Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
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"
  1. LIGO/Virgo MS200619bf: Retraction of a test binary neutron star candidate
  2. LIGO/Virgo MS200618bx: Retraction of a test binary neutron star candidate
  3. LIGO/Virgo MS200618bq: Retraction of a test binary neutron star candidate
  4. GRB 200619B: Fermi GBM Final Real-time Localization
  5. GRB 200619A: Insight-HXMT/HE detection
  6. Fermi trigger No 614226976: Global MASTER-Net observations report
  7. GRB 200613A: continued Kitab optical observations
  8. GRB 200613A: SAO RAS optical observations
  9. GRB 200617A: Insight-HXMT/HE detection
  10. IceCube-200530A - SN2020lls likely unrelated
  11. Swift/UVOT Observations of IceCube 200615A
  12. GRB 200613A: Mondy optical observations
  13. LIGO/Virgo MS200614ct: Identification of a test binary black hole candidate
  14. Fermi trigger No 614103490: Global MASTER-Net observations report
  15. Baksan Neutrino Observatory Alert 200617.47: Global MASTER-Net observations report
  16. GRB 200615B: CALET Gamma-Ray Burst Monitor detection
  17. Swift-XRT observations of IceCube 200615A
  18. IceCube-200615A: No significant detection in HAWC
  19. GRB 200613A: Jet-break from Xinglong-2.16m optical observations
  20. Fermi-LAT Gamma-ray Observations of IceCube-200615A
  21. IceCube-200614A: No significant detection in HAWC
  22. IceCube-200615A: Upper limits from a search for additional neutrino events in IceCube
  23. GRB 200616B: Fermi GBM Final Real-time Localization
  24. Fermi-LAT Gamma-ray Observations of IceCube-200614A and detection of a new gamma-ray source, Fermi J0202.8+3132
  25. LIGO/Virgo MS200615ce: Identification of a test binary black hole candidate
  26. GRB 200613A: CALET Gamma-Ray Burst Monitor detection
  27. LIGO/Virgo MS200614bz: Test Identification of a binary neutron star candidate
  28. GRB 200613A: MITSuME Akeno optical upper limits
  29. Fermi GRB 200616A: Global MASTER-Net observations report
  30. GRB 200615B: MAXI/GSC detection
  31. GRB 200616A: Fermi GBM Final Real-time Localization
  32. GRB 200613A: continued AbAO optical afterglow observations
  33. IceCube-200615A: Upper limits from Fermi-GBM Observations
  34. IceCube-200614A: Upper limits from a search for additional neutrino events in IceCube
  35. IceCube-200614A: not observable by Fermi-GBM
  36. IceCube-200615A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  37. IceCube Alert 200615.62: Global MASTER-Net observations report
  38. IceCube-200614A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  39. LIGO/Virgo MS200615h: Retraction of a test binary neutron star candidate
  40. IceCube-200615A: IceCube observation of a high-energy neutrino candidate event
  41. GRB 200613A: Continued Xinglong-2.16m optical observations
  42. Fermi GRB 200615A: Global MASTER-Net observations report
  43. GRB 200615A: Fermi GBM Final Real-time Localization
  44. Baksan Neutrino Observatory Alert 200614.34: Global MASTER-Net observations report
  45. IceCube Alert 200614.53: Global MASTER-Net observations report
  46. GRB 200613A: Swift/UVOT Detection
  47. GRB 200613A: Xinglong-2.16m optical observations
  48. Fermi GRB 200614A: Global MASTER-Net observations report
  49. IceCube-200614A - IceCube observation of a high-energy neutrino candidate track-like event
  50. GRB 200614A: Fermi GBM Final Real-time Localization
  51. GRB 200613A: Liverpool Telescope observations
  52. GRB 200613A: OAJ Afterglow: Error in Coordinates
  53. GRB 200613A: Kitab and AbAO optical afterglow observations, host galaxy candidate
  54. GRB 200613A: Swift-XRT afterglow detection
  55. GRB 200613A: Candidate afterglow from OAJ
  56. GRB 200612A: Fermi GBM detection
  57. Fermi GRB 200613A: Global MASTER-Net observations report
  58. GRB 200613A: Swift ToO observations
  59. GRB 200613A: Fermi-LAT detection
  60. GRB 200613A: Fermi GBM observation
  61. GRB 200612A: Swift/UVOT Upper Limits
  62. Baksan Neutrino Observatory Alert 200611.74: Global MASTER-Net observations report
  63. BALROG localization (Fermi Trigger 613719013 / GRB 200613229)
  64. GRB 200613A: Fermi GBM Final Real-time Localization
  65. GRB 200612A: Swift-BAT refined analysis
  66. GRB 200612A: Swift-XRT refined Analysis
  67. Konus-Wind observation of ultra-long GRB 200612A
  68. GRB 200612A: Enhanced Swift-XRT position
  69. GRB 200612A: Late Optical Maximum Deteted by MASTER
  70. GRB 200612A: BOOTES-3/YA optical upper limit
  71. Fermi trigger No 613630183: Global MASTER-Net observations report
  72. Swift GRB200612.19: Global MASTER-Net OT detection
  73. Swift GRB200612.19: Global MASTER-Net observations report
  74. GRB 200612A: Swift detection of a burst
  75. GRB 200609A: Insight-HXMT/HE detection
  76. GRB 200608A: Swift-BAT refined analysis
  77. Konus-Wind detection of GRB 200605A
  78. GRB 200605A: CALET Gamma-Ray Burst Monitor detection
  79. IceCube-200530A - SN2020lam classified as SN II without evidence of CSM interaction
  80. GRB 200609A: Fermi GBM Final Real-time Localization
  81. Swift GRB 200608A: Global MASTER-Net observations report
  82. GRB 200608A: BOOTES-3 and BOOTES-4 optical upper limit
  83. GRB 200608A: Swift detection of a burst
  84. GRB 200607B: AstroSat CZTI detection
  85. GRB 200522A: Further HST F125W Observations
  86. Fermi GRB 200607B: Global MASTER-Net observations report
  87. GRB 200607B: Fermi GBM Final Real-time Localization
  88. Fermi GRB 200607A: Global MASTER-Net observations report
  89. IPN triangulation of GRB 200605A (short)
  90. GRB 200607A: Fermi GBM Final Localization
  91. GRB 200607A: BALROG localization (Fermi Trigger 613212114 / GRB 200607362)
  92. GRB 200530A: Fermi GBM detection
  93. GRB 200530A: CALET Gamma-Ray Burst Monitor detection
  94. Correction to the GCN 27886: Previous bursts of 1RXS J1708-4009 (Swift trigger 975998)
  95. 1RXS J1708−4009: Swift-BAT refined analysis
  96. Fermi GRB 200605A: Global MASTER-Net observations report
  97. GRB 200605A: Fermi GBM Final Real-time Localization
  98. GRB 200530A: Fermi-LAT detection
  99. GRB 200604A: AstroSat CZTI detection
  100. Fermi trigger No 612988790: Global MASTER-Net observations report

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