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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"
  1. ANTARES 200108A: No detection by Swift-XRT
  2. IceCube-200109A: INTEGRAL was inactive at the time of the event
  3. IceCube-200109A: Upper limits from Fermi-GBM Observations
  4. IceCube-200109A: IceCube observation of a high-energy neutrino candidate event
  5. IceCube Alert 200109.99: Global MASTER-Net observations report
  6. IceCube Alert 200109.99: Global MASTER-Net observations report
  7. GRB 200107B: Swift/UVOT Observations
  8. GRB 200109A: Swift-BAT refined analysis
  9. Swift follow-up observations of IceCube-200107A: Identification of X-ray high state for 4FGL J0955.1+3551
  10. GRB 200109A: Swift/UVOT Upper Limits
  11. GRB 200109A: Fermi GBM observation
  12. LIGO/Virgo S200105ae: Updated Sky Localization and EM-Bright Probabilities
  13. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
  14. LIGO/Virgo S200105ae: Gaia Photometric Alerts transient candidate
  15. GRB 200107B: Swift-XRT refined Analysis
  16. Fermi-LAT ANTARES coincidence /ANTARES alert 200108.39: MASTER alert and inspect observation
  17. Fermi-LAT ANTARES coincidence: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  18. GRB 200109A: Swift-XRT refined Analysis
  19. GRB 200109A: Enhanced Swift-XRT position
  20. Fermi trigger No 600227156: Global MASTER-Net observations report
  21. Swift GRB200109.07: Global MASTER-Net observations report
  22. GRB 200109A: Swift detection of a burst
  23. GRB 200109A: Fermi GBM Final Real-time Localization
  24. Fermi-LAT ANTARES coincidence: Upper limits from Fermi-GBM Observations
  25. LIGO/Virgo S200105ae: GW data still under study
  26. Fermi-LAT ANTARES coincidence
  27. LIGO/Virgo S200105ae: Candidates from the Zwicky Transient Facility
  28. Swift GRB 200107B: Global MASTER-Net observations report
  29. GRB 200107B: Fermi GBM observation
  30. GRB 200107B: Swift-BAT refined analysis
  31. Fermi-LAT Gamma-ray Observations of IceCube-200107A
  32. IceCube-200107A: No significant detection in HAWC
  33. IceCube-200107A: No candidates from the Zwicky Transient Facility
  34. IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  35. LIGO/Virgo S200108v: Retraction of GW compact binary merger candidate
  36. LIGO/Virgo S200105ae: Upper limits from CALET observations.
  37. GRB 200101A: CALET Gamma-Ray Burst Monitor detection
  38. LIGO/Virgo S200105ae: Upper Limits from the Zwicky Transient Facility
  39. GRB 200107B: Swift detection of a burst
  40. Swift GRB200107.81: Global MASTER-Net OT detection
  41. GRB 200107B: Fermi GBM Final Real-time Localization
  42. Swift GRB200107.81: Global MASTER-Net observations report
  43. LIGO/Virgo S200105ae: Further study ongoing for GW compact binary merger candidate
  44. IceCube-200107A: Upper limits from Fermi-GBM Observations
  45. IceCube-200107A: IceCube observation of a high-energy neutrino candidate event
  46. LIGO/Virgo 200105ae: No counterpart candidates in Fermi-LAT observations
  47. GRB 191228A: FRAM-ORM optical limit
  48. LIGO/Virgo S200105ae: AstroSat CZTI upper limits
  49. LIGO/Virgo S200105ae: Coverage and upper limits from MAXI/GSC observations
  50. LIGO/Virgo S200105ae: No counterpart candidates in HAWC observations
  51. LIGO/Virgo S200105ae: no counterpart candidates in the Swift/BAT observations
  52. LIGO/Virgo S200105ae: Upper limits from IceCube neutrino searches
  53. LIGO/Virgo S200105ae: not observable by AGILE-MCAL
  54. LIGO/Virgo S200105ae: Global MASTER-Net observations report
  55. LIGO/Virgo S200105ae: Upper limits from Fermi-GBM Observations
  56. LIGO/Virgo S200105ae: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  57. LIGO/Virgo S200105ae : no neutrino counterpart candidate in ANTARES search
  58. LIGO/Virgo S200105ae: We have issued GCN Notices to support automated processing
  59. S200106au and S200106av: Retraction of GW compact binary merger candidates
  60. LIGO/Virgo S200105ae: A subthreshold GW compact binary merger candidate
  61. Fermi trigger No 599954133: Global MASTER-Net observations report
  62. GRB 200105A: MAXI/GSC detection
  63. Konus-Wind observation of GRB200101A
  64. Fermi trigger No 599761015: Global MASTER-Net observations report
  65. IPN triangulation of GRB 200101A
  66. GRB 200103A: Fermi GBM Final Real-time Localization
  67. Fermi-LAT Gamma-ray Observations of IceCube-191231A
  68. GRB 200101A : AstroSat CZTI detection
  69. IceCube-191231A: Upper limits from a search for additional neutrino events in IceCube
  70. GRB 191228A: Early Optical Upper Limits from LCO
  71. IceCube Alert 200101.46: Global MASTER-Net observations report
  72. IceCube-191231A: No significant detection in HAWC
  73. GRB 200101A: Fermi GBM detection
  74. Fermi trigger No 599603971: Global MASTER-Net observations report
  75. GRB 200101A: BALROG localization (Fermi Trigger 599603971 / GRB 200101861)
  76. GRB 200101A: Fermi GBM Final Real-time Localization
  77. IceCube-191231A: No Neutrino Counterpart in ANTARES data
  78. IceCube-191231A: Upper limits from Fermi-GBM Observations
  79. IceCube-191231A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  80. IceCube-191231A: IceCube observation of a high-energy neutrino candidate event
  81. IceCube Alert 191231.46: Global MASTER-Net observations report
  82. GRB 191227A: Insight-HXMT/HE observation
  83. GRB 191227B: Insight-HXMT/HE observation
  84. GRB 191221B: CALET Gamma-Ray Burst Monitor detection
  85. GRB 191228A: Mondy optical upper limit
  86. Konus-Wind observation of GRB 191227A
  87. Konus-Wind observation of GRB 191227B
  88. IPN triangulation of GRB 191227B (short)
  89. GRB 191228A: Swift/UVOT Upper Limits
  90. GRB 191225A : AstroSat CZTI detection
  91. GRB 191228A: Swift-XRT refined Analysis
  92. GRB 191227A: Swift-BAT refined analysis
  93. GRB 191228A: Swift-BAT refined analysis
  94. GRB 191228A: Enhanced Swift-XRT position
  95. LIGO/Virgo S191216ap: Two candidate counterparts from UKIRT/WFCAM z-band observations
  96. GRB 191228A: ePESSTO+ NTT optical upper limit
  97. GRB 191228A: UKIRT NIR upper limit
  98. LIGO/Virgo S191222n: No transient candidates in CALET observations
  99. GRB 191228A: Swift detection of a burst
  100. Swift GRB191228.00: Global MASTER-Net observations report

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