Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. 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"

45691 results found.

  1. The EP-WXT trigger 01709281429 is likely a flaring star
  2. EP260812a: AZT-22 optical upper limit
  3. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  4. EP260806a: WFST optical observations
  5. The EP-WXT trigger 01709280562 is likely a flaring star
  6. EP260812b: Optical upper limit with Kinder
  7. The EP-WXT trigger 01709279838 is likely a flaring star
  8. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  9. GRB 260808B: Liverpool Telescope further optical observations
  10. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  11. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  12. GRB 260813A: Fermi GBM Final Real-time Localization
  13. EP260812a: NOT and Liverpool Telescope upper limits:
  14. EP260812b: Liverpool Telescope observations
  15. EP260812b: GOTO detection of the optical counterpart
  16. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  17. EP260812a: SVOM/C-GFT optical upper limit
  18. EP260812b: COLIBRÍ optical observations
  19. EP260812b: SVOM/VT optical observation
  20. GRB 260808A: SVOM/GRM observation
  21. EP260812b: Einstein Probe detection of an X-ray transient
  22. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  23. Fermi GBM Sub-Threshold Detection of GRB 260809A
  24. GRB 260810A: Glowbug gamma-ray detection
  25. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  26. GRB 260810A: AstroSat CZTI detection of a long burst
  27. EP260812a: Einstein Probe detection of an X-ray transient
  28. GRB 260809A: SAO RAS optical observations
  29. GRB 260808B: SAO RAS optical observations
  30. GRB 260808B: SVOM/VT optical re-brightening at day 3
  31. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  32. GRB 260806A: CALET Gamma-Ray Burst Monitor detection
  33. GRB 260808A: GECAM-B observation
  34. GRB 260807A: SVOM/ECLAIRs refined analysis
  35. EP260806a: MAO/AZT-22 optical observations
  36. IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
  37. GRB260808B: MAO/AZT-22 optical observations
  38. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  39. GRB 260809A: J-band upper limit with WINTER
  40. EP260809a: VLT/X-shooter spectroscopic redshift z = 3.07
  41. GRB 260806A: Glowbug gamma-ray detection
  42. GRB 260808A: CALET Gamma-Ray Burst Monitor detection
  43. GRB 260805C: CALET Gamma-Ray Burst Monitor detection
  44. GRB 260804A: CALET Gamma-Ray Burst Monitor detection
  45. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  46. The EP-WXT trigger 01709278015 is likely a flaring star
  47. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  48. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  49. GRB 260809A: NOT optical observations
  50. GRB260809A: MAO/AZT-22 optical observations
  51. GRB260809A: OHP/T193 optical observations
  52. IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 260809A: SVOM/VT optical counterpart
  54. EP260809a: J-band upper limit with WINTER
  55. GRB 260808B: J-band upper limit with WINTER
  56. GRB 260808B: SVOM/ECLAIRs refined analysis
  57. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  58. GRB 260809A: SVOM detection of a faint burst
  59. GRB 260808B: Liverpool Telescope optical observations
  60. GRB 260808B: NOT optical observations
  61. GRB 260808B: LCO optical observations
  62. GRB 260808A: NuSTAR detection of prompt emission
  63. EP260809a: COLIBRÍ optical observations
  64. EP260809a: LCO optical observation
  65. EP260809a: OHP/T193 optical observations
  66. GRB260808B: OHP/T193 optical observations
  67. GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
  68. EP260809a: Einstein Probe detection of an X-ray transient
  69. GRB 260808B: SVOM/VT optical afterglow confirmation
  70. GRB 260808C: Fermi GBM Final Real-time Localization
  71. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  72. GRB 260808B: SVOM/VT optical candidate from VHF data
  73. GRB 260808B: SVOM detection of a faint burst
  74. GRB 260808A: BALROG localization (Fermi Trigger 807850307 / GRB 260808119)
  75. Fermi GRB 260808A: Global MASTER-Net observations report
  76. GRB 260808A: Fermi GBM Final Real-time Localization
  77. EP260806a: ZTF serendipitous detection of ZTF26abmjjnm / AT 2026yeh
  78. IceCube Alert 260807A: Global MASTER-Net observations report
  79. IceCube-260805A: One candidate from the Zwicky Transient Facility
  80. GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  81. GRB 260807A: SVOM possible detection of a faint burst
  82. IceCube-260807A - IceCube observation of a high-energy neutrino candidate track-like event
  83. EP260806a: COLIBRÍ optical observations
  84. EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  85. EP260806a: SVOM/VT optical observation
  86. EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
  87. EP260806a: OSIRIS+/GTC redshift z=0.089
  88. EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  89. EP260806a: LCO likely optical counterpart
  90. EP260806a: Einstein Probe detection of an X-ray transient
  91. GRB 260715A: cubesat Avion detection
  92. GRB 260709A: cubesat Avion detection
  93. GRB 260708A: cubesat Avion detection
  94. SN 2026stf / GRB 260708A: ATLAS forced photometry
  95. IceCube-260805A - IceCube observation of a high-energy neutrino candidate track-like event
  96. GRB 260730B: Glowbug gamma-ray detection
  97. GRB 260805C: Glowbug gamma-ray detection
  98. GRB 260805B: Glowbug gamma-ray detection
  99. Fermi GRB 260805A: Global MASTER-Net observations report
  100. GRB 260805B: Fermi GBM Final Localization

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