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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"

28050 results found.

  1. Swift Detection of a burst from SGR Swift J1818.0-1607
  2. Swift GRB200506.73: Global MASTER-Net observations report
  3. Insight-HXMT detection of a short bright burst from SGR 1935+2154
  4. GRB 200502A: AstroSat CZTI detection
  5. GRB 200503B: BALROG localization (Fermi Trigger 610219118 / GRB 200503721)
  6. Insight-HXMT X-ray and hard X-ray upper limits to the radio burst detected by FAST from SGR 1935+2154
  7. No optical bursts detected from SGR J1935+2154 by 24 fps observations with Tomo-e Gozen
  8. GRB 200424A: Swift-XRT afterglow detection
  9. Insight-HXMT X-ray and hard X-ray detection of the double peaks of the Fast Radio Burst from SGR 1935+2154
  10. Fermi GBM observation of a flare from the magnetar SGR 1806-20
  11. GRB 200501A: Fermi GBM Final Real-time Localization
  12. SGR 1935+2154: INTEGRAL hard X-ray counterpart of radio burst
  13. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  14. A Forest of Bursts from SGR 1935+2154
  15. SGR 1935+2154 the Insight-HXMT observation plan
  16. IceCube-200425A: No significant detection in HAWC
  17. IceCube-200425A: Upper limits from a search for additional neutrino events in IceCube
  18. Fermi-LAT Gamma-ray Observations of IceCube-200425A
  19. IceCube-200425A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  20. GRB 200425A: Swift-BAT refined analysis
  21. GRB 200424A: Swift/UVOT Upper Limits
  22. GRB 200425A: LCO Optical Upper Limits
  23. GRB 200425A: Swift/UVOT Upper Limits
  24. GRB 200424A: AstroSat CZTI detection
  25. GRB 200425A: Swift-XRT refined Analysis
  26. GRB 200424A: Swift-XRT observations
  27. GRB 200425A: Enhanced Swift-XRT position
  28. GRB 200425A: Swift detection of a burst
  29. GRB 200424A: LCO Optical Upper Limit
  30. IPN Triangulation of a bright burst from SGR 1935+2154
  31. IceCube-200421A: Upper limits from a search for additional neutrino events in IceCube
  32. GRB 200415A: ASIM observation
  33. GRB 200410A: Liverpool Telescope First Hour Observations
  34. Fermi-LAT Gamma-ray Observations of IceCube-200421A
  35. IceCube-200421A: No Neutrino Counterpart in ANTARES data
  36. IceCube-200421A: No significant detection in HAWC
  37. IceCube-200421A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  38. GRB 200412B: continued Mondy and Terskol optical observations
  39. GRB 200412B: continued Terskol optical observations
  40. GRB 200412B: continued AbAO, Mondy, TSHAO, Terskol optical observations
  41. GRB 200410A: Optical upper limit
  42. GRB 200416A: Swift/UVOT Detection
  43. GRB 200416A: Swift-BAT refined analysis
  44. GRB 200412B: Swift XRT confirmation of afterglow and UVOT upper limits
  45. GRB 200415A: MASTER imspection and possible localisation
  46. GRB200412B: GROWTH India detection of afterglow
  47. Konus-Wind observation of GRB 200415A (a magnetar Giant Flare in Sculptor Galaxy?)
  48. GRB 200416A: Swift-XRT refined Analysis
  49. GRB 200412B: continued Tautenburg observations
  50. GRB 200416A: Fermi GBM observation
  51. GRB 200416A: Swift detection of a burst with an optical afterglow
  52. GRB 200415A: Fermi GBM observation
  53. IPN triangulation of GRB 200415A (possible Magnetar Giant Flare in Sculptor Galaxy?)
  54. GRB 200412B: Mondy optical observations
  55. GRB 200412B: continued Tautenburg observations
  56. GRB 200415A: BALROG localization (Fermi Trigger 608633290 / GRB 200415367)
  57. GRB 200410A: Swift-BAT refined analysis
  58. GRB 200412B: Tautenburg observations
  59. GRB 200412B: contunued AbAO optical observations
  60. GRB 200412B: SAO RAS observations of OT
  61. IceCube-200410A: No significant detection in HAWC
  62. GRB 200412B: Tautenburg observations
  63. GRB 200412B: AbAO optical observations
  64. GRB 200412B: Insight-HXMT/HE detection
  65. IceCube-200410A : Upper limits from Insight-HXMT/HE observations
  66. GRB 200412B: Swift-XRT afterglow detection
  67. Fermi GRB 200412A: Global MASTER-Net observations report
  68. GRB 200412B: Fermi GBM detection
  69. IceCube-200410A: Upper limits from a search for additional neutrino events in IceCube
  70. GRB 200412A: Fermi GBM detection
  71. GRB 200412B: BALROG localization (Fermi Trigger 608375325 / GRB 200412381)
  72. GRB 200412A: BALROG localization (Fermi Trigger 608367436 / GRB 200412290)
  73. GRB 200411A: Swift-BAT refined analysis
  74. Fermi-LAT Gamma-ray Observations of IceCube-200410A
  75. GRB 200411A: Swift-XRT refined Analysis
  76. GRB 200411A: Swift/UVOT Upper Limits
  77. GRB 200411A: Enhanced Swift-XRT position
  78. IceCube-200410A: Possible associated excess in INTEGRAL SPI-ACS prompt observation
  79. GRB 200411A: Swift detection of a short burst
  80. GRB 200410A: Swift/UVOT Detection
  81. LIGO/Virgo S200225q: Swift XRT observations, 1 X-ray sources
  82. LIGO/Virgo S200224ca: Swift XRT observations, 8 X-ray sources
  83. GRB 200410A: Swift-XRT refined Analysis
  84. GRB 200410A: Enhanced Swift-XRT position
  85. GRB 200409A: Swift-BAT refined analysis
  86. GRB 200410A: Swift detection of a burst with a possible optical counterpart
  87. GRB 200405B: ATCA follow-up and ASKAP limits on pre-burst radio emission
  88. Baksan Neutrino Observatory Alert 200408.26: Global MASTER-Net observations report
  89. Fermi GBM Sub-Threshold Detection of GRB 200409A
  90. GRB 200409A: Swift-XRT refined Analysis
  91. GRB 200409A: Enhanced Swift-XRT position
  92. GRB 200409A: Swift detection of a burst with an optical counterpart
  93. GRB 200405B: LCO Optical Upper Limits
  94. GRB 200405B: Swift-XRT observations
  95. GRB 200405B: Swift/BAT-GUANO detection and *possible* arcminute localization of a short GRB
  96. GRB 200404A: BALROG localization (Fermi Trigger 607712227 / GRB 200404706)
  97. LIGO/Virgo S200316bj: Upper limits from Konus-Wind observations
  98. LIGO/Virgo S200311bg: Upper limits from Konus-Wind observations
  99. LIGO/Virgo S200302c: Upper limits from Konus-Wind observations
  100. LIGO/Virgo S200225q: Upper limits from Konus-Wind observations

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