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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"

2900 results found.

  1. GRB 210306A: continued Mondy optical observations
  2. Fermi trigger No 636926765: Global MASTER-Net observations report
  3. GRB 210306A: iTelescope T24 optical observations
  4. Trigger 1035744: Swift detection of Sco X-1 due to Star Tracker loss of lock
  5. Fermi trigger No 636459103: Global MASTER-Net observations report
  6. GRB 210217A: 3.6m DOT optical observations
  7. Integral GRB210227.20: Global MASTER-Net observations report
  8. GRB 210226A: Swift-BAT refined analysis
  9. GRB 210217A: Swift detection of a burst with an optical counterpart
  10. IceCube Alert 210213.78: Global MASTER-Net observations report
  11. GRB 210213A: Fermi GBM Final Real-time Localization
  12. GRB 210204A (ZTF21aagwbjr/AT2021buv): continued CrAO and AbAO optical observations
  13. GRB 210211A: Swift/UVOT Detection
  14. Fermi GRB 210210B: Global MASTER-Net observations report
  15. IceCube-210210A: Two Candidate Counterparts from the Zwicky Transient Facility
  16. GRB 210207B: AbAO optical upper limit
  17. GRB 210204A (ZTF21aagwbjr/AT2021buv): Mondy and AbAO optical observations
  18. GRB 210205A: Swift detection of a burst
  19. GRB 210204B: Fermi GBM Final Real-time Localization
  20. GRB 210127A: Fermi GBM Final Real-time Localization
  21. GECAM detection of a burst possibly from the X-ray burster 4U 0614+09 or GRB 210124A
  22. Correction to GCN 29288: NuEm-210111A: No counterpart candidates in INTEGRAL SPI-ACS observation
  23. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-210111A
  24. GRB 210110A: MAXI/GSC detection
  25. Fermi trigger No 631602681: Global MASTER-Net observations report
  26. GRB 210105A: Fermi GBM Final Real-time Localization
  27. Fermi GRB 210102C: Global MASTER-Net observations report
  28. MAXI GRB210102.38: Global MASTER-Net observations report
  29. GRB 201216C: TSHAO, Terskol, Mondy optical upper limits
  30. Fermi GRB 201229B: Global MASTER-Net observations report
  31. Baksan Neutrino Observatory Alert 201228.36: Global MASTER-Net observations report
  32. Fermi GRB 201228B: Global MASTER-Net observations report
  33. Fermi trigger No 630681391: Global MASTER-Net observations report
  34. IceCube-201222A: No Candidate Counterparts from the Zwicky Transient Facility
  35. Baksan Neutrino Observatory Alert 201223.60: Global MASTER-Net observations report
  36. GRB 201221D: LCOGT upper limits
  37. GRB 201221E: Fermi GBM Final Real-time Localization
  38. correction to GCN 29110 - Fermi GBM Sub-Threshold Detection of GRB 201221A
  39. Fermi GBM Sub-Threshold Detection of GRB 201221A
  40. Konus-Wind detection of GRB 201216C
  41. Baksan Neutrino Observatory Alert 201216.94: Global MASTER-Net observations report
  42. GRB 201216C: VLT afterglow candidate discovery
  43. GRB 201015A: optical observations and supernova identification
  44. IceCube-201209A: No Candidate Counterparts from the Zwicky Transient Facility
  45. GRB 201209A: Swift detection of a burst
  46. Fermi GRB 201208A: Global MASTER-Net observations report
  47. IceCube-201130A: No Candidate Counterparts from the Zwicky Transient Facility
  48. IceCube-201130A: No significant detection in HAWC
  49. GRB201130A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 628407054)
  50. Fermi trigger No 628140709: Global MASTER-Net observations report
  51. Fermi GRB 201121A: Global MASTER-Net observations report
  52. Fermi GRB 201120B: Global MASTER-Net observations report
  53. Fermi trigger No 627198169: Global MASTER-Net observations report
  54. GRB 201116A: Fermi-LAT detection
  55. IceCube Alert 201115.09: Global MASTER-Net observations report
  56. GRB 201116A: BALROG localization (Fermi Trigger 627180592 / GRB 201116035)
  57. GRB 201116A: Fermi GBM Final Real-time Localization
  58. IceCube-201114A: No neutrino counterpart candidates in ANTARES search
  59. Fermi-LAT Gamma-ray Observations of NuEm-201107A
  60. Konus-Wind observation of GRB 201103B
  61. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201107A
  62. Fermi trigger No 626247072: Global MASTER-Net observations report
  63. GRB 201103B (ZTF20acozryr/AT2020yxz): Nanshan/NEXT-0.6m optical observations
  64. IPN triangulation of GRB 201103B (consistent with ZTF20acozryr/AT2020yxz)
  65. GRB 201105B: Fermi GBM observation
  66. ZTF20acozryr/AT2020yxz: Zwicky Transient Facility discovery of a fast optical transient with no associated GRB
  67. GRB 201026A: Swift detection of a burst
  68. GRB 201020B: follow-up observations with Savelli Telescope
  69. GRB 201024A: Redshift from GTC/OSIRIS
  70. IceCube-201021A: No significant detection in HAWC
  71. IceCube-201021A: One candidate counterpart from the Zwicky Transient Facility
  72. Konus-Wind detection of GRB 201020A
  73. IceCube-201021A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  74. GRB 201020A: DOAO optical afterglow observations
  75. GRB 201020A: Fermi GBM observation
  76. GRB 201020A: Swift detection of a burst with an optical counterpart.
  77. GRB 201008A: Swift-XRT afterglow detection
  78. GRB 201016A: Fermi GBM detection
  79. GRB 201013A: TSHAO and AbAO optical observations, afterglow confirmation
  80. GRB 201013A: FRAM-ORM possible afterglow candidate
  81. IceCube-201007A: No candidate counterparts from the Zwicky Transient Facility
  82. GRB 201013A: Swift detection of a burst
  83. GRB 201008A: Swift-XRT observations
  84. Fermi trigger No 623470566: Global MASTER-Net observations report
  85. Fermi trigger No 623493962: Global MASTER-Net observations report
  86. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  87. IceCube-200929A: No significant detection in HAWC
  88. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  89. IceCube-200926B: No significant detection in HAWC
  90. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  91. IceCube Alert 200926.33: Global MASTER-Net observations report
  92. Fermi GRB 200925A: Global MASTER-Net observations report
  93. Fermi GRB 200924A: Global MASTER-Net observations report
  94. Fermi GRB 200923A: Global MASTER-Net observations report
  95. IceCube Alert 200921.80: Global MASTER-Net observations report
  96. GRB 200922A: Swift/UVOT Detection
  97. IceCube-200921A: no significant detection in HAWC observations
  98. Fermi GRB 200922B: Global MASTER-Net observations report
  99. GRB 200922A: LCO observations
  100. GRB 200920A: Fermi GBM Final Real-time Localization

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