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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"

11049 results found.

  1. GRB 191031B: Fermi GBM Final Real-time Localization
  2. GRB 191031A: COATLI Optical Observations
  3. GRB 191031A: Fermi GBM Final Real-time Localization
  4. Konus-Wind observation of GRB 191027A
  5. Correction to GCN 26079 regarding GRB 191027A
  6. GRB 191028B: MASTER optical observation
  7. IPN triangulation of GRB 191027A
  8. GRB 191028B: BALROG localization (Fermi Trigger 593964489 / GRB 191028589)
  9. GRB 191028B: Fermi GBM Final Real-time Localization
  10. Fermi GBM trigger 593931926/191028212 is not a GRB
  11. GRB 191028A: Fermi GBM Final Real-time Localization
  12. GRB 191027A: BALROG localization (Fermi Trigger 593882352 / GRB 191027638)
  13. GRB 191027A: Fermi GBM Final Real-time Localization
  14. GRB 191026A: Fermi GBM Final Real-time Localization
  15. GRB 191023A: MASTER optical observation
  16. GRB 191023A: BALROG localization (Fermi Trigger 593536021 / GRB 191023630)
  17. GRB 191023A: Fermi GBM Final Real-time Localization
  18. GRB 191019B: AstroSat CZTI detection
  19. GRB 191022B: Fermi GBM Final Real-time Localization
  20. GRB 191022A: BALROG localization (Fermi Trigger 593419810 / GRB 191022285)
  21. GRB 191022A: Fermi GBM Final Real-time Localization
  22. GRB 191019B: Fermi GBM Final Real-time Localization
  23. Fermi trigger No 593176520: Global MASTER-Net observations report
  24. FACT follow-up of ANTARES-Fermi 191011A
  25. Fermi trigger No 593045905: Global MASTER-Net observations report
  26. GRB 191017C: Fermi GBM Final Real-time Localization
  27. GRB 191017A: Fermi GBM Final Localization
  28. 191017A: BALROG localization (Fermi Trigger 592997024 / GRB 191017391)
  29. Fermi trigger No 592818648: Global MASTER-Net observations report
  30. ANTARES 191011A: AMON + ANTARES Identification of a High-Energy Neutrino + Fermi LAT Coincidence
  31. GRB 191009A: AstroSat CZTI detection
  32. GRB 191011A: Swift/UVOT Detection
  33. GRB 191011A: Fermi GBM observation
  34. GRB 19011A: Optical Afterglow Detection with LCO
  35. GRB 191009A: Insight-HXMT/HE detection
  36. GRB 191011A: BALROG localization (Fermi Trigger 592461363 / GRB 191011192)
  37. GRB 191011A: VLT X-shooter redshift from RRM Observations
  38. GRB 191011A: Fermi GBM Final Real-time Localization
  39. GRB 191009A: BALROG localization (Fermi Trigger 592297741 / GRB 191009298)
  40. GRB 191009A: Fermi GBM Final Real-time Localization
  41. Fermi trigger No 592211224: Global MASTER-Net observations report
  42. Fermi trigger No 592211224: Global MASTER-Net observations report
  43. GRB 191008A: Fermi GBM Final Real-time Localization
  44. Fermi/GBM observation of a bright burst from magnetar SGR 1935+2154
  45. GRB 191001A: Swift-XRT observations
  46. GRB 191001A: Fermi GBM observation
  47. GRB 190919A: AstroSat CZTI detection
  48. Fermi-LAT Gamma-ray Observations of IceCube-191001A
  49. IceCube-191001A: Not observable by Fermi-GBM
  50. IPN triangulation of GRB 191001A
  51. GRB 191001A: Swift ToO observations
  52. GRB 191001A: KAIT Optical Upper Limit
  53. GRB 191001A: RATIR Optical and NIR Observations
  54. IceCube-191001A - IceCube observation of a high-energy neutrino candidate event
  55. GRB 191001A: DDOTI Optical Counterpart Candidate
  56. LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
  57. Fermi trigger No 591604915: Global MASTER-Net observations report
  58. LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
  59. GRB 191001A: BALROG localization (Fermi Trigger 591604915 / GRB 191001279)
  60. GRB 191001A: Fermi GBM Final Real-time Localization
  61. LIGO/Virgo S190930t: Upper limits from Fermi-GBM Observations
  62. LIGO/Virgo S190930s: Upper limits from Fermi-GBM Observations
  63. GRB 190928A: Insight-HXMT/HE detection
  64. Fermi trigger No 591532362: Global MASTER-Net observations report
  65. GRB 190930A: Fermi GBM Final Real-time Localization
  66. IPN triangulation of GRB 190928A (long/bright)
  67. Fermi trigger No 591391412: Global MASTER-Net observations report
  68. Fermi trigger No 591321287: Global MASTER-Net observations report
  69. LIGO/Virgo S190924h: No counterpart candidates in Fermi-LAT observations
  70. LIGO/Virgo S190924h: Upper limits from Fermi-GBM Observations
  71. Fermi-LAT Gamma-ray Observations of IceCube-190922B
  72. LIGO/Virgo S190923y: No counterpart candidates in Fermi-LAT observations
  73. Fermi-LAT Gamma-ray Observations of IceCube-190922A
  74. LIGO/Virgo S190923y: Upper limits from Fermi-GBM Observations
  75. GRB 190923A: BALROG localization (Fermi Trigger 590942887 / GRB 190923617)
  76. GRB 190923A: Fermi GBM Final Real-time Localization
  77. Fermi trigger No 590899086: Global MASTER-Net observations report
  78. IceCube-190922B: Upper limits from Fermi-GBM Observations
  79. IceCube-190922A: Upper limits from Fermi-GBM Observations
  80. IceCube-190922B - IceCube observation of a high-energy neutrino candidate event
  81. IceCube-190922A - IceCube observation of a high-energy neutrino candidate event
  82. Fermi trigger No 590777160: Global MASTER-Net observations report
  83. GRB 190921A: Fermi GBM Final Real-time Localization
  84. GRB 190919B: LCO Optical Afterglow Detection
  85. Fermi trigger No 590621700: Global MASTER-Net observations report
  86. Fermi trigger No 590610007: Global MASTER-Net observations report
  87. GRB 190919A: Fermi GBM Final Real-time Localization
  88. HAWC-190916A: Upper limits from Fermi-GBM Observations
  89. GRB 190828B: AstroSat CZTI detection
  90. Fermi trigger No 590335819: Global MASTER-Net observations report
  91. LIGO/Virgo S190915ak: Upper limits from Fermi-GBM Observations
  92. LIGO/Virgo S190915ak: No counterpart candidates in Fermi-LAT observations
  93. GRB 190916A: Fermi GBM Final Real-time Localization
  94. GRB 190915A: Insight-HXMT/HE detection
  95. GRB190915A: MASTER optical observation of BALROG Fermi GRB localization
  96. GRB 190915A: BALROG localization (Fermi Trigger 590219102 / GRB 190915240)
  97. GRB 190915A: Fermi GBM Final Real-time Localization
  98. GRB 190914A: Fermi GBM Final Real-time Localization
  99. GRB 190828C: AstroSat CZTI detection
  100. Fermi trigger No 590038994: Global MASTER-Net observations report

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