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"

32570 results found.

  1. Fermi GRB 260125B: Global MASTER-Net observations report
  2. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  3. GRB 260114A: SVOM/VT optical upper limits
  4. GRB 260120A: AstroSat CZTI detection
  5. GRB 260122B: Swift-BAT refined analysis
  6. GRB 260120B: SVOM/GRM observation
  7. GRB 260120A: GECAM-B observation
  8. GRB 260120B: AstroSat CZTI detection
  9. GRB 260114A: Insight-HXMT/HE detection
  10. EP260119a: Assy AZT-20 optical observations
  11. EP260119a: Mondy and SAO RAS optical upper limits
  12. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  13. EP260119a: Xinglong optical upper limit
  14. Fermi GRB 260120C: Global MASTER-Net observations report
  15. GRB 260120B: Swift-BAT refined analysis
  16. EP260116a: COLIBRÍ further observations
  17. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  18. GRB 260120B: Fermi GBM Observation
  19. EP260105a: GTC/HiPERCAM optical observations
  20. GRB 260120B: Swift/UVOT Detection
  21. GRB 260120B: COLIBRÍ optical upper limits
  22. GRB 260120B: SVOM/C-GFT optical counterpart detection
  23. GRB 260101A: 239Alferov CubeSat detection
  24. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  25. EP260119A: Mondy I-Band Observations
  26. GRB 260114A: Swift/UVOT Upper Limits
  27. EP260119a: Liverpool Telescope optical follow-up observations
  28. GRB 251202A: further radio observations with the VLA
  29. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  30. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  31. EP260119a: KAIT optical observations
  32. EP260119a: SVOM/VT optical observation
  33. EP260119a: update of EP-FXT follow-up observation
  34. EP260119a: NOT optical observations
  35. EP260119a: SAO RAS optical observations
  36. EP260116a: COLIBRÍ detection of a fading optical source
  37. GRB 251208D: SVOM/ECLAIRs refined analysis
  38. GRB 251208D: SVOM/ECLAIRs refined analysis
  39. GRB 260117A: Swift-XRT afterglow detection
  40. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  41. EP260119a: Global MASTER-Net observations report
  42. GRB 260115A: AstroSat CZTI detection
  43. EP260119a: LCO optical observations
  44. GRB 260117A: ZTSh optical upper limit
  45. EP260119a: COLIBRÍ optical counterpart candidate
  46. EP260119a: preliminary result from the EP-FXT observation
  47. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  48. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  49. Swift trigger on the HMXB 1A 1118-61
  50. GRB 260117A: SVOM/VT optical candidate
  51. GRB 260117A: SVOM/C-GFT upper limit
  52. GRB 260117A: Swift ToO observations
  53. EP 260116a: COLIBRÍ optical upper limit
  54. GRB 260115A: GECAM-B observation
  55. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  56. EP260116a: Liverpool Telescope upper limits
  57. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  58. EP260116A: 1.3m DFOT optical upper limit
  59. GRB 260114A: VLT/MUSE spectroscopic observations
  60. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  61. EP260116a: Global MASTER-Net observations report
  62. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  63. EP260116a: Xinglong optical upper limit
  64. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  65. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  66. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  67. Fermi GRB 260115A: Global MASTER-Net observations report
  68. GRB260114A: STEP/T80S optical limits
  69. GRB 251222A: radio detection with the VLA
  70. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  71. Konus-Wind detection of GRB 260114A
  72. GRB 260114A: 6 GHz VLA observations
  73. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  74. GRB 260114A : MITSuME Akeno optical upper limits
  75. GRB 260114A: COLIBRÍ optical upper limits
  76. GRB 260114A: TNG NIR upper limit
  77. GRB 260114A: NOT optical observations
  78. Konus-Wind detection of GRB 251230A / EP251230a
  79. GRB 260114A: SVOM/GRM observation of a short burst
  80. Swift GRB 260114A: Global MASTER-Net observations report
  81. GRB 260114A: GECAM-B observation of a short burst
  82. GRB 260114A: Mondy optical observations
  83. GRB 260114A: Fermi GBM observation
  84. GRB 260112B: GECAM-B observation
  85. GRB 260114A: GMG Optical Observation
  86. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  87. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  88. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  89. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  90. EP260110a: TRT optical upper limits
  91. Konus-Wind detection of GRB 260101A
  92. GRB 260111A: Swift-XRT observations
  93. GRB 260111A: COLIBRÍ optical afterglow candidate
  94. GRB 260111A: GECAM-B observation of a burst
  95. GRB 260111A: Fermi GBM Observation
  96. Swift Trigger 1434591 is not a GRB
  97. GRB 260111A: GOTO optical upper limits
  98. GRB 260111A: Swift ToO observations
  99. GRB 251230A: Mondy Optical Observations
  100. GRB 260111A: Swift/BAT-GUANO arcminute localization of a 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