Skip to main content
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. Swift Trigger 1180055 is not a GRB
  2. GRB 230718A: Final Localization Correction
  3. GRB 230718A: Fermi GBM Final Real-time Localization
  4. Fermi Gamma-ray Burst Monitor trigger 711329677/230717982 is not a GRB
  5. IPN triangulation of GRB 230712C (short)
  6. IPN triangulation of GRB 230712A (short)
  7. LIGO/Virgo/KAGRA S230708z: Updated Sky localization
  8. GRB 230717A: Fermi GBM Final Real-time Localization
  9. LIGO/Virgo/KAGRA S230715bw: Retraction of GW compact binary merger candidate
  10. Fermi trigger No 711088412: Global MASTER-Net observations report
  11. GRB 230715A: Fermi GBM Final Real-time Localization
  12. Fermi GRB 230713A: Global MASTER-Net observations report
  13. IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
  14. GRB 230713A: Fermi GBM Final Real-time Localization
  15. LIGO/Virgo/KAGRA S230709bi: Updated Sky localization
  16. LIGO/Virgo/KAGRA S230708t: Updated Sky localization
  17. GRB 230709B: CALET Gamma-Ray Burst Monitor detection
  18. GRB 230703A: CALET Gamma-Ray Burst Monitor detection
  19. GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  20. IceCube-230708A: Upper limits from Swift/BAT-GUANO
  21. GRB 230712B: Fermi GBM Final Localization
  22. LIGO/Virgo/KAGRA S230712a: Retraction of GW compact binary merger candidate
  23. GRB 230707A: Swift/BAT-GUANO position correction
  24. GRB 230712A: Fermi GBM Final Real-time Localization
  25. IceCube-230708A - Correction to GCN Circular 34170
  26. Fermi trigger No 710741042: Global MASTER-Net observations report
  27. GRB 230709C: GRBAlpha detection
  28. GRB 230709B: GRBAlpha detection
  29. GRB 230709C: Fermi GBM Detection
  30. GRB 230709C: Fermi GBM Final Localization
  31. GRB 230707B: Fermi GBM Observation
  32. GRB 230710A: Fermi GBM Final Real-time Localization
  33. LIGO/Virgo/KAGRA S230708z: Identification of a GW compact binary merger candidate
  34. LIGO/Virgo/KAGRA S230708t: Identification of a GW compact binary merger candidate
  35. IceCube-230707A: No candidates detected by Swift-XRT
  36. Swift Trigger 1178410 is not an astrophysical event
  37. GRB 230709C: AstroSat CZTI detection
  38. LIGO/Virgo/KAGRA S230708cf: Updated Sky localization
  39. GRB 230707B: CALET Gamma-Ray Burst Monitor detection
  40. GRB 230703A detected with multiple GRID detectors
  41. GRB 230709C: BALROG localization (Fermi Trigger 710617111 / GRB 230709735)
  42. LIGO/Virgo/KAGRA S230707ai: Updated Sky localization
  43. IceCube-230707A: No candidates from the Zwicky Transient Facility
  44. Fermi-LAT gamma-ray observations of IceCube-230708A
  45. Fermi-LAT gamma-ray observations of IceCube-230707B
  46. Fermi-LAT gamma-ray observations of IceCube-230707A
  47. LIGO/Virgo/KAGRA S230630am: Updated Sky localization
  48. LIGO/Virgo/KAGRA S230630am: Updated Sky localization
  49. GRB 230709B: BALROG localization (Fermi Trigger 710614579 / GRB 230709706)
  50. IceCube-230708A: Upper limits from a search for additional neutrino events in IceCube
  51. IceCube-230707B: Upper limits from a search for additional neutrino events in IceCube
  52. IceCube-230707A: Upper limits from a search for additional neutrino events in IceCube
  53. LIGO/Virgo/KAGRA S230709bi: Identification of a GW compact binary merger candidate
  54. Swift Trigger 1178410: possible GRB 230709A
  55. LIGO/Virgo/KAGRA S230708cf: Identification of a GW compact binary merger candidate
  56. LIGO/Virgo/KAGRA S230708bi: Retraction of GW compact binary merger candidate
  57. GRB 230628C: GRID Detection
  58. IceCube-230708A - IceCube observation of a high-energy neutrino candidate track-like event
  59. GRB 230707B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  60. GRB 230707A: Swift-XRT observations
  61. IceCube Alert 230708.35: Global MASTER-Net observations report
  62. IceCube-230707B - IceCube observation of a high-energy neutrino candidate track-like event
  63. GRB 230707B: Fermi GBM Final Real-time Localization
  64. IceCube Alert 230707.71: Global MASTER-Net observations report
  65. IceCube-230707A - IceCube observation of a high-energy neutrino candidate track-like event
  66. GRB 230707A: Fermi GBM Detection
  67. LIGO/Virgo/KAGRA S230707ai: Identification of a GW compact binary merger candidate
  68. GRB 230707A: Swift ToO observations
  69. GRB 230707A: Swift/BAT-GUANO arcminute localization of a burst
  70. ZTF23aaoohpy/AT2023lcr : HCT follow-up observations
  71. Fermi GRB 230707A: Global MASTER-Net observations report
  72. GRB 230707A: Fermi GBM Final Real-time Localization
  73. LIGO/Virgo/KAGRA S230706ah: Updated Sky localization
  74. Integral GRB230706.70: Global MASTER-Net observations report
  75. LIGO/Virgo/KAGRA S230704f: Updated Sky localization
  76. LIGO/Virgo/KAGRA S230630bq: Updated Sky localization
  77. IBAS trigger number 10311: not a real GRB
  78. LIGO/Virgo/KAGRA S230702an: Updated Sky localization
  79. GRB 230625A: Detection by GRID
  80. LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
  81. LIGO/Virgo/KAGRA S230706ah: Identification of a GW compact binary merger candidate
  82. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  83. ZTF23aaoohpy/AT2023lcr: AMI-LA radio detection
  84. Fermi trigger No 710117592: Global MASTER-Net observations report
  85. GRB 230626A: VZLUSAT-2 detection
  86. LVK S230619bd/GBM-230619: Upper limits from a two-week IceCube neutrino search
  87. GRB 230328B: LBT detection of the likely host galaxy
  88. LIGO/Virgo/KAGRA S230704f: Identification of a GW compact binary merger candidate
  89. Konus-Wind detection of GRB 220623A
  90. GRB 230701B: AstroSat CZTI detection
  91. LIGO/Virgo/KAGRA S230627c: observations of ZTF23aaptsuy/AT2023lx in AbAO observatory
  92. LIGO/Virgo/KAGRA S230702an: Identification of a GW compact binary merger candidate
  93. GRB 230628E: Swift/UVOT Detection
  94. GRB 230628E: Swift-BAT refined analysis
  95. GRB 230702A: Fermi GBM Final Real-time Localization
  96. GRB 230628E: ATCA rapid radio follow-up
  97. GRB 230701A: Fermi GBM Final Real-time Localization
  98. LIGO/Virgo/KAGRA S230627c: GRANDMA observations of galaxies and ZTF counterpart candidates
  99. LIGO/Virgo/KAGRA low-significance gravitational wave candidate S230701z: one counterpart neutrino candidate from IceCube neutrino searches
  100. LIGO/Virgo/KAGRA S230627c: Upper limits from Swift/BAT-GUANO

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