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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. Swift follow-up observations of IceCube-200107A: Identification of X-ray high state for 4FGL J0955.1+3551
  2. GRB 200109A: Swift/UVOT Upper Limits
  3. GRB 200109A: Fermi GBM observation
  4. LIGO/Virgo S200105ae: Updated Sky Localization and EM-Bright Probabilities
  5. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
  6. LIGO/Virgo S200105ae: Gaia Photometric Alerts transient candidate
  7. GRB 200107B: Swift-XRT refined Analysis
  8. Fermi-LAT ANTARES coincidence /ANTARES alert 200108.39: MASTER alert and inspect observation
  9. Fermi-LAT ANTARES coincidence: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  10. GRB 200109A: Swift-XRT refined Analysis
  11. GRB 200109A: Enhanced Swift-XRT position
  12. Fermi trigger No 600227156: Global MASTER-Net observations report
  13. Swift GRB200109.07: Global MASTER-Net observations report
  14. GRB 200109A: Swift detection of a burst
  15. GRB 200109A: Fermi GBM Final Real-time Localization
  16. Fermi-LAT ANTARES coincidence: Upper limits from Fermi-GBM Observations
  17. LIGO/Virgo S200105ae: GW data still under study
  18. Fermi-LAT ANTARES coincidence
  19. LIGO/Virgo S200105ae: Candidates from the Zwicky Transient Facility
  20. Swift GRB 200107B: Global MASTER-Net observations report
  21. GRB 200107B: Fermi GBM observation
  22. GRB 200107B: Swift-BAT refined analysis
  23. Fermi-LAT Gamma-ray Observations of IceCube-200107A
  24. IceCube-200107A: No significant detection in HAWC
  25. IceCube-200107A: No candidates from the Zwicky Transient Facility
  26. IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  27. LIGO/Virgo S200108v: Retraction of GW compact binary merger candidate
  28. LIGO/Virgo S200105ae: Upper limits from CALET observations.
  29. GRB 200101A: CALET Gamma-Ray Burst Monitor detection
  30. LIGO/Virgo S200105ae: Upper Limits from the Zwicky Transient Facility
  31. GRB 200107B: Swift detection of a burst
  32. Swift GRB200107.81: Global MASTER-Net OT detection
  33. GRB 200107B: Fermi GBM Final Real-time Localization
  34. Swift GRB200107.81: Global MASTER-Net observations report
  35. LIGO/Virgo S200105ae: Further study ongoing for GW compact binary merger candidate
  36. IceCube-200107A: Upper limits from Fermi-GBM Observations
  37. IceCube-200107A: IceCube observation of a high-energy neutrino candidate event
  38. LIGO/Virgo 200105ae: No counterpart candidates in Fermi-LAT observations
  39. GRB 191228A: FRAM-ORM optical limit
  40. LIGO/Virgo S200105ae: AstroSat CZTI upper limits
  41. LIGO/Virgo S200105ae: Coverage and upper limits from MAXI/GSC observations
  42. LIGO/Virgo S200105ae: No counterpart candidates in HAWC observations
  43. LIGO/Virgo S200105ae: no counterpart candidates in the Swift/BAT observations
  44. LIGO/Virgo S200105ae: Upper limits from IceCube neutrino searches
  45. LIGO/Virgo S200105ae: not observable by AGILE-MCAL
  46. LIGO/Virgo S200105ae: Global MASTER-Net observations report
  47. LIGO/Virgo S200105ae: Upper limits from Fermi-GBM Observations
  48. LIGO/Virgo S200105ae: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  49. LIGO/Virgo S200105ae : no neutrino counterpart candidate in ANTARES search
  50. LIGO/Virgo S200105ae: We have issued GCN Notices to support automated processing
  51. S200106au and S200106av: Retraction of GW compact binary merger candidates
  52. LIGO/Virgo S200105ae: A subthreshold GW compact binary merger candidate
  53. Fermi trigger No 599954133: Global MASTER-Net observations report
  54. GRB 200105A: MAXI/GSC detection
  55. Konus-Wind observation of GRB200101A
  56. Fermi trigger No 599761015: Global MASTER-Net observations report
  57. IPN triangulation of GRB 200101A
  58. GRB 200103A: Fermi GBM Final Real-time Localization
  59. Fermi-LAT Gamma-ray Observations of IceCube-191231A
  60. GRB 200101A : AstroSat CZTI detection
  61. IceCube-191231A: Upper limits from a search for additional neutrino events in IceCube
  62. GRB 191228A: Early Optical Upper Limits from LCO
  63. IceCube Alert 200101.46: Global MASTER-Net observations report
  64. IceCube-191231A: No significant detection in HAWC
  65. GRB 200101A: Fermi GBM detection
  66. Fermi trigger No 599603971: Global MASTER-Net observations report
  67. GRB 200101A: BALROG localization (Fermi Trigger 599603971 / GRB 200101861)
  68. GRB 200101A: Fermi GBM Final Real-time Localization
  69. IceCube-191231A: No Neutrino Counterpart in ANTARES data
  70. IceCube-191231A: Upper limits from Fermi-GBM Observations
  71. IceCube-191231A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  72. IceCube-191231A: IceCube observation of a high-energy neutrino candidate event
  73. IceCube Alert 191231.46: Global MASTER-Net observations report
  74. GRB 191227A: Insight-HXMT/HE observation
  75. GRB 191227B: Insight-HXMT/HE observation
  76. GRB 191221B: CALET Gamma-Ray Burst Monitor detection
  77. GRB 191228A: Mondy optical upper limit
  78. Konus-Wind observation of GRB 191227A
  79. Konus-Wind observation of GRB 191227B
  80. IPN triangulation of GRB 191227B (short)
  81. GRB 191228A: Swift/UVOT Upper Limits
  82. GRB 191225A : AstroSat CZTI detection
  83. GRB 191228A: Swift-XRT refined Analysis
  84. GRB 191227A: Swift-BAT refined analysis
  85. GRB 191228A: Swift-BAT refined analysis
  86. GRB 191228A: Enhanced Swift-XRT position
  87. LIGO/Virgo S191216ap: Two candidate counterparts from UKIRT/WFCAM z-band observations
  88. GRB 191228A: ePESSTO+ NTT optical upper limit
  89. GRB 191228A: UKIRT NIR upper limit
  90. LIGO/Virgo S191222n: No transient candidates in CALET observations
  91. GRB 191228A: Swift detection of a burst
  92. Swift GRB191228.00: Global MASTER-Net observations report
  93. GRB 191227A: Fermi GBM detection
  94. GRB 191227A: Marginal detection by Fermi-LAT
  95. GRB 191227A: MITSuME Akeno optical upper limits
  96. Swift GRB191227A: Global MASTER-Net OT detection
  97. GRB 191227A: Swift detection of a burst
  98. Swift GRB191227.07: Global MASTER-Net observations report
  99. GRB 191227A: Fermi GBM Final Real-time Localization
  100. Swift Trigger 946234: further Swift analysis

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