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"

20509 results found.

  1. GRB 251203C: SVOM/ECLAIRs refined analysis
  2. GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
  3. GRB 251203C: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  4. GRB 251202A: SVOM/GRM observation
  5. GRB 251203A: SVOM/GRM observation
  6. GRB 251203C: J-band observations with WINTER
  7. GRB 251203C: SVOM/VT optical counterpart
  8. GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis
  9. GRB 251203B: Swift-XRT observations
  10. GRB 251203C: LCO optical upper limits
  11. GRB 251203B: LCO optical upper limits
  12. GRB 251203B: SVOM/VT optical observation
  13. GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations
  14. GRB 251203B: SVOM detection of a burst
  15. GRB 251129A / EP251129a: SVOM/VT optical color bluer
  16. EP251130a: MAO/AZT-22 optical observations
  17. EP251202a / GRB251202A: AstroSat CZTI detection
  18. GRB 251201B: Fermi GBM Observation
  19. EP251202a/GRB 251202A: KAIT optical observations
  20. EP251130a: ULL-ASTRO-MASTER late detection of the optical afterglow with LCO 1-m telescope at Teide Observatory
  21. IPN triangulation of GRB 251129B (short/hard)
  22. GRB251129A/EP251129a: Swift UVOT detection
  23. GRB 251202A: Swift/UVOT Detection
  24. GRB 251201B: Kilonova-Catcher optical afterglow detection
  25. GRB 251201B: Swift/UVOT Detection
  26. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  27. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  28. GRB 251126A: SAO RAS optical marginal detection
  29. GRB 251202A: Swift-XRT afterglow detection
  30. EP251129a/GRB 251129A: NOWT Detection
  31. GRB 251126A: SVOM/VT optical observation
  32. EP251130a: SVOM/VT optical observation
  33. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  34. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  35. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  36. GRB 251201A: SVOM/GRM observation of a burst
  37. GRB 251201B: SVOM/VT optical fading
  38. Swift GRB 251201B : MASTER optical counterpart detection
  39. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  40. GRB 251201B: Enhanced Swift-XRT position
  41. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  42. GRB 251130B: AstroSat CZTI detection
  43. GRB 251201B: Swift detection of a burst with an optical counterpart
  44. EP251130a: Mondy optical observations
  45. EP251130a: Optical detections with Kinder observations
  46. EP251130a: SAO RAS optical observations
  47. EP251130A: Optical observation from 1.3m DFOT
  48. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  49. EP251130a: JinShan optical observations
  50. GRB 251127A: SVOM/GRM observation
  51. EP251130a: COLIBRÍ optical counterpart candidate
  52. EP251130a: Einstein Probe detection of an X-ray transient
  53. GRB 251129A / EP251129a: SAO RAS optical observations
  54. GRB 251126A: SAO RAS optical observations
  55. GRB 251128A: GECAM-B detection
  56. GRB 251128A: SVOM/GRM observation of a long burst
  57. SVOM GRB 251129A : MASTER optical counterpart detection
  58. GRB 251129A: Swift-XRT afterglow detection
  59. EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
  60. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  61. GRB 251129A: SVOM detection of a burst
  62. GRB 251129A: SVOM detection of a burst
  63. GRB 251126A: Swift-BAT refined analysis
  64. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  65. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  66. GRB 251126A: further SAO RAS optical observations
  67. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  68. GRB251126A: MAO/AZT-22 optical observations
  69. GRB251126A: Continued optical observation from 1.3m DFOT
  70. GRB 251126A: Swift/UVOT Detection
  71. EP251124a: Pan-STARRS ri-band imaging and photometry
  72. GRB 251126A: Mondy and SAO RAS optical observations
  73. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  74. GRB 251126A: 1.3m DFOT optical afterglow detection
  75. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  76. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  77. GRB 251126A: Enhanced Swift-XRT position
  78. GRB 251126A: Kilonova-Catcher optical afterglow detection
  79. GRB 251126A: Nanshan/HMT optical afterglow detection
  80. GRB 251126A: GIT discovery of the likely optical afterglow
  81. GRB 251126A: Swift detection of a burst
  82. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  83. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  84. EP251124b: NOT r- and z-band optical upper limits
  85. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  86. EP251124b: EP-WXT detection of a fast X-ray transient
  87. EP251124a: Xinglong GWAC-F60A optical observation
  88. EP251124a: NOT r- and z-band optical upper limits
  89. EP251124a: Swift-XRT observations
  90. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  91. EP251124a: Optical upper limit with Kinder observations
  92. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  93. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  94. EP251124a: GROWTH-India Telescope optical upper limits
  95. EP251124a: Einstein Probe detection of an X-ray transient
  96. GRB 251116C: Swift-XRT confirmation of fading
  97. GRB 251122A/EP251122A: 1.3m DFOT optical detection
  98. GRB 251122A / EP251122a: Xinglong 2.16m optical observation
  99. EP251118A: 3.6m DOT optical afterglow detection
  100. EP251122a: refined analysis of the EP-WXT and 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