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"

35431 results found.

  1. Fermi Gamma-ray Burst Monitor trigger 231107654 / 721064512 is not a GRB
  2. GRB 231104A: FRAM-ORM optical limit
  3. LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
  4. Fermi GRB 231106A: Global MASTER-Net observations report
  5. GRB 231104A: Wendelstein Optical/Infrared Observations
  6. GRB 231104A: NuSTAR Observation of the prompt emission
  7. GRB 231106A: Fermi GBM Final Real-time Localization
  8. GRB 231104A: 3.6m DOT optical upper limit
  9. IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
  10. GRB 231104A: NOT upper limit
  11. GRB 231104A: Fermi GBM Observation
  12. GRB 231104B: Fermi GBM Final Real-time Localization
  13. Fermi GRB 231103A: Global MASTER-Net observations report
  14. GRB 231104A: AKO Upper Limit
  15. GRB 231104A: AstroSat CZTI detection
  16. GRB 231104A: Swift-XRT refined Analysis
  17. GRB 231104A: Fermi-LAT detection
  18. GRB 231104A: Swift/UVOT Upper Limits
  19. GRB 231104A: Enhanced Swift-XRT position
  20. GRB231104A: LCOGT Optical Upper Limits
  21. GRB 231104A: Swift detection of a bright burst
  22. GRB 231104A: Fermi GBM Final Real-time Localization
  23. GRB 231103A: Fermi GBM Final Real-time Localization
  24. GRB 231101A: Glowbug gamma-ray detection
  25. GRB 231024A: GRANDMA observations of AT2023vuc/GOTO23baj candidate
  26. GRB 231101A: Fermi GBM Final Real-time Localization
  27. GRB 231030B: GRBAlpha detection
  28. GRB 231028B: VZLUSAT-2 detection
  29. GRB 231030B: Fermi GBM Detection
  30. GRB 231030B: AstroSat CZTI detection
  31. Fermi GRB 231030B: Global MASTER-Net observations report
  32. IPN triangulation of GRB 231020A
  33. GRB 231030B: BALROG localization (Fermi Trigger 720388704 / GRB 231030832)
  34. GRB 231030B: Fermi GBM Final Real-time Localization
  35. GRB 231028A: Swift-BAT refined analysis
  36. IceCube-231027A: Upper limits from a search for additional neutrino events in IceCube
  37. LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
  38. GRB 231024A: AKO Optical Counterpart Candidate
  39. GRB 231028A: CALET Gamma-Ray Burst Monitor detection
  40. Fermi GRB 231030A: Global MASTER-Net observations report
  41. GRB 231030A: Fermi GBM Final Real-time Localization
  42. GRID detection of GRB 231020A
  43. GRB 231028A: AstroSat CZTI detection
  44. GRB 231028A: Glowbug gamma-ray detection
  45. GRB 231028A: Fermi GBM Detection
  46. Swift GRB 231028A: Global MASTER-Net observations report
  47. GRB 231028A: Swift detection of a burst
  48. GRB 231028A: Fermi GBM Final Real-time Localization
  49. GRB 231019A: Glowbug gamma-ray detection
  50. GRB 231025A: Fermi GBM Observation
  51. GRB 231024A: Fermi GBM Observation
  52. GRB 231025A: Swift/BAT-GUANO detection of a likely short burst
  53. GRB 231025A: Fermi GBM Final Localization
  54. GRB 231024A: X-shooter spectroscopy of AT2023vuc/GOTO23baj reveals a young supernova with flash ionisation features
  55. GRB 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
  56. GRB 231020A: AstroSat CZTI detection
  57. GRB 231020B: AstroSat CZTI detection
  58. GRB 231024A: GOTO optical counterpart candidate
  59. GRB 231024A: Fermi GBM Final Localization
  60. GRB 231018A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  61. LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO
  62. GRB 231020A: Fermi GBM Detection
  63. GRID detection of GRB 231004A
  64. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  65. GRB 231019A: VZLUSAT-2 detection
  66. GRB 231018A: VZLUSAT-2 detection
  67. GRB 231020B: BALROG localization (Fermi Trigger 719530557 / GRB 231020900)
  68. GRB 231020B: Fermi GBM Final Real-time Localization
  69. GRB 231020A: BALROG localization (Fermi Trigger / GRB 231020790)
  70. LIGO/Virgo/KAGRA S231020ba: Upper limits from Fermi-GBM Observations
  71. GRB 231015A: NuSTAR Detection of Prompt Emission
  72. Fermi GRB 231020A: Global MASTER-Net observations report
  73. GRB 231020A: Fermi GBM Final Real-time Localization
  74. GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  75. GRB 231017A: 1.3m DFOT Optical upper limit
  76. IceCube-231004A: Upper limits from Fermi-GBM Observations
  77. GRB 231018A: GRBAlpha detection
  78. GRB 231018A: CALET Gamma-Ray Burst Monitor detection
  79. Fermi GRB 231019A: Global MASTER-Net observations report
  80. GRB 231018A: Glowbug gamma-ray detection
  81. Konus-Wind detection of GRB 231018A
  82. IPN triangulation of GRB 231018A
  83. GRB 231017A: Swift/UVOT Upper Limit
  84. GRB 230911C: ATCA detection of possible radio counterpart
  85. GRB 231019A: Fermi GBM Final Real-time Localization
  86. GRB 231017A: GOTO optical upper limits
  87. GRB 231017A: JinShan optical upper limit
  88. GRB 231018A: GROWTH-India Follow-Up of a Fermi Long GRB
  89. GRB 231017A: Las Cumbres optical upper limit
  90. GRB 231015A: Glowbug gamma-ray detection
  91. GRB 231017A: LCOGT Optical Upper Limits
  92. GRB231017A: GROWTH-India upper limits on the optical afterglow
  93. GRB 231015A: AstroSat CZTI detection
  94. GRB 231018A: Fermi GBM Detection
  95. GRB 231017A: Fermi GBM Detection
  96. GRB 231017A: Swift-XRT observations
  97. GRB 231012B may not be a GRB
  98. GRB 231018A: BALROG localization (Fermi Trigger / GRB 231018521)
  99. GRB 231018A: Fermi GBM Final Real-time Localization
  100. GRB 231017A: Swift ToO 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