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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. GRB 201017A: Xinglong TNT upper limit
  2. GRB 201017A: Enhanced Swift-XRT position
  3. Trigger 1000631: Swift detection of Cen X-3
  4. GRB 201015A: classification as long GRB
  5. Swift GRB 201017A: Global MASTER-Net observations report
  6. GRB 201017A: Swift detection of a burst
  7. GRB 201017A: Fermi GBM Final Real-time Localization
  8. GRB 201015A: FRAM-ORM afterglow detection
  9. Fermi GBM Sub-Threshold Detection of GRB 201015A
  10. GRB 201015A: Swift/UVOT Detection
  11. GRB 201015A: redshift confirmation
  12. GRB 201015A: Swift-XRT refined Analysis
  13. MAGIC observations of GRB 201015A: hint of very high energy gamma-ray signal
  14. GRB 201015A: Swift-BAT refined analysis (a soft short pulse with a tail emission)
  15. IceCube-201014A: No significant detection in HAWC
  16. GRB 201015A: CrAO/ZTSH optical observations
  17. GRB 201014A: Nanshan/NEXT optical observations
  18. GRB 201014A: Lowell Discovery Telescope afterglow imaging
  19. GRB201015A: Nanshan/NEXT early optical observations
  20. Konus-Wind observation of GRB 201013A
  21. GRB 201016A: AstroSat CZTI detection
  22. GRB 201014A: Redshift from GTC/OSIRIS
  23. GRB 201015A: Redshift from GTC/OSIRIS
  24. GRB 201008A: Swift-XRT afterglow detection
  25. GRB 201015A: Enhanced Swift-XRT position
  26. GRB 201016A: Fermi GBM detection
  27. GRB 201015A: BOOTES-1 early optical afterglow detection
  28. GRB 201014A: Swift/UVOT Upper Limits
  29. Fermi GRB 201016B: Global MASTER-Net observations report
  30. GRB 201016B: BALROG localization (Fermi Trigger 624510986 / GRB 201016136)
  31. GRB 201016A: BALROG localization (Fermi Trigger 624500874 / GRB 201016019)
  32. GRB 201016B: Fermi GBM Final Real-time Localization
  33. GRB 201015A: GOTO confirmation of afterglow detection
  34. GRB 201014A: Swift-XRT refined Analysis
  35. GRB 201015A: NOT optical afterglow confirmation
  36. GRB 201016A: Fermi GBM Final Real-time Localization
  37. GRB 201015A: Swift-XRT observations
  38. Swift GRB 201015A: Global MASTER-Net observations report
  39. Swift GRB201015.95: Global MASTER-Net OT detection
  40. GRB 201015A: Swift detection of a burst
  41. IceCube-201014A: Upper limits from a search for additional neutrino events in IceCube
  42. GRB 201014A: BOOTES-1 and -2 early optical upper limits
  43. GRB 201014A: Swift-BAT refined analysis
  44. GRB 201014A (Swift trigger =1000255): CrAO/ZTSH optical afterglow discovery
  45. IceCube Alert 201014.09: Global MASTER-Net observations report
  46. Swift-BAT trigger 1000255: XRT afterglow detection of GRB 201014A
  47. GRB 201013A: Insight-HXMT/HE detection
  48. IceCube-201014A: No neutrino counterpart candidates in ANTARES search
  49. Swift Trigger 1000255 is probably not a GRB
  50. Fermi-LAT Gamma-ray Observations of IceCube-201014A
  51. GRB 201013A: TSHAO and AbAO optical observations, afterglow confirmation
  52. GRB 201013A: AstroSat CZTI detection
  53. IceCube-201014A: Not observable by GBM
  54. GRB 201013A: CALET Gamma-Ray Burst Monitor detection
  55. IceCube-201014A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  56. IceCube-201014A - IceCube observation of a high-energy neutrino candidate track-like event
  57. GRB 201013A: FRAM-ORM possible afterglow candidate
  58. GRB 201013A: Swift-BAT refined analysis
  59. GRB 201013A: Swift/UVOT Upper Limits
  60. Swift GRB 201013A: Global MASTER-Net observations report
  61. GRB 201013A: Swift-XRT refined Analysis
  62. SGR 1830-0645: Swift/UVOT Upper Limits
  63. IceCube-201007A: No candidate counterparts from the Zwicky Transient Facility
  64. GRB 201013A: Enhanced Swift-XRT position
  65. GRB 201013A: Swift detection of a burst
  66. GRB 201011A: Fermi GBM detection of a likely Long GRB in the direction of SGR 1830-0645
  67. Fermi trigger No 624139481: AGILE detection
  68. GRB 201012A: Fermi GBM Final Real-time Localization
  69. SGR 1830-0645: pre-discovery detection in Swift/BAT
  70. Fermi trigger No 624139481: Global MASTER-Net observations report
  71. SGR 1830-0645 / GRB 201010A: 1.5m OSN optical upper limit
  72. Fermi trigger No 624121589: Global MASTER-Net observations report
  73. SGR 1830-0645: Swift-BAT refined analysis
  74. GRB 201006A: Chandra upper limit on the X-ray afterglow
  75. SGR 1830-0645 / GRB 201010A: Kitab optical non-detection
  76. GRB 201010A: Enhanced Swift-XRT position
  77. Swift GRB201010.62: Global MASTER-Net observations report
  78. Swift detection of a new SGR 1830-0645 or a short GRB 201010A
  79. IceCube-200929A: JCMT/SCUBA2 observations
  80. IceCube-201007A: No significant detection in HAWC
  81. GRB 201008B: Fermi GBM Final Localization
  82. IceCube-201007A: Upper limits from a search for additional neutrino events in IceCube
  83. GRB 201009A: AstroSat CZTI detection
  84. GRB 201009A: AGILE detection of a burst
  85. GRB 201008A: Swift-XRT observations
  86. IceCube-200926A: Upper limits from Insight-HXMT Observations
  87. GRB 201008A: Swift ToO observations
  88. IceCube-201007A: Upper limits from Fermi-GBM Observations
  89. GRB 201008A: Swift/BAT-GUANO detection and possible arcminute localization
  90. Fermi-LAT Gamma-ray Observations of IceCube-201007A
  91. Fermi trigger No 623846261: Global MASTER-Net observations report
  92. Fermi trigger No 623873165: Global MASTER-Net observations report
  93. Swift-XRT observations of IceCube 201007A
  94. Baksan Neutrino Observatory Alert 201008.47: Global MASTER-Net observations report
  95. GRB 201008A: BALROG localization (Fermi Trigger 623846261 / GRB 201008443)
  96. IceCube-201007A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  97. IceCube-201007A - IceCube observation of a high-energy neutrino candidate track-like event
  98. IceCube Alert 201007.92: Global MASTER-Net observations report
  99. GRB 201006A: GROWTH-India Telescope optical upper limit
  100. GRB 201006A: Lowell Discovery Telescope upper limits

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