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"

19611 results found.

  1. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  2. GRB 250704A: SVOM/VT optical observation
  3. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart
  4. EP250704a / GRB 250704B: SVOM/VT optical blue counterpart
  5. EP250704a: refined analysis of the EP-WXT and FXT follow-up observations
  6. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  7. GRBs 250702B/C/D/E / EP250702a: Swift/UVOT Upper Limits
  8. EP250704a / GRB250704B: Swift-XRT counterpart detection
  9. GRB 250704A: Swift-XRT afterglow detection
  10. GRB 250702B / EP2050702a: FTW optical and NIR observations
  11. Konus-Wind detection of GRB 250702F
  12. GRB 250702F: GROWTH-India Telescope optical observations
  13. EP250702a: WFST optical observations
  14. GRB 250702F: SVOM/VT optical observation
  15. GRB 250702F: Swift/UVOT Detection
  16. Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst
  17. GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit
  18. GRB 250702F: Swift-XRT refined Analysis
  19. GRB 250702F: Fermi GBM Observation
  20. GRB 250702F: Leavitt Observatory optical observations
  21. GRB 250702F: AKO Optical Afterglow Detection
  22. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  23. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  24. GRB 250702F: Skynet Optical Observations
  25. GRB 250424A: VIRT Optical Upper Limit
  26. GRBs 250702B/C/D/E / EP250702a: Swift XRT localization
  27. GRB 250702F: TRT Optical Observation
  28. GRBs 250702B,C,D,E / EP250702a: Konus-Wind detection of a hard X-ray transient activity
  29. GRB 250702F: REM optical afterglow detection
  30. GRB 250702F: DDOTI Optical Observation
  31. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  32. GRB 250702F: COLIBRÍ Observations of the Afterglow
  33. EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E
  34. GRB 250702D, C, E: Swift/BAT-GUANO localization skymap of a burst or galactic transient
  35. GRB 250702F: Enhanced Swift-XRT position
  36. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  37. GRB 250702F: NOT observations of the optical afterglow
  38. GRB 250702F: MASTER optical afterglow observation
  39. GRB 250702F: GOTO optical counterpart detection
  40. GRB 250702F: Ondrejov D50 optical afterglow detection
  41. GRB 250702F: Swift detection of a burst with an optical counterpart
  42. Swift GRB 250702F: Global MASTER-Net observations report
  43. GRB 250628B: Swift-XRT observations
  44. GRB 250628B: SVOM/VT optical upper limit
  45. GRB 250628A: REM optical/NIR upper limits
  46. GRB 250625A: VLT/X-shooter spectroscopic observations at the afterglow position
  47. GRB 250628A: VLT/X-shooter upper limits
  48. GRB 250628A: Swift/UVOT Upper Limits
  49. GRB 250628A: Swift-XRT refined Analysis
  50. Swift GRB 250628A: Global MASTER-Net observations report
  51. GRB 250628A: Enhanced Swift-XRT position
  52. GRB 250628A: Swift detection of a burst
  53. GRB 250625A: Swift-BAT refined analysis
  54. GRB 250625A: Leavitt Observatory afterglow detection
  55. GRB 250625A: GTC/OSIRIS+ spectroscopic observations of the potential host galaxy
  56. GRB 250625A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  57. GRB 250625A: SVOM/C-GFT upper limit in early phase
  58. GRB 250625A: GECAM-B detection
  59. GRB 250625A: Swift/UVOT Upper Limits
  60. GRB 250625A: ABObservatory afterglow detection
  61. GRB 250625A: COLIBRÍ optical observations
  62. GRB 250625A: Fermi-LAT detection
  63. GRB 250625A: Swift-XRT refined Analysis
  64. GRB 250625A: JinShan optical observations
  65. GRB250625A: Fermi GBM Observation
  66. Swift GRB 250625A: Global MASTER-Net observations report
  67. GRB 250625A: SVOM/VT optical confirmation
  68. GRB 250620B: Fermi GBM Observation
  69. GRB 250625A: Enhanced Swift-XRT position
  70. GRB 250625A: Swift detection of a burst
  71. GRB 250620A: AstroSat CZTI detection
  72. GRB 241018A: Maidanak optical observations
  73. GRB 250617B: Swift-BAT refined analysis
  74. IPN triangulation of GRB 250620C (long/bright)
  75. GRB 250620A: SVOM/GRM observation of a short burst
  76. GRB250620A: Fermi GBM Observation
  77. GRB 250617B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  78. GRB 250619B: Fermi GBM Observation
  79. GRB 250620B: Swift/BAT-GUANO localization skymap of a burst
  80. GRB 250620A: Swift/BAT-GUANO subthreshold detection of a possibly short burst
  81. GRB 250619B: Swift/BAT-GUANO localization skymap of a burst
  82. GRB 250615A: Kilonova-Catcher optical upper limits
  83. GRB 250617B: Assy AZT-20 Optical Observations
  84. GRB 250612A / Swift J1643.6−3854: Swift-BAT refined analysis
  85. GRB 250615A/EP250615a: FTW optical and NIR observations
  86. sb25061218/SVOM: OHP/T120 and OHP/T193 optical imaging and spectroscopic observations
  87. GRB 250617B: Swift/UVOT Detection
  88. GRB 250617B: Kilonova-Catcher optical afterglow detection
  89. GRB 250617B: VLT/X-shooter spectroscopic redshift z = 1.396
  90. GRB 250617B: NOT NIR observations of the afterglow
  91. GRB 250617B: Swift-XRT refined Analysis
  92. GRB 250617B: SVOM/VT optical observation
  93. Swift GRB 250617B: Global MASTER-Net observations report
  94. GRB 250617B: GOTO optical upper limit
  95. GRB 250617B: Enhanced Swift-XRT position
  96. GRB 250617B: Fermi GBM Observation
  97. GRB 250615A: Swift-BAT refined analysis
  98. GRB 250617B: Fermi GBM Final Localization
  99. GRB 250617B: Ondrejov D50 optical afterglow detection
  100. GRB 250617B: Swift detection of a burst with an optical counterpart

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