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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"

28059 results found.

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

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