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"

14926 results found.

  1. GRB 250403A: LCO optical counterpart detection
  2. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  3. GRB 250402A: EP-FXT afterglow detection
  4. GRB 250403A: Optical counterpart detection by LCO.
  5. GRB 250322A: 10 GHz VLA radio upper limits
  6. GRB 250403A: 1.6m Mephisto multi-band optical detection
  7. GRB 250403A: GOTO detection of the optical afterglow
  8. GRB 250403A : SVOM detection of a burst
  9. GRB 250403A: Fermi GBM Final Real-time Localization
  10. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  11. GRB 250402A: VLT/FORS2 spectroscopic redshift z = 2.823
  12. GRB 250402A: LCO optical counterpart detection
  13. EP250402a: Einstein Probe detection of a fast X-ray transient
  14. GRB 250402B: AstroSat CZTI detection of a short burst
  15. GRB 250402A: SVOM detection of a burst
  16. GRB 250314A: ALMA detection
  17. GRB 250329A: Swift/UVOT Upper Limit
  18. GRB 250327B: Swift/UVOT Detection
  19. GRB 250219A: NOT candidate host galaxy detection
  20. GRB 250322B: GRBAlpha detection
  21. GRB 250322B possible detection by the AstroSat Satellite
  22. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 2)
  23. GRB 250330B: EIRSAT-1 GMOD Detection
  24. GRB 250331E: Fermi GBM Final Real-time Localization
  25. GRB 250329B: CAHA 2.2m telescope optical limit
  26. Konus-Wind detection of GRB 250327B
  27. GRB 250320C : SVOM detection of a burst through offline search
  28. LIGO/Virgo/KAGRA S250328ae: Swift XRT observations, 34 possible X-ray sources
  29. GRB 250330A: VLT/FORS2 Afterglow Detection
  30. GRB 250328A: Swift/UVOT Detection
  31. GRB 250331D: Fermi GBM Final Real-time Localization
  32. GRB 250331C: Swift detection of a burst
  33. GRB 250331B: Swift detection of a burst
  34. GRB 250331A: MAXI/GSC detection
  35. SVOM/sb25033102: SVOM detection of an X-ray transient
  36. GRB 250314A: VLA detection
  37. GRB 250330B: Fermi GBM Final Real-time Localization
  38. GRB 250330A: BOOTES-7 early optical upper limit
  39. GRB 250330A: Swift-XRT afterglow detection
  40. GRB 250328A: 1.6m Mephisto optical observations
  41. GRB 250330A: Fermi GBM Final Localization
  42. IceCube-250330A - IceCube observation of a high-energy neutrino candidate track-like event
  43. GRB 250329B: Swift-XRT afterglow detection
  44. GRB 250330A: Swift detection of a burst
  45. GRB 250327B: ALMA detection
  46. GRB 250327B: VLA detection
  47. GRB250329A: REM optical afterglow detection
  48. GRB 250329B: SVOM detection of a faint transient
  49. GRB 250329A: Swift-XRT afterglow detection
  50. GRB 250329A: Fading optical counterpart detection by LCO.
  51. GRB 250329A: VLT/X-shooter redshift z = 2.921
  52. GRB 250329A: SVOM detection of a burst
  53. GRB 250329A: SVOM/COLIBRÍ (F-GFT) Detection of a Bright Optical Counterpart Candidate
  54. GRB 250327B: MASTER detection of OT rebrightening
  55. GRB 250327B: LCO optical counterpart detection
  56. GRB 250328A: SVOM detection of a burst
  57. GRB 250327B: OHP/T193 spectroscopic observations and redshift confirmation
  58. EP250315a: Pan-STARRS r and i-band imaging and photometry
  59. GRB 250327b: Liverpool Telescope optical observations
  60. GRB 250327B: Las Cumbres optical counterpart detection
  61. GRB 250327B: Swift-XRT detection of the X-ray afterglow
  62. GRB 250327B: NOT spectroscopic redshift z = 3.035
  63. GRB 250327B: GOTO optical counterpart detection
  64. GRB 250327B: SVOM detection of a burst
  65. FRB 20250316A: Pan-STARRS r and i-band imaging and photometry
  66. GRB 250327A: DDOTI Optical Observations
  67. GRB 250327A: Swift detection of a burst
  68. GRB 250327A: Fermi GBM Final Real-time Localization
  69. Konus-Wind detection of GRB 250322A (short)
  70. IPN triangulation of GRB 250322B
  71. Swift follow-up observations of FRB250316A and EP J120944.2+585060
  72. FRB 250316A: NOT optical upper limit for the X ray source EP J120944.2+585060
  73. EP-WXT trigger 01709133021: Optical upper limit through Kinder observations
  74. GRB 250322B: NuSTAR detection of the prompt emission and regular dips during the burst
  75. EP250321a: TNOT Observation of Optical Counterpart
  76. FRB 250316A: DDOTI Continued Optical Observations (Third Epoch)
  77. SVOM/sb25032302: SVOM detection of a long X-ray transient
  78. GRB 250322A: AstroSat CZTI detection of a short burst
  79. GRB 250322B: AstroSat CZTI detection of a bright long burst
  80. FRB 20250316A: Kinder optical upper limits of the Einstein Probe candidate X-ray source EP J120944.2+585060
  81. EP250321a: Liverpool Telescope optical follow-up
  82. GRB 250322A: Swift detection of a short burst
  83. FRB 20250316A: detection of a candidate associated X-ray source EP J120944.2+585060 by Einstein Probe
  84. GRB 250225B: GECAM-A detection
  85. GRB 250312A: GECAM-A detection
  86. EP250321a: WFST optical observations
  87. GRB 250320B: NuSTAR detection of the prompt emission from two broad bursts and preliminary analysis
  88. GRB 250321C: Fermi GBM Final Real-time Localization
  89. GRB 250320A: NuSTAR Detection of the Prompt Emission and Preliminary Results
  90. GRB 250320B: Fermi-LAT detection
  91. GRB 250321B: SVOM detection of a sub-threshold transient event
  92. EP 250321A: Optical counterpart detection by LCO.
  93. EP250321a: LCO optical counterpart detection
  94. EP250321a: Swift-XRT detection of an X-ray source
  95. EP250321a: VLT/X-shooter redshift z = 4.368
  96. GRB 250320B: AstroSat CZTI detection
  97. EP250321a: REM optical/NIR afterglow detection
  98. EP250321a: BOOTES-5/JGT optical afterglow detection
  99. EP250321a: TRT optical counterpart detection
  100. EP250321a: Einstein Probe detection of an X-ray transient

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