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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"

5401 results found.

  1. GRB 210317A: GECAM detection
  2. Fermi trigger No 637521056: Global MASTER-Net observations report
  3. GRB 210312B: Redshift from OSIRIS/GTC
  4. GRB 210312B: GTC photometry
  5. GRB 210312B: MASTER OT confirmation
  6. Integral GRB210312.87: Global MASTER-Net observations report
  7. Fermi GRB 210312A: Global MASTER-Net observations report
  8. INTEGRAL SPI-ACS on 2021-03-12 (04)11-08:15) are due to calibration activity
  9. GRB 210306A: LBT observations
  10. Konus-Wind detection of GRB 210306A
  11. GRB 171205A: Continued ATCA observations
  12. Fermi trigger No 637027080: Global MASTER-Net observations report
  13. GRB 210306A: continued Mondy optical observations
  14. GRB 210308A: Mondy and AbAO optical observations
  15. Fermi trigger No 636926765: Global MASTER-Net observations report
  16. Swift GRB 210308A: Global MASTER-Net observations report
  17. GRB 210308A: Nanshan/NEXT optical upper limits
  18. GRB 210308A: MITSuME Okayama optical upper limits
  19. GRB 210306A: continued Mondy optical observations
  20. GRB 210306A: Mondy optical observations
  21. GRB 210307B: GECAM detection
  22. Swift GRB210307.36: Global MASTER-Net observations report
  23. GRB 210306A: MITSuME Akeno optical observation
  24. GRB 210306A: NEXT optical observations
  25. Swift GRB 210306A: Global MASTER-Net observations report
  26. GRB 210306A: Fermi GBM observation
  27. GRB 210306A: iTelescope T24 optical observations
  28. GRB 210306A: Fermi-LAT detection
  29. GRB 210306A: iTelescope optical afterglow observations
  30. GRB 210306A: DDOTI Afterglow Confirmation
  31. GRB 210306A: Swift detection of a burst with a bright optical counterpart
  32. Swift GRB 210305A: Global MASTER-Net observations report
  33. GRB 210305A: Swift detection of a burst
  34. Fermi trigger No 636459103: Global MASTER-Net observations report
  35. GRB 210222B: Zeiss-1000 of Koshka observatory, optical observations
  36. Swift GRB210222.94: Global MASTER-Net observations report
  37. GRB 210218A: Swift-XRT observations
  38. GRB 210212A: Lowell Discovery Telescope observations
  39. GRB 210218A: MITSuME Akeno optical upper limits
  40. Swift-XRT observations of IceCube-210210A
  41. GRB 210210A: FRAM-ORM afterglow detection
  42. GRB 210112A: LBT host detection and correction to GCN 29319 (CAHA observations)
  43. GRB 210210A: MASTER afterglow observation
  44. ZTF21aahifke/AT2021clk: ZTF discovery of an optical fast transient (possible afterglow)
  45. Fermi GRB 210202A: Global MASTER-Net observations report
  46. Fermi trigger No 633963272: Global MASTER-Net observations report
  47. Recent activity of SGR 1935+2154 as observed by CGBM
  48. Fermi trigger No 633879387: Global MASTER-Net observations report
  49. Fermi trigger No 633348010: Global MASTER-Net observations report
  50. GECAM detection of a burst possibly from the X-ray burster 4U 0614+09 or GRB 210124A
  51. GRB 210112A: Deep CAHA 2.2m detection
  52. GRB 210112A: Swift/UVOT Detection
  53. GRB 210112A: Swift-BAT refined analysis
  54. GRB 210112A: OSN Reddened Afterglow Detection
  55. GRB 210112A: Kitab a optical upper limit
  56. GRB 210112A: Enhanced Swift-XRT position
  57. GRB 210112A: Swift detection of a burst with an optical counterpart
  58. GRB 210109A: MAXI/GSC detection
  59. GRB 210105A: Fermi GBM Final Real-time Localization
  60. GRB 210102B: Assy optical observations
  61. Fermi GRB 210102C: Global MASTER-Net observations report
  62. Swift GRB 210102C: Global MASTER-Net observations report
  63. GRB 210102B: MAXI/GSC detection
  64. Fermi GRB 210101A: Global MASTER-Net observations report
  65. Fermi trigger No 631119348: Global MASTER-Net observations report
  66. Fermi trigger No 631113166: Global MASTER-Net observations report
  67. Fermi trigger No 631104264: Global MASTER-Net observations report
  68. GRB 201229A: SAO RAS optical observations
  69. IPN triangulation of GRB 201227A (short)
  70. ZTF20acozryr/AT2020yxz (GRB 201103B): Maidanak optical observations
  71. Fermi trigger No 630681391: Global MASTER-Net observations report
  72. Baksan Neutrino Observatory Alert 201225.54: Global MASTER-Net observations report
  73. IceCube-201221A: No significant detection in HAWC
  74. Fermi GRB 201222B: Global MASTER-Net observations report
  75. GRB 201222B: BALROG localization (Fermi Trigger / GRB 201222461)
  76. GRB 201222B: Fermi GBM Final Real-time Localization
  77. GRB 201209A: Mondy optical observations, afterglow confirmation
  78. Fermi GRB 201218A: Global MASTER-Net observations report
  79. Fermi GRB 201216A: Global MASTER-Net observations report
  80. Fermi GRB 201214B: Global MASTER-Net observations report
  81. IceCube-201209: No significant detection in HAWC
  82. GRB 201203A: Zeiss-1000 (Koshka observatory) optical upper limit
  83. IceCube-201209A: No Candidate Counterparts from the Zwicky Transient Facility
  84. GRB 201203A: 1.3m DFOT, optical upper limits
  85. IceCube Alert 201209.43: Global MASTER-Net observations report
  86. GRB 201208A: Fermi GBM observation
  87. GRB 201208A: Fermi-LAT detection
  88. GRB 201208A: AstroSat CZTI detection
  89. GRB 201208A: Fermi GBM Final Real-time Localization
  90. Swift GRB 201203A: Global MASTER-Net observations report
  91. IceCube-201130A: No Candidate Counterparts from the Zwicky Transient Facility
  92. GRB 201203A: DDOTI Observations
  93. GRB 201201A: DDOTI Observations
  94. Fermi trigger No 628278856: Global MASTER-Net observations report
  95. GRB 201121B: Fermi GBM Final Real-time Localization
  96. Fermi GRB 201120B: Global MASTER-Net observations report
  97. Baksan Neutrino Observatory Alert 201120.43: Global MASTER-Net observations report
  98. GRB 201116A: OSN Afterglow Candidate
  99. Fermi trigger No 627198169: Global MASTER-Net observations report
  100. IceCube-201114A: No significant detection in HAWC

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