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"

37563 results found.

  1. GRB 250704B: Insight-HXMT detection
  2. Konus-Wind detection of GRB 250703A
  3. IPN triangulation of GRB 250703A
  4. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  5. EP250704a/GRB 250704B: FTW optical and NIR observations of the counterpart
  6. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  7. Konus-Wind detection of short/hard GRB 250704B/ EP250704a
  8. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  9. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  10. GRB 250702F: Kilonova-Catcher optical afterglow detection
  11. GRB 250702F: Monte Agliale Observatory optical observations
  12. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  13. EP250704a / GRB 250704B: VLT/X-shooter spectroscopic redshift z = 0.661
  14. EP250704a / GRB 250704B: JinShan optical observations
  15. GRB 250704A: SVOM/VT optical observation
  16. EP250704a / GRB 250704B: SAO RAS optical observations
  17. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  18. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart
  19. EP250704a / GRB 250704B: SVOM/VT optical blue counterpart
  20. EP250704a / GRB 250704B: Pan-STARRS iz-band imaging and photometry
  21. LIGO/Virgo/KAGRA S250704ab: Upper limits from Fermi-GBM Observations
  22. GRB 250702A: Insight-HXMT detection
  23. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  24. GRBs 250702B/C/D/E / EP250702a: Swift/UVOT Upper Limits
  25. EP250704a / GRB250704B: Swift-XRT counterpart detection
  26. GRB 250704A: Swift-XRT afterglow detection
  27. GRB 250702B / EP2050702a: FTW optical and NIR observations
  28. Konus-Wind detection of GRB 250702F
  29. EP250704a / GRB 250704B - REM observations
  30. GRB 250702F: GROWTH-India Telescope optical observations
  31. EP250704a / GRB 250704B: VLT/FORS2 optical afterglow detection
  32. GRB 250704A: REM retraction of optical afterglow detection and updated limit
  33. EP250702a: WFST optical observations
  34. EP250704a: Einstein Probe detection of an X-ray transient
  35. GRB 250704B: SVOM/GRM observation of a short burst
  36. GRB 250702F: optical photometry from Konkoly
  37. GRB 250704A: REM detection of the optical afterglow
  38. GRB 250702F: SVOM/VT optical observation
  39. GRB 250704A: SVOM detection of a burst
  40. GRB 250702F: Swift/UVOT Detection
  41. GRB 250702A: CALET Gamma-Ray Burst Monitor detection
  42. Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst
  43. Fermi GRB 250703A: Global MASTER-Net observations report
  44. GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit
  45. GRB 250702F: Swift-XRT refined Analysis
  46. GRB 250702F: Fermi GBM Observation
  47. GRB 250702F: Leavitt Observatory optical observations
  48. GRB 250702F: AKO Optical Afterglow Detection
  49. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  50. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  51. GRB 250702A: GECAM-B detection
  52. GRB 250702F: Skynet Optical Observations
  53. GRB 250424A: VIRT Optical Upper Limit
  54. GRBs 250702B/C/D/E / EP250702a: Swift XRT localization
  55. GRB 250702B,C,D,E/EP250702a: COLIBRÍ optical upper limit
  56. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  57. GRB 250702F: TRT Optical Observation
  58. GRB 250703A: DDOTI Optical Upper Limit
  59. GRBs 250702B,C,D,E / EP250702a: Konus-Wind detection of a hard X-ray transient activity
  60. GRB 250702F: REM optical afterglow detection
  61. GRB 250702F: DDOTI Optical Observation
  62. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  63. GRB 250703A: Fermi GBM Final Real-time Localization
  64. EP250702a/GRB 250702B,C,D,E: GOTO optical upper limits
  65. GRB 250702F: COLIBRÍ Observations of the Afterglow
  66. EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E
  67. Fermi GRB 250702E: Global MASTER-Net observations report
  68. Fermi GRB 250702B: Global MASTER-Net observations report
  69. GRB 250702D, C, E: Swift/BAT-GUANO localization skymap of a burst or galactic transient
  70. GRB 250702F: Enhanced Swift-XRT position
  71. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  72. GRB 250702F: NOT observations of the optical afterglow
  73. GRB 250702F: MASTER optical afterglow observation
  74. Fermi GRB 250702F: Global MASTER-Net observations report
  75. Fermi GRB 250702C: Global MASTER-Net observations report
  76. GRB 250702F: GOTO optical counterpart detection
  77. GRB 250702F: Ondrejov D50 optical afterglow detection
  78. GRB 250702F: Swift detection of a burst with an optical counterpart
  79. Swift GRB 250702F: Global MASTER-Net observations report
  80. GRB 250702F: Fermi GBM Final Real-time Localization
  81. Fermi GBM Triggers 250702B, C, D and E are likely from the same source
  82. GRB 250702E: Fermi GBM Final Real-time Localization
  83. Konus-Wind detection of GRB 250627A
  84. IPN triangulation of GRB 250627A (short)
  85. GRB 250702A: Fermi GBM Detection
  86. GRB 250702D: Fermi GBM Final Localization Correction
  87. GRB 250702C: Fermi GBM Final Real-time Localization
  88. GRB 250702B: Fermi GBM Final Real-time Localization
  89. GRB 250702A: BALROG localization (Fermi Trigger 773142852 / GRB 250702413)
  90. GRB 250702A: Fermi GBM Final Real-time Localization
  91. Fermi Gamma-ray Burst Monitor trigger 772838080/250628885 is not a GRB
  92. GRB 250628B: Swift-XRT observations
  93. Fermi Gamma-ray Burst Monitor trigger 772981768/250630548 is not a GRB
  94. GRB 250628B: SVOM/VT optical upper limit
  95. GRB 250628B: EP-FXT counterpart detection
  96. GRB 250627A: Insight-HXMT detection
  97. GRB 250627A: SVOM/GRM detection of a short burst
  98. GRB 250628A: REM optical/NIR upper limits
  99. GRB 250628C: Fermi GBM Final Real-time Localization
  100. GRB 250628B: SVOM detection of a long burst

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