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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"

19566 results found.

  1. GRB 200512A: Swift/UVOT Upper Limits
  2. GRB 200512A: Enhanced Swift-XRT position
  3. GRB 200512A: Swift detection of a burst
  4. IceCube-200512A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  5. IPN triangulation of a bright burst from SGR 1935+2154 on 2020-05-10 at 06:12 UT
  6. GRB 200509A: GROWTH-India r band upper limits
  7. GRB 200509A: Swift/UVOT Detection
  8. GRB 200509A: Enhanced Swift-XRT position
  9. GRB 200509A: Zadko observatory - Gingin optical upper limits
  10. GRB 200509A: Swift detection of a burst with a possible optical counterpart
  11. Swift Detection of a burst from SGR Swift J1818.0-1607
  12. GRB 200424A: Swift-XRT afterglow detection
  13. Fermi GBM observation of a flare from the magnetar SGR 1806-20
  14. SGR 1935+2154: INTEGRAL hard X-ray counterpart of radio burst
  15. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  16. IceCube-200425A: No significant detection in HAWC
  17. Fermi-LAT Gamma-ray Observations of IceCube-200425A
  18. IceCube-200425A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  19. GRB 200425A: Swift/UVOT Upper Limits
  20. GRB 200425A: Enhanced Swift-XRT position
  21. GRB 200425A: Swift detection of a burst
  22. GRB 200424A: Swift ToO observations
  23. IPN Triangulation of a bright burst from SGR 1935+2154
  24. GRB 200410A: Liverpool Telescope First Hour Observations
  25. Fermi-LAT Gamma-ray Observations of IceCube-200421A
  26. IceCube-200421A: No significant detection in HAWC
  27. IceCube Alert 200421.02: Global MASTER-Net observations report
  28. IceCube-200421A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  29. GRB 200412B: continued Mondy and Terskol optical observations
  30. GRB 200412B: continued Terskol optical observations
  31. GRB 200412B: continued AbAO, Mondy, TSHAO, Terskol optical observations
  32. GRB 200410A: Optical upper limit
  33. GRB 200416A: Swift/UVOT Detection
  34. GRB 200412B: Swift XRT confirmation of afterglow and UVOT upper limits
  35. GRB200412B: GROWTH India detection of afterglow
  36. GRB 200412B: continued Tautenburg observations
  37. GRB 200416A: Swift detection of a burst with an optical afterglow
  38. GRB 200411A: Chandra observations indicative of temporal steepening
  39. IPN triangulation of GRB 200415A (possible Magnetar Giant Flare in Sculptor Galaxy?)
  40. GRB 200412B: Mondy optical observations
  41. GRB 200412B: continued Tautenburg observations
  42. GRB 200412B: Tautenburg observations
  43. GRB 200412B: contunued AbAO optical observations
  44. GRB 200412B: SAO RAS observations of OT
  45. IceCube-200410A: No significant detection in HAWC
  46. GRB 200412B: Tautenburg observations
  47. GRB 200412B: AbAO optical observations
  48. GRB 200412B: Swift-XRT afterglow detection
  49. GRB 200412B: Tiled Swift observations
  50. GRB 200411A: Swift-BAT refined analysis
  51. Fermi-LAT Gamma-ray Observations of IceCube-200410A
  52. GRB 200411A: Swift-XRT refined Analysis
  53. GRB 200411A: Swift/UVOT Upper Limits
  54. GRB 200411A: Enhanced Swift-XRT position
  55. IceCube-200410A: Possible associated excess in INTEGRAL SPI-ACS prompt observation
  56. GRB 200411A: Swift detection of a short burst
  57. IceCube-200410A - IceCube observation of a high-energy neutrino candidate event
  58. GRB 200410A: Swift/UVOT Detection
  59. LIGO/Virgo S200224ca: Swift XRT observations, 8 X-ray sources
  60. GRB 200410A: Swift-XRT refined Analysis
  61. GRB 200410A: Enhanced Swift-XRT position
  62. GRB 200410A: Swift detection of a burst with a possible optical counterpart
  63. GRB 200405B: ATCA follow-up and ASKAP limits on pre-burst radio emission
  64. GRB 200409A: Enhanced Swift-XRT position
  65. GRB 200409A: Swift detection of a burst with an optical counterpart
  66. GRB 200405B: Swift ToO observations
  67. GRB 200405B: Swift/BAT-GUANO detection and *possible* arcminute localization of a short GRB
  68. GRB 200325B: Optical upper limit
  69. GRB 200325B: Tautenburg observations
  70. IPN triangulation of GRB 200327A (short)
  71. GRB 200327A: AGILE/MCAL observations
  72. Fermi trigger No 607035413: Global MASTER-Net observations report
  73. GRB 200325B: Swift-XRT and UVOT observations
  74. GRB 200325B: Mondy and CrAO observations, Master MASTER OT J111012.51+274912.8 confirmation
  75. GRB 200325B: Swift ToO observations
  76. GRB 200325B: MASTERt OT detection
  77. GRB 200324A: AROMA-N Optical Observation
  78. GRB 200325A: Swift/BAT detection and probable arcminute localization of a short GRB from GUANO
  79. GRB 200324A:: TSHAO optical upper limit
  80. GRB 200324A: Swift/UVOT Upper Limits
  81. GRB 200325A: AGILE/MCAL observations
  82. GRB 200324A: Konkoly Obs. optical upper limit
  83. GRB 200324A: NOT optical upper limit
  84. GRB 200324A: Tautenburg observations
  85. GRB 200324A: Enhanced Swift-XRT position
  86. GRB 200324A: Swift detection of a burst
  87. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
  88. Chandra observations of GW170817 at 2.5 years since merger (All epochs 4 of 4)
  89. GW170817: Continued X-ray emission detected with Chandra at 940 days post-merger
  90. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  91. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  92. LIGO/Virgo S200316bj: No neutrino candidates at Pierre Auger Observatory
  93. LIGO/Virgo S200316bj: No counterpart candidates in Fermi-LAT observations
  94. LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
  95. LIGO/Virgo S200316bj: no counterpart candidates in the Swift/BAT observations
  96. Konus-Wind observation of GRB 200311A
  97. LIGO/Virgo S200316bj: No counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
  98. LIGO/Virgo S200316bj : no neutrino counterpart candidate in ANTARES search
  99. Swift-BAT trigger 960986: Swift detection of a new SGR Swift J1818.0-1607
  100. LIGO/Virgo S200311bg: No significant counterpart candidates in Fermi-LAT observations

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