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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. Fermi Trigger 575108474 / GRB 190324348: BALROG localization
  2. Fermi Trigger 575067924 / GRB 190323879: BALROG localization
  3. Swift detection of LS I +61 303
  4. Fermi Trigger 575018216 / GRB 190323303: BALROG localization
  5. Swift Trigger 894268: Detection of GRO J2058+42 in outburst
  6. Fermi Trigger 574850558 / GRB 190321363: BALROG localization
  7. GRB 190114C: photometric detection of a SN component
  8. GRB 190320A: Swift/UVOT Upper Limits
  9. GRB 190320A: Swift-XRT refined Analysis
  10. GRB 190320A: Swift-BAT refined analysis
  11. GRB190320A: MASTER GRB counterpart decay
  12. GRB 190320A: Enhanced Swift-XRT position
  13. GRB 190320A: Swift-XRT observations
  14. Fermi Trigger 574678842 / GRB 190319375: BALROG localization
  15. Fermi Trigger 574676902 / GRB 190319353: BALROG localization
  16. Fermi Trigger 574345067 / GRB 190315512: BALROG localization
  17. Fermi trigger 574140965 / GRB190313.15: MASTER Global Robotic Net optical observation
  18. GRB 190311A: OSN optical afterglow detection
  19. GRB 190311A: Swift/UVOT Detection
  20. GRB 190311A: Swift-BAT refined analysis
  21. GRB190305A: MASTER Global Robotic Net optical observation
  22. GRB190311A: OAO observations
  23. Fermi Trigger 574080135 / GRB 190312446: BALROG localization
  24. Improved Fermi/GBM GRB localizations
  25. [Hxmt-ba]GRB 190310A: Insight-HXMT/HE detection
  26. GRB 190311A: GMG observation
  27. GRB 190311A: Fermi GBM observation
  28. GRB 190311A: Swift-XRT refined Analysis
  29. GRB 190311A: TSHAO optical observations
  30. GRB 190311A: Enhanced Swift-XRT position
  31. GRB190311A: MASTER Global Robotic Net OT optical observation
  32. GRB 190311A: NEXT-0.6m optical afterglow detection
  33. GRB 190311A: Mondy optical observations
  34. GRB 190311A: Swift detection of a burst with optical counterpart
  35. GRB 190305A: Swift-XRT afterglow detection
  36. Konus-Wind observation of GRB 190304A
  37. IPN Triangulation of GRB 190304A (long)
  38. GRB 190306A: Swift-XRT observations
  39. GRB 190306B: Insight-HXMT/HE detection
  40. GRB 190306A: MAXI/GSC detection
  41. IPN Triangulation of GRB 190305A
  42. GRB 190305A: Swift-XRT observations
  43. GRB 190305A: Insight-HXMT/HE detection
  44. GRB 190305A: MAXI/GSC detection
  45. GRB 190226A: Insight-HXMT/HE detection
  46. Trigger 890732: Swift detection of MAXI J1631-479
  47. INTEGRAL observation of IceCube-190221A
  48. IceCube-190221A: Swift-XRT Follow-up Observations
  49. IceCube-190221A: Fermi-LAT Gamma-ray observations
  50. GRB 190220B: Fermi GBM observation
  51. GRB 190219A: CrAO and AbAO optical upper limit
  52. GRB 190220B: Kitab Observatory optical upper limit
  53. GRB 190220A: Swift-XRT refined Analysis
  54. GRB 190220B: a long GRB detected by IBAS
  55. GRB 190220A: Swift-BAT refined analysis
  56. GRB 190219A: Swift-BAT refined analysis
  57. GRB 190220A: Enhanced Swift-XRT position
  58. GRB 190219A: NOT optical afterglow candidate
  59. GRB 190219A: NEXT-0.6m optical upper limit
  60. GRB 190219A: Swift-XRT refined Analysis
  61. GRB 190220A: Swift detection of a burst with an optical counterpart
  62. GRB 190219A: Enhanced Swift-XRT position
  63. GRB 190219A: BOOTES-1 optical limits
  64. GRB 190219A: Swift detection of a burst
  65. Trigger 889483: Swift detection of Swift J1858.6-0814
  66. GRB 190215A: Insight-HXMT/HE detection
  67. GRB 190215A: Fermi GBM detection
  68. GRB 190212A: Insight-HXMT/HE detection
  69. GRB190211A: GROWTH-India detection of optical afterglow
  70. GRB 190211A: Tautenburg observations
  71. GRB 190211A: Swift/UVOT Detection
  72. GRB 190211A: NOT optical observations
  73. GRB 180703A: VLT/MUSE host galaxy redshift measurement
  74. GRB 190211A: Swift-XRT refined Analysis
  75. GRB 190211A: Swift-BAT refined analysis
  76. GRB 190211A: NEXT-0.6m optical afterglow detection
  77. GRB 190211A: Swift detection of a burst
  78. Trigger 888312: Swift detection of 4U 1901+03
  79. GRB 190202A: Terskol 2-m optical observations
  80. IPN Triangulation of GRB 190206A (short/extremely bright)
  81. GRB 190203A: Mondy optical observations
  82. GRB190202A: GROWTH-India detection of optical afterglow
  83. GRB 190203A: Swift-BAT refined analysis
  84. GRB 190204A: Swift-BAT refined analysis
  85. GRB 190202A: Xinglong-2.16m optical observations
  86. GRB 190202A: SAO RAS further optical observations
  87. Konus-Wind observation of GRB 190204A
  88. GRB 190204A: SAO RAS optical observations
  89. GRB 190204A: Mondy optical upper limit
  90. GRB190203A: UVOT analysis
  91. GRB 190203A: COATLI Optical Observations
  92. GRB 190204A: Swift/UVOT Detection
  93. GRB 190204A: Enhanced Swift-XRT position
  94. GRB 190204A: COATLI Optical Detection of the Fading Afterglow
  95. GRB 190203A: Liverpool Telescope near-IR observations
  96. GRB 190203A: Swift-XRT refined Analysis
  97. GRB 190204A: Swift-XRT refined Analysis
  98. Swift Trigger 887541: MASTER inspect
  99. GRB 190204A: MAXI/GSC detection
  100. GRB 190202A: R and I band observation from HCT

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