Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. 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 240513A: Swift-XRT observations
  2. LIGO/Virgo/KAGRA S240513ei: Updated Sky localization
  3. LIGO/Virgo/KAGRA S240514x: Identification of a GW compact binary merger candidate
  4. GRB 240514D: AstroSat CZTI detection
  5. GRB 240514C: Fermi GBM Final Real-time Localization
  6. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  7. Fermi GRB 240514B: Global MASTER-Net observations report
  8. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  9. Fermi Gamma-ray Burst Monitor triggers 737345659/240514093 and GRB240514A are not GRBs
  10. GRB 240514B: Fermi GBM Final Real-time Localization
  11. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  12. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  13. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  14. GRB 240514A: Fermi GBM Final Real-time Localization
  15. GRB 240513A: Tiled Swift observations
  16. LAT GRB240513.31: Global MASTER-Net observations report
  17. GRB 240513A: Fermi-LAT detection
  18. LIGO/Virgo/KAGRA S240513ei: Identification of a GW compact binary merger candidate
  19. GRB 240511A: Fermi GBM Observation
  20. GRB 240511A: Swift-BAT refined analysis
  21. Fermi GRB 240513B: Global MASTER-Net observations report
  22. Fermi trigger No 737277727: Global MASTER-Net observations report
  23. GRB 240513B: Fermi GBM Final Real-time Localization
  24. GRB 240513A: AstroSat CZTI detection
  25. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  26. Fermi trigger No 737258655: Global MASTER-Net observations report
  27. GRB 240511A: J-band observations with WINTER
  28. Fermi trigger No 737247400: Global MASTER-Net observations report
  29. Fermi trigger No 737244199: Global MASTER-Net observations report
  30. Fermi trigger No 737218721: Global MASTER-Net observations report
  31. Fermi trigger No 737196587: Global MASTER-Net observations report
  32. Fermi trigger No 737168073: Global MASTER-Net observations report
  33. GRB 240511A: Enhanced Swift-XRT position
  34. GRB 240511A : MITSuME Akeno optical upper limits
  35. LIGO/Virgo/KAGRA S240512r: Updated Sky localization and EM Bright Classification
  36. GRB 240511A: Swift-XRT refined Analysis
  37. GRB 240511A: optical afterglow detection from the NOT
  38. Fermi Gamma-ray Burst Monitor trigger 737102480/240511279 is not a GRB
  39. Fermi Gamma-ray Burst Monitor trigger 737111207/240511380 is not a GRB
  40. Fermi GBM trigger 737105243/240511311 is not a GRB
  41. Fermi trigger No 737173236: Global MASTER-Net observations report
  42. LIGO/Virgo/KAGRA S240512r: Identification of a GW compact binary merger candidate
  43. Fermi GRB 240511A: Global MASTER-Net observations report
  44. Swift GRB 240511A: Global MASTER-Net observations report
  45. Fermi trigger No 737105243: Global MASTER-Net observations report
  46. Fermi Gamma-ray Burst Monitor trigger 737133200/240511634 is not a GRB
  47. Fermi trigger No 737152719: Global MASTER-Net observations report
  48. GRB 240511A: Prompt enhanced Swift-XRT position
  49. GRB 240511A: Swift detection of a burst
  50. LIGO/Virgo/KAGRA S240511i: Updated Sky localization
  51. GRB 240511A: Fermi GBM Final Real-time Localization
  52. Fermi trigger No 737102480: Global MASTER-Net observations report
  53. Fermi trigger No 737111207: Global MASTER-Net observations report
  54. LIGO/Virgo/KAGRA S240511i: Identification of a GW compact binary merger candidate
  55. Fermi Gamma-ray Burst Monitor trigger 737076431/240510977 is not a GRB
  56. LIGO/Virgo/KAGRA S240422ed: GMOS-S photometry of J-GEM24a
  57. LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
  58. LIGO/Virgo/KAGRA S240422ed: Candidates from the latest GW-MMADS DECam Observations
  59. Fermi trigger No 736967879: Global MASTER-Net observations report
  60. EP240506a: Xinglong optical upper limit
  61. Fermi Gamma-ray Burst Monitor trigger 230925241/717313591 is not a GRB
  62. EP240506a: CrAO ZTSH optical upper limit
  63. GRB 240504A: Fermi GBM Observation
  64. Fermi Gamma-ray Burst Monitor trigger 736837160/240508208 is not a GRB
  65. EP240506a: Archival radio searching
  66. EP240506a: TRT optical upper limit
  67. EP240506a: BOOTES Network optical upper limit
  68. LIGO/Virgo/KAGRA S240507p: Updated Sky localization and EM Bright Classification
  69. LIGO/Virgo/KAGRA S240422ed: Upper limits from a two-week IceCube neutrino search
  70. Fermi trigger No 736733320: Global MASTER-Net observations report
  71. EP240506a: Optical upper limit with Kinder observations
  72. IPN triangulation of GRB 240504A
  73. GRB 240502A: 1.3m DFOT Optical upper limit
  74. EP240506a: EP-WXT detection of a new fast X-ray transient
  75. LIGO/Virgo/KAGRA S240507p: Identification of a GW compact binary merger candidate
  76. LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
  77. LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfr and AT2024hfs
  78. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  79. Fermi GBM triggers 736668287/240506253 and 736669277/240506265 are not GRBs
  80. LIGO/Virgo/KAGRA S240505av: Updated Sky localization and EM Bright Classification
  81. Fermi trigger No 736564880: Global MASTER-Net observations report
  82. LIGO/Virgo/KAGRA S240505av: Identification of a GW compact binary merger candidate
  83. IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
  84. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  85. Fermi trigger No 736461232: Global MASTER-Net observations report
  86. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  87. Fermi GRB 240504A: Global MASTER-Net observations report
  88. Fermi trigger No 736472503: Global MASTER-Net observations report
  89. GW170817: VLA observations at ~5.5 yrs since merger
  90. GRB 240503A: AstroSat CZTI detection
  91. GRB 240504A: BALROG localization (Fermi Trigger 736492377 / GRB 240504217)
  92. GRB 240504A: Fermi GBM Final Real-time Localization
  93. Fermi trigger No 736387941: Global MASTER-Net observations report
  94. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  95. GRB 240502A: GOTO optical upper limit
  96. Fermi trigger No 736379109: Global MASTER-Net observations report
  97. GRB 240502A: Fermi GBM Observation
  98. GRB 240415A 1.3m DFOT Optical upper limit
  99. GRB 240502C: GOTO possible optical counterpart candidates
  100. LIGO/Virgo/KAGRA S240501an: Updated Sky localization and EM Bright Classification

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