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"

12338 results found.

  1. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  2. LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
  3. GRB 250205A: REM NIR upper limit
  4. GRB 250205A: Swift/UVOT Upper Limits
  5. GRB 250205A: GOTO optical upper limits
  6. EP 250108A: Upper limits from Fermi-GBM Observations
  7. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  8. Swift GRB250129A: MASTER 4 days observations report
  9. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  10. EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
  11. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  12. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  13. GRB 250128B: VLA radio upper limit
  14. Ep250125A: 1.3m DFOT optical upper limit
  15. GRB 250128B: TNG optical upper limit
  16. GRB 250127A: CrAO and Terskol optical upper limits
  17. GRB 250128B: NOT optical upper limit
  18. GRB 250128B: OHP/T193 optical upper limit
  19. Swift GRB 250129A: Global MASTER-Net observations report
  20. Fermi GRB 250128B: Global MASTER-Net observations report
  21. Swift GRB 250129A: Global MASTER-Net OT detection
  22. GRB 250128B: GOTO optical upper limit
  23. Swift GRB 250128B: Global MASTER-Net observations report
  24. EP250125a: Upper limits from Swift/BAT-GUANO
  25. GRB 250128B: Swift detection of a short burst
  26. GRB 250127A: Swift-XRT observations
  27. GRB 250127B: DDOTI Upper Limit on the Afterglow
  28. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  29. Fermi GRB 250128A: Global MASTER-Net observations report
  30. Fermi GRB 250127B: Global MASTER-Net observations report
  31. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  32. GRB 250127A: SVOM/VT upper limit
  33. GRB 250127A: LCO optical upper limit
  34. GRB 250126A: MAXI/GSC detection
  35. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  36. EP250125a: Optical upper limit with Kinder observations
  37. EP250108a: AbAO, CMO and Terskol optical upper limits
  38. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  39. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  40. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  41. EP250108a / AT2025kg: VLA radio upper limit
  42. GRB 250114B: SVOM/VT upper limit
  43. EP250108a: MeerKAT radio upper limit
  44. Konus-Wind detection of GRB 250113A
  45. GRB 250114B: Liverpool Telescope optical upper limit
  46. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  47. GRB 250114B: Swift-XRT observations
  48. GRB 250114B: OHP/T193 optical upper limit
  49. Integral GRB250114.55: Global MASTER-Net observations report
  50. GRB 250114B : GIT optical upper limit
  51. EP250111a: SAO RAS optical upper limit
  52. Swift GRB250114A: Global MASTER-Net OT detection
  53. Swift GRB 250114A: Global MASTER-Net observations report
  54. EP241021a: SMA radio observation
  55. EP250109b: optical upper limits with the Liverpool Telescope
  56. Fermi trigger No 758442826: Global MASTER-Net observations report
  57. GRB 250109A / EP250109a: Mephisto optical upper limits
  58. EP250108a: Mephisto detection
  59. EP250111a: Global MASTER-Net observations report
  60. EP250108a / AT 2025kg: Swift UVOT detections
  61. EP250108a: EP-FXT follow-up observation
  62. GRB 250109a: GMG Optical Upper Limit
  63. EP250109a: Swift/UVOT non-detection
  64. GRB 250108B: 1.3m DFOT upper limit
  65. GRB 250108B: REM optical/NIR upper limits
  66. EP250109a: SVOM/VT optical candidate
  67. EP250109a: Global MASTER-Net observations report
  68. EP250109a: GOTO optical upper limits
  69. EP250109a: Swift/XRT non-detection
  70. GRB 250108A: Swift/UVOT Upper Limits
  71. EP250108a: Global MASTER-Net observations report
  72. GRB 250108A: NOT optical upper limit
  73. Swift GRB 250108B: Global MASTER-Net observations report
  74. GRB 250103A: 1.6m Mephisto optical observations
  75. GRB 250108A: Swift-XRT afterglow detection
  76. GRB 250108B: Swift/UVOT Upper Limits
  77. GRB 250108B: Swift detection of a burst
  78. Fermi GRB 250107B: Global MASTER-Net observations report
  79. GRB 250101A: J band upper limit by SYSU 80cm telescope
  80. GRB 250103B: REM optical/NIR upper limits
  81. GRB 250106A: Swift-XRT observations
  82. Fermi trigger No 757753930: Global MASTER-Net observations report
  83. GRB 250103A: Bassano Bresciano Observatory upper limit
  84. GRB 250103A: Swift-XRT observations
  85. GRB 241229A: 1.3m DFOT upper limit
  86. GRB 241228A: 1.3m DFOT upper limit
  87. GRB 250103A: TSHAO optical upper limit
  88. GRB 250103B: LCOGT Optical Upper Limit
  89. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  90. Swift GRB 250103B: Global MASTER-Net observations report
  91. EP250101a: Liverpool Telescope optical upper limit
  92. IceCube-250101A: Upper limits from a search for additional neutrino events in IceCube
  93. Fermi GRB 250102A: Global MASTER-Net observations report
  94. GRB 250103A: GOTO optical upper limit
  95. GRB 250103A: SVOM/C-GFT optical upper limit
  96. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  97. IceCube Alert 250102.58: Global MASTER-Net observations report
  98. EP241231b: optical upper limit with the Liverpool Telescope
  99. EP250101a: Xinglong optical upper limit
  100. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO

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