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"

3113 results found.

  1. EP EP240918a: Global MASTER-Net observations report
  2. GRB 240914B: AstroSat CZTI detection
  3. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  4. GRB 240914B: BALROG localization (Fermi Trigger 747990592 / GRB 240914298)
  5. GRB 240912A: SVOM/GRM observation
  6. GRB 240825A: 7DT Optical Upper Limit
  7. GRB 240902B: AstroSat CZTI detection of a long burst
  8. GRB 240825A: Montarrenti Observatory optical follow-up observations
  9. Fermi trigger No 746923430: Global MASTER-Net observations report
  10. GRB 240828B: SVOM/C-GFT optical upper limit
  11. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  12. Fermi trigger No 746438824: Global MASTER-Net observations report
  13. GRB 240828A: Fermi GBM Final Real-time Localization
  14. Swift GRB240824.04: Global MASTER-Net observations report
  15. GRB 240822A: AstroSat CZTI detection of a short burst
  16. Fermi trigger No 746019401: Global MASTER-Net observations report
  17. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  18. Fermi trigger No 745935375: Global MASTER-Net observations report
  19. Fermi trigger No 745866488: Global MASTER-Net observations report
  20. EP240820a: EP detection of a fast X-ray transient
  21. Fermi trigger No 745871958: Global MASTER-Net observations report
  22. GRB 240817A: Fermi GBM Final Real-time Localization
  23. EP EP240816b: Global MASTER-Net observations report
  24. EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  25. Fermi GRB 240814B: Global MASTER-Net observations report
  26. EP EP240807a: Global MASTER-Net observations report
  27. EP EP240806a: Global MASTER-Net observations report
  28. EP240806A: Liverpool Telescope optical follow-up observations
  29. Fermi trigger No 744629911: Global MASTER-Net observations report
  30. Konus-Wind detection of GRB 240802A (EP240802a)
  31. EP240806a: EP-WXT detection of a fast X-ray transient
  32. EP240801a: BTA BVRI photometry
  33. Fermi GRB 240805A: Global MASTER-Net observations report
  34. Swift GRB 240805A: Global MASTER-Net observations report
  35. GRB 240804A: Fermi GBM Final Real-time Localization
  36. Fermi trigger No 744128417: Global MASTER-Net observations report
  37. Fermi trigger No 743953682: Global MASTER-Net observations report
  38. Fermi Gamma-ray Burst Monitor trigger 743953682/240729575 is not a GRB
  39. GRB 240726A: Fermi GBM Final Real-time Localization
  40. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  41. Fermi trigger No 743418632: Global MASTER-Net observations report
  42. Fermi trigger No 743219692: Global MASTER-Net observations report
  43. IceCube Alert 240721.68: Global MASTER-Net observations report
  44. Fermi GRB 240720A: Global MASTER-Net observations report
  45. GRB 240720A: Fermi GBM observation
  46. Fermi GRB 240718A: Global MASTER-Net observations report
  47. Konus-Wind detection of GRB 240715A
  48. GRB 240715A: Fermi GBM Observation
  49. GRB 240713B: AstroSat CZTI detection of a long burst
  50. GRB 240712A: Swift detection of a burst
  51. Fermi trigger No 742317942: Global MASTER-Net observations report
  52. GRB 240710A: Fermi GBM Final Real-time Localization
  53. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  54. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  55. GRB 240627A: AstroSat CZTI detection
  56. Fermi trigger No 741211696: Global MASTER-Net observations report
  57. GRB 240619B: Fermi GBM Final Real-time Localization
  58. Fermi trigger No 740430582: Global MASTER-Net observations report
  59. Fermi GRB 240616A: Global MASTER-Net observations report
  60. Fermi trigger No 740166710: Global MASTER-Net observations report
  61. Fermi GRB 240610A: Global MASTER-Net observations report
  62. Fermi GRB 240607A: Global MASTER-Net observations report
  63. GRB 240529A: SAO RAS optical observations
  64. Fermi GRB 240603C: Global MASTER-Net observations report
  65. GRB 240603C: Fermi GBM Final Real-time Localization
  66. GRB 240529A: continued SAO RAS optical observations
  67. Fermi GRB 240602A: Global MASTER-Net observations report
  68. GRB 240529A: J-band detections with WINTER
  69. GRB 240529A: NOT optical observations
  70. GRB 240523A: Swift-BAT refined analysis
  71. Fermi trigger No 738348224: Global MASTER-Net observations report
  72. GRB 240523A: Swift detection of a burst
  73. Fermi trigger No 737996942: Global MASTER-Net observations report
  74. Fermi GRB 240517A: Global MASTER-Net observations report
  75. GRB 240516A: Fermi GBM Observation
  76. Fermi trigger No 737523389: Global MASTER-Net observations report
  77. MAXI GRB240514.78: Global MASTER-Net observations report
  78. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  79. Fermi Gamma-ray Burst Monitor triggers 737345659/240514093 and GRB240514A are not GRBs
  80. GRB 240514A: Fermi GBM Final Real-time Localization
  81. LAT GRB240513.31: Global MASTER-Net observations report
  82. Fermi GRB 240513B: Global MASTER-Net observations report
  83. GRB 240513B: Fermi GBM Final Real-time Localization
  84. Fermi trigger No 737247400: Global MASTER-Net observations report
  85. Fermi trigger No 737196587: Global MASTER-Net observations report
  86. Fermi trigger No 737168073: Global MASTER-Net observations report
  87. Fermi trigger No 737105243: Global MASTER-Net observations report
  88. GRB 240511A: Fermi GBM Final Real-time Localization
  89. Fermi trigger No 737111207: Global MASTER-Net observations report
  90. IPN triangulation of GRB 240504A
  91. Fermi trigger No 736564880: Global MASTER-Net observations report
  92. GRB 240503A: AstroSat CZTI detection
  93. Fermi trigger No 736387941: Global MASTER-Net observations report
  94. Fermi GRB 240501A: Global MASTER-Net observations report
  95. Fermi trigger No 736197684: Global MASTER-Net observations report
  96. GRB 240501B: AstroSat CZTI detection
  97. GRB 240426A: AstroSat CZTI detection
  98. EP240426a: YAHPT optical upper limit
  99. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  100. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate 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