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"

28236 results found.

  1. EP261015a: VST optical observations
  2. GRB 261024A: BALROG localization (Fermi Trigger 814551785 / GRB 261024683)
  3. EP261023a: Mondy optical upper limit
  4. EP261015a: MAO/AZT-22 optical observations
  5. EP261015a: VLA non-detection
  6. EP261023a: NOT optical counterpart candidate
  7. EP261023a: Einstein Probe detection of an X-ray transient
  8. The EP-WXT trigger 01709321472 is likely a flaring star
  9. IceCube-261020A: Upper limits from a search for additional neutrino events in IceCube
  10. NuSTAR 261020, a 830s hard X-ray transient
  11. EP261015a: GSP multiband optical follow-up observations
  12. GRB 261017A: SVOM/GRM observation
  13. EP261015a: Further optical observations with the 1.3m DFOT
  14. GRB 261020B: AstroSat CZTI detection of a short burst
  15. Fermi-LAT Gamma-ray Observations of IceCube-261020A
  16. EP261015a: AZT-20 Assy-Turgen optical observations
  17. GRB 261020A: Fermi GBM Observation
  18. GRB 261017A: SAO RAS optical upper limit
  19. GRB 260903A
  20. EP261015a: Follow-up with the 1.3m DFOT
  21. EP261015a: Terskol Zeiss-2000 optical upper limit
  22. EP261007b: Further EP-FXT follow-up observations
  23. GRB 261017A: COLIBRÍ optical upper limit
  24. GRB 261020A: MAXI GSC detection
  25. EP261015a: COLIBRÍ optical observations of a rebrightening
  26. GRB 261017A: Possible Swift/UVOT Detection
  27. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  28. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  29. GRB 261017A: Swift-BAT refined analysis
  30. EP261015b: NOT Optical Observations
  31. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  32. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  33. GRB 261017A : MITSuME Akeno optical upper limits
  34. GRB 261017A: Swift-XRT refined Analysis
  35. GRB 261017A: Nanshan/NEXT optical upper limit
  36. GRB 261017A: Enhanced Swift-XRT position
  37. GRB 261017A: Fermi GBM Observation
  38. GRB 261017A: Swift detection of a burst
  39. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  40. EP261015b: Refined analysis of EP-FXT observations
  41. EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
  42. EP261015a: refined analysis of EP-FXT observations
  43. EP261015c: J-band upper limit with WINTER
  44. EP261015a: J-band upper limit with WINTER
  45. EP261006a / AT 2026aetp: Optical follow-up with the 1.3-m DFOT
  46. GRB 261011A: 1.3m DFOT optical upper limit
  47. GRB 261010A: Pan-STARRS z-band imaging and upper limit
  48. EP261015a: SVOM/VT optical observation
  49. GRB 261010A: VLA radio observations
  50. EP261015a: COLIBRÍ optical observations
  51. EP261015c: Einstein Probe detection of a fast X-ray transient
  52. EP261015b: Einstein Probe detection of an X-ray transient
  53. EP261015a: Einstein Probe detection of a fast X-ray transient
  54. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  55. GRB 261010A: LBT tentative near-infrared detection
  56. GRB 261011A: SAO RAS and AbAO optical observations
  57. GRB 261010A: Glowbug gamma-ray detection
  58. GRB 261008A: SVOM/GRM observation
  59. GRB 261009A: GECAM-B detection of a burst
  60. EP261006a : MeerKAT radio observations.
  61. IceCube-261012A: Upper limits from a search for additional neutrino events in IceCube
  62. GRB 261010A: a short minimum variability timescale and a distinct pulse evolution compatible with a merger origin
  63. Fermi-LAT Gamma-ray Observations of IceCube-261012A
  64. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  65. GRB 261010A: Swift-XRT refined Analysis
  66. GRB 261011A: Swift-XRT refined Analysis
  67. GRB 261011A: Enhanced Swift-XRT position
  68. GRB 261010A: a Type I-L (merger-driven) GRB candidate
  69. GRB 261011A: Swift-BAT refined analysis
  70. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  71. MAXI GRB261012.23: Global MASTER-Net observations report
  72. GRB 261011A: REM optical/NIR observations
  73. GRB 261011A: SOAR optical afterglow observations at ~17 hours
  74. EP261006a: 10 GHz VLA observations
  75. GRB 261011A: VLT/X-shooter redshift constraints
  76. GRB 261012A: MAXI GSC detection
  77. GRB 261010A: Swift-BAT refined analysis
  78. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  79. GRB 261011A: Optical followup from Sichuan South Observatory
  80. GRB 261011A: GMG Optical Observation
  81. GRB 261011A: Liverpool Telescope optical observations
  82. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  83. GRB 261010A: NOT confirmation of the optical afterglow
  84. GRB 261010A: Fermi GBM Observation
  85. GRB 261011A: continued LCO optical observations
  86. EP261007b: Global MASTER-Net observations report
  87. GRB 261011A: GROWTH-India Telescope optical observations
  88. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  89. Swift GRB 261011A: Global MASTER-Net observations report
  90. GRB 261011A: Optical follow-up observations with Kinder
  91. GRB 261011A: SVOM/C-GFT optical observations
  92. EP261007b: Second EP-FXT follow-up observation and a possible X-ray counterpart to the optical transient
  93. GRB 261011A: LCO optical observations
  94. GRB 261011A: SVOM/VT optical observation from VHF data
  95. GRB 261011A: LCO optical observations
  96. GRB 261011A: TRT optical afterglow detection
  97. GRB 261011A: Swift detection of an unusual burst
  98. GRB 261011A: SVOM detection of a long bright burst
  99. GRB 261010A: Enhanced Swift-XRT position
  100. EP261010a: refined analysis of the EP-WXT and autonomous EP-FXT 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