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"

43717 results found.

  1. GRB 251230A / EP251230a: SVOM/VT optical observation
  2. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  3. GRB 251230A: Enhanced Swift-XRT position
  4. GRB 251230A: Early optical counterpart detection by LCO.
  5. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  6. GRB 251230A: Optical Observations via Virtual Telescope Project, Italy
  7. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  8. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  9. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  10. Swift GRB 251230A: Global MASTER-Net observations report
  11. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  12. EP251229a: Global MASTER-Net observations report
  13. EP251229a: Einstein Probe detection of an X-ray transient
  14. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  15. GRB 251226A: Glowbug gamma-ray detection
  16. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  17. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  18. Fermi GRB 251228A: Global MASTER-Net observations report
  19. The EP-WXT trigger 01709250662 is likely a flaring star
  20. GRB 251228A: Fermi GBM Final Real-time Localization
  21. GRB 251226A: SVOM/GRM observation
  22. GRB 251226A: GECAM-B detection
  23. SVOM GRB251227.07: Global MASTER-Net observations report
  24. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  25. The EP-WXT trigger 01709250617 is likely a flaring star
  26. IceCube Alert 251225.84: Global MASTER-Net observations report
  27. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  28. Fermi Gamma-ray Burst Monitor trigger 788368008/251225630 is not a GRB
  29. GRB 251222A: NUTTelA-TAO Early Measurements
  30. GRB 251222A/EP251222b: Optical detection with Kinder observations
  31. EP251222a: Optical upper limit with Kinder observations
  32. GRB 251221A: Swift-BAT refined analysis
  33. GRB 251222A/EP251222b: FTW optical and NIR observations
  34. EP251222a: FTW optical and NIR observations
  35. GRB 251205A: Kilonova-Catcher optical afterglow detection
  36. GRB 251222A: AbAO optical observations
  37. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  38. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  39. EP251222a: VLT/FORS2 spectroscopic redshift z = 0.505
  40. GRB 251222A: ZTSH BVRI optical observations
  41. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  42. GRB 251222A: Continued 1.3m DFOT optical observation
  43. EP251220a: 3.6m DOT optical afterglow detection
  44. GRB 251222A: Fermi GBM Observation
  45. EP251220a: CrAO ZTSh optical observations
  46. EP251221a: PRIME upper limit
  47. EP251222a: Global MASTER-Net observations report
  48. GRB 251222A / EP251222b: GECAM-B observation
  49. EP251221a: Liverpool Telescope upper limits
  50. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  51. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  52. Konus-Wind detection of GRB 251222A / EP251222b
  53. GRB 251222A: Swift-XRT afterglow detection
  54. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  55. EP251222a: NTT/ULTRACAM optical observations
  56. EP251222a: GOTO optical upper limit
  57. GRB 251222A / EP251222b: GOTO optical counterpart detection
  58. GRB 251222A / EP251222b: LCO optical observations
  59. GRB 251222A: 1.3m DFOT optical detection
  60. GRB251221A: 7DT optical upper limits
  61. EP251222a: GSP Optical Counterpart Detection
  62. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  63. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  64. EP251222b/GRB 251222A: SVOM/GRM observation
  65. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  66. EP251222a: Einstein Probe detection of an X-ray transient
  67. The EP-WXT trigger 01709250397 is likely a flaring star
  68. EP251221a: Global MASTER-Net observations report
  69. GRB 251222A: PRIME near-infrared detection
  70. EP251221a: NOT optical upper limit
  71. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  72. GRB 251222A: NOT optical observations
  73. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  74. IPN triangulation of GRB 251220B (short)
  75. GRB 251222A: Swift ToO observations
  76. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  77. GRB 251222A: SVOM/VT optical candidate
  78. GRB 251222A: SVOM detection of a long burst
  79. SVOM GRB251222A: Global MASTER-Net observations report
  80. GRB 251222A: Fermi GBM Final Real-time Localization
  81. EP251220a: PRIME upper limit
  82. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  83. GRB 251221A: PRIME near-infrared observation
  84. EP251220a: NOT optical observations
  85. EP251220a: FTW optical and NIR observations
  86. GRB 251221A: UAFO and Mondy optical upper limit
  87. GRB 251221A: Swift-XRT refined Analysis
  88. EP251221a: Einstein Probe detection of a fast X-ray transient
  89. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  90. GRB 251221A: Enhanced Swift-XRT position
  91. GRB 251221A: Fermi GBM Observation
  92. GRB 251221B: Fermi GBM Final Real-time Localization
  93. EP251220a: EP-FXT follow-up observation
  94. GRB 251220B: SVOM/GRM observation of a short burst
  95. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  96. EP 251220a: GOTO optical counterpart detection
  97. GRB 251221A: COLIBRÍ detection of the optical counterpart
  98. EP 251220a: COLIBRÍ detection of the optical counterpart
  99. GRB 251221A: Swift detection of a burst
  100. Swift GRB251221A: Global MASTER-Net observations report

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