 250912A: SVOM/ECLAIRs refined analysis
  22. GRB 250918A: BALROG localization (Fermi Trigger 779891543 / GRB 250918522)
  23. GRB 250918A: Fermi GBM Final Real-time Localization
  24. GRB 250917B: Swift/UVOT Upper Limits
  25. GRB 250916A: OSIRIS+/GTC redshift z = 2.015
  26. GRB 250916A: Swift-XRT observations
  27. GRB 250916A: MAO/AZT-22 optical observations
  28. GRB 250916A: SAO RAS optical observations
  29. GRB 250916A : GIT optical observations
  30. GRB 250916A: Glowbug gamma-ray detection
  31. GRB250917B: WFST optical observations
  32. GRB 250916A: Swift ToO observations
  33. GRB 250917B: Fermi GBM Observation
  34. Fermi GRB 250917B: Global MASTER-Net observations report
  35. GRB 250916A: GOTO optical counterpart candidate
  36. GRB 250917B: Fermi GBM Final Real-time Localization
  37. GRB 250917A: Fermi GBM Final Real-time Localization
  38. GRB 250916A: AstroSat CZTI detection of a bright long burst
  39. Fermi GRB 250916A: Global MASTER-Net observations report
  40. GRB 250916A: Fermi GBM Final Real-time Localization
  41. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  42. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  43. GRB 250912A: Swift-XRT observations
  44. GRB250912A: VLT/HAWK-I follow-up observations
  45. GRB 250912A: Fermi GBM Observation
  46. GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
  47. GRB 250912A: LCO optical upper limit
  48. Fermi GRB 250912A: Global MASTER-Net observations report
  49. GRB 250912A: SVOM detection of a burst
  50. GRB 250912A: Fermi GBM Final Real-time Localization
  51. EP250911a: Upper limit from Fermi-GBM Observations
  52. GRB 250910B: SVOM/GRM observation
  53. GRB 250910C: Fermi GBM Final Localization Correction
  54. Fermi GRB 250910B: Global MASTER-Net observations report
  55. GRB 250910B: BALROG localization (Fermi Trigger 779223130 / GRB 250910786)
  56. GRB 250910B: Fermi GBM Final Real-time Localization
  57. GRB 250909A: AstroSat CZTI detection
  58. GRB 250702B: Late time Chandra observations
  59. Fermi GRB 250909A: Global MASTER-Net observations report
  60. GRB 250909A: Fermi GBM Final Real-time Localization
  61. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  62. IceCube-250905A - IceCube observation of a high-energy neutrino candidate track-like event
  63. GRB 250905B: Fermi GBM Final Localization
  64. EP250827a and EP250827b: Upper limit from Fermi-GBM Observations
  65. GRB 250902B: CALET Gamma-Ray Burst Monitor detection
  66. GRB 250902A: CALET Gamma-Ray Burst Monitor detection
  67. GRB 250902A: VZLUSAT-2 detection
  68. GRB 250902A: GECAM-B detection
  69. GRB 250902B: AstroSat CZTI detection
  70. GRB 250902B: SVOM/GRM observation
  71. Fermi GRB 250902B: Global MASTER-Net observations report
  72. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  73. GRB 250902A: Fermi GBM Detection
  74. GRB 250902B: Fermi GBM Final Real-time Localization
  75. GRB 250902A: SVOM/GRM observation
  76. GRB 250902A: Fermi GBM Final Real-time Localization
  77. IceCube-250831A - IceCube observation of a high-energy neutrino candidate track-like event
  78. LIGO/Virgo/KAGRA S250725j: Observations with the NSF-DOE Vera C. Rubin Observatory
  79. GRB 250828A: Fermi GBM Final Localization
  80. GRID detection of GRB 250824A
  81. Fermi GRB 250827A: Global MASTER-Net observations report
  82. GRB 250826A: SVOM/GRM observation
  83. GRB 250827A: Fermi GBM Final Real-time Localization
  84. Fermi GRB 250826A: Global MASTER-Net observations report
  85. Fermi trigger No 777883624: Global MASTER-Net observations report
  86. Fermi Gamma-ray Burst Monitor trigger 777883624/250826283 is not a GRB
  87. GRB 250826A: Fermi GBM Final Real-time Localization
  88. Fermi GRB 250824B: Global MASTER-Net observations report
  89. GRB 250821B: AstroSat CZTI detection
  90. GRB 250821B: Insight-HXMT detection
  91. GRB 250824B: Fermi GBM Final Real-time Localization
  92. GRB 250823A: COLIBRÍ optical observations
  93. GRB 250823A: SVOM/VT optical observation
  94. GRB 250824A: Fermi GBM Final Real-time Localization
  95. GRB 250823A: NOT optical observations
  96. GRB 250823A: Fermi GBM Observation
  97. GRB 250823A: BOOTES6/DPRT early optical detection
  98. GRB 250823A: Liverpool Telescope optical detection
  99. GRB 250823A: Fermi GBM Final Real-time Localization
  100. Konus-Wind detection of GRB 250821B

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