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"

45698 results found.

  1. Fermi Gamma-ray Burst Monitor trigger 776620220/250811660 is not a GRB
  2. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  3. GRB 250807A: Swift-BAT refined analysis
  4. LIGO/Virgo/KAGRA S250810ck: Updated Sky localization and EM Bright Classification
  5. GRB 250809A: Swift/UVOT Detection
  6. LIGO/Virgo/KAGRA S250810ck: Identification of a GW compact binary merger candidate
  7. Corrected Swift-XRT Refined Analysis of GRB 250809A
  8. GRB 250809A: Swift-XRT refined Analysis
  9. GRB 250807B: SVOM/VT optical observation
  10. EP250807a: EP-FXT follow-up observation upper limit
  11. GRB 250809A: LCOGT Optical Upper Limits
  12. GRB 250702B: Chandra X-ray Detection
  13. EP250807a: Global MASTER-Net observations report
  14. Fermi GRB 250808A: Global MASTER-Net observations report
  15. Fermi Gamma-ray Burst Monitor trigger 776449964/250809689 is not a GRB
  16. GRB 250808A: VLT X-shooter candidate counterpart
  17. GRB 250809A: Prompt enhanced Swift-XRT position
  18. GRB 250809A: Swift detection of a gamma ray burst
  19. GRB 250808A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  20. GRB 250808A: Fermi GBM Observation
  21. GRB 250808A: Swift-XRT candidate counterpart detection
  22. GRB 250807A: SVOM/VT optical continued observation
  23. EP-WXT trigger 01709195487: KAIT confirmation of the stellar flare
  24. GRB 250808A: SVOM detection of a long burst
  25. GRB 250808A: Fermi GBM Final Real-time Localization
  26. Konus-Wind detection of GRB 250807A
  27. GRB 250807B: Swift/UVOT Detection
  28. GRB 250807B: Kilonova-Catcher optical afterglow detection
  29. IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
  30. GRB 250807A: Swift/UVOT Detection
  31. GRB 250807A: Swift-XRT refined Analysis
  32. GRB 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
  33. GRB 250806A: SVOM/MXT refined analysis
  34. GRB 250806A: SVOM/ECLAIRs refined analysis
  35. EP250807a: NTT z-band optical upper limit
  36. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  37. GRB 250804B: Insight-HXMT detection
  38. GRB 250807A: SVOM/GRM observation
  39. Swift GRB250807.45: Global MASTER-Net observations report
  40. GRB 250807A: AstroSat CZTI detection of bright long burst
  41. GRB 250807B: Swift-XRT refined Analysis
  42. GRB 250806A: NOT z-band upper limit and host galaxy candidate
  43. GRB 250807B: NTT optical observations
  44. EP250807a: EP-WXT detection of a fast X-ray transient
  45. EP 250807.979: GOTO optical upper limit
  46. EP250807a: COLIBRÍ optical upper limit
  47. GRB 250807A: SVOM/VT optical observation
  48. EP250806a: Upper limit from Fermi-GBM Observations
  49. GRB 250807B: Enhanced Swift-XRT position
  50. Swift GRB250807.65: Global MASTER-Net observations report
  51. GRB 250807A: Enhanced Swift-XRT position
  52. IceCube-Cascade 250804A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 250807B: Swift detection of a burst with an optical counterpart.
  54. GRB 250805A: Kilonova-Catcher optical upper limits
  55. EP250806a:SVOM/VT refined analysis
  56. GRB 250805A: Swift/UVOT Upper Limits
  57. GRB 250806A: Swift/UVOT U-band detection
  58. EP250806a: Liverpool telescope optical upper limit
  59. GRB 250807A: Swift detection of a burst with an optical counterpart
  60. IceCube Alert 250804.84: Global MASTER-Net observations report
  61. GRB 250806A: EP-FXT observation
  62. EP#01709198415/EP250806a: Swift-XRT observations
  63. EP250806a: Global MASTER-Net observations report
  64. EP250802a: EP-FXT follow-up observation
  65. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  66. EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
  67. EP250806a: SVOM /VT optical candidate
  68. GRB 250806A: J-band upper limit from WINTER
  69. GRB 250805A: Swift-BAT refined analysis
  70. GRB 250806A: KAIT optical upper limit
  71. GRB 250806A: SVOM/VT refined analysis
  72. GRB 250806A: Swift-XRT counterpart detection
  73. EP250806a: COLIBRÍ optical upper limit
  74. GRB 250806A: Kilonova-Catcher optical upper limits
  75. EP250806a: Einstein Probe detection of an X-ray transient
  76. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  77. GRB 250806A: SVOM/VT optical upper limit
  78. GRB 250806A: SVOM detection of a soft burst
  79. GRB 250805A: SVOM/VT optical counterpart
  80. GRB 250805A: ESO/VLT observations
  81. GRB 250805A: Swift-XRT refined Analysis
  82. GRB 250804B: Swift-XRT observations
  83. GRB 250805A: Enhanced Swift-XRT position
  84. GRB 250804C: AstroSat CZTI detection of a long burst
  85. GRB 250805A: TRT optical upper limits
  86. IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
  87. GRB 250805A: Swift-XRT observations
  88. GRB 250805A: Swift detection of a burst
  89. Swift GRB250805.26: Global MASTER-Net observations report
  90. GRB 250804B: Tiled Swift observations
  91. Fermi trigger No 776041355: Global MASTER-Net observations report
  92. GRB 250804B: SVOM/GRM observation of a short burst
  93. GRB 250804A: Fermi GBM Final Localization
  94. EP250802a: additional Liverpool Telescope upper limits
  95. EP250730a: SVOM/VT optical upper limit
  96. Fermi Gamma-ray Burst Monitor trigger 775945985/250803856 is not a GRB
  97. EP250802a: Liverpool Telescope optical upper limits
  98. EP250802a: Global MASTER-Net observations report
  99. EP250802a: GROWTH-India Telescope optical upper limit
  100. EP250802a: 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