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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"

19662 results found.

  1. SGR 1935+2154 the Insight-HXMT observation plan
  2. Fermi GBM observation of a bright flare from magnetar SGR 1935+2154
  3. Swift detection of multiple bursts from SGR 1935+2154
  4. Gagarin-day GRB 200412B: observations with the 3.6m Devasthal Optical Telescope
  5. GRB 200425A: Swift-BAT refined analysis
  6. GRB 200424A: Swift/UVOT Upper Limits
  7. GRB 200425A: LCO Optical Upper Limits
  8. Swift GRB 200425A: Global MASTER-Net observations report
  9. GRB 200425A: Swift/UVOT Upper Limits
  10. GRB 200424A: AstroSat CZTI detection
  11. GRB 200425A: Swift-XRT refined Analysis
  12. GRB 200424A: Swift-XRT observations
  13. GRB 200425A: Enhanced Swift-XRT position
  14. GRB 200425A: Swift detection of a burst
  15. GRB 200424A: Swift ToO observations
  16. IPN triangulation of GRB 200422A (long/very bright)
  17. IPN Triangulation of a bright burst from SGR 1935+2154
  18. bright SGR burst detected by CALET Gamma-Ray Burst Monitor
  19. GRB 200410A: Liverpool Telescope First Hour Observations
  20. GRB 200410A: Optical upper limit
  21. GRB 200416A: Swift/UVOT Detection
  22. GRB 200416A: Swift-BAT refined analysis
  23. GRB 200412B: Swift XRT confirmation of afterglow and UVOT upper limits
  24. Improved IPN error box for GRB 200415A (consistent with the Sculptor Galaxy)
  25. GRB 200416A: Swift-XRT refined Analysis
  26. GRB 200416A: Fermi GBM observation
  27. GRB 200416A: Swift detection of a burst with an optical afterglow
  28. GRB 200411A: Chandra observations indicative of temporal steepening
  29. IPN triangulation of GRB 200415A (possible Magnetar Giant Flare in Sculptor Galaxy?)
  30. GRB 200410A: CALET Gamma-Ray Burst Monitor detection
  31. GRB 200410A: Swift-BAT refined analysis
  32. GRB 200411A: ATCA 5/9 GHz radio observations
  33. GRB 200405B: Further Swift-XRT observations
  34. GRB 200412B : AstroSat CZTI detection
  35. GRB 200412B: Swift-XRT afterglow detection
  36. GRB 200412B: Fermi-LAT detection
  37. Correction to GCN 27551 - Swift is observing GRB 200412*B*
  38. GRB 200412B: Tiled Swift observations
  39. GRB 200411A: Swift-BAT refined analysis
  40. GRB 200411A: Fermi GBM observation
  41. Swift GRB 200411A: Global MASTER-Net observations report
  42. GRB 200411A: Swift-XRT refined Analysis
  43. GRB 200411A: Swift/UVOT Upper Limits
  44. GRB 200411A: Enhanced Swift-XRT position
  45. GRB 200411A: Swift detection of a short burst
  46. GRB 200410A: Swift/UVOT Detection
  47. LIGO/Virgo S200225q: Swift XRT observations, 1 X-ray sources
  48. LIGO/Virgo S200224ca: Swift XRT observations, 8 X-ray sources
  49. GRB 200410A: Swift-XRT refined Analysis
  50. GRB 200410A: Enhanced Swift-XRT position
  51. GRB 200409A: Swift-BAT refined analysis
  52. GRB 200410A: Swift detection of a burst with a possible optical counterpart
  53. Swift GRB200410.10: Global MASTER-Net observations report
  54. GRB 200405B: ATCA follow-up and ASKAP limits on pre-burst radio emission
  55. Fermi GBM Sub-Threshold Detection of GRB 200409A
  56. Swift GRB 200409A: Global MASTER-Net observations report
  57. GRB 200409A: Swift-XRT refined Analysis
  58. GRB 200409A: Enhanced Swift-XRT position
  59. GRB 200409A: Swift detection of a burst with an optical counterpart
  60. IPN triangulation of GRB 200405B (short)
  61. GRB 200405B: LCO Optical Upper Limits
  62. GRB 200405B: Swift-XRT observations
  63. GRB 200405B: Swift ToO observations
  64. GRB 200405B: Swift/BAT-GUANO detection and *possible* arcminute localization of a short GRB
  65. GRB 200325B: Optical upper limit
  66. GRB 200325B: further Swift-XRT observations
  67. IPN triangulation of GRB 200327A (short)
  68. GRB 200325B: Fermi GBM observation
  69. GRB 200325B: Swift-XRT and UVOT observations
  70. GRB 200325A: Fermi GBM observation
  71. GRB 200325B: Swift ToO observations
  72. IPN triangulation of GRB 200325A (short)
  73. GRB 200324A: AROMA-N Optical Observation
  74. GRB 200325A: Swift/BAT detection and probable arcminute localization of a short GRB from GUANO
  75. GRB 200324A, Swift-BAT refined analysis
  76. GRB 200324A:: TSHAO optical upper limit
  77. GRB 200324A: Swift/UVOT Upper Limits
  78. GRB 200324A: LCO Optical Upper Limit
  79. GRB 200324A: Swift-XRT refined Analysis
  80. GRB 200324A: Enhanced Swift-XRT position
  81. GRB 200324A:MITSuME Akeno optical upper limits
  82. GRB 200324A: Swift detection of a burst
  83. Swift GRB200324.69: Global MASTER-Net observations report
  84. LIGO/Virgo S200316bj: no counterpart candidates in the Swift/BAT observations
  85. LIGO/Virgo S200213t: Continued Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)
  86. SGR Swift J1818.0-1607: Swift-BAT refined analysis
  87. SGR Swift J1818.0-1607: BOOTES-4/MET optical limit
  88. Swift GRB200312.89: Global MASTER-Net observations report
  89. Swift-BAT trigger 960986: Swift detection of a new SGR Swift J1818.0-1607
  90. LIGO/Virgo S200311bg: Swift/BAT in the South Atlantic Anomaly
  91. IPN triangulation of GRB 200307A (short)
  92. GRB 200307A: Updated localization from Fermi/GBM and Swift/BAT-GUANO
  93. GRB 200306C: Swift-BAT refined analysis
  94. GRB 200306C: Swift/UVOT Detection
  95. GRB 200306A: Swift/UVOT Upper Limits
  96. GRB 200306A: Swift-BAT refined analysis
  97. GRB 200306C: Swift-XRT refined Analysis
  98. GRB 200306A: RATIR Optical Observations
  99. GRB 200306C: Enhanced Swift-XRT position
  100. GRB 200306C: VIRT optical upper limits

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