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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"

28058 results found.

  1. GRB 201017A: MITSuME Akeno optical upper limits
  2. GRB 201017A: Swift-BAT refined analysis
  3. GRB 201015A: GROWTH-India Telescope (GIT) upper limit
  4. GRB 201015A: HCT optical photometric follow-up
  5. GRB 201017A: Swift-XRT refined Analysis
  6. GRB 201015A: Xinglong-2.16m optical observations
  7. GRB 201017A: Fermi GBM detection
  8. GRB 201017A: Enhanced Swift-XRT position
  9. GRB 201015A: classification as long GRB
  10. GRB 201017A: Swift detection of a burst
  11. Fermi GBM Sub-Threshold Detection of GRB 201015A
  12. GRB 201015A: Swift/UVOT Detection
  13. GRB 201015A: Swift-XRT refined Analysis
  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 201014A: Nanshan/NEXT optical observations
  17. GRB 201014A: Lowell Discovery Telescope afterglow imaging
  18. GRB201015A: Nanshan/NEXT early optical observations
  19. GRB 201016A: AstroSat CZTI detection
  20. GRB 201008A: Swift-XRT afterglow detection
  21. GRB 201015A: Enhanced Swift-XRT position
  22. GRB 201016A: Fermi GBM detection
  23. GRB 201015A: BOOTES-1 early optical afterglow detection
  24. GRB 201014A: Swift/UVOT Upper Limits
  25. GRB 201016B: BALROG localization (Fermi Trigger 624510986 / GRB 201016136)
  26. GRB 201016A: BALROG localization (Fermi Trigger 624500874 / GRB 201016019)
  27. GRB 201015A: GOTO confirmation of afterglow detection
  28. GRB 201014A: Swift-XRT refined Analysis
  29. GRB 201015A: NOT optical afterglow confirmation
  30. GRB 201015A: Swift-XRT observations
  31. Swift GRB201015.95: Global MASTER-Net OT detection
  32. IceCube-201014A: Upper limits from a search for additional neutrino events in IceCube
  33. GRB 201014A: BOOTES-1 and -2 early optical upper limits
  34. GRB 201014A: Swift-BAT refined analysis
  35. GRB 201014A (Swift trigger =1000255): CrAO/ZTSH optical afterglow discovery
  36. IceCube Alert 201014.09: Global MASTER-Net observations report
  37. Swift-BAT trigger 1000255: XRT afterglow detection of GRB 201014A
  38. GRB 201013A: Insight-HXMT/HE detection
  39. IceCube-201014A: No neutrino counterpart candidates in ANTARES search
  40. Fermi-LAT Gamma-ray Observations of IceCube-201014A
  41. GRB 201013A: TSHAO and AbAO optical observations, afterglow confirmation
  42. IceCube-201014A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  43. GRB 201013A: Swift-BAT refined analysis
  44. GRB 201013A: Swift/UVOT Upper Limits
  45. GRB 201013A: Swift-XRT refined Analysis
  46. SGR 1830-0645: Swift/UVOT Upper Limits
  47. GRB 201013A: Enhanced Swift-XRT position
  48. GRB 201013A: Swift detection of a burst
  49. SGR 1830-0645: Swift-BAT refined analysis
  50. SGR 1830-0645 / GRB 201010A: Kitab optical non-detection
  51. GRB 201010A: Enhanced Swift-XRT position
  52. Swift GRB201010.62: Global MASTER-Net observations report
  53. Swift detection of a new SGR 1830-0645 or a short GRB 201010A
  54. IceCube-200929A: JCMT/SCUBA2 observations
  55. IceCube-201007A: No significant detection in HAWC
  56. IceCube-201007A: Upper limits from a search for additional neutrino events in IceCube
  57. GRB 201009A: AstroSat CZTI detection
  58. GRB 201008A: Swift-XRT observations
  59. IceCube-200926A: Upper limits from Insight-HXMT Observations
  60. GRB 201008A: Swift/BAT-GUANO detection and possible arcminute localization
  61. Fermi-LAT Gamma-ray Observations of IceCube-201007A
  62. Swift-XRT observations of IceCube 201007A
  63. GRB 201008A: BALROG localization (Fermi Trigger 623846261 / GRB 201008443)
  64. IceCube-201007A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  65. GRB 201006A: GROWTH-India Telescope optical upper limit
  66. GRB 201006A: Lowell Discovery Telescope upper limits
  67. GRB 201006A: MITSuME Akeno optical upper limits
  68. GRB 201006A: Swift-XRT refined Analysis
  69. GRB 201006A: Swift-BAT refined analysis
  70. GRB 201006A: Swift/UVOT Upper Limits
  71. GRB 201006A: Enhanced Swift-XRT position
  72. GRB 201006A: Swift detection of a burst
  73. GRB 201001A: Swift/UVOT Upper Limits
  74. IceCube-200926B: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  75. IceCube-200929A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  76. GRB 201001A: TSHAO optical upper limit
  77. GRB 201001A: Xinglong-2.16m optical upper limit
  78. GRB 201001A: MITSuME Akeno optical upper limits
  79. IceCube-200926A: JCMT/SCUBA2 observations
  80. IceCube-200929A: No significant detection in HAWC
  81. GRB 201001A: Swift-BAT refined analysis
  82. GRB 201001A: Fermi GBM observation
  83. Swift-XRT observations of IceCube 200929A
  84. GRB 201001A: Enhanced Swift-XRT position
  85. GRB 201001A: Swift detection of a burst
  86. GRB 201001A: Fermi GBM Final Real-time Localization
  87. Fermi-LAT Gamma-ray Observations of IceCube-200929A
  88. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  89. IceCube-200926B: No significant detection in HAWC
  90. GRB 200928B: Insight-HXMT/HE detection
  91. IceCube-200926A: No significant detection in HAWC
  92. GRB 200928B: AstroSat CZTI detection
  93. GRB 200928B: BALROG localization (Fermi Trigger 622991684 / GRB 200928552)
  94. Fermi-LAT Gamma-ray Observations of IceCube-200926B
  95. IceCube-200926B: No neutrino counterpart candidates in ANTARES search
  96. Swift-XRT observations of IceCube 200926A
  97. Konus-Wind detection of GRB 200920B
  98. Fermi-LAT Gamma-ray Observations of IceCube-200926A
  99. GRB 200925B: Swift-XRT refined analysis update
  100. GRB 200925B NUTTelA-TAO / BSTI Early Measurements (Preliminary)

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