Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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"

28054 results found.

  1. GRB 230818A: Swift/UVOT Detection
  2. GRB 230818A: Enhanced Swift-XRT position
  3. GRB 230818A: SAO RAS Zeiss-1000 observations
  4. Fermi trigger No 713974668: Global MASTER-Net observations report
  5. GRB 230818A: GOTO optical afterglow detection
  6. GRB 230818A: Swift detection of a burst
  7. Swift GRB230818.98: Global MASTER-Net OT detection
  8. GRB 230812B: SAO RAS observations, possible re-brightening
  9. GRB 230816A: Swift-BAT refined analysis
  10. GRB 230812B: SAO RAS optical observations
  11. GRB 230816A: Swift-XRT refined Analysis
  12. GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
  13. GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
  14. GRB 230817A: BALROG localization (Fermi Trigger 713966581 / GRB 230817502)
  15. GRB 230816A: Enhanced Swift-XRT position
  16. GRB 230812B: SAO RAS optical observations
  17. GRB230816A: Possible host and GIT detection of optical counterpart
  18. GRB 230816A: Tautenburg observations
  19. GRB 230816A: AKO Optical Observations
  20. GRB 230816A: TShAO and Assy optical observations
  21. GRB 230816A: SAO RAS optical observations
  22. IPN triangulation of GRB 230815B
  23. GRB 230816A: Nanshan/HMT optical afterglow detection
  24. GRB 230816A: Swift detection of a burst
  25. GRB 230815A: Swift-BAT refined analysis
  26. GRB 230815B: GECAM-B and GECAM-C detection of a burst
  27. GRB230815A: Swift/UVOT upper limits
  28. GRB 230812B: GAD Observatory optical observations (upper limit)
  29. GRB 230815A: Swift-XRT refined Analysis
  30. GRB 230812B: iTelescope optical upper limit
  31. GRB 230812B: continued SAO RAS optical observation
  32. GRB 230815A: Fermi GBM detection
  33. GRB 230815A: Enhanced Swift-XRT position
  34. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  35. GRB 230812B: Tautenburg observations
  36. GRB 230815A: Swift detection of a burst
  37. GRB 230812B: AMI-LA radio detection of afterglow candidate
  38. GRB 230812B: continued AbAO optical afterglow observations
  39. GRB 230812B: Optical observaions from Rozhen Observatory
  40. GRB 230812B: Further Bassano Bresciano Observatory optical observations
  41. LIGO/Virgo/KAGRA S230814ah: Identification of a GW compact binary merger candidate
  42. GRB 230812B: further SAO RAS optical observations
  43. GRB 230812B: Upper limits from a neutrino search with IceCube
  44. LIGO/Virgo/KAGRA S230814r: Updated Sky localization
  45. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  46. GRB 230814A: BALROG localization (Fermi Trigger 713732101 / GRB 230814788)
  47. GRB 230812B: CrAO ZTSh optical observations
  48. GRB 230812B: Koshka Zeiss-1000 optical observations
  49. GRB 230812B: GIT optical follow-up
  50. GRB 230812B: Leavitt Observatory optical observations
  51. GRB 230812B : optical observations from Observatoire de Haute-Provence
  52. GRB 230812B: Bassano Bresciano Observatory optical observations
  53. GRB 230812B: Faulkes Telescope North optical afterglow follow-up
  54. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  55. GRB 230812B: OASDG optical observations
  56. GRB 230812B: AbAO optical observations
  57. LIGO/Virgo/KAGRA S230814r: Identification of a GW compact binary merger candidate
  58. GRB 230812B: Montarrenti Observatory optical observations
  59. LIGO/Virgo/KAGRA S230812aj: two counterpart neutrino candidates from IceCube neutrino searches
  60. GRB 230812B: SAO RAS optical observations
  61. GRB 230812B: Detected Optical Afterglow Candidate
  62. GRB 230812B: GMG - GRANDMA observations
  63. GRB 230812B: Swift-XRT afterglow detection
  64. GRB 230812: Swift/UVOT Detection
  65. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  66. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  67. Fermi GRB 230812B: MASTER optical counterpart
  68. GRB 230812B: Fermi GBM detection of an extremely bright GRB
  69. LIGO/Virgo/KAGRA S230811n: Updated Sky localization
  70. GRB 230808A: Fermi GBM Detection
  71. LIGO/Virgo/KAGRA S230811n: Identification of a GW compact binary merger candidate
  72. GRB 230805B: Swift-BAT refined analysis
  73. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  74. GRB 230805B: AstroSat CZTI detection
  75. GRB 230808A: Swift/BAT-GUANO detection of a burst
  76. GRB 230805B : MITSuME Akeno optical upper limits
  77. LIGO/Virgo/KAGRA S230808i: Identification of a GW unmodeled transient candidate
  78. LIGO/Virgo/KAGRA S230807f: Updated Sky localization and EM Bright Classification
  79. LIGO/Virgo/KAGRA S230807f: Identification of a GW compact binary merger candidate
  80. LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
  81. GRB 230805B: Fermi GBM observation
  82. GRB 230805B : OHP/T193 optical upper limit
  83. LIGO/Virgo/KAGRA S230806ak: Updated Sky localization and EM Bright Classification
  84. GRB 230805B: Enhanced Swift-XRT position
  85. LIGO/Virgo/KAGRA S230806ak: Identification of a GW compact binary merger candidate
  86. GRB 230805B: Swift/UVOT Upper Limits
  87. GRB 230805B: Bassano Bresciano observatory upper limit
  88. GRB 230805B: Swift-XRT refined Analysis
  89. GRB 230805B: SAO RAS optical observations
  90. LIGO/Virgo/KAGRA S230805x: Updated Sky localization
  91. GRB 230805B: Swift detection of a burst
  92. LIGO/Virgo/KAGRA S230805x: Identification of a GW compact binary merger candidate
  93. LIGO/Virgo/KAGRA S230802aq: Updated Sky localization and EM Bright Classification
  94. GRB 230802A: Fermi GBM observation
  95. GRB 230802A: Swift-BAT refined analysis
  96. GRB 230802A: Swift/UVOT Upper Limits
  97. GRB 230803A: AstroSat CZTI detection
  98. LIGO/Virgo/KAGRA S230802aq: AstroSat CZTI non-detection and upper limits
  99. LIGO/Virgo/KAGRA S230802aq: Upper limits from Fermi-GBM Observations
  100. GRB 230802A: Swift-XRT refined Analysis

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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