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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"

3115 results found.

  1. GRB 210411B: AstroSat CZTI detection
  2. Fermi GRB 210411B: Global MASTER-Net observations report
  3. GRB 210406A: 10.4m GTC follow-up observation
  4. GRB 210411B: Fermi GBM Final Real-time Localization
  5. Fermi GRB 210411A: Global MASTER-Net observations report
  6. GRB 210406B: Fermi GBM detection
  7. GRB 210324C: AstroSat CZTI detection
  8. GRB 210320A: MAXI/GSC detection
  9. GRB 210318A: Swift detection of a burst
  10. Fermi trigger No 637521056: Global MASTER-Net observations report
  11. Fermi GRB 210312A: Global MASTER-Net observations report
  12. GRB 210306A: continued Mondy optical observations
  13. Fermi trigger No 636926765: Global MASTER-Net observations report
  14. GRB 210306A: iTelescope T24 optical observations
  15. Trigger 1035744: Swift detection of Sco X-1 due to Star Tracker loss of lock
  16. Fermi trigger No 636459103: Global MASTER-Net observations report
  17. GRB 210217A: 3.6m DOT optical observations
  18. Integral GRB210227.20: Global MASTER-Net observations report
  19. GRB 210226A: Swift-BAT refined analysis
  20. GRB 210217A: Swift detection of a burst with an optical counterpart
  21. IceCube Alert 210213.78: Global MASTER-Net observations report
  22. GRB 210213A: Fermi GBM Final Real-time Localization
  23. GRB 210204A (ZTF21aagwbjr/AT2021buv): continued CrAO and AbAO optical observations
  24. GRB 210211A: Swift/UVOT Detection
  25. Fermi GRB 210210B: Global MASTER-Net observations report
  26. IceCube-210210A: Two Candidate Counterparts from the Zwicky Transient Facility
  27. GRB 210207B: AbAO optical upper limit
  28. GRB 210204A (ZTF21aagwbjr/AT2021buv): Mondy and AbAO optical observations
  29. GRB 210205A: Swift detection of a burst
  30. GRB 210204B: Fermi GBM Final Real-time Localization
  31. GRB 210127A: Fermi GBM Final Real-time Localization
  32. GECAM detection of a burst possibly from the X-ray burster 4U 0614+09 or GRB 210124A
  33. Correction to GCN 29288: NuEm-210111A: No counterpart candidates in INTEGRAL SPI-ACS observation
  34. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-210111A
  35. GRB 210110A: MAXI/GSC detection
  36. Fermi trigger No 631602681: Global MASTER-Net observations report
  37. GRB 210105A: Fermi GBM Final Real-time Localization
  38. Fermi GRB 210102C: Global MASTER-Net observations report
  39. MAXI GRB210102.38: Global MASTER-Net observations report
  40. GRB 201216C: TSHAO, Terskol, Mondy optical upper limits
  41. Fermi GRB 201229B: Global MASTER-Net observations report
  42. Baksan Neutrino Observatory Alert 201228.36: Global MASTER-Net observations report
  43. Fermi GRB 201228B: Global MASTER-Net observations report
  44. Fermi trigger No 630681391: Global MASTER-Net observations report
  45. IceCube-201222A: No Candidate Counterparts from the Zwicky Transient Facility
  46. Baksan Neutrino Observatory Alert 201223.60: Global MASTER-Net observations report
  47. GRB 201221D: LCOGT upper limits
  48. GRB 201221E: Fermi GBM Final Real-time Localization
  49. correction to GCN 29110 - Fermi GBM Sub-Threshold Detection of GRB 201221A
  50. Fermi GBM Sub-Threshold Detection of GRB 201221A
  51. Konus-Wind detection of GRB 201216C
  52. Baksan Neutrino Observatory Alert 201216.94: Global MASTER-Net observations report
  53. GRB 201216C: VLT afterglow candidate discovery
  54. GRB 201015A: optical observations and supernova identification
  55. IceCube-201209A: No Candidate Counterparts from the Zwicky Transient Facility
  56. GRB 201209A: Swift detection of a burst
  57. Fermi GRB 201208A: Global MASTER-Net observations report
  58. IceCube-201130A: No Candidate Counterparts from the Zwicky Transient Facility
  59. IceCube-201130A: No significant detection in HAWC
  60. GRB201130A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 628407054)
  61. Fermi trigger No 628140709: Global MASTER-Net observations report
  62. Fermi GRB 201121A: Global MASTER-Net observations report
  63. Fermi GRB 201120B: Global MASTER-Net observations report
  64. Fermi trigger No 627198169: Global MASTER-Net observations report
  65. GRB 201116A: Fermi-LAT detection
  66. IceCube Alert 201115.09: Global MASTER-Net observations report
  67. GRB 201116A: BALROG localization (Fermi Trigger 627180592 / GRB 201116035)
  68. GRB 201116A: Fermi GBM Final Real-time Localization
  69. IceCube-201114A: No neutrino counterpart candidates in ANTARES search
  70. Fermi-LAT Gamma-ray Observations of NuEm-201107A
  71. Konus-Wind observation of GRB 201103B
  72. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201107A
  73. Fermi trigger No 626247072: Global MASTER-Net observations report
  74. GRB 201103B (ZTF20acozryr/AT2020yxz): Nanshan/NEXT-0.6m optical observations
  75. IPN triangulation of GRB 201103B (consistent with ZTF20acozryr/AT2020yxz)
  76. GRB 201105B: Fermi GBM observation
  77. ZTF20acozryr/AT2020yxz: Zwicky Transient Facility discovery of a fast optical transient with no associated GRB
  78. GRB 201026A: Swift detection of a burst
  79. GRB 201020B: follow-up observations with Savelli Telescope
  80. GRB 201024A: Redshift from GTC/OSIRIS
  81. IceCube-201021A: No significant detection in HAWC
  82. IceCube-201021A: One candidate counterpart from the Zwicky Transient Facility
  83. Konus-Wind detection of GRB 201020A
  84. IceCube-201021A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  85. GRB 201020A: DOAO optical afterglow observations
  86. GRB 201020A: Fermi GBM observation
  87. GRB 201020A: Swift detection of a burst with an optical counterpart.
  88. GRB 201008A: Swift-XRT afterglow detection
  89. GRB 201016A: Fermi GBM detection
  90. GRB 201013A: TSHAO and AbAO optical observations, afterglow confirmation
  91. GRB 201013A: FRAM-ORM possible afterglow candidate
  92. IceCube-201007A: No candidate counterparts from the Zwicky Transient Facility
  93. GRB 201013A: Swift detection of a burst
  94. GRB 201008A: Swift-XRT observations
  95. Fermi trigger No 623470566: Global MASTER-Net observations report
  96. Fermi trigger No 623493962: Global MASTER-Net observations report
  97. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  98. IceCube-200929A: No significant detection in HAWC
  99. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  100. IceCube-200926B: No significant detection in HAWC

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