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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. IceCube-200107A: Upper limits from a search for additional neutrino events in IceCube
  2. LIGO/Virgo S200105ae: AT2020pq, AT2020ps and AT2020pv 10.4m GTC spectroscopy
  3. LIGO/Virgo S200105ae: AT2020pp and AT2020py 10.4m GTC spectroscopy
  4. LIGO/Virgo S200105ae: AT2020oo 10.4m GTC spectroscopy
  5. IceCube-200109A: Swift-XRT and UVoT Follow-up Observations
  6. ANTARES 200108A: No detection by Swift-XRT
  7. IceCube-200109A: INTEGRAL was inactive at the time of the event
  8. IceCube-200109A: Upper limits from Fermi-GBM Observations
  9. IceCube-200109A: IceCube observation of a high-energy neutrino candidate event
  10. IceCube Alert 200109.99: Global MASTER-Net observations report
  11. IceCube Alert 200109.99: Global MASTER-Net observations report
  12. GRB 200107B: Swift/UVOT Observations
  13. GRB 200109A: Swift-BAT refined analysis
  14. Swift follow-up observations of IceCube-200107A: Identification of X-ray high state for 4FGL J0955.1+3551
  15. GRB 200109A: Swift/UVOT Upper Limits
  16. GRB 200109A: Fermi GBM observation
  17. LIGO/Virgo S200105ae: Updated Sky Localization and EM-Bright Probabilities
  18. LIGO/Virgo S200105ae : No significant candidates in TAROT - FRAM - GRANDMA observations.
  19. LIGO/Virgo S200105ae: Gaia Photometric Alerts transient candidate
  20. GRB 200107B: Swift-XRT refined Analysis
  21. Fermi-LAT ANTARES coincidence /ANTARES alert 200108.39: MASTER alert and inspect observation
  22. Fermi-LAT ANTARES coincidence: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  23. GRB 200109A: Swift-XRT refined Analysis
  24. GRB 200109A: Enhanced Swift-XRT position
  25. Fermi trigger No 600227156: Global MASTER-Net observations report
  26. Swift GRB200109.07: Global MASTER-Net observations report
  27. GRB 200109A: Swift detection of a burst
  28. GRB 200109A: Fermi GBM Final Real-time Localization
  29. Fermi-LAT ANTARES coincidence: Upper limits from Fermi-GBM Observations
  30. LIGO/Virgo S200105ae: GW data still under study
  31. Fermi-LAT ANTARES coincidence
  32. LIGO/Virgo S200105ae: Candidates from the Zwicky Transient Facility
  33. Swift GRB 200107B: Global MASTER-Net observations report
  34. GRB 200107B: Fermi GBM observation
  35. GRB 200107B: Swift-BAT refined analysis
  36. Fermi-LAT Gamma-ray Observations of IceCube-200107A
  37. IceCube-200107A: No significant detection in HAWC
  38. IceCube-200107A: No candidates from the Zwicky Transient Facility
  39. IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  40. LIGO/Virgo S200108v: Retraction of GW compact binary merger candidate
  41. LIGO/Virgo S200105ae: Upper limits from CALET observations.
  42. GRB 200101A: CALET Gamma-Ray Burst Monitor detection
  43. LIGO/Virgo S200105ae: Upper Limits from the Zwicky Transient Facility
  44. GRB 200107B: Swift detection of a burst
  45. Swift GRB200107.81: Global MASTER-Net OT detection
  46. GRB 200107B: Fermi GBM Final Real-time Localization
  47. Swift GRB200107.81: Global MASTER-Net observations report
  48. LIGO/Virgo S200105ae: Further study ongoing for GW compact binary merger candidate
  49. IceCube-200107A: Upper limits from Fermi-GBM Observations
  50. IceCube-200107A: IceCube observation of a high-energy neutrino candidate event
  51. LIGO/Virgo 200105ae: No counterpart candidates in Fermi-LAT observations
  52. GRB 191228A: FRAM-ORM optical limit
  53. LIGO/Virgo S200105ae: AstroSat CZTI upper limits
  54. LIGO/Virgo S200105ae: Coverage and upper limits from MAXI/GSC observations
  55. LIGO/Virgo S200105ae: No counterpart candidates in HAWC observations
  56. LIGO/Virgo S200105ae: no counterpart candidates in the Swift/BAT observations
  57. LIGO/Virgo S200105ae: Upper limits from IceCube neutrino searches
  58. LIGO/Virgo S200105ae: not observable by AGILE-MCAL
  59. LIGO/Virgo S200105ae: Global MASTER-Net observations report
  60. LIGO/Virgo S200105ae: Upper limits from Fermi-GBM Observations
  61. LIGO/Virgo S200105ae: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  62. LIGO/Virgo S200105ae : no neutrino counterpart candidate in ANTARES search
  63. LIGO/Virgo S200105ae: We have issued GCN Notices to support automated processing
  64. S200106au and S200106av: Retraction of GW compact binary merger candidates
  65. LIGO/Virgo S200105ae: A subthreshold GW compact binary merger candidate
  66. Fermi trigger No 599954133: Global MASTER-Net observations report
  67. GRB 200105A: MAXI/GSC detection
  68. Konus-Wind observation of GRB200101A
  69. Fermi trigger No 599761015: Global MASTER-Net observations report
  70. IPN triangulation of GRB 200101A
  71. GRB 200103A: Fermi GBM Final Real-time Localization
  72. Fermi-LAT Gamma-ray Observations of IceCube-191231A
  73. GRB 200101A : AstroSat CZTI detection
  74. IceCube-191231A: Upper limits from a search for additional neutrino events in IceCube
  75. GRB 191228A: Early Optical Upper Limits from LCO
  76. IceCube Alert 200101.46: Global MASTER-Net observations report
  77. IceCube-191231A: No significant detection in HAWC
  78. GRB 200101A: Fermi GBM detection
  79. Fermi trigger No 599603971: Global MASTER-Net observations report
  80. GRB 200101A: BALROG localization (Fermi Trigger 599603971 / GRB 200101861)
  81. GRB 200101A: Fermi GBM Final Real-time Localization
  82. IceCube-191231A: No Neutrino Counterpart in ANTARES data
  83. IceCube-191231A: Upper limits from Fermi-GBM Observations
  84. IceCube-191231A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  85. IceCube-191231A: IceCube observation of a high-energy neutrino candidate event
  86. IceCube Alert 191231.46: Global MASTER-Net observations report
  87. GRB 191227A: Insight-HXMT/HE observation
  88. GRB 191227B: Insight-HXMT/HE observation
  89. GRB 191221B: CALET Gamma-Ray Burst Monitor detection
  90. GRB 191228A: Mondy optical upper limit
  91. Konus-Wind observation of GRB 191227A
  92. Konus-Wind observation of GRB 191227B
  93. IPN triangulation of GRB 191227B (short)
  94. GRB 191228A: Swift/UVOT Upper Limits
  95. GRB 191225A : AstroSat CZTI detection
  96. GRB 191228A: Swift-XRT refined Analysis
  97. GRB 191227A: Swift-BAT refined analysis
  98. GRB 191228A: Swift-BAT refined analysis
  99. GRB 191228A: Enhanced Swift-XRT position
  100. LIGO/Virgo S191216ap: Two candidate counterparts from UKIRT/WFCAM z-band observations

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