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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"

19572 results found.

  1. GRB 200519A: Swift detection of a burst with an optical afterglow
  2. GRB 200517A: Swift-XRT afterglow detection
  3. GRB 200517A: Tiled Swift observations
  4. Swift Detection of a burst from SGR Swift J1818.0-1607
  5. GRB 200514A: MITSuME Akeno optical upper limits
  6. GRB 200514B: GROWTH-India follow-up of ZTF20aazpphd (AT2020jww)
  7. GRB 200512A: Swift/UVOT Upper Limits
  8. GRB 200512A: Enhanced Swift-XRT position
  9. GRB 200512A: Swift detection of a burst
  10. IceCube-200512A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  11. IPN triangulation of a bright burst from SGR 1935+2154 on 2020-05-10 at 06:12 UT
  12. GRB 200509A: GROWTH-India r band upper limits
  13. GRB 200509A: Swift/UVOT Detection
  14. GRB 200509A: Enhanced Swift-XRT position
  15. GRB 200509A: Zadko observatory - Gingin optical upper limits
  16. GRB 200509A: Swift detection of a burst with a possible optical counterpart
  17. Swift Detection of a burst from SGR Swift J1818.0-1607
  18. GRB 200424A: Swift-XRT afterglow detection
  19. Fermi GBM observation of a flare from the magnetar SGR 1806-20
  20. SGR 1935+2154: INTEGRAL hard X-ray counterpart of radio burst
  21. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  22. IceCube-200425A: No significant detection in HAWC
  23. Fermi-LAT Gamma-ray Observations of IceCube-200425A
  24. IceCube-200425A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  25. GRB 200425A: Swift/UVOT Upper Limits
  26. GRB 200425A: Enhanced Swift-XRT position
  27. GRB 200425A: Swift detection of a burst
  28. GRB 200424A: Swift ToO observations
  29. IPN Triangulation of a bright burst from SGR 1935+2154
  30. GRB 200410A: Liverpool Telescope First Hour Observations
  31. Fermi-LAT Gamma-ray Observations of IceCube-200421A
  32. IceCube-200421A: No significant detection in HAWC
  33. IceCube Alert 200421.02: Global MASTER-Net observations report
  34. IceCube-200421A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  35. GRB 200412B: continued Mondy and Terskol optical observations
  36. GRB 200412B: continued Terskol optical observations
  37. GRB 200412B: continued AbAO, Mondy, TSHAO, Terskol optical observations
  38. GRB 200410A: Optical upper limit
  39. GRB 200416A: Swift/UVOT Detection
  40. GRB 200412B: Swift XRT confirmation of afterglow and UVOT upper limits
  41. GRB200412B: GROWTH India detection of afterglow
  42. GRB 200412B: continued Tautenburg observations
  43. GRB 200416A: Swift detection of a burst with an optical afterglow
  44. GRB 200411A: Chandra observations indicative of temporal steepening
  45. IPN triangulation of GRB 200415A (possible Magnetar Giant Flare in Sculptor Galaxy?)
  46. GRB 200412B: Mondy optical observations
  47. GRB 200412B: continued Tautenburg observations
  48. GRB 200412B: Tautenburg observations
  49. GRB 200412B: contunued AbAO optical observations
  50. GRB 200412B: SAO RAS observations of OT
  51. IceCube-200410A: No significant detection in HAWC
  52. GRB 200412B: Tautenburg observations
  53. GRB 200412B: AbAO optical observations
  54. GRB 200412B: Swift-XRT afterglow detection
  55. GRB 200412B: Tiled Swift observations
  56. GRB 200411A: Swift-BAT refined analysis
  57. Fermi-LAT Gamma-ray Observations of IceCube-200410A
  58. GRB 200411A: Swift-XRT refined Analysis
  59. GRB 200411A: Swift/UVOT Upper Limits
  60. GRB 200411A: Enhanced Swift-XRT position
  61. IceCube-200410A: Possible associated excess in INTEGRAL SPI-ACS prompt observation
  62. GRB 200411A: Swift detection of a short burst
  63. IceCube-200410A - IceCube observation of a high-energy neutrino candidate event
  64. GRB 200410A: Swift/UVOT Detection
  65. LIGO/Virgo S200224ca: Swift XRT observations, 8 X-ray sources
  66. GRB 200410A: Swift-XRT refined Analysis
  67. GRB 200410A: Enhanced Swift-XRT position
  68. GRB 200410A: Swift detection of a burst with a possible optical counterpart
  69. GRB 200405B: ATCA follow-up and ASKAP limits on pre-burst radio emission
  70. GRB 200409A: Enhanced Swift-XRT position
  71. GRB 200409A: Swift detection of a burst with an optical counterpart
  72. GRB 200405B: Swift ToO observations
  73. GRB 200405B: Swift/BAT-GUANO detection and *possible* arcminute localization of a short GRB
  74. GRB 200325B: Optical upper limit
  75. GRB 200325B: Tautenburg observations
  76. IPN triangulation of GRB 200327A (short)
  77. GRB 200327A: AGILE/MCAL observations
  78. Fermi trigger No 607035413: Global MASTER-Net observations report
  79. GRB 200325B: Swift-XRT and UVOT observations
  80. GRB 200325B: Mondy and CrAO observations, Master MASTER OT J111012.51+274912.8 confirmation
  81. GRB 200325B: Swift ToO observations
  82. GRB 200325B: MASTERt OT detection
  83. GRB 200324A: AROMA-N Optical Observation
  84. GRB 200325A: Swift/BAT detection and probable arcminute localization of a short GRB from GUANO
  85. GRB 200324A:: TSHAO optical upper limit
  86. GRB 200324A: Swift/UVOT Upper Limits
  87. GRB 200325A: AGILE/MCAL observations
  88. GRB 200324A: Konkoly Obs. optical upper limit
  89. GRB 200324A: NOT optical upper limit
  90. GRB 200324A: Tautenburg observations
  91. GRB 200324A: Enhanced Swift-XRT position
  92. GRB 200324A: Swift detection of a burst
  93. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
  94. Chandra observations of GW170817 at 2.5 years since merger (All epochs 4 of 4)
  95. GW170817: Continued X-ray emission detected with Chandra at 940 days post-merger
  96. LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
  97. LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
  98. LIGO/Virgo S200316bj: No neutrino candidates at Pierre Auger Observatory
  99. LIGO/Virgo S200316bj: No counterpart candidates in Fermi-LAT observations
  100. LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations

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