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"
  1. GRB 240529A: radio detection with AMI-LA
  2. GRB 240607A: BALROG localization (Fermi Trigger 739450879 / GRB 240607459)
  3. GRB 240607A: Fermi GBM Final Real-time Localization
  4. GRB 240606B: GECAM-B detection a long burst
  5. Fermi trigger No 739373591: Global MASTER-Net observations report
  6. GRB 240606B: Swift-XRT afterglow detection
  7. Swift GRB240606.15: Global MASTER-Net observations report
  8. GRB 240606B: Swift ToO observations
  9. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  10. Konus-Wind detection of GRB 240603A
  11. Swift Trigger 1235109: a possible GRB 240606A
  12. Fermi GRB 240604A: Global MASTER-Net observations report
  13. IPN triangulation of GRB 240531A (short)
  14. Fermi GRB 240605A: Global MASTER-Net observations report
  15. Fermi GRB 240605C: Global MASTER-Net observations report
  16. Fermi Gamma-ray Burst Monitor trigger 739290883/240605607 is not a GRB
  17. LIGO/Virgo/KAGRA S240601co: Updated Sky localization
  18. GRB 240605C: Fermi GBM Final Real-time Localization
  19. IPN triangulation of GRB 240603A
  20. GRB 240605B: Fermi GBM Final Real-time Localization
  21. GRB 240604A: Fermi GBM Final Localization
  22. GRB 240605A: Fermi GBM Final Real-time Localization
  23. GRB 240604A: GECAM detection of a long burst
  24. GRB 240529A: SAO RAS optical observations
  25. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  26. Fermi GRB 240603C: Global MASTER-Net observations report
  27. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  28. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  29. GRB 240603A: Fermi GBM Final Localization
  30. GRB 240603C: BALROG localization (Fermi Trigger 739102156 / GRB 240603423)
  31. GRB 240603C: Fermi GBM Final Real-time Localization
  32. Swift Trigger 1232465: consistent with noise
  33. GRB 240603B: Swift detection of a possible burst
  34. GRB 240529A: MASTER prompt OT detection
  35. GRB 240603A: GECAM detection of a short burst
  36. GRB 240529A: continued SAO RAS optical observations
  37. Fermi GRB 240602A: Global MASTER-Net observations report
  38. GRB 240529A: OSN optical detection
  39. The EP-WXT source triggered on June 1st is likely a flaring star
  40. GRB 240529A: further SAO RAS optical observations
  41. LIGO/Virgo/KAGRA S240601aj: Updated Sky localization
  42. GRB 240602A: Fermi GBM Final Real-time Localization
  43. LIGO/Virgo/KAGRA S240601co: Identification of a GW compact binary merger candidate
  44. Swift Trigger 1232465 is not a GRB
  45. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  46. LIGO/Virgo/KAGRA S240530a: Updated Sky localization
  47. LXT 240528A: GSP optical upper limit
  48. GRB 240529A: 1.3m DFOT Optical observations
  49. LIGO/Virgo/KAGRA S240527en: Updated Sky localization
  50. LIGO/Virgo/KAGRA S240601aj: Identification of a GW compact binary merger candidate
  51. GRB 240531A: AstroSat CZTI detection of a short burst
  52. GRB 240529A : Mondy optical observations
  53. Konus-Wind detection of GRB 240529A
  54. IPN triangulation of the initial episode of GRB 240529A
  55. GRB 240529A: SAO RAS optical observations
  56. LIGO/Virgo/KAGRA S240531bp: Updated Sky localization
  57. LIGO/Virgo/KAGRA S240531bp: Identification of a GW compact binary merger candidate
  58. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  59. GRB 240529A: Insight-HXMT/HE detection
  60. GRB 240529A: optical photometry from Konkoly
  61. GRB 240529A: GROWTH-India optical follow-up
  62. GRB 240529A: T193/MISTRAL observations
  63. GRB 240529A: Redshift from GTC/OSIRIS+
  64. GRB 240529A: AKO Optical Afterglow Detection
  65. LIGO/Virgo/KAGRA S240530a: Identification of a GW compact binary merger candidate
  66. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  67. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  68. GRB 240529A: J-band detections with WINTER
  69. GRB 240529A: Skynet Optical Observations
  70. LXT 240528A: LEIA detection of a fast X-ray transient
  71. GRB 240529A: Swift-BAT refined analysis
  72. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  73. GRB 240529A: Swift-XRT refined Analysis
  74. GRB240529A: BOOTES-6/DPRT optical detection
  75. GRB 240529A: Swift/UVOT Detection
  76. GRB 240529A: NOT optical observations
  77. GRB 240529A: AstroSat CZTI detection
  78. GRB 240529A: GOTO optical afterglow detection
  79. GRB 240527B: Swift-XRT afterglow detection
  80. GRB 240529A: Enhanced Swift-XRT position
  81. GRB 240529A: Swift detection of a burst with an optical counterpart
  82. Swift GRB240529.12: Global MASTER-Net observations report
  83. LIGO/Virgo/KAGRA S240527fv: Updated Sky localization
  84. GRB 240527B: Fermi GBM Observation
  85. Fermi GRB 240527A: Global MASTER-Net observations report
  86. LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate
  87. GRB 240527B: Fermi-LAT detection
  88. LAT GRB240527.59: Global MASTER-Net observations report
  89. LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate
  90. Fermi GRB 240527B: Global MASTER-Net observations report
  91. GRB 240527B: Fermi GBM Final Localization
  92. GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
  93. GRB 240527A: Fermi GBM Final Real-time Localization
  94. GRB 240523A: Swift-BAT refined analysis
  95. Fermi trigger No 738348224: Global MASTER-Net observations report
  96. Fermi trigger No 738330463: Global MASTER-Net observations report
  97. LIGO/Virgo/KAGRA S240525p: Updated Sky localization
  98. LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate
  99. GRB 240523A: Swift-XRT refined Analysis
  100. GRB 240523A: Enhanced Swift-XRT position

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