Skip to main content
New! BOOM Notices and Schema v7.0.0. See news and announcements

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"

5039 results found.

  1. Baksan Neutrino Observatory Alert 201128.90: Global MASTER-Net observations report
  2. GRB 201128A: Swift-XRT refined Analysis
  3. IceCube-201114A: Updated photometry for three DECam candidate optical counterparts
  4. IceCube Alert 201124.34: Global MASTER-Net observations report
  5. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201124A
  6. GRB 201015A radio afterglow with e-MERLIN
  7. Fermi GRB 201120B: Global MASTER-Net observations report
  8. Baksan Neutrino Observatory Alert 201120.43: Global MASTER-Net observations report
  9. ZTF20acozryr/AT2020yxz (GRB 201103B): correction to the GCN #28883 CrAO/ZTSh optical observations
  10. GRB 201116A: OSN Afterglow Candidate
  11. Fermi trigger No 627198169: Global MASTER-Net observations report
  12. IceCube-201114A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  13. ZTF20acozryr/AT2020yxz (GRB 201103B): CrAO/ZTSh optical observations
  14. Fermi GRB 201111A: Global MASTER-Net observations report
  15. Fermi GRB 201104A: Global MASTER-Net observations report
  16. Fermi GRB 201031B: Global MASTER-Net observations report
  17. GRB 201031B: BALROG localization (Fermi Trigger 625859489 / GRB 201031744)
  18. GRB 201031B: Fermi GBM Final Real-time Localization
  19. GRB 201029A: Swift-XRT refined Analysis
  20. Fermi trigger No 625695596: Global MASTER-Net observations report
  21. GRB 201027A: Swift-XRT refined Analysis
  22. GRB 201026A: Swift-XRT refined Analysis
  23. GRB 201020A: 1.3m DFOT, optical upper limits
  24. GRB 201024A: 1.3m DFOT optical observations
  25. GRB 201020B: 1.3m DFOT continued optical follow-up observations
  26. GRB 201024A: MITSuME Akeno optical upper limits
  27. GRB 201024A: Swift-XRT refined Analysis
  28. GRB 201024A: VIRT optical observations
  29. GRB 201020B: Redshift from GTC/OSIRIS
  30. GRB 201024A: Redshift from GTC/OSIRIS
  31. GRB 201024A: BOOTES-2/TELMA early optical observation and 1.5m OSN follow-up
  32. GRB 201024A: MASTER correction to GCN 28760
  33. Swift GRB201024A: Global MASTER-Net OT detection
  34. Swift GRB201024.12: Global MASTER-Net observations report
  35. GRB 201021C: Swift-XRT refined Analysis
  36. GRB 201020A: Swift/UVOT Observations
  37. GRB 201020A: Swift-XRT refined Analysis
  38. GRB 201020A: Swift detection of a burst with an optical counterpart.
  39. GRB 201017A: SAO RAS optical observations
  40. GRB 201015A: 6 GHz VLA radio afterglow candidate detection
  41. GRB 201017A: Swift-XRT refined Analysis
  42. GRB 201015A: MMT afterglow imaging
  43. GRB 201015A: Assy and Mondy optical observations
  44. GRB 201015A: Swift-XRT refined Analysis
  45. GRB 201015A: Enhanced Swift-XRT position
  46. GRB 201015A: GOTO confirmation of afterglow detection
  47. GRB 201015A: NOT optical afterglow confirmation
  48. GRB 201015A: Swift-XRT observations
  49. IceCube Alert 201014.09: Global MASTER-Net observations report
  50. GRB 201013A: Swift-XRT refined Analysis
  51. SGR 1830-0645: pre-discovery detection in Swift/BAT
  52. Fermi trigger No 624121589: Global MASTER-Net observations report
  53. Swift detection of a new SGR 1830-0645 or a short GRB 201010A
  54. Fermi trigger No 623846261: Global MASTER-Net observations report
  55. GRB 201006A: Swift-XRT refined Analysis
  56. Baksan Neutrino Observatory Alert 201006.88: Global MASTER-Net observations report
  57. IceCube-200926A: No significant detection in HAWC
  58. Fermi GRB 200929A: Global MASTER-Net observations report
  59. GRB 200928A: Fermi GBM Final Localization
  60. IceCube Alert 200926.94: Global MASTER-Net observations report
  61. Fermi GRB 200925A: Global MASTER-Net observations report
  62. Fermi GRB 200924A: Global MASTER-Net observations report
  63. GRB 200924B: Fermi GBM Final Localization
  64. Fermi trigger No 622618714: Global MASTER-Net observations report
  65. GRB 200924A: Fermi GBM Final Real-time Localization
  66. Fermi GRB 200923A: Global MASTER-Net observations report
  67. IceCube Alert 200921.80: Global MASTER-Net observations report
  68. Swift GRB 200922A: Global MASTER-Net observations report
  69. GRB 200922A: Swift-XRT refined Analysis
  70. GRB 200922B: Fermi GBM Final Real-time Localization
  71. Fermi GRB 200919C: Global MASTER-Net observations report
  72. GRB 200917A: Swift-XRT refined Analysis
  73. IPN triangulation of GRB 200916B (short)
  74. IceCube Alert 200914.00: Global MASTER-Net observations report
  75. IPN triangulation of GRB 200907A (short)
  76. Fermi GRB 200909A: Global MASTER-Net observations report
  77. GRB 200907B: AstroSat CZTI detection
  78. GRB 200907B: Swift-XRT refined Analysis
  79. Fermi GRB 200907C: Global MASTER-Net observations report
  80. GRB 200907C: Fermi GBM Final Real-time Localization
  81. GRB 200907A: AGILE/MCAL detection of a burst
  82. GRB 200906A: Swift-XRT refined Analysis
  83. Fermi GRB 200903B: Global MASTER-Net observations report
  84. GRB 200901B: Swift-XRT refined Analysis
  85. GRB 200901A: Swift-XRT refined Analysis
  86. GRB 200829A: Continued Nanshan/NEXT optical observations
  87. Fermi GRB 200830A: Global MASTER-Net observations report
  88. Konus-Wind detection of GRB 200829A (a clone of GRB 200826B?)
  89. GRB 200829A: Swift-XRT refined Analysis
  90. Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
  91. Fermi GRB 200826B: Global MASTER-Net observations report
  92. Fermi GRB 200824A: Global MASTER-Net observations report
  93. Fermi GRB 200826A: Global MASTER-Net observations report
  94. GRB 200824A: Fermi GBM Final Real-time Localization
  95. GRB 200819A: Swift-XRT refined Analysis
  96. Fermi trigger No 619270776: Global MASTER-Net observations report
  97. GRB 200809B: Swift-XRT afterglow detection
  98. GRB 200806A: Swift-XRT refined Analysis
  99. GRB 200803A: Swift-XRT afterglow detection
  100. LAT GRB200803.15: Global MASTER-Net observations report

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov