Skip to main content
New! BOOM Notices and Schema v7.0.0. 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"

38302 results found.

  1. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  2. Fermi trigger No 737476171: Global MASTER-Net observations report
  3. GRB 240511A: radio detection of afterglow candidate
  4. GRB 240514B: GOTO candidate optical counterpart
  5. MAXI GRB240514.78: Global MASTER-Net observations report
  6. Fermi Gamma-ray Burst Monitor list of triggers that are not a GRB
  7. GRB 240514E: MAXI/GSC detection of a probable afterglow
  8. GRB 240514B: GRBAlpha detection
  9. GRB 240514B: Fermi GBM Detection
  10. GRB 240513A: Fermi GBM observation
  11. GRB 240513A: Swift-XRT observations
  12. GRB 240514D: AstroSat CZTI detection
  13. GRB 240514C: Fermi GBM Final Real-time Localization
  14. Fermi GRB 240514B: Global MASTER-Net observations report
  15. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  16. GRB 240514B: Fermi GBM Final Real-time Localization
  17. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  18. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  19. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  20. GRB 240514A: Fermi GBM Final Real-time Localization
  21. GRB 240513A: Tiled Swift observations
  22. LAT GRB240513.31: Global MASTER-Net observations report
  23. GRB 240513A: Fermi-LAT detection
  24. GRB 240511A: Fermi GBM Observation
  25. GRB 240511A: Swift-BAT refined analysis
  26. Fermi GRB 240513B: Global MASTER-Net observations report
  27. Fermi trigger No 737277727: Global MASTER-Net observations report
  28. GRB 240513B: Fermi GBM Final Real-time Localization
  29. GRB 240513A: AstroSat CZTI detection
  30. Fermi trigger No 737258655: Global MASTER-Net observations report
  31. GRB 240511A: J-band observations with WINTER
  32. Fermi trigger No 737247400: Global MASTER-Net observations report
  33. Fermi trigger No 737244199: Global MASTER-Net observations report
  34. Fermi trigger No 737218721: Global MASTER-Net observations report
  35. Fermi trigger No 737196587: Global MASTER-Net observations report
  36. Fermi trigger No 737168073: Global MASTER-Net observations report
  37. GRB 240511A: Enhanced Swift-XRT position
  38. GRB 240511A : MITSuME Akeno optical upper limits
  39. GRB 240511A: Swift-XRT refined Analysis
  40. GRB 240511A: optical afterglow detection from the NOT
  41. Fermi Gamma-ray Burst Monitor trigger 737102480/240511279 is not a GRB
  42. Fermi Gamma-ray Burst Monitor trigger 737111207/240511380 is not a GRB
  43. Fermi GBM trigger 737105243/240511311 is not a GRB
  44. Fermi trigger No 737173236: Global MASTER-Net observations report
  45. Fermi GRB 240511A: Global MASTER-Net observations report
  46. Swift GRB 240511A: Global MASTER-Net observations report
  47. Fermi trigger No 737105243: Global MASTER-Net observations report
  48. Fermi Gamma-ray Burst Monitor trigger 737133200/240511634 is not a GRB
  49. Fermi trigger No 737152719: Global MASTER-Net observations report
  50. GRB 240511A: Prompt enhanced Swift-XRT position
  51. GRB 240511A: Swift detection of a burst
  52. GRB 240511A: Fermi GBM Final Real-time Localization
  53. Fermi trigger No 737102480: Global MASTER-Net observations report
  54. Fermi trigger No 737111207: Global MASTER-Net observations report
  55. Fermi Gamma-ray Burst Monitor trigger 737076431/240510977 is not a GRB
  56. LIGO/Virgo/KAGRA S240422ed: Candidates from the latest GW-MMADS DECam Observations
  57. Fermi trigger No 736967879: Global MASTER-Net observations report
  58. Fermi Gamma-ray Burst Monitor trigger 230925241/717313591 is not a GRB
  59. EP240506a: CrAO ZTSH optical upper limit
  60. GRB 240504A: Fermi GBM Observation
  61. Fermi Gamma-ray Burst Monitor trigger 736837160/240508208 is not a GRB
  62. EP240506a: Archival radio searching
  63. EP240506a: TRT optical upper limit
  64. Fermi trigger No 736733320: Global MASTER-Net observations report
  65. IPN triangulation of GRB 240504A
  66. GRB 240502A: 1.3m DFOT Optical upper limit
  67. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  68. Fermi trigger No 736564880: Global MASTER-Net observations report
  69. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  70. Fermi trigger No 736461232: Global MASTER-Net observations report
  71. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  72. Fermi GRB 240504A: Global MASTER-Net observations report
  73. Fermi trigger No 736472503: Global MASTER-Net observations report
  74. GRB 240503A: AstroSat CZTI detection
  75. GRB 240504A: BALROG localization (Fermi Trigger 736492377 / GRB 240504217)
  76. GRB 240504A: Fermi GBM Final Real-time Localization
  77. Fermi trigger No 736387941: Global MASTER-Net observations report
  78. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  79. GRB 240502A: GOTO optical upper limit
  80. Fermi trigger No 736379109: Global MASTER-Net observations report
  81. GRB 240502A: Fermi GBM Observation
  82. GRB 240415A 1.3m DFOT Optical upper limit
  83. GRB 240502C: GOTO possible optical counterpart candidates
  84. Fermi GRB 240502B: Global MASTER-Net observations report
  85. GRB 240502C: Fermi GBM Final Localization
  86. Fermi GRB 240502A: Global MASTER-Net observations report
  87. GRB 240501B: GRBAlpha detection
  88. GRB 240430A: GRBAlpha detection
  89. GRB 240502B: Fermi GBM Final Real-time Localization
  90. Integral GRB240502.23: Global MASTER-Net observations report
  91. GRB 240502A long GRB detected by INTEGRAL
  92. GRB 240502A: Fermi GBM Final Real-time Localization
  93. LIGO/Virgo/KAGRA S240422ed: Host redshifts of AT2024hfq, AT2024hfu, and AT2024hmo from DBSP
  94. Fermi GRB 240501A: Global MASTER-Net observations report
  95. Fermi trigger No 736197684: Global MASTER-Net observations report
  96. GRB 240426A: VZLUSAT-2 detection
  97. GRB 240425A: VZLUSAT-2 detection
  98. MeerKAT Discovery of a Probable Radio Counterpart to EP240414a
  99. GRB240430A: Fermi GBM Final Localization
  100. GRB 240501B: AstroSat CZTI detection

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