Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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. IceCube-230725A: Upper limits from a search for additional neutrino events in IceCube
  2. IceCube-230724A: Upper limits from a search for additional neutrino events in IceCube
  3. Integral GRB230726.26: Global MASTER-Net observations report
  4. GRB 230723B: Further CAHA observations and host galaxy detection
  5. LIGO/Virgo/KAGRA S230726a: Updated Sky localization
  6. Konus-Wind detection of GRB 230723A
  7. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  8. GRB 230723B: ATCA rapid radio follow-up
  9. LIGO/Virgo/KAGRA S230726b: one counterpart neutrino candidate from IceCube neutrino searches
  10. IceCube-230724A - IceCube observation of a high-energy neutrino candidate track-like event
  11. LIGO/Virgo/KAGRA S230726a: Identification of a GW compact binary merger candidate
  12. IBAS trigger number 10337: not a real GRB
  13. Integral GRB230725.99: Global MASTER-Net observations report
  14. IceCube-230725A - IceCube observation of a high-energy neutrino candidate track-like event
  15. IceCube Alert 230725.90: Global MASTER-Net observations report
  16. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  17. IPN triangulation of GRB 230723A (short)
  18. Fermi Gamma-ray Burst Monitor trigger 711982704/230725540 is not a GRB
  19. GRB 230725B: Fermi GBM Final Real-time Localization
  20. GRB 230725A: Fermi GBM Final Real-time Localization
  21. GRB 230723B: Leavitt Observatory upper limit
  22. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  23. GRB 230723B: Montarrenti Observatory upper limit
  24. GRB 230723B: Optical afterglow candidate from CAHA
  25. GRB 230723B: Bassano Bresciano Observatory upper limit
  26. GRB 230723B: Fermi GBM observation
  27. GRB 230723B: Swift-XRT refined Analysis
  28. GRB 230723B: non-detections from Observatoire de Haute-Provence
  29. IceCube Alert 230724.08: Global MASTER-Net observations report
  30. LIGO/Virgo/KAGRA S230723ac: Updated Sky localization
  31. Fermi trigger No 711853834: Global MASTER-Net observations report
  32. GRB 230724A: Fermi GBM Final Real-time Localization
  33. Fermi trigger No 711805358: Global MASTER-Net observations report
  34. GRB 230723B: Optical limit from CAHA
  35. GRB 230723B: Swift/UVOT Upper Limits
  36. Swift GRB 230723B: Global MASTER-Net observations report
  37. Swift-XRT position for GRB 230723B
  38. GRB 230723A: AGILE/MCAL detection
  39. GRB 230723B: Swift-XRT observations
  40. LIGO/Virgo/KAGRA S230723ac: Identification of a GW compact binary merger candidate
  41. GRB 230723B: Swift detection of a burst
  42. Fermi GRB 230723A: Global MASTER-Net observations report
  43. GRB 230723A: Fermi GBM Final Real-time Localization
  44. Swift GRB230720.30: Global MASTER-Net observations report
  45. IPN triangulation of GRB 230715D
  46. Swift Trigger 1180063 is not a GRB
  47. Swift Trigger 1180060 is not a GRB
  48. Swift Trigger 1180055 is not a GRB
  49. GRB 230718A: Final Localization Correction
  50. GRB 230718A: Fermi GBM Final Real-time Localization
  51. Fermi Gamma-ray Burst Monitor trigger 711329677/230717982 is not a GRB
  52. IPN triangulation of GRB 230712C (short)
  53. IPN triangulation of GRB 230712A (short)
  54. LIGO/Virgo/KAGRA S230708z: Updated Sky localization
  55. GRB 230717A: Fermi GBM Final Real-time Localization
  56. LIGO/Virgo/KAGRA S230715bw: Retraction of GW compact binary merger candidate
  57. Fermi trigger No 711088412: Global MASTER-Net observations report
  58. GRB 230715A: Fermi GBM Final Real-time Localization
  59. Fermi GRB 230713A: Global MASTER-Net observations report
  60. IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
  61. GRB 230713A: Fermi GBM Final Real-time Localization
  62. LIGO/Virgo/KAGRA S230709bi: Updated Sky localization
  63. LIGO/Virgo/KAGRA S230708t: Updated Sky localization
  64. GRB 230709B: CALET Gamma-Ray Burst Monitor detection
  65. GRB 230703A: CALET Gamma-Ray Burst Monitor detection
  66. GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  67. IceCube-230708A: Upper limits from Swift/BAT-GUANO
  68. GRB 230712B: Fermi GBM Final Localization
  69. LIGO/Virgo/KAGRA S230712a: Retraction of GW compact binary merger candidate
  70. GRB 230707A: Swift/BAT-GUANO position correction
  71. GRB 230712A: Fermi GBM Final Real-time Localization
  72. IceCube-230708A - Correction to GCN Circular 34170
  73. Fermi trigger No 710741042: Global MASTER-Net observations report
  74. GRB 230709C: GRBAlpha detection
  75. GRB 230709B: GRBAlpha detection
  76. GRB 230709C: Fermi GBM Detection
  77. GRB 230709C: Fermi GBM Final Localization
  78. GRB 230707B: Fermi GBM Observation
  79. GRB 230710A: Fermi GBM Final Real-time Localization
  80. LIGO/Virgo/KAGRA S230708z: Identification of a GW compact binary merger candidate
  81. LIGO/Virgo/KAGRA S230708t: Identification of a GW compact binary merger candidate
  82. IceCube-230707A: No candidates detected by Swift-XRT
  83. Swift Trigger 1178410 is not an astrophysical event
  84. GRB 230709C: AstroSat CZTI detection
  85. LIGO/Virgo/KAGRA S230708cf: Updated Sky localization
  86. GRB 230707B: CALET Gamma-Ray Burst Monitor detection
  87. GRB 230703A detected with multiple GRID detectors
  88. GRB 230709C: BALROG localization (Fermi Trigger 710617111 / GRB 230709735)
  89. LIGO/Virgo/KAGRA S230707ai: Updated Sky localization
  90. IceCube-230707A: No candidates from the Zwicky Transient Facility
  91. Fermi-LAT gamma-ray observations of IceCube-230708A
  92. Fermi-LAT gamma-ray observations of IceCube-230707B
  93. Fermi-LAT gamma-ray observations of IceCube-230707A
  94. LIGO/Virgo/KAGRA S230630am: Updated Sky localization
  95. LIGO/Virgo/KAGRA S230630am: Updated Sky localization
  96. GRB 230709B: BALROG localization (Fermi Trigger 710614579 / GRB 230709706)
  97. IceCube-230708A: Upper limits from a search for additional neutrino events in IceCube
  98. IceCube-230707B: Upper limits from a search for additional neutrino events in IceCube
  99. IceCube-230707A: Upper limits from a search for additional neutrino events in IceCube
  100. LIGO/Virgo/KAGRA S230709bi: Identification of a GW compact binary merger candidate

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