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"

2463 results found.

  1. EP260417a/GRB 260417A: refined analysis of the EP-WXT and follow-up EP-FXT observations
  2. EP260416a: NOT tentative spectroscopic redshift of z =1.909
  3. GRB 260418A: Fermi GBM Final Real-time Localization
  4. EP260416a: GMG Optical Observation
  5. Fermi GRB 260417A: Global MASTER-Net observations report
  6. GRB 260417B: Fermi GBM Final Real-time Localization
  7. GRB 260417A: AstroSat CZTI detection
  8. EP260416a: LCO observations confirm end of flaring phase
  9. EP260324a / AT2026hir: Further multiband optical follow-up with the PKU 60cm Telescope
  10. EP260417a: Einstein Probe detection of an X-ray transient
  11. EP260416a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  12. EP260417b: Einstein Probe detection of a fast X-ray transient
  13. GRB 260414A: Insight-HXMT/HE detection
  14. EP260416a: COLIBRÍ confirmation of the optical rebrightening
  15. EP260416a: WFST optical observations and rebrightening
  16. GRB 260417A: Fermi GBM Final Real-time Localization
  17. GOTO26djh/AT2026jpw: ZTSh R,I bands observations of the transient
  18. EP260416a: SVOM/VT optical observation
  19. GOTO26djh/AT2026jpw: SVOM/VT optical observation
  20. GRB 260415B: Glowbug gamma-ray detection
  21. GRB 260411B: Glowbug gamma-ray detection
  22. GRB 260415A: Insight-HXMT/HE detection
  23. EP260416a: COLIBRÍ optical counterpart candidate
  24. COLIBRI optical observations of the transient GOTO26djh/AT2026jpw
  25. EP260416a: Global MASTER-Net observations report
  26. EP260416a: Einstein Probe detection of an X-ray transient
  27. GOTO26djh/AT2026jpw : MASTER OT observation
  28. GOTO26djh/AT2026jpw: EP-FXT X-ray counterpart detection
  29. GOTO26djh/AT2026jpw transient: SAO RAS optical observations
  30. NOT r-band observations of the transient GOTO26djh/AT2026jpw
  31. GRB 260415B: NuSTAR detection of long prompt emission
  32. GOTO discovery of fast-fading transient GOTO26djh/AT2026jpw, a candidate orphan afterglow
  33. GRB 260415B: Fermi GBM Final Localization
  34. GRB 260415A: Fermi GBM Final Real-time Localization
  35. Fermi trigger No 797912738: Global MASTER-Net observations report
  36. GRB 260414A: Glowbug gamma-ray detection
  37. EP260409a: Early NIR limits from MIRAGE on the MDM 1.3m telescope
  38. EP260321a: CMO SAI J,K observations
  39. GRB 260412A: Insight-HXMT/HE detection
  40. GRB 260414A: Fermi GBM Final Real-time Localization
  41. The EP-WXT trigger 01709260122 is likely a flaring star
  42. Fermi GRB 260413A: Global MASTER-Net observations report
  43. GRB 260410A: Glowbug gamma-ray detection of a short burst
  44. GRB 260413A: Fermi GBM Final Real-time Localization
  45. GRB 260410B: Insight-HXMT/HE detection
  46. GRB 260410A: Insight-HXMT/HE detection
  47. GRB 260411B: GECAM-B observation of a long burst
  48. EP260321a: SVOM/VT optical observations and color changes around peak
  49. GRB 260410A: CALET Gamma-Ray Burst Monitor detection
  50. The EP-WXT trigger 01709260010 is likely a flaring star
  51. GRB 260412A: GECAM-B observation of a long burst
  52. Fermi GRB 260412A: Global MASTER-Net observations report
  53. GRB 260412A: Fermi GBM Observation
  54. GRB 260310A / AT2026fgk: NuSTAR detection of the rebrightening
  55. GRB 260411B: Fermi-LAT detection
  56. GRB 260412A: SVOM detection of a long burst
  57. GRB 260412A: Fermi GBM Final Real-time Localization
  58. GRB 260411B: COLIBRÍ optical observations
  59. GRB 260410B: Fermi GBM Observation
  60. GRB260411B: 3.6m DOT optical observation
  61. GRB 260411A: SVOM/GRM observation
  62. GRB 260407B: SVOM/GRM detection of a possible magnetar X-ray burst
  63. GRB 260411B: SVOM/GRM observation of a long burst
  64. GRB 260409A: Insight-HXMT/HE detection
  65. GRB 260411B: Fermi GBM Detection
  66. GRB 260411B: GOTO optical counterpart candidate
  67. EP260409a: Gemini/FLAMINGOS2 J-band counterpart
  68. GRB 260411B: BALROG localization (Fermi Trigger 797587480 / GRB 260411337)
  69. GRB 260411B: Fermi GBM Final Real-time Localization
  70. GRB 260411A: Fermi GBM Final Real-time Localization
  71. GRB 260410A: COLIBRÍ optical upper limit
  72. EP-WXT01709259790: Optical Upper limits with kinder observations
  73. GRB 260410A: Fermi GBM Observation
  74. GRB 260410B: SVOM/GRM detection of a short faint burst
  75. The EP-WXT trigger 01709259790 is likely a flaring star
  76. GRB 260410B: Fermi GBM Final Real-time Localization
  77. EP-WXT01709259790: Xinglong optical upper limit
  78. GRB 260410A: Fermi-LAT detection
  79. GRB 260410A: Fermi GBM Final Real-time Localization
  80. EP260409a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  81. EP260321a: Chandra X-ray Non-detection
  82. GRB 260409A: Fermi GBM Final Real-time Localization
  83. The EP-WXT trigger 01709259773 is likely a flaring star
  84. GRB 260407A: GECAM-A detection
  85. GRB 260407A: Insight-HXMT/HE detection
  86. EP260409a: SVOM/VT optical upper limits
  87. EP260409a: COLIBRÍ optical upper limits
  88. GRB 260407A: CALET Gamma-Ray Burst Monitor detection
  89. EP260409a: Global MASTER-Net observations report
  90. EP260409a: Einstein Probe detection of an X-ray transient
  91. GRB 260404A: Fermi GBM Final Localization
  92. GRB 260407A: Glowbug gamma-ray detection
  93. GRB 260402A: SVOM/ECLAIRs refined analysis
  94. GRB 260310A: Continued VLA Multi-frequency Radio Observations
  95. GRB 260310A / AT2026fgk: X-ray rebrightening
  96. EP260402a / GRB 260402A: Mephisto optical upper limits
  97. EP-WXT01709259586: Xinglong optical upper limit
  98. EP260403a: Mephisto optical upper limits
  99. EP260402a/GRB 260402A: Xinglong optical upper limit
  100. EP260321a: Upper limits from VLA radio observations

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