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"

11841 results found.

  1. GRB 260101A: COLIBRÍ optical observations
  2. GRB 260102B: Fermi GBM Final Real-time Localization
  3. Fermi GBM Sub-Threshold Detection of GRB 260102A
  4. Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB
  5. GRB 260101A: Fermi GBM Observation
  6. GRB 260101A: GECAM-B detection
  7. GRB 260101A: NOT spectroscopic observations
  8. GRB 260101A: SVOM/GRM observation
  9. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  10. GRB 260101A: LCO detection of the optical counterpart
  11. GRB 260101A: Fermi GBM Final Real-time Localization
  12. Fermi Gamma-ray Burst Monitor trigger 788833547/251231018 is not a GRB
  13. GRB 251231A: Fermi GBM Final Real-time Localization
  14. GRB 251222A: Mondy Optical Observations
  15. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  16. Fermi GRB 251228A: Global MASTER-Net observations report
  17. GRB 251228A: Fermi GBM Final Real-time Localization
  18. GRB 251226A: GECAM-B detection
  19. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  20. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  21. Fermi Gamma-ray Burst Monitor trigger 788368008/251225630 is not a GRB
  22. GRB 251222A/EP251222b: Optical detection with Kinder observations
  23. GRB 251222A/EP251222b: FTW optical and NIR observations
  24. GRB 251205A: Kilonova-Catcher optical afterglow detection
  25. GRB 251222A: AbAO optical observations
  26. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  27. GRB 251222A: ZTSH BVRI optical observations
  28. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  29. GRB 251222A: Continued 1.3m DFOT optical observation
  30. GRB 251222A: Fermi GBM Observation
  31. GRB 251222A / EP251222b: GECAM-B observation
  32. Konus-Wind detection of GRB 251222A / EP251222b
  33. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  34. GRB 251222A / EP251222b: GOTO optical counterpart detection
  35. GRB 251222A / EP251222b: LCO optical observations
  36. GRB 251222A: 1.3m DFOT optical detection
  37. GRB251221A: 7DT optical upper limits
  38. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  39. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  40. EP251222b/GRB 251222A: SVOM/GRM observation
  41. GRB 251222A: PRIME near-infrared detection
  42. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  43. GRB 251222A: NOT optical observations
  44. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  45. IPN triangulation of GRB 251220B (short)
  46. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  47. GRB 251222A: SVOM detection of a long burst
  48. GRB 251222A: Fermi GBM Final Real-time Localization
  49. GRB 251221A: PRIME near-infrared observation
  50. GRB 251221A: UAFO and Mondy optical upper limit
  51. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  52. GRB 251221A: Fermi GBM Observation
  53. GRB 251221B: Fermi GBM Final Real-time Localization
  54. GRB 251220B: SVOM/GRM observation of a short burst
  55. GRB 251221A: COLIBRÍ detection of the optical counterpart
  56. GRB 251221A: Fermi GBM Final Real-time Localization
  57. GRB 251220B: Fermi GBM Final Real-time Localization
  58. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  59. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  60. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  61. GRB 251214B: VIRT Optical Upper Limit
  62. Fermi trigger No 787736968: Global MASTER-Net observations report
  63. Fermi GRB 251217A: Global MASTER-Net observations report
  64. GRB 251217A: Fermi GBM Final Real-time Localization
  65. GRB 251215A: Swift/UVOT Upper LImits
  66. GRB 251215A: Fermi GBM Observation
  67. Fermi GRB 251216A: Global MASTER-Net observations report
  68. GRB 251202A/EP251202a: Koshka optical upper limit
  69. GRB 251214B: Mondy optical upper limit
  70. GRB 251215A: COLIBRÍ optical upper limit
  71. GRB 251216A: Fermi GBM Final Real-time Localization
  72. Fermi GRB 251215A: Global MASTER-Net observations report
  73. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  74. GRB 251215A: Glowbug gamma-ray detection
  75. GRB 251214B: UAFO optical upper limit
  76. GRB 251214B: VLT/X-shooter observations
  77. GRB 251202A: radio detection with the VLA
  78. GRB 251214B: AbAO optical observations
  79. GRB 251214B: LCO detection of the optical counterpart
  80. GRB 251209A: GECAM-B observation of a long burst
  81. GRB 251214B: Fermi GBM Observation
  82. GRB 251209A: Insight-HXMT/HE detection
  83. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  84. GRB 251214B: GECAM-B observation of a long burst
  85. GRB 251214A: AstroSat CZTI detection
  86. GRB 251213A: GECAM-B detection
  87. GRB 251215A: Fermi GBM Final Real-time Localization
  88. GRB 251214B: COLIBRÍ observations of the afterglow
  89. GRB 251214A: GECAM-B observation of a likely long burst
  90. GRB 251214B: 1.3m DFOT optical detection
  91. GRB 251214C: Fermi GBM Final Localization
  92. GRB 251214B : MASTER optical afterglow detection
  93. Fermi trigger No 787396657: Global MASTER-Net observations report
  94. GRB 251214B: SVOM/C-GFT optical observations
  95. EP251214a: COLIBRÍ optical upper limit
  96. GRB 251214B: Fermi GBM Final Real-time Localization
  97. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  98. Fermi GRB 251214A: Global MASTER-Net observations report
  99. GRB 251214A: Fermi GBM Final Real-time Localization
  100. GRB 251211B: AstroSat CZTI detection

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