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"
  1. GRB 221025A: AstroSat CZTI detection
  2. GRB 221009A: SARA-RM 1m Optical Afterglow Detection
  3. GRB 221025A: Fermi GBM Observation
  4. GRB 221009A: spectroscopic confirmation of SN in LBT spectra
  5. Konus-Wind detection of GRB 221023A
  6. GRB 221024A: Swift/UVOT UV upper limits
  7. GRB 221022A: Swift-XRT observations
  8. GRB 221024A: Swift-XRT refined Analysis
  9. GRB 221023A: Fermi GBM Observation
  10. GRB 221022B: Detection by GRBAlpha
  11. GRB 221025A: Fermi-LAT detection
  12. IPN triangulation of GRB 221022B (long)
  13. GRB 221024A: GIT confirmation of the optical afterglow
  14. LAT GRB221025.04: Global MASTER-Net observations report
  15. GRB 221024A: Enhanced Swift-XRT position
  16. GRB 221024A: D50 candidate afterglow
  17. GRB 221022B: AstroSat CZTI detection
  18. GRB 221022A: Fermi GBM detection
  19. GRB 221022A: Swift ToO observations
  20. Fermi Gamma-ray Burst Monitor detections of SGR 1935+2154
  21. GRB 221023A: Fermi-LAT detection
  22. GRB 221022B: Fermi GBM detection
  23. GRB 221021A: Fermi GBM observation
  24. GRB 221009A: Determination of the black holes mass and spin
  25. GRB 221024A: Swift detection of a burst
  26. GRB 221023A: Fermi GBM Final Localization
  27. GRB 221023A: AGILE detection of a burst
  28. GRB 221022A: Swift/BAT-GUANO detection
  29. GRB 221022B: Swift/BAT-GUANO detection outside the coded FOV
  30. GRB 221022B: AGILE detection
  31. GRB 221009A: James Webb Space Telescope Observations
  32. GRB 221022B: Fermi GBM Final Real-time Localization
  33. GRB 221009A: Analysis of the initial episode using data of GBM/Fermi and SPI-ACS/INTEGRAL
  34. GRB 221009A: optical observations, SN photometric evidence
  35. GRB 221021A: Swift/BAT-GUANO detection outside the coded FOV
  36. GRB 221022A: Fermi GBM Final Real-time Localization
  37. GRB 221020A: Detection by GRBAlpha
  38. SGR 1935+21542: VZLUSAT-2 and GRBAlpha joint detection
  39. GRB 221017A: CALET Gamma-Ray Burst Monitor detection
  40. GRB 221021A: Fermi GBM Final Real-time Localization
  41. GRB 221009A: 1.3m DFOT Optical Observations
  42. Fermi GBM trigger 687320613 / 221013100 (GRB 221013B) is not a GRB
  43. GRB221009A: LBT optical imaging
  44. GRB 221009A: Peak luminosity of the supernova vs. synchrotron afterglow
  45. GRB 221017A: Swift-XRT observations
  46. GRB 221020A: Fermi GBM Final Real-time Localization
  47. Improved IPN localization for GRB 221009A (BepiColombo-MGNS light curve)
  48. GRB 221009A: TNG NIR detection
  49. GRB 221009A: BOAO NIR detections
  50. GRB 221009A X-ray light-curve and the indication of TeV light-curve
  51. AGILE detection of a burst from SGR J1935+2154 reported by VZLUSAT-2
  52. GRB 221009A: Spectroscopic detection of emerging SN features
  53. GRB 221009A: Continued LDT Afterglow Monitoring
  54. GRB 221013B: Swift/BAT-GUANO detection
  55. SGR 1935+2154: Bursting activity detected by VZLUSAT-2
  56. AGILE detection of the 2022 October 17 burst from SGR J1935+2154 reported by Konus-Wind
  57. GRB 221009A: GRANDMA observations
  58. SGR 1935+2154: Detection by GRBAlpha
  59. The probability of observing GRB 221009A at z = 0.151
  60. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 October 17
  61. GRB 221009A: Medicina Radio Telescope observations
  62. GRB 221017A: Swift ToO observations
  63. AGILE detection of short X-ray flaring activity contemporary to SGR J1935+2154 reported bursts
  64. GRB 221009A: Second epoch of NuSTAR data
  65. IPN triangulation of GRB 221017A (long)
  66. GRB 221016A: Swift-BAT refined analysis
  67. GRB 221016A: Swift/UVOT Detection
  68. GRB 221016A: Swift-XRT refined Analysis
  69. Konus-Wind detection of GRB 221016A
  70. GRB 221016A: Fermi GBM observation
  71. GRB 220926B: Detection by GRBAlpha
  72. GRB 221009A: A type I BdHN of exceptional energetics
  73. MAXI GRB221017.24: Global MASTER-Net observations report
  74. GRB 221016A: z-band upper limit, possible afterglow brightening
  75. GRB 221017A: MAXI/GSC detection
  76. GRB 221016A: Enhanced Swift-XRT position
  77. GRB 221016A: LCOGT Optical Afterglow Detection
  78. GRB 221016A: Swift detection of a burst
  79. GRB 221016A: Fermi GBM Final Real-time Localization
  80. Swift GRB221016.99: Global MASTER-Net observations report
  81. GRB 221009A: Faulkes Telescope North continued optical afterglow follow-up
  82. Konus-Wind detection of a short burst coincident with a bright radio burst from SGR 1935+2154
  83. GRB 221009A: continued Assy optical afterglow observations, possible SN evidence
  84. Konus-Wind observation of the recent SGR 1935+2154 activity
  85. GRB 221009A: LEIA X-ray Afterglow Detection
  86. GRB 221009A: ATCA radio spectrum
  87. GRB 221009A: VLT spectroscopic detection of the host galaxy
  88. Fermi Gamma-ray Burst Monitor detections of SGR 1935+2154
  89. GRB 221009A: ATCA detection
  90. GRB 221009A: Armchair Energetics
  91. GRB 221009A: ALMA and ACA detections
  92. GRB 221009A: Fermi LAT data rate effects due to extremely high flux
  93. GRB 221009A: Large Binocular Telescope Observatory optical afterglow detection
  94. GRB 221009A: Pan-STARRS optical photometry
  95. GRB 221009A: VLA detection
  96. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  97. GRB 221009A: continued REM optical/NIR observations and evidence for an achromatic steepening in the afterglow light curve
  98. GRB 221009A: IXPE preliminary upper limits of X-ray polarization
  99. GRB 221009A: OHP optical observations
  100. GRB221009A: RTT-150 optical 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