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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"

5038 results found.

  1. IceCube-221224A: Upper limits from a search for additional neutrino events in IceCube
  2. IceCube-221223A: Upper limits from a search for additional neutrino events in IceCube
  3. GRB 221226B: Swift-XRT refined Analysis
  4. Fermi-LAT gamma-ray observations of IceCube-221224A
  5. IceCube-221224A: BOOTES-4/MET Optical Upper Limit
  6. Fermi GRB 221223A: Global MASTER-Net observations report
  7. IceCube Alert 221224.04: Global MASTER-Net observations report
  8. IceCube-221224A - IceCube observation of a high-energy neutrino candidate track-like event
  9. GRB 221218A: MITSuME Akeno optical upper limits
  10. GRB 221216A: Swift-XRT refined Analysis
  11. GRB 221216A: Swift detection of a burst
  12. IPN triangulation of GRB 221209A (long)
  13. Fermi trigger No 692713692: Global MASTER-Net observations report
  14. Swift Trigger 1144538 is not a GRB
  15. Fermi trigger No 692607435: Global MASTER-Net observations report
  16. Fermi GRB 221211A: Global MASTER-Net observations report
  17. GRB 221209A: BALROG localization (Fermi Trigger 692257829 / GRB 221209243)
  18. GRB 221209A: Fermi GBM Final Real-time Localization
  19. GRB 221206C: Fermi GBM Final Real-time Localization
  20. GRB 221201A: Fermi GBM observation
  21. GRB 221202A: Swift-XRT refined Analysis
  22. GRB 221201A: Swift-XRT refined Analysis
  23. GRB 221201A: Fermi GBM Final Real-time Localization
  24. IceCube-221124A: Upper limits from a search for additional neutrino events in IceCube
  25. IceCube-221124A: BOOTES-4/MET and BOOTES-2/TELMA optical upper limit
  26. IPN triangulation of GRB 221124A (long)
  27. GRB 221124A: Swift/BAT-GUANO detection
  28. Fermi-LAT gamma-ray observations of IceCube-221124A
  29. GRB 221124A: CALET Gamma-Ray Burst Monitor detection
  30. IceCube-221124A - IceCube observation of a high-energy neutrino candidate track-like event
  31. IceCube Alert 221124.66: Global MASTER-Net observations report
  32. GRB 221120A: Swift-XRT refined Analysis
  33. GRB 221110A: Swift-XRT refined Analysis
  34. GRB 221107A: Fermi GBM Final Localization
  35. GRB 221028A: Swift-XRT refined Analysis
  36. GRB 221028A: MITSuME Okayama optical upper limits
  37. GRB 221028B: MAXI/GSC detection
  38. GRB 221028A: BOOTES-4/MET optical upper limit
  39. GRB 221027B: Swift-XRT refined Analysis
  40. Konus-Wind detection of GRB 221022B
  41. IPN triangulation of GRB 221022B (long)
  42. LAT GRB221025.04: Global MASTER-Net observations report
  43. GRB 221022B: Fermi GBM Final Real-time Localization
  44. Improved IPN localization for GRB 221009A (BepiColombo-MGNS light curve)
  45. AGILE detection of short X-ray flaring activity contemporary to SGR J1935+2154 reported bursts
  46. IPN triangulation of GRB 221017A (long)
  47. GRB 221016A: Swift-XRT refined Analysis
  48. GRB 221017A: MAXI/GSC detection
  49. GRB 221016A: Swift detection of a burst
  50. Konus-Wind observation of the recent SGR 1935+2154 activity
  51. Fermi Gamma-ray Burst Monitor detections of SGR 1935+2154
  52. GRB221009A: RTT-150 optical observations
  53. Fermi trigger No 687345829: Global MASTER-Net observations report
  54. Fermi trigger No 687344475: Global MASTER-Net observations report
  55. Fermi trigger No 687340841: Global MASTER-Net observations report
  56. Fermi trigger No 687337536: Global MASTER-Net observations report
  57. GRB 221009A: MITSuME Okayama optical observation
  58. Fermi trigger No 687281393: Global MASTER-Net observations report
  59. GRB221009A: optical afterglow measurements from Konkoly Observatory
  60. Fermi trigger No 687205006: Global MASTER-Net observations report
  61. GRB 221009A: Sintez-Newton/CrAO optical observations
  62. Swift/XRT discovery of multiple dust-scattering X-ray rings around GRB 221009A
  63. GRB 221009A/Swift J1913.1+1946: Assy optical afterglow observation
  64. ​GRB 221009A: Multi-color detection of the optical
  65. GRB 221006A: MAXI/GSC detection
  66. GRB 220930A: MITSuME Akeno optical upper limits
  67. GRB 220921A: ATCA detection of radio counterpart
  68. Fermi trigger No 686403226: Global MASTER-Net observations report
  69. Fermi trigger No 686350260: Global MASTER-Net observations report
  70. GRB 220930A: Swift-XRT refined Analysis
  71. GRB 220930A: LCOGT Optical Upper Limits
  72. Swift GRB 220930A: Global MASTER-Net observations report
  73. IceCube-220928A: Upper limits from a search for additional neutrino events in IceCube
  74. GRB 220611A: Host galaxy redshift from VLT/X-shooter
  75. GRB 220924A: Fermi GBM detection
  76. Fermi GRB 220925A: Global MASTER-Net observations report
  77. GRB 220921A: further MeerLICHT observations
  78. Fermi trigger No 685748699: Global MASTER-Net observations report
  79. GRB 220924A: Fermi GBM Final Real-time Localization
  80. Swift GRB220923.47: Global MASTER-Net observations report
  81. GRB 220921A: ALMA detection
  82. GRB 220921A: DDOTI Detection of the Afterglow
  83. GRB 220921A: Swift-XRT Observations
  84. GRB 220921A: MASTER OT inside Fermi-LAT error-box
  85. Fermi trigger No 685452089: Global MASTER-Net observations report
  86. Fermi trigger No 684716840: Global MASTER-Net observations report
  87. Fermi GRB 220912A: Global MASTER-Net observations report
  88. GRB 220912A: AstroSat CZTI detection
  89. GRB 220909A: Swift-XRT observations
  90. Fermi GRB 220902A: Global MASTER-Net observations report
  91. GRB 220831A, VLT/HAWK-I near-infrared observations
  92. Fermi trigger No 683202084: Global MASTER-Net observations report
  93. Fermi trigger No 683183601: Global MASTER-Net observations report
  94. Fermi trigger No 683152759: Global MASTER-Net observations report
  95. GRB 220826A: Swift-XRT refined Analysis
  96. Fermi trigger No 682918137: Global MASTER-Net observations report
  97. GRB 220813A: Swift-XRT refined Analysis
  98. GRB 220813A: Swift detection of a burst with an optical counterpart
  99. Fermi trigger No 681998863: Global MASTER-Net observations report
  100. GRB 220806A: Swift detection of a burst

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