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"

35321 results found.

  1. GRB 251214B: UAFO optical upper limit
  2. GRB 251214B: VLT/X-shooter observations
  3. GRB 251213A: GRID-10B observation
  4. GRB 251214B: Swift-BAT refined analysis
  5. GRB 251202A: radio detection with the VLA
  6. GRB 251214B: AbAO optical observations
  7. GRB 251214B: LCO detection of the optical counterpart
  8. GRB 251209A: GECAM-B observation of a long burst
  9. GRB 251214D: GECAM-B observation of a long burst
  10. GRB 251214B: Fermi GBM Observation
  11. GRB 251209A: Insight-HXMT/HE detection
  12. GRB 251215A: Swift ToO observations
  13. GRID detection of GRB 251213A
  14. GRB 251203B: AbAO optical observations
  15. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  16. GRB 251214B: GECAM-B observation of a long burst
  17. GRB 251214B: Swift-XRT refined Analysis
  18. GRB 251213A: SVOM/GRM observation
  19. EP251214a: KAIT optical upper limit
  20. GRB 251214D: AstroSat CZTI detection of a long burst
  21. GRB 251213A: AstroSat CZTI detection
  22. GRB 251214A: AstroSat CZTI detection
  23. GRB 251213A: GECAM-B detection
  24. GRB 251214B: Swift/UVOT Detection
  25. GRB 251215A: Fermi GBM Final Real-time Localization
  26. GRB 251214B: COLIBRÍ observations of the afterglow
  27. GRB 251214A: GECAM-B observation of a likely long burst
  28. GRB 251214B: 1.3m DFOT optical detection
  29. GRB 251214B: Enhanced Swift-XRT position
  30. GRB 251214B: Xinglong-2.16m optical observation
  31. GRB 251214C: Fermi GBM Final Localization
  32. GRB 251214B : MASTER optical afterglow detection
  33. GRB 251214B: SVOM/C-GFT optical observations
  34. EP251214a: COLIBRÍ optical upper limit
  35. Swift GRB 251214B: Global MASTER-Net observations report
  36. GRB 251214B: Swift detection of a burst with an optical counterpart
  37. GRB 251214B: Fermi GBM Final Real-time Localization
  38. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  39. Fermi GRB 251214A: Global MASTER-Net observations report
  40. GRB 251214A: Fermi GBM Final Real-time Localization
  41. EP251212a: KAIT optical upper limit
  42. EP251212a / GRB 251212A: AstroSat CZTI detection
  43. GRB 251211B: AstroSat CZTI detection
  44. GRB 251209A: NuSTAR detection of prompt emission
  45. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  46. Fermi GRB 251211B: Global MASTER-Net observations report
  47. GRB 251211B: Fermi GBM Final Real-time Localization
  48. GRB 251211A: Fermi GBM Final Real-time Localization
  49. GRB 251209A: Fermi GBM observation
  50. GRB 251205A: 1.3m DFOT optical upper limit
  51. GRB 251209A: AstroSat CZTI detection
  52. EP251124a: Mondy optical upper limit
  53. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  54. EP251130a: Mondy and AbAO optical observations
  55. GRB 251208A: AstroSat CZTI detection
  56. Fermi GBM Sub-Threshold Detection of GRB 251205A
  57. GRB 251208A: Glowbug gamma-ray detection
  58. GRB 251208B: COLIBRÍ optical upper limits
  59. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  60. GRB 251208C: GECAM-B observation of a short burst
  61. GRB 251208A: GECAM-B observation of a short burst
  62. Fermi GRB 251209A: Global MASTER-Net observations report
  63. Fermi GRB 251208C: Global MASTER-Net observations report
  64. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  65. GRB 251208B: Swift-XRT afterglow detection
  66. GRB 251208D: LAST optical upper limit
  67. GRB 251209A: Fermi GBM Final Real-time Localization
  68. GRB 251208D: LCO analysis of the XRT sources
  69. GRB 251208B: Fermi GBM Observation
  70. GRB 251208B: GROWTH-India Telescope optical upper limits
  71. GRB 251205A: J-band detection with WINTER
  72. GRB 251208D: Swift-XRT observations
  73. GRB 251208A: SVOM/GRM observation of a short burst
  74. GRB 251208C: SVOM/GRM observation of a short burst
  75. GRB 251129A: e-MERLIN C-band observations
  76. GRB 251205A: Liverpool Telescope further optical follow-up observations
  77. GRB 251208D: LCO optical upper limits
  78. GRB 251208B: Swift ToO observations
  79. GRB 251208B: Fermi-LAT detection
  80. GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
  81. GRB 251208D: SVOM possible detection of a faint burst
  82. GRB 251206A: SVOM detection of a burst through offline search
  83. GRB 251208C: Fermi GBM Final Real-time Localization
  84. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  85. GRB 251208B: Fermi GBM Final Real-time Localization
  86. GRB 251208A: Fermi GBM Final Real-time Localization
  87. GRB 251205A: FTW optical and NIR observations
  88. EP-WXT trigger 01709249380: KAIT confirmation of a stellar flare
  89. GRB 251205A: Liverpool Telescope further optical follow-up observations
  90. GRB 251205A: ZTF and ATLAS optical afterglow detections
  91. GRB 251205A: GROWTH-India Telescope optical observations
  92. GRB 251205A: Swift-BAT refined analysis
  93. GRB 251205A: Swift-XRT refined Analysis
  94. GRB 251205A: Swift/UVOT Detection
  95. GRB 251205A: Liverpool Telescope optical follow-up observations
  96. GRB 251203C: Swift/UVOT Upper Limit
  97. Konus-Wind detection of GRB 251118A
  98. GRB 251205A: Zeiss-1000 Koshka observatory optical observations
  99. GRB 251205A: COLIBRÍ optical observations
  100. GRB 251205A: GOTO optical afterglow 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