Skip to main content
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"
  1. GRB 190630B: KAIT Optical Afterglow Confirmation
  2. GRB 190630C: Enhanced Swift-XRT position
  3. Swift GRB190631. Global MASTER-Net observations report
  4. LIGO/Virgo S190630ag: Upper limits from Fermi-GBM Observations
  5. GRB 190630C: Swift detection of a burst
  6. LIGO/Virgo S190630ag: Coverage and upper limits from MAXI/GSC observations
  7. LIGO/Virgo S190630ag: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  8. LIGO/Virgo S190630ag: No neutrino counterpart candidates in ANTARES search
  9. LIGO/Virgo S190630ag: No counterpart candidates in HAWC observations
  10. LIGO/Virgo S190630ag: Identification of a GW compact binary merger candidate
  11. LIGO/Virgo S190630ag Global MASTER-Net observations report
  12. LIGO/Virgo S190630ag: Upper limits from IceCube neutrino searches
  13. GRB 190630B: Swift-XRT refined Analysis
  14. GRB 190630B, Swift-BAT refined analysis
  15. IceCube-190629A: Upper limits from Fermi-GBM Observations
  16. GRB 190627A: VLT/FORS2 spectroscopic redshift
  17. Fermi trigger No 583567803 Global MASTER-Net observations report
  18. GRB Swift Trigger 912102: KAIT Optical Afterglow Candidate
  19. Swift Trigger 912102: possible GRB 190630B
  20. GRB 190630A: Fermi GBM Final Real-time Localization
  21. GRB 190627A: Koshka Zeiss-1000 optical counterpart observations
  22. IceCube-190629A - IceCube observation of a high-energy neutrino candidate event
  23. Baksan Neutrino Observatory Alert 190629.56 Global MASTER-Net observations report
  24. IceCube Alert 190629.81 Global MASTER-Net observations report
  25. GRB 190627A : Xinglong 2.16m optical observation
  26. GRB 190627A: Swift-XRT refined Analysis
  27. GRB 190627A: GMG observation at the second epoch
  28. GRB 190627A: NOT optical observations
  29. GRB 190627A: Optical imaging by D50 from Ondrejov
  30. GRB 190627A: NIR imaging from Liverpool Telescope
  31. GRB 190627A: Optical imaging and spectroscopy from Calar Alto
  32. GRB 190627A: NUTTelA-TAO optical counterpart observations
  33. GRB 190627A: Swift-BAT refined analysis (short-soft burst)
  34. GRB 190610A: Further Swift-XRT observations
  35. GRB 190628A: Fermi GBM Final Real-time Localization
  36. GRB 190627A: GMG observation
  37. GRB 190627A: MASTER optical counterpart observation
  38. GRB190627A: VIRT Afterglow observation
  39. GRB 190627A: Montarrenti Observatory optical detection
  40. GRB 190627A: NUTTelA-TAO optical observations
  41. Fermi trigger No 583327924 Global MASTER-Net observations report
  42. GRB 190627A: Enhanced Swift-XRT position
  43. GRB 190627A: Swift/UVOT Detection
  44. GRB 190627A: Swift detection of a burst
  45. Fermi trigger No 583245413 Global MASTER-Net observations report
  46. Fermi trigger No 583245413 Global MASTER-Net observations report
  47. Fermi trigger No 583221986 Global MASTER-Net observations report
  48. GRB 190626B: Fermi GBM Final Real-time Localization
  49. GRB 190619B: AstroSat CZTI detection
  50. GRB 190626A: Fermi GBM Final Real-time Localization
  51. Fermi trigger No 583111521 Global MASTER-Net observations report
  52. Swift Trigger 911102 is likely not an astrophysical event
  53. IceCube-190619A: prompt emission upper limits from AstroSat-CZTI
  54. Swift GRB190624.86 Global MASTER-Net observations report
  55. Swift trigger 911102: D50 optical limit
  56. Swift Trigger 911102: a possible GRB
  57. GRB 190623A: Fermi GBM Final Real-time Localization
  58. Fermi trigger No 582886211 Global MASTER-Net observations report
  59. GRB 190622A: BALROG localization (Fermi Trigger 582886211 / GRB 190622368)
  60. GRB 190622A: Fermi GBM Final Real-time Localization
  61. Fermi trigger No 582856902 Global MASTER-Net observations report
  62. GRB 190615B: AstroSat CZTI detection
  63. Fermi trigger No 582748289 Global MASTER-Net observations report
  64. Fermi trigger No 582759998 Global MASTER-Net observations report
  65. Fermi-LAT Gamma-ray Observations of IceCube-190619A
  66. IceCube-190619A: No counterpart candidates in ANTARES data
  67. IceCube-190619A: IceCube additional correlated neutrino search: upper limits
  68. IceCube-190619A - HAWC follow-up
  69. LIGO/Virgo S190426c: Swift UVOT - no new counterpart candidates identified
  70. LIGO/Virgo S190510g: Swift UVOT - no new counterpart candidates identified
  71. GRB 190620A: BALROG localization (Fermi Trigger 582725415 / GRB 190620507)
  72. GRB 190620A: Fermi GBM Final Real-time Localization
  73. Fermi trigger No 582615488 Global MASTER-Net observations report
  74. IceCube-190619A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  75. Fermi trigger No 582615488 Global MASTER-Net observations report
  76. IceCube-190619A: not observable by Fermi-GBM
  77. Fermi GBM trigger 190619235/582615488 likely not a GRB
  78. IceCube-190619A - IceCube observation of a high-energy neutrino candidate event
  79. Fermi trigger No 582646590 Global MASTER-Net observations report
  80. GRB 190619B: BALROG localization (Fermi Trigger 582646590 / GRB 190619595)
  81. GRB 190619B: Fermi GBM Final Real-time Localization
  82. GRB 190613A: SEDM Observations
  83. Fermi trigger No 582596766 Global MASTER-Net observations report
  84. GRB 190613B: JCMT SCUBA-2 sub-mm observations
  85. GRB 190619A: Fermi GBM Final Real-time Localization
  86. GRB 190613B: AstroSat CZTI detection
  87. GRB 190611B: AstroSat CZTI detection
  88. Konus-Wind observation of GRB 190613B
  89. GRB 190615B: Insight-HXMT/HE detection
  90. GRB 190615A: Insight-HXMT/HE detection
  91. GRB 190613B: Kitab observatory optical upper limit
  92. Fermi trigger No 582304592 Global MASTER-Net observations report
  93. GRB 190615A: Fermi GBM Final Real-time Localization
  94. GRB 190613A: Kitab and AbAO optical upper limit
  95. Fermi trigger No 582159815 Global MASTER-Net observations report
  96. GRB 190613B: SEDM Observations
  97. GRB 190613A: SEDM Observations
  98. GRB 190610A: Swift/UVOT Upper Limits
  99. GRB 190610A: Swift-XRT observations
  100. GRB 190613B: Optical observation from Asiago Schmidt

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