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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"

26330 results found.

  1. GRB 200529A: NOT optical afterglow
  2. GRB 200529A: Swift detection of a burst
  3. GRB 200528A: NOT optical upper limits
  4. GRB 200528A: Fermi GBM Observation
  5. GRB 200528A: Swift/UVOT Upper Limits
  6. GRB 200528A: Swift-BAT refined analysis
  7. GRB 200528A: Nanshan/NEXT optical upper limit
  8. GRB 200528A: Enhanced Swift-XRT position
  9. GRB 200528A: MITSuME Akeno optical upper limits
  10. GRB 200528A: Swift detection of a burst
  11. GRB 200524A: Assy optical observations
  12. IceCube-200523A: Upper limits from a search for additional neutrino events in IceCube
  13. GRB 200522A: Hubble Space Telescope Near-IR F160W Observations
  14. GRB 200524A: optical upper limits from further MITSuME Akeno observation
  15. GRB 200522A: Gemini North optical imaging
  16. GRB 200524A: AstroSat CZTI detection
  17. GRB 200524A: Further Liverpool Telescope observations
  18. Fermi-LAT Gamma-ray Observations of IceCube-190523A
  19. GRB200521A: ASIM observation
  20. GRB 200524A: KAIT Optical Observations
  21. GRB 200524A: MITSuME Akeno optical observation
  22. GRB 200524A: Swift-XRT afterglow detection
  23. GRB 200524A: OAJ multicolor afterglow detection
  24. GRB 200524A: Fermi GBM detection
  25. GRB 200524: Swift/UVOT observations missed the ZTF20abbiixp position
  26. GRB 200524A: CAHA multicolor afterglow detection
  27. GRB 200524A: Correction to the GCN 27800
  28. GRB 200524A: 3.6m DOT observations of the afterglow candidate ZTF20abbiixp
  29. GRB 200524A: GROWTH-India confirmation of optical afterglow
  30. GRB 200522A: Swift-BAT refined analysis
  31. GRB 200522A: LCO Optical Afterglow Detection
  32. GRB 200522A: 6 GHz VLA radio source detection
  33. GRB 200522A: Swift-XRT refined Analysis
  34. GRB 200522A: Swift/UVOT Upper Limits
  35. GRB 200522A: Enhanced Swift-XRT position
  36. GRB 200522A: Swift detection of a short burst
  37. GRB 200519A: Swift-BAT refined analysis
  38. GRB 200519A: Insight-HXMT/HE detection
  39. GRB 200519A: Swift/UVOT Detection
  40. GRB 200519A: GROWTH-India optical follow-up
  41. GRB 200519A: AstroSat CZTI detection
  42. GRB 200519A: Swift-XRT refined Analysis
  43. GRB 200519A: Enhanced Swift-XRT position
  44. GRB 200519A: LCO Optical Afterglow Detection
  45. Fermi GBM Sub-Threshold Detection of GRB 200517A
  46. GRB 200519A: iTelescope optical afterglow detection
  47. GRB 200519A: Swift detection of a burst with an optical afterglow
  48. GRB 200517A: Swift-XRT afterglow detection
  49. GRB 200517A: MAXI/GSC detection
  50. GRB 200514B: BALROG localization (Fermi Trigger 611140062 / GRB 200514380)
  51. Swift GRB200516.63: Global MASTER-Net observations report
  52. Swift Detection of a burst from SGR Swift J1818.0-1607
  53. GRB 200514B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 611140062) - More Candidates
  54. GRB 200514A: MITSuME Akeno optical upper limits
  55. GRB 200512A: Swift-BAT refined analysis
  56. GRB 200514B: GROWTH-India follow-up of ZTF20aazpphd (AT2020jww)
  57. GRB 200514A: MAXI/GSC detection
  58. Baksan Neutrino Observatory Alert 200512.: Global MASTER-Net observations report
  59. GRB 200512A: LCO Optical Upper Limits
  60. IceCube-200512A: Upper limits from a search for additional neutrino events in IceCube
  61. Fermi GBM Sub-Threshold Detection of GRB 200512A
  62. GRB 200512A: Swift/UVOT Upper Limits
  63. GRB 200512A: Swift-XRT refined Analysis
  64. GRB 200512A: Enhanced Swift-XRT position
  65. GRB 200512A: Swift detection of a burst
  66. Fermi-LAT Gamma-ray Observations of IceCube-200512A
  67. IceCube-200512A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  68. Insight-HXMT's continued observation plan for SGR J1935+2154
  69. Konus-Wind observation of SGR 1935+2154 activity on 2020 May 10
  70. IPN triangulation of a bright burst from SGR 1935+2154 on 2020-05-10 at 06:12 UT
  71. GRB 200509A: Swift-BAT refined analysis
  72. GRB 200510A: BALROG localization (Fermi Trigger 610800081 / GRB 200510445)
  73. GRB 200509A: GROWTH-India r band upper limits
  74. GRB 200509A: Swift/UVOT Detection
  75. GRB 200509A: LCO Optical Afterglow Detection
  76. GRB 200509A: Swift-XRT refined Analysis
  77. GRB 200509A: Enhanced Swift-XRT position
  78. GRB 200509A: Zadko observatory - Gingin optical upper limits
  79. GRB 200509A: Swift detection of a burst with a possible optical counterpart
  80. FRB/X-ray bursts from SGR 1935+2154: No Neutrino Counterpart in ANTARES data
  81. Swift Detection of a burst from SGR Swift J1818.0-1607
  82. Swift GRB200506.73: Global MASTER-Net observations report
  83. Insight-HXMT detection of a short bright burst from SGR 1935+2154
  84. GRB 200502A: AstroSat CZTI detection
  85. GRB 200503B: BALROG localization (Fermi Trigger 610219118 / GRB 200503721)
  86. Insight-HXMT X-ray and hard X-ray upper limits to the radio burst detected by FAST from SGR 1935+2154
  87. No optical bursts detected from SGR J1935+2154 by 24 fps observations with Tomo-e Gozen
  88. GRB 200424A: Swift-XRT afterglow detection
  89. Insight-HXMT X-ray and hard X-ray detection of the double peaks of the Fast Radio Burst from SGR 1935+2154
  90. Fermi GBM observation of a flare from the magnetar SGR 1806-20
  91. GRB 200501A: Fermi GBM Final Real-time Localization
  92. SGR 1935+2154: INTEGRAL hard X-ray counterpart of radio burst
  93. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  94. A Forest of Bursts from SGR 1935+2154
  95. SGR 1935+2154 the Insight-HXMT observation plan
  96. IceCube-200425A: No significant detection in HAWC
  97. IceCube-200425A: Upper limits from a search for additional neutrino events in IceCube
  98. Fermi-LAT Gamma-ray Observations of IceCube-200425A
  99. IceCube-200425A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  100. GRB 200425A: Swift-BAT refined analysis

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