Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

11649 results found.

  1. GRB 250725A: Fermi GBM Observation
  2. Konus-Wind detection of GRB 250725A
  3. GRB 250725A: SVOM/GRM observation
  4. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  5. GRB 250725A: Fermi-LAT detection
  6. GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
  7. GRB 250725A: SVOM/VT optical candidate
  8. GRB 250725A: Fermi GBM Final Real-time Localization
  9. Fermi GRB 250725A: Global MASTER-Net observations report
  10. GRB 250723B: Fermi GBM Final Real-time Localization
  11. GRB 250721A: Fermi GBM Observation
  12. GRB 250723A: Fermi GBM Final Real-time Localization
  13. GRB 250722A: Fermi GBM Final Real-time Localization
  14. GRB 250717B: SVOM/GRM observation
  15. GRB 250721A: MAXI/GSC detection
  16. GRB 250721A: Fermi GBM Final Localization
  17. GRB 250720B: Fermi GBM Final Localization Correction
  18. GRB 250720A: Fermi GBM Final Localization
  19. Fermi trigger No 774730635: Global MASTER-Net observations report
  20. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  21. Fermi Gamma-ray Burst Monitor trigger 774670514/250720094 is not a GRB
  22. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  23. GRB 250717B: COLIBRÍ optical upper limit
  24. GRB 250717B: Swift-XRT observations
  25. GRB 250718B: Fermi GBM Final Localization Correction
  26. GRB 250718B: Fermi GBM Final Real-time Localization
  27. GRB 250717B: Swift ToO observations
  28. GRB 250717B: Fermi GBM Observation
  29. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  30. Konus-Wind detection of GRB 250716A
  31. GRB 250716A: Swift-XRT afterglow detection
  32. GRB 250717B: Fermi GBM Final Real-time Localization
  33. GRB 250716A: Lesedi Detection of Fading Optical Transient GOTO25eyp
  34. GRB 250717A: Fermi GBM Final Real-time Localization
  35. GRB 250716A: Swift ToO observations
  36. GRB 250716A: GOTO tentative optical counterpart candidate
  37. GRB 250716A: Fermi GBM Observation
  38. GRB 250714A: SVOM/GRM observation
  39. Fermi GRB 250716A: Global MASTER-Net observations report
  40. GRB 250716A: Fermi GBM Final Real-time Localization
  41. Fermi GRB 250715A: Global MASTER-Net observations report
  42. GRB 250715A: Fermi GBM Final Real-time Localization
  43. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  44. Fermi GRB 250714A: Global MASTER-Net observations report
  45. GRB 250714A: Fermi GBM Final Real-time Localization
  46. GRB 250711A: DDOTI Optical Upper Limit
  47. GRB 250711A: SVOM/GRM observation
  48. Fermi GRB 250711A: Global MASTER-Net observations report
  49. GRB 250711A: BALROG localization (Fermi Trigger 773937617 / GRB 250711611)
  50. GRB 250711A: Fermi GBM Final Real-time Localization
  51. GRB 250702B,D,E / EP250702a: ALMA detection
  52. GRB 250702B,D,E / EP250702a: 10 GHz detection with the VLA
  53. GRB 250709A: Fermi GBM Final Localization
  54. GRB 250706B/C: Insight-HXMT detection
  55. GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
  56. IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
  57. IceCube-250708A - IceCube observation of a high-energy neutrino candidate track-like event
  58. Fermi GRB 250708A: Global MASTER-Net observations report
  59. GRB 250708A: Fermi GBM Final Real-time Localization
  60. GRB 250706B/C: Konus-Wind analysis of the prompt emission
  61. GRB 250706B: SVOM observations interpreted as the afterglow of GRB 250706C
  62. GRB 250702F: radio detection with the VLA
  63. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  64. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  65. GRB 250706B/C: Fermi-LAT detection
  66. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  67. GRB 250702F: GRANDMA observations
  68. IceCube-250706A - IceCube observation of a high-energy neutrino candidate track-like event
  69. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  70. GRB 250703A: EIRSAT-1 GMOD Detection
  71. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  72. Konus-Wind detection of GRB 250703A
  73. IPN triangulation of GRB 250703A
  74. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  75. GRB 250702F: Kilonova-Catcher optical afterglow detection
  76. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  77. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart
  78. LIGO/Virgo/KAGRA S250704ab: Upper limits from Fermi-GBM Observations
  79. GRB 250702A: Insight-HXMT detection
  80. GRBs 250702B/C/D/E / EP250702a: Swift/UVOT Upper Limits
  81. GRB 250702B / EP2050702a: FTW optical and NIR observations
  82. Konus-Wind detection of GRB 250702F
  83. GRB 250702F: GROWTH-India Telescope optical observations
  84. EP250702a: WFST optical observations
  85. GRB 250702F: optical photometry from Konkoly
  86. GRB 250702F: SVOM/VT optical observation
  87. GRB 250702A: CALET Gamma-Ray Burst Monitor detection
  88. Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst
  89. Fermi GRB 250703A: Global MASTER-Net observations report
  90. GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit
  91. GRB 250702F: Fermi GBM Observation
  92. GRB 250702F: Leavitt Observatory optical observations
  93. GRB 250702F: AKO Optical Afterglow Detection
  94. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  95. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  96. GRB 250702A: GECAM-B detection
  97. GRBs 250702B/C/D/E / EP250702a: Swift XRT localization
  98. GRB 250702B,C,D,E/EP250702a: COLIBRÍ optical upper limit
  99. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  100. GRB 250702F: TRT Optical Observation

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