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"

36225 results found.

  1. EP250702a/ GRB 250702B: NuSTAR X-ray Observations
  2. GRB 250706C: Konus-Wind detection of a very bright GRB ~1200 s before GRB 250706B
  3. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  4. GRB 250702F: GRANDMA observations
  5. GRB 250706A: Swift-XRT refined Analysis
  6. GRB 250706B: refined SVOM/MXT data analysis
  7. GRB 250706A: Swift/UVOT Upper Limits
  8. GRB 250706B: REM optical observations
  9. GRB 250706A: REM optical/NIR observations
  10. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  11. IceCube-250706A: COLIBRÍ optical upper limits
  12. Swift GRB 250706A: Global MASTER-Net observations report
  13. GRB 250706A: JinShan optical upper limits
  14. GRB 250706A: SAO RAS optical observations
  15. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  16. GRB250706B: Swift-XRT counterpart detection
  17. GRB 250706B: iTelescope optical observations
  18. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  19. GRB 250706B: SVOM/VT optical observation
  20. GRB 250706B: TRT bright optical counterpart detection
  21. GRB 250706A: GROWTH-India Telescope optical upper limit
  22. GRB 250706B: SVOM detection of a long burst
  23. GRB 250706A: Swift detection of a burst
  24. GRB 250704B: Swift-XRT refined Analysis
  25. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  26. GRB 250703A: EIRSAT-1 GMOD Detection
  27. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  28. GRB 250704B: Swift/UVOT Upper Limits
  29. GRB 250704A: Swift/UVOT Detection
  30. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  31. GRB 250704B: Insight-HXMT detection
  32. Konus-Wind detection of GRB 250703A
  33. IPN triangulation of GRB 250703A
  34. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  35. EP250704a/GRB 250704B: FTW optical and NIR observations of the counterpart
  36. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  37. Konus-Wind detection of short/hard GRB 250704B/ EP250704a
  38. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  39. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  40. GRB 250702F: Kilonova-Catcher optical afterglow detection
  41. GRB 250702F: Monte Agliale Observatory optical observations
  42. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  43. EP250704a / GRB 250704B: VLT/X-shooter spectroscopic redshift z = 0.661
  44. EP250704a / GRB 250704B: JinShan optical observations
  45. GRB 250704A: SVOM/VT optical observation
  46. EP250704a / GRB 250704B: SAO RAS optical observations
  47. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  48. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart
  49. EP250704a / GRB 250704B: SVOM/VT optical blue counterpart
  50. EP250704a / GRB 250704B: Pan-STARRS iz-band imaging and photometry
  51. LIGO/Virgo/KAGRA S250704ab: Upper limits from Fermi-GBM Observations
  52. GRB 250702A: Insight-HXMT detection
  53. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  54. EP250704a / GRB250704B: Swift-XRT counterpart detection
  55. GRB 250704A: Swift-XRT afterglow detection
  56. GRB 250702B / EP2050702a: FTW optical and NIR observations
  57. Konus-Wind detection of GRB 250702F
  58. EP250704a / GRB 250704B - REM observations
  59. GRB 250702F: GROWTH-India Telescope optical observations
  60. EP250704a / GRB 250704B: VLT/FORS2 optical afterglow detection
  61. GRB 250704A: REM retraction of optical afterglow detection and updated limit
  62. EP250704a: Einstein Probe detection of an X-ray transient
  63. GRB 250704B: SVOM/GRM observation of a short burst
  64. GRB 250702F: optical photometry from Konkoly
  65. GRB 250704A: REM detection of the optical afterglow
  66. GRB 250702F: SVOM/VT optical observation
  67. GRB 250704A: SVOM detection of a burst
  68. GRB 250702F: Swift/UVOT Detection
  69. GRB 250702A: CALET Gamma-Ray Burst Monitor detection
  70. Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst
  71. Fermi GRB 250703A: Global MASTER-Net observations report
  72. GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit
  73. GRB 250702F: Swift-XRT refined Analysis
  74. GRB 250702F: Fermi GBM Observation
  75. GRB 250702F: Leavitt Observatory optical observations
  76. GRB 250702F: AKO Optical Afterglow Detection
  77. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  78. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  79. GRB 250702A: GECAM-B detection
  80. GRB 250702F: Skynet Optical Observations
  81. GRB 250424A: VIRT Optical Upper Limit
  82. GRB 250702B,C,D,E/EP250702a: COLIBRÍ optical upper limit
  83. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  84. GRB 250702F: TRT Optical Observation
  85. GRB 250703A: DDOTI Optical Upper Limit
  86. GRB 250702F: REM optical afterglow detection
  87. GRB 250702F: DDOTI Optical Observation
  88. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  89. GRB 250703A: Fermi GBM Final Real-time Localization
  90. EP250702a/GRB 250702B,C,D,E: GOTO optical upper limits
  91. GRB 250702F: COLIBRÍ Observations of the Afterglow
  92. EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E
  93. Fermi GRB 250702E: Global MASTER-Net observations report
  94. Fermi GRB 250702B: Global MASTER-Net observations report
  95. GRB 250702D, C, E: Swift/BAT-GUANO localization skymap of a burst or galactic transient
  96. GRB 250702F: Enhanced Swift-XRT position
  97. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  98. GRB 250702F: NOT observations of the optical afterglow
  99. GRB 250702F: MASTER optical afterglow observation
  100. Fermi GRB 250702F: 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