Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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"

2853 results found.

  1. Fermi trigger No 586788607 Global MASTER-Net observations report
  2. GRB 190804B: MAXI/GSC detection
  3. Fermi trigger No 586574612 Global MASTER-Net observations report
  4. GRB 190731A: no OT detected by MASTER
  5. Fermi trigger No 586305505 Global MASTER-Net observations report
  6. LIGO/Virgo S190728q: ZTF Forced Photometry for PS1 and DECam-GROWTH optical candidates, and a note on DECam Photometry from GCN 25215
  7. LIGO/Virgo S190728q: Optical transients from Pan-STARRS coverage during first 2 nights
  8. LIGO/Virgo S190728q: No counterpart candidates in KAIT observations
  9. Fermi trigger No 585988241 Global MASTER-Net observations report
  10. LIGO/Virgo S190727h: No counterpart candidates in KAIT observations
  11. GRB 190727B: Swift detection of a burst
  12. GRB 190720A: CALET Gamma-Ray Burst Monitor detection
  13. IPN triangulation of GRB 190720A
  14. LIGO/Virgo S190720a: No counterpart candidates in KAIT observations
  15. GRB 190720A: Fermi GBM detection
  16. GRB 190720A: BALROG localization (Fermi Trigger 585326534 / GRB 190720613)
  17. GRB 190720A: Fermi GBM Final Real-time Localization
  18. LIGO/Virgo S190718y: No counterpart candidates in CNEOST
  19. LIGO/Virgo S190720a Global MASTER-Net observations report
  20. LIGO/Virgo S190718y: No counterpart candidates in KAIT observations
  21. GRB 190719A: Fermi GBM Final Real-time Localization
  22. Swift GRB190718.2 Global MASTER-Net observations report
  23. GRB 190718A: Swift detection of a burst
  24. Fermi trigger No 585007213 Global MASTER-Net observations report
  25. Fermi trigger No 584977168 Global MASTER-Net observations report
  26. Fermi trigger No 584804684 Global MASTER-Net observations report
  27. GRB 190706C: Insight-HXMT/HE detection
  28. IceCube Alert 190712.05 Global MASTER-Net observations report
  29. Fermi trigger No 584590606 Global MASTER-Net observations report
  30. Fermi trigger No 584583925 Global MASTER-Net observations report
  31. Konus-Wind observation of GRB 190706C
  32. GRB 190706C: CALET Gamma-Ray Burst Monitor detection
  33. GRB 190708B: MAXI/GSC detection
  34. IPN triangulation of GRB 190706D (short)
  35. IPN triangulation of GRB 190706C (long/very bright)
  36. LIGO/Virgo S190706ai: No counterpart candidates in KAIT observations
  37. IPN triangulation of GRB 190704A (short)
  38. GRB 190706B: Swift detection of a burst
  39. Fermi trigger No 583854113 Global MASTER-Net observations report
  40. LIGO/Virgo S190630ag: no counterpart candidate in the SVOM/GWAC observations
  41. LIGO/Virgo S190701ah: Coverage and upper limits from MAXI/GSC observations
  42. GRB 190630B: Tien Shan and Koshka Zeiss-1000 optical upper limits
  43. GRB 190630C: ISON-Castelgrande optical upper limit
  44. LIGO/Virgo S190630ag: No counterpart candidates in AGILE-GRID observations
  45. GRB 190701A: MAXI/GSC detection
  46. Fermi trigger No 583567803 Global MASTER-Net observations report
  47. GRB 190627A: Koshka Zeiss-1000 optical counterpart observations
  48. GRB 190627A: Optical imaging and spectroscopy from Calar Alto
  49. Fermi trigger No 583327924 Global MASTER-Net observations report
  50. Fermi trigger No 583221986 Global MASTER-Net observations report
  51. Fermi trigger No 583111521 Global MASTER-Net observations report
  52. Swift GRB190624.86 Global MASTER-Net observations report
  53. Swift trigger 911102: D50 optical limit
  54. Fermi trigger No 582856902 Global MASTER-Net observations report
  55. GRB 190615B: AstroSat CZTI detection
  56. Fermi trigger No 582615488 Global MASTER-Net observations report
  57. Fermi trigger No 582615488 Global MASTER-Net observations report
  58. Fermi trigger No 582596766 Global MASTER-Net observations report
  59. GRB 190615B: Insight-HXMT/HE detection
  60. Fermi trigger No 582115625 Global MASTER-Net observations report
  61. Fermi trigger No 581986074 Global MASTER-Net observations report
  62. GRB 190604A: Insight-HXMT/HE detection
  63. Fermi trigger No 581469752 Global MASTER-Net observations report
  64. GRB 190604A: AstroSat CZTI detection
  65. GRB190604A: BALROG localization (Fermi Trigger 581337762 / GRB 190604446)
  66. GRB 190604A: Fermi GBM Final Real-time Localization
  67. Fermi Fermi trigger No 581002688 Global MASTER-Net observations report
  68. LIGO/Virgo S190521r: CNEOST follow-up observations
  69. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC observations.
  70. LIGO/Virgo S190512at: SVOM/GWAC-F60A observations
  71. LIGO/Virgo S190519bj: MAXI/GSC Observations
  72. LIGO/Virgo S190519bj Global MASTER-Net observations report
  73. Fermi GRB190517.81 Global MASTER-Net observations report
  74. LIGO/Virgo S190517h Global MASTER-Net observations report
  75. LIGO/Virgo S190517h: IceCube Neutrino Search
  76. Fermi GRB190514.67 Global MASTER-Net observations report
  77. LIGO/Virgo S190513bm: Lick/KAIT Follow-Up Observations
  78. LIGO/Virgo S190513bm: Insight-HXMT/HE observation
  79. LIGO/Virgo S190510g: Further KMTNet observation of DECam-GROWTH and DESGW candidates
  80. LIGO/Virgo S190513bm Global MASTER-Net observations report
  81. LIGO/Virgo S190510g: Pan-STARRS and ATLAS observations and candidates
  82. LIGO/Virgo S190512at Global MASTER-Net observations report
  83. Fermi GRB190512.61 Global MASTER-Net observations report
  84. IPN triangulation of GRB 190510A (short)
  85. LIGO/Virgo S190510g: Update on candidate significance
  86. LIGO/Virgo S190510g: Las Cumbres Observatory Galaxy Targeted Counterpart Search
  87. LIGO/Virgo S190510g: Dabancheng/HMT Follow-Up Observations
  88. LIGO/Virgo S190510g: Xinglong/Schmidt Follow-Up Observations
  89. LIGO/Virgo S190510g: SOAR/Goodman follow-up observations
  90. LIGO/Virgo S190510g: CNEOST Follow-Up Observations
  91. LIGO/Virgo S190510g: Lick/KAIT Follow-Up Observations
  92. LIGO/Virgo S190510g: Lulin Optical Follow-up Observations
  93. LIGO/Virgo S190510g Global MASTER-Net observations report
  94. LIGO/Virgo S190503bf: TAROT-GRANDMA observation report
  95. Fermi GRB190507.27 Global MASTER-Net observations report
  96. IceCube-190504A: MASTER optical monitoring analysis
  97. Fermi GRB190505.05 Global MASTER-Net observations report
  98. Fermi GRB190504.68 Global MASTER-Net observations report
  99. LIGO/Virgo S190503bf Global MASTER-Net observations report
  100. IceCube-190503A: Lick/KAIT Follow-Up Observations

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