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"

32572 results found.

  1. Fermi GRB 251202B: Global MASTER-Net observations report
  2. IPN triangulation of GRB 251129B (short/hard)
  3. GRB251129A/EP251129a: Swift UVOT detection
  4. GRB 251202A: Fermi GBM Observation
  5. GRB 251202A: Swift/UVOT Detection
  6. GRB 251201B: Kilonova-Catcher optical afterglow detection
  7. GRB 251201B: Swift/UVOT Detection
  8. GRB 251130B: Glowbug gamma-ray detection
  9. GRB 251201B: GECAM-B observation of a long burst
  10. EP251130a: continued NOT optical observations indicate steep fading phase
  11. GRB 251122A/EP251122a: CrAO ZTSh optical observations
  12. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  13. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  14. GRB 251202A: GOTO optical afterglow detection
  15. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  16. GRB 251201A: GECAM-B observation of a burst
  17. GRB 251126A: SAO RAS optical marginal detection
  18. GRB 251202A: Swift-XRT afterglow detection
  19. EP251129a/GRB 251129A: NOWT Detection
  20. GRB 251126A: SVOM/VT optical observation
  21. EP251130a: SVOM/VT optical observation
  22. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  23. Fermi GRB 251202A: Global MASTER-Net observations report
  24. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  25. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  26. GRB 251201A: SVOM/GRM observation of a burst
  27. GRB 251201B: SVOM/VT optical fading
  28. Swift GRB 251201B : MASTER optical counterpart detection
  29. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  30. Swift GRB 251201B: Global MASTER-Net observations report
  31. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  32. GRB 251130B: AstroSat CZTI detection
  33. EP251130a: Mondy optical observations
  34. EP251130a: Optical detections with Kinder observations
  35. EP251130a: SAO RAS optical observations
  36. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  37. EP251130a: KAIT optical observations
  38. EP251130A: Optical observation from 1.3m DFOT
  39. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  40. EP251130a: JinShan optical observations
  41. Fermi GRB 251130B: Global MASTER-Net observations report
  42. GRB 251127A: SVOM/GRM observation
  43. EP251130a: Swift-XRT counterpart detection
  44. EP251130a: Global MASTER-Net observations report
  45. EP251130a: COLIBRÍ optical counterpart candidate
  46. EP251129a/GRB 251129A: EP-FXT follow-up observations
  47. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  48. GRB 251128A: AstroSat CZTI detection
  49. GRB 251129A / EP251129a: SAO RAS optical observations
  50. GRB 251126A: SAO RAS optical observations
  51. GRB 251128A: GECAM-B detection
  52. GRB 251128A: SVOM/GRM observation of a long burst
  53. GRB 251128A: Insight-HXMT/HE detection
  54. SVOM GRB 251129A : MASTER optical counterpart detection
  55. GRB 251129A: Swift-XRT afterglow detection
  56. GRB 251129A: Swift ToO observations
  57. GRB 251129A / EP251129a: SVOM/VT optical fading
  58. EP251129a: Global MASTER-Net observations report
  59. GRB 251129A: Optical Observations via Virtual Telescope Project, Italy
  60. EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
  61. GRB 251129A: Correction to the position of the optical counterpar
  62. GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
  63. GRB 251128A: Fermi GBM Observation
  64. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  65. GRB 251126A: Swift-BAT refined analysis
  66. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  67. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  68. Fermi GRB 251128A: Global MASTER-Net observations report
  69. GRB 251127A: Glowbug gamma-ray detection
  70. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  71. GRB 251126A: further SAO RAS optical observations
  72. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  73. GRB 251126A NUTTelA-TAO Early Measurements
  74. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  75. GRB251126A: MAO/AZT-22 optical observations
  76. GRB251126A: Continued optical observation from 1.3m DFOT
  77. GRB 251126A: Swift/UVOT Detection
  78. EP251124a: Pan-STARRS ri-band imaging and photometry
  79. GRB 251126A: Mondy and SAO RAS optical observations
  80. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  81. GRB 251126A: NOT optical observations
  82. GRB 251126A: 1.3m DFOT optical afterglow detection
  83. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  84. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  85. GRB 251125B: GECAM-B detection
  86. Fermi GRB 251127A: Global MASTER-Net observations report
  87. GRB 251126A: Kilonova-Catcher optical afterglow detection
  88. GRB 251126A: Asiago i-band detection
  89. GRB 251126A: Nanshan/HMT optical afterglow detection
  90. Swift GRB 251126A: Global MASTER-Net observations report
  91. GRB 251121A: Fermi GBM Observation
  92. GRB 251126A: GIT discovery of the likely optical afterglow
  93. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  94. EP251124b follow-up observation by EP-FXT
  95. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  96. EP251124b: NOT r- and z-band optical upper limits
  97. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  98. Fermi GRB 251125B: Global MASTER-Net observations report
  99. EP251124b: Global MASTER-Net observations report
  100. EP251124a: Xinglong GWAC-F60A optical observation

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