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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"

5039 results found.

  1. IceCube-230524A: Upper limits from a search for additional neutrino events in IceCube
  2. GRB 230524A: Fermi GBM Observation
  3. IceCube Alert 230524.47: Global MASTER-Net observations report
  4. IceCube-230524A - IceCube observation of a high-energy neutrino candidate track-like event
  5. GRB 230524B: AstroSat CZTI detection
  6. GRB 230524A: AstroSat CZTI detection
  7. GRB 230524A: AGILE detection
  8. Fermi trigger No 706610076: Global MASTER-Net observations report
  9. LIGO/Virgo S230524b: Global MASTER-Net observations report
  10. GRB 230524A: Fermi GBM Final Real-time Localization
  11. Fermi trigger No 706599831: Global MASTER-Net observations report
  12. Fermi trigger No 706536788: Global MASTER-Net observations report
  13. LIGO/Virgo S230522a: Global MASTER-Net observations report
  14. LIGO/Virgo S230521k: Global MASTER-Net observations report
  15. LIGO/Virgo S230520ae: Global MASTER-Net observations report
  16. Fermi trigger No 706317104: Global MASTER-Net observations report
  17. GRB 230520A: CALET Gamma-Ray Burst Monitor detection
  18. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  19. GRB 230520A: MAXI/GSC detection
  20. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  21. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  22. LIGO/Virgo S230518h: Global MASTER-Net observations report
  23. GRB 230510A: GRBAlpha detection
  24. Fermi trigger No 705565670: Global MASTER-Net observations report
  25. GRB 230510A: OHP/T193 and OHP/T120 optical observations
  26. GRB 230511D: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705537623)
  27. GRB 230510A: Swift-XRT refined Analysis
  28. Fermi trigger No 705413051: Global MASTER-Net observations report
  29. GRB 230506B: Swift-XRT refined Analysis
  30. GRB 230506C: Swift-XRT analysis
  31. GRB 230506C: TSHAO possible afterglow candidate
  32. GRB 230427A: Nanshan/HMT optical upper limit
  33. Fermi trigger No 704365743: Global MASTER-Net observations report
  34. GRB 230427A: MITSuME Akeno optical upper limits
  35. GRB 230426A: Fermi GBM Detection
  36. Fermi trigger No 704233744: Global MASTER-Net observations report
  37. GRB 230426A: Fermi GBM Final Real-time Localization
  38. Konus-Wind detection of GRB 230418A
  39. GRB 230420A: MITSuME Akeno optical observation
  40. GRB 230402A: Fermi GBM detection
  41. GRB 230402A: Fermi-LAT detection
  42. Fermi GRB 230414A: Global MASTER-Net observations report
  43. Fermi GRB 230409A: Global MASTER-Net observations report
  44. GRB 230409B: Swift-XRT refined Analysis
  45. MAXI GRB230408.82: Global MASTER-Net observations report
  46. IceCube Alert 230405.56: Global MASTER-Net observations report
  47. GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
  48. GRB 230328B: Swift/UVOT Detection
  49. Fermi trigger No 701883729: Global MASTER-Net observations report
  50. Konus-Wind detection of GRB 230328B
  51. GRB 230328B: Swift-XRT refined Analysis
  52. GRB 230328B: Mondy optical afterglow confirmation
  53. GRB 230328B: Swift detection of a burst with an optical afterglow
  54. GRB 230328A: Fermi GBM Final Real-time Localization
  55. GRB 230325A: Swift-XRT refined Analysis
  56. Fermi trigger No 701313046: Global MASTER-Net observations report
  57. Fermi trigger No 701321709: Global MASTER-Net observations report
  58. GRB 230322B: Swift-XRT refined Analysis
  59. Fermi trigger No 701071944: Global MASTER-Net observations report
  60. Fermi trigger No 701058254: Global MASTER-Net observations report
  61. GRB 230321B: AstroSat CZTI detection
  62. GRB 230314A: TURBO Optical Upper Limit
  63. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  64. IPN triangulation of GRB 230304B
  65. GRB 230314A: Fermi GBM Final Real-time Localization
  66. Further improved IPN localization for GRB 230307A
  67. Triggers 1159434, 1159435 and 1159437: Swift detection of Sco X-1 due to Star Tracker loss of lock
  68. Trigger 1159327: Swift detection of SGR1806-20
  69. IceCube Alert 230306.46: Global MASTER-Net observations report
  70. Fermi trigger No 699294715: Global MASTER-Net observations report
  71. GRB 230228A: Swift-XRT refined Analysis
  72. Fermi GRB 230227A: Global MASTER-Net observations report
  73. Fermi trigger No 699029364: Global MASTER-Net observations report
  74. GRB 230217A: Gemini-South Optical Observation
  75. GRB 230220A: MAXI/GSC detection
  76. IceCube Alert 230217.87: Global MASTER-Net observations report
  77. GRB 230216A: Swift-XRT refined Analysis
  78. Fermi trigger No 697678542: Global MASTER-Net observations report
  79. Fermi GRB 230207A: Global MASTER-Net observations report
  80. GRB 230204B: LCOGT Optical Upper Limits
  81. GRB 230205A: Swift-XRT refined Analysis
  82. GRB 230204B: MAXI/GSC detection
  83. GRB 230204A: Swift-XRT refined Analysis
  84. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  85. Fermi trigger No 697208885: Global MASTER-Net observations report
  86. Fermi trigger No 697098930: Global MASTER-Net observations report
  87. Fermi GRB 230201B: Global MASTER-Net observations report
  88. GRB 230124A: Fermi GBM Observation
  89. GRB 230123A: LCOGT Optical Upper Limits
  90. Fermi GRB 230124A: Global MASTER-Net observations report
  91. GRB 230124A: Fermi GBM Final Real-time Localization
  92. GRB 230122A: Swift/BAT-GUANO detection
  93. GRB 230123A: Swift-XRT refined Analysis
  94. GRB 230116D: LCOGT Optical Upper Limit
  95. GRB 230116D: Swift-XRT refined Analysis
  96. Fermi GRB 230117A: Global MASTER-Net observations report
  97. GRB 230116D: Swift detection of a burst
  98. Fermi GRB 230112A: Global MASTER-Net observations report
  99. IceCube-221223A: JCMT/SCUBA2 observations
  100. GRB 221231A: Swift-XRT observations

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