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"
  1. Konus-Wind detection of GRB 230818A
  2. Swift Trigger 1186386 is not a GRB
  3. Swift triggers 1186294-1186304 are not astrophysical transients
  4. GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
  5. Swift GRB230820.81: Global MASTER-Net observations report
  6. Swift GRB230820.80: Global MASTER-Net observations report
  7. GRB 230820A: AstroSat CZTI detection
  8. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
  9. Swift GRB230820.82: Global MASTER-Net observations report
  10. Swift Triggers 1186280 and 1186291 are not GRBs
  11. GRB 230818A: Fermi GBM Observation
  12. GRB 230812B: GIT Confirmation of SN rise
  13. LIGO/Virgo/KAGRA S230819ax: Updated Sky localization
  14. GRB 230818A: Nickel and KAIT telescope optical observations
  15. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  16. GRB 230812B: SAO RAS Zeiss-1000 observations
  17. GRB 230818A: further SAO RAS Zeiss-1000 observations
  18. LIGO/Virgo/KAGRA S230819ax: Identification of a GW compact binary merger candidate
  19. GRB 230818A: AKO Upper Limit
  20. GRB 230818A: AstroSat CZTI detection
  21. GRB 230818A: Tautenburg observations
  22. GRB 230818A: Leavitt Observatory upper limit
  23. GRB 230818A: Swift-XRT refined Analysis
  24. GRB 230818A: Bassano Bresciano Observatory optical observations
  25. GRB 230818A: KGO RC-25 optical observations
  26. GRB 230818A: Swift/UVOT Detection
  27. GRB 230818A: NOT photometry and spectroscopy
  28. GRB 230818A: Enhanced Swift-XRT position
  29. GRB 230818A: SAO RAS Zeiss-1000 observations
  30. Fermi GRB 230818A: Global MASTER-Net observations report
  31. Fermi trigger No 713974668: Global MASTER-Net observations report
  32. GRB 230818A: GOTO optical afterglow detection
  33. GRB 230818A: Swift detection of a burst
  34. GRB 230818A: Fermi GBM Final Real-time Localization
  35. Swift GRB230818.98: Global MASTER-Net observations report
  36. Swift GRB230818.98: Global MASTER-Net OT detection
  37. GRB 230812B: SAO RAS observations, possible re-brightening
  38. GRB 230816A: Swift-BAT refined analysis
  39. GRB 230816A: SVOM/C-GFT optical detection
  40. GRB 230817A: AstroSat CZTI detection
  41. GRB 230812B: SAO RAS optical observations
  42. GRB 230816A: Swift-XRT refined Analysis
  43. GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
  44. GRB 230812B: NOEMA detection
  45. GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
  46. Fermi GRB 230817A: Global MASTER-Net observations report
  47. GRB 230817A: BALROG localization (Fermi Trigger 713966581 / GRB 230817502)
  48. GRB 230817A: Fermi GBM Final Real-time Localization
  49. GRB 230812B: optical photometry from Konkoly
  50. GRB 230816A: Enhanced Swift-XRT position
  51. GRB 230812B: SAO RAS optical observations
  52. GRB230816A: Possible host and GIT detection of optical counterpart
  53. GRB 230816A: Tautenburg observations
  54. GRB 230816A: AKO Optical Observations
  55. GRB 230816A: TShAO and Assy optical observations
  56. GRB 230816A: SAO RAS optical observations
  57. Swift GRB230816.80: Global MASTER-Net observations report
  58. IPN triangulation of GRB 230815B
  59. GRB 230816A: Nanshan/HMT optical afterglow detection
  60. GRB 230815A: SOAR/Goodman follow-up imaging
  61. Swift GRB230816.67: Global MASTER-Net observations report
  62. GRB 230816A: Swift detection of a burst
  63. GRB 230815A: Swift-BAT refined analysis
  64. GRB 230815B: GECAM-B and GECAM-C detection of a burst
  65. GRB 230815B: AstroSat CZTI detection
  66. GRB230815A: Swift/UVOT upper limits
  67. GRB 230812B: GAD Observatory optical observations (upper limit)
  68. GRB 230815A: Swift-XRT refined Analysis
  69. GRB 230812B: iTelescope optical upper limit
  70. GRB 230812B: continued SAO RAS optical observation
  71. GRB230815A: BOOTES-6/DPRT optical upper limit
  72. GRB 230815A: Fermi GBM detection
  73. Swift GRB 230815A: Global MASTER-Net observations report
  74. Fermi GRB 230814A: Global MASTER-Net observations report
  75. GRB 230815A: Enhanced Swift-XRT position
  76. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  77. GRB 230812B: Tautenburg observations
  78. GRB 230815A: Swift detection of a burst
  79. GRB 230812B: AMI-LA radio detection of afterglow candidate
  80. GRB 230812B: continued AbAO optical afterglow observations
  81. GRB 230812B: Optical observaions from Rozhen Observatory
  82. GRB 230812B: Further Bassano Bresciano Observatory optical observations
  83. LIGO/Virgo/KAGRA S230814ah: Identification of a GW compact binary merger candidate
  84. GRB 230812B: further SAO RAS optical observations
  85. GRB 230812B: Upper limits from a neutrino search with IceCube
  86. LIGO/Virgo/KAGRA S230814r: Updated Sky localization
  87. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  88. GRB 230814A: BALROG localization (Fermi Trigger 713732101 / GRB 230814788)
  89. GRB 230812B: CrAO ZTSh optical observations
  90. GRB 230814A: Fermi GBM Final Real-time Localization
  91. GRB 230812B: Koshka Zeiss-1000 optical observations
  92. GRB 230812B: GIT optical follow-up
  93. GRB 230812B: Leavitt Observatory optical observations
  94. GRB 230812B : optical observations from Observatoire de Haute-Provence
  95. GRB 230812B: Bassano Bresciano Observatory optical observations
  96. GRB 230812B: Faulkes Telescope North optical afterglow follow-up
  97. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  98. GRB 230812B: rest-frame energetics from Konus-Wind observation
  99. GRB 230812B: OASDG optical observations
  100. GRB 230812B: AbAO optical observations

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