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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"

11519 results found.

  1. Fermi trigger No 596387570: Global MASTER-Net observations report
  2. GRB 191125B: Fermi GBM Final Real-time Localization
  3. GRB 191125A: Fermi GBM Final Real-time Localization
  4. Fermi-LAT Gamma-ray Observations of IceCube-191122A
  5. GRB 191118A: Insight-HXMT/HE detection
  6. IceCube-191122A - IceCube observation of a high-energy neutrino candidate event
  7. GRB 191119A: AstroSat CZTI detection of a short GRB
  8. Fermi-LAT Gamma-ray Observations of IceCube-191119A
  9. IceCube-191119A: Upper limits from Fermi-GBM Observations
  10. IceCube-191119A - IceCube observation of a high-energy neutrino candidate event
  11. GRB 191118A: BALROG localization (Fermi Trigger 595807926 / GRB 191118925)
  12. GRB 191118A: Fermi GBM Final Real-time Localization
  13. GRB 191117B: Fermi GBM Final Real-time Localization
  14. GRB 191117A: Fermi GBM Final Real-time Localization
  15. GRB 191111A: Insight-HXMT/HE detection
  16. GRB 191027A: CALET Gamma-Ray Burst Monitor detection
  17. Announcing the GW Treasure Map
  18. LIGO/Virgo S191110af: Potential pulsar counterparts
  19. GRB 191113A: Fermi GBM Final Real-time Localization
  20. GRB 191031D: CALET Gamma-Ray Burst Monitor detection
  21. GRB 191112A: Fermi GBM Final Real-time Localization
  22. GRB 191111B: BALROG localization (Fermi Trigger 595170435 / GRB 191111547)
  23. GRB 191111B: Fermi GBM Final Real-time Localization
  24. LIGO/Virgo S191110af: No counterpart candidates in Fermi-LAT observations
  25. GRB 191111A: Fermi GBM Final Real-time Localization
  26. LIGO/Virgo S191110af: Upper limits from Fermi-GBM Observations
  27. LIGO/Virgo S191109d: No counterpart candidates in Fermi-LAT observations
  28. GRB 191110A: Fermi GBM Final Real-time Localization
  29. LIGO/Virgo S191109d: Upper limits from Fermi-GBM Observations
  30. GRB 191108A: Fermi GBM Final Real-time Localization
  31. LIGO/Virgo S191105e: No counterpart candidates in Fermi-LAT observations
  32. LIGO/Virgo S191105e: Upper limits from Fermi-GBM Observations
  33. GRB 191031D: Chandra upper limit
  34. Fermi trigger No 594592184: Global MASTER-Net observations report
  35. Fermi trigger No 594523229: Global MASTER-Net observations report
  36. Fermi GBM GRB 191104C (trigger 594592184 / 191104854) is not a GRB
  37. GRB 191104C: Fermi GBM Final Real-time Localization
  38. Fermi GBM GRBs 191104 A, B, C and triggers 594534420/191104185 and 594563923/191104527 are not GRBs
  39. Fermi trigger No 594563923: Global MASTER-Net observations report
  40. GRB 191104B/GRB 191104C are SGR 1935+2154
  41. Fermi trigger No 594557071: Global MASTER-Net observations report
  42. GRB 191104C: BALROG localization (Fermi Trigger 594557071 / GRB 191104448)
  43. GRB 191104C: Fermi GBM Final Real-time Localization
  44. Fermi trigger No 594551878: Global MASTER-Net observations report
  45. Fermi trigger No 594528816: Global MASTER-Net observations report
  46. GRB 191104B: Fermi GBM Final Real-time Localization
  47. Fermi GBM triggers 594523229/191104056 and 594528816/191104120 are not GRBs
  48. GRB 191104A: Fermi GBM Final Real-time Localization
  49. GRB 191031D: Zwicky Transient Facility Follow-Up of a Swift Short GRB (Trigger 594249816/191031891)
  50. GRB 191031D: Gemini optical upper limit
  51. GRB 191031C: Insight-HXMT/HE detection
  52. Fermi trigger No 594336535: Global MASTER-Net observations report
  53. Fermi trigger No 594227699: Global MASTER-Net observations report
  54. GRB 191101B: Fermi GBM Final Real-time Localization
  55. GRB 191031D: MMT Binospec Optical Upper Limit
  56. GRB 191031D: AstroSat CZTI detection
  57. Konus-Wind observation of GRB 191031D
  58. GRB 191031D: MITSuME Akeno optical upper limits
  59. GRB 191031D: AGILE/MCAL observations
  60. GRB 191031D: COATLI Optical Observations
  61. GRB 191031D: RATIR Optical and NIR Observations
  62. GRB 191031D: VLA 9.8 GHz upper limit
  63. GRB 191031C: Fermi GBM detection
  64. GRB 191031D: Fermi GBM detection
  65. GRB 191031A: Fermi GBM detection
  66. Correction in name: GRB 191031D (not GRB 191031C)
  67. GRB 191031D: Swift detection of a short hard burst
  68. GRB 191031C: Fermi GBM Final Real-time Localization
  69. GRB 191031C: Fermi GBM Final Real-time Localization
  70. Fermi trigger No 594175000: Global MASTER-Net observations report
  71. GRB 191031B: Fermi GBM Final Real-time Localization
  72. GRB 191031A: COATLI Optical Observations
  73. GRB 191031A: Fermi GBM Final Real-time Localization
  74. Konus-Wind observation of GRB 191027A
  75. Correction to GCN 26079 regarding GRB 191027A
  76. GRB 191028B: MASTER optical observation
  77. IPN triangulation of GRB 191027A
  78. GRB 191028B: BALROG localization (Fermi Trigger 593964489 / GRB 191028589)
  79. GRB 191028B: Fermi GBM Final Real-time Localization
  80. Fermi GBM trigger 593931926/191028212 is not a GRB
  81. GRB 191028A: Fermi GBM Final Real-time Localization
  82. GRB 191027A: BALROG localization (Fermi Trigger 593882352 / GRB 191027638)
  83. GRB 191027A: Fermi GBM Final Real-time Localization
  84. GRB 191026A: Fermi GBM Final Real-time Localization
  85. GRB 191023A: MASTER optical observation
  86. GRB 191023A: BALROG localization (Fermi Trigger 593536021 / GRB 191023630)
  87. GRB 191023A: Fermi GBM Final Real-time Localization
  88. GRB 191019B: AstroSat CZTI detection
  89. GRB 191022B: Fermi GBM Final Real-time Localization
  90. GRB 191022A: BALROG localization (Fermi Trigger 593419810 / GRB 191022285)
  91. GRB 191022A: Fermi GBM Final Real-time Localization
  92. GRB 191019B: Fermi GBM Final Real-time Localization
  93. Fermi trigger No 593176520: Global MASTER-Net observations report
  94. FACT follow-up of ANTARES-Fermi 191011A
  95. Fermi trigger No 593045905: Global MASTER-Net observations report
  96. GRB 191017C: Fermi GBM Final Real-time Localization
  97. GRB 191017A: Fermi GBM Final Localization
  98. 191017A: BALROG localization (Fermi Trigger 592997024 / GRB 191017391)
  99. Fermi trigger No 592818648: Global MASTER-Net observations report
  100. ANTARES 191011A: AMON + ANTARES Identification of a High-Energy Neutrino + Fermi LAT Coincidence

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