Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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: SAO RAS optical observations
  2. LIGO/Virgo/KAGRA S240531bp: Updated Sky localization
  3. LIGO/Virgo/KAGRA S240531bp: Identification of a GW compact binary merger candidate
  4. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  5. GRB 240529A: Insight-HXMT/HE detection
  6. GRB 240529A: optical photometry from Konkoly
  7. GRB 240529A: GROWTH-India optical follow-up
  8. GRB 240529A: T193/MISTRAL observations
  9. GRB 240529A: Redshift from GTC/OSIRIS+
  10. GRB 240529A: AKO Optical Afterglow Detection
  11. LIGO/Virgo/KAGRA S240530a: Identification of a GW compact binary merger candidate
  12. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  13. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  14. GRB 240529A: J-band detections with WINTER
  15. GRB 240529A: Skynet Optical Observations
  16. LXT 240528A: LEIA detection of a fast X-ray transient
  17. GRB 240529A: Swift-BAT refined analysis
  18. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  19. GRB 240529A: Swift-XRT refined Analysis
  20. GRB240529A: BOOTES-6/DPRT optical detection
  21. GRB 240529A: Swift/UVOT Detection
  22. GRB 240529A: NOT optical observations
  23. GRB 240529A: AstroSat CZTI detection
  24. GRB 240529A: GOTO optical afterglow detection
  25. GRB 240527B: Swift-XRT afterglow detection
  26. GRB 240529A: Enhanced Swift-XRT position
  27. GRB 240529A: Swift detection of a burst with an optical counterpart
  28. Swift GRB240529.12: Global MASTER-Net observations report
  29. LIGO/Virgo/KAGRA S240527fv: Updated Sky localization
  30. GRB 240527B: Fermi GBM Observation
  31. Fermi GRB 240527A: Global MASTER-Net observations report
  32. LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate
  33. GRB 240527B: Fermi-LAT detection
  34. LAT GRB240527.59: Global MASTER-Net observations report
  35. LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate
  36. Fermi GRB 240527B: Global MASTER-Net observations report
  37. GRB 240527B: Fermi GBM Final Localization
  38. GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
  39. GRB 240527A: Fermi GBM Final Real-time Localization
  40. GRB 240523A: Swift-BAT refined analysis
  41. Fermi trigger No 738348224: Global MASTER-Net observations report
  42. Fermi trigger No 738330463: Global MASTER-Net observations report
  43. LIGO/Virgo/KAGRA S240525p: Updated Sky localization
  44. LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate
  45. GRB 240523A: Swift-XRT refined Analysis
  46. GRB 240523A: Enhanced Swift-XRT position
  47. GRB 240523A: Swift detection of a burst
  48. GRB 240521B: Fermi GBM Observation
  49. Fermi GBM Sub-Threshold Detection of GRB 240516B
  50. GRB 240513A: Swift-XRT afterglow detection
  51. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  52. Fermi trigger No 737996942: Global MASTER-Net observations report
  53. LIGO/Virgo/KAGRA S240520cv: Updated Sky localization and EM Bright Classification
  54. EP240518a: GSP optical upper limit
  55. GRB 240521A: GECAM-B detection of a long burst
  56. GRB 240516B: AstroSat CZTI detection
  57. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  58. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  59. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  60. LIGO/Virgo/KAGRA S240520cv: Identification of a GW compact binary merger candidate
  61. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  62. GRB 240514B: VZLUSAT-2 detection
  63. GRB 240504A: VZLUSAT-2 detection
  64. GRB 240502A: VZLUSAT-2 detection
  65. GRB 240519A: GRBAlpha detection
  66. GRB 240516A: Swift/UVOT Upper Limits
  67. GRB 240519A: AstroSat CZTI detection
  68. Fermi trigger No 737788024: Global MASTER-Net observations report
  69. EP240518a: possibly identified with a flare star by EP-FXT
  70. GRB 240519A: BALROG localization (Fermi Trigger 737788024 / GRB 240519213)
  71. EP240518a: EP-WXT detection of a new X-ray transient
  72. LIGO/Virgo/KAGRA S240514c: Updated Sky localization
  73. GRB 240516A: Swift-BAT refined analysis
  74. Fermi GRB 240517A: Global MASTER-Net observations report
  75. GRB 240516A ATCA radio observations
  76. IPN triangulation of GRB 240514B (short)
  77. GRB 240513A: Swift ToO observations
  78. GRB 240517A: Fermi GBM Final Real-time Localization
  79. Konus-Wind detection of GRB 240513A
  80. GRB 240516A: AstroSat CZTI detection
  81. GRB 240516A: Swift-XRT refined Analysis
  82. GRB 240514E: A possible candidate BD-21 1074
  83. Fermi trigger No 737559855: Global MASTER-Net observations report
  84. GRB 240516A: Fermi GBM Observation
  85. GRB 240511A: Observations from GTC/OSIRIS+
  86. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  87. GRB 240516A: GOTO optical upper limit
  88. LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits
  89. Fermi trigger No 737523389: Global MASTER-Net observations report
  90. GRB 240516A: Swift detection of a burst
  91. Swift GRB240516.15: Global MASTER-Net observations report
  92. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  93. Fermi trigger No 737476171: Global MASTER-Net observations report
  94. GRB 240511A: radio detection of afterglow candidate
  95. GRB 240514B: GOTO candidate optical counterpart
  96. MAXI GRB240514.78: Global MASTER-Net observations report
  97. Fermi Gamma-ray Burst Monitor list of triggers that are not a GRB
  98. GRB 240514E: MAXI/GSC detection of a probable afterglow
  99. GRB 240514B: GRBAlpha detection
  100. LIGO/Virgo/KAGRA S240514x: Updated Sky localization

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