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"

20519 results found.

  1. GRB261026A: Infrared detection with MDM/MIRAGE
  2. GRB 261026A: SAO RAS optical observations
  3. GRB 261026A: Upper Limit with 60cm Panzhihua Telescope
  4. EP 261025a: J-band upper limit with MIRAGE
  5. GRB 261026A: Ondrejov D50 optical limit
  6. GRB 261026A: ULL-ASTRO-MASTER optical detection with LCO 40-cm telescope at Haleakalā Observatory
  7. GRB 261026A: J-band observations by the SYSU 80cm infrared telescope
  8. GRB 261026A: WINTER J-band observations
  9. GRB 261024D: AstroSat CZTI detection of a long burst
  10. GRB 261019A: SVOM/GRM observation
  11. GRB 261026A: KAIT optical observations
  12. GRB 261026A: SVOM/COLIBRÍ (FM-GFT) optical observations
  13. GRB 261026A: SVOM detection of a burst
  14. EP261025a: J-band upper limit with WINTER
  15. EP261023a: J-band upper limit with WINTER
  16. EP 261025a: COLIBRÍ optical upper limit
  17. EP261025a: Einstein Probe detection of a fast X-ray transient
  18. EP261023a: J band upper limit by SYSU 80cm infrared telescope
  19. EP261015a: VST optical observations
  20. EP261023a: Mondy optical upper limit
  21. EP261015a: MAO/AZT-22 optical observations
  22. EP261015a: VLA non-detection
  23. EP261023a: NOT optical counterpart candidate
  24. EP261023a: Einstein Probe detection of an X-ray transient
  25. IceCube-261020A: Upper limits from a search for additional neutrino events in IceCube
  26. EP261015a: GSP multiband optical follow-up observations
  27. GRB 261017A: SVOM/GRM observation
  28. EP261015a: Further optical observations with the 1.3m DFOT
  29. EP261015a: AZT-20 Assy-Turgen optical observations
  30. GRB 261017A: SAO RAS optical upper limit
  31. GRB 260903A
  32. EP261015a: Follow-up with the 1.3m DFOT
  33. EP261015a: Terskol Zeiss-2000 optical upper limit
  34. EP261007b: Further EP-FXT follow-up observations
  35. GRB 261017A: COLIBRÍ optical upper limit
  36. EP261015a: COLIBRÍ optical observations of a rebrightening
  37. GRB 261017A: Possible Swift/UVOT Detection
  38. GRB 261017A: Luminance-band upper limit from a 28cm telescope in Chengde
  39. GRB 261017A: R-band upper limit with the 1.3-m DFOT
  40. GRB 261017A: a short minimum variability timescale compatible with a compact object merger origin
  41. EP261015b: NOT Optical Observations
  42. GRB 261017A: J band upper limit by the SYSU 80cm infrared telescope
  43. EP261015c: refined analysis of the EP-FXT observation favors a stellar flare interpretation
  44. GRB 261017A : MITSuME Akeno optical upper limits
  45. GRB 261017A: Swift-XRT refined Analysis
  46. GRB 261017A: Nanshan/NEXT optical upper limit
  47. GRB 261017A: Enhanced Swift-XRT position
  48. GRB 261017A: Swift detection of a burst
  49. EP261015a: Tentative fading of the candidate optical counterpart from the NOT
  50. EP261015b: Refined analysis of EP-FXT observations
  51. EP261015b: J-band upper limit by the SYSU 80cm infrared telescope
  52. EP261015a: refined analysis of EP-FXT observations
  53. EP261015c: J-band upper limit with WINTER
  54. EP261015a: J-band upper limit with WINTER
  55. EP261006a / AT 2026aetp: Optical follow-up with the 1.3-m DFOT
  56. GRB 261011A: 1.3m DFOT optical upper limit
  57. GRB 261010A: Pan-STARRS z-band imaging and upper limit
  58. EP261015a: SVOM/VT optical observation
  59. GRB 261010A: VLA radio observations
  60. EP261015a: COLIBRÍ optical observations
  61. EP261015c: Einstein Probe detection of a fast X-ray transient
  62. EP261015b: Einstein Probe detection of an X-ray transient
  63. EP261015a: Einstein Probe detection of a fast X-ray transient
  64. EP261015a (WXT 11900947714): Possible optical counterpart from NOT and LCO
  65. GRB 261010A: LBT tentative near-infrared detection
  66. GRB 261011A: SAO RAS and AbAO optical observations
  67. GRB 261008A: SVOM/GRM observation
  68. EP261006a : MeerKAT radio observations.
  69. IceCube-261012A: Upper limits from a search for additional neutrino events in IceCube
  70. GRID detection of GRB 261010A
  71. GRB 261010A: J-band upper limit by the SYSU 80cm infrared telescope
  72. GRB 261010A: Swift-XRT refined Analysis
  73. GRB 261011A: Swift-XRT refined Analysis
  74. GRB 261011A: Enhanced Swift-XRT position
  75. GRB 261010A: 10.4m GTC spectroscopy of the galaxy 2" from the afterglow
  76. MAXI GRB261012.23: Global MASTER-Net observations report
  77. GRB 261011A: REM optical/NIR observations
  78. GRB 261011A: SOAR optical afterglow observations at ~17 hours
  79. EP261006a: 10 GHz VLA observations
  80. GRB 261011A: VLT/X-shooter redshift constraints
  81. GRB 261011A : MITSuME Akeno optical afterglow candidate detection
  82. GRB 261011A: Optical followup from Sichuan South Observatory
  83. GRB 261011A: GMG Optical Observation
  84. GRB 261011A: Liverpool Telescope optical observations
  85. GRB 261011A: J-band observations by the SYSU 80cm infrared telescope
  86. GRB 261011A: GROWTH-India Telescope optical observations
  87. GRB 261011A: Luminance-band upper limit from a 28cm telescope in Chengde
  88. GRB 261011A: Optical follow-up observations with Kinder
  89. GRB 261011A: SVOM/C-GFT optical observations
  90. EP261007b: Second EP-FXT follow-up observation and a possible X-ray counterpart to the optical transient
  91. GRB 261011A: LCO optical observations
  92. GRB 261011A: LCO optical observations
  93. GRB 261011A: TRT optical afterglow detection
  94. GRB 261011A: Swift detection of an unusual burst
  95. GRB 261011A: SVOM detection of a long bright burst
  96. GRB 261010A: Enhanced Swift-XRT position
  97. EP261010a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  98. EP261006a / AT 2026aetp: Luminance-band optical follow-up with small-aperture telescopes
  99. GRB 261010A: Swift detection of a burst
  100. EP261006a: Kilonova-Catcher optical follow-up and detection

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