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"

18393 results found.

  1. EP260126a: Einstein Probe detection of a fast X-ray transient
  2. GRB 251222A: SVOM/ECLAIRs refined analysis
  3. GRB 260125A: GOTO candidate optical counterpart
  4. GRB 260114A: SVOM/VT optical upper limits
  5. GRB 260122B: Swift-BAT refined analysis
  6. GRB 260120B: SVOM/GRM observation
  7. GRB 260120B: AstroSat CZTI detection
  8. EP260119a: Assy AZT-20 optical observations
  9. EP260119a: Mondy and SAO RAS optical upper limits
  10. EP260119a: Xinglong optical upper limit
  11. The EP-WXT trigger 01709251871 is likely a flaring star
  12. GRB 260120B: Swift-BAT refined analysis
  13. GRB 260120B: Swift-XRT refined Analysis
  14. EP260116a: COLIBRÍ further observations
  15. EP260105a: GTC/HiPERCAM optical observations
  16. GRB 260120B: Swift/UVOT Detection
  17. GRB 260120B: COLIBRÍ optical upper limits
  18. GRB 260120B: Enhanced Swift-XRT position
  19. GRB 260120B: SVOM/C-GFT optical counterpart detection
  20. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  21. GRB 260120B: Swift detection of a burst
  22. EP260119A: Mondy I-Band Observations
  23. GRB 260114A: Swift/UVOT Upper Limits
  24. EP260119a: Liverpool Telescope optical follow-up observations
  25. GRB 251202A: further radio observations with the VLA
  26. EP260119a: KAIT optical observations
  27. EP260119a: SVOM/VT optical observation
  28. EP260119a: update of EP-FXT follow-up observation
  29. EP260119a: NOT optical observations
  30. EP260119a: SAO RAS optical observations
  31. EP260116a: COLIBRÍ detection of a fading optical source
  32. GRB 260117A: Swift-XRT afterglow detection
  33. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  34. GRB 260115A: AstroSat CZTI detection
  35. EP260119a: LCO optical observations
  36. GRB 260117A: ZTSh optical upper limit
  37. EP260119a: COLIBRÍ optical counterpart candidate
  38. EP260119a: preliminary result from the EP-FXT observation
  39. EP260119a: EP-WXT detection of a fast X-ray transient
  40. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  41. Swift trigger on the HMXB 1A 1118-61
  42. GRB 260117A: SVOM/C-GFT upper limit
  43. EP 260116a: COLIBRÍ optical upper limit
  44. Swift triggered on the HMXB 1A 1118-61
  45. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  46. EP260116a: Liverpool Telescope upper limits
  47. EP260116A: 1.3m DFOT optical upper limit
  48. GRB 260114A: VLT/MUSE spectroscopic observations
  49. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  50. EP260116a: Xinglong optical upper limit
  51. EP260116a: Einstein Probe detection of an X-ray transient
  52. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  53. Fermi GRB 260115A: Global MASTER-Net observations report
  54. GRB 251222A: radio detection with the VLA
  55. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  56. GRB 260114A: Swift-XRT refined Analysis
  57. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  58. GRB 260114A : MITSuME Akeno optical upper limits
  59. GRB 260114A: COLIBRÍ optical upper limits
  60. GRB 260114A: TNG NIR upper limit
  61. GRB 260114A: NOT optical observations
  62. GRB 260114A: SVOM/GRM observation of a short burst
  63. GRB 260114A: Mondy optical observations
  64. GRB 260114A: GMG Optical Observation
  65. GRB 260114A: Swift detection of a short burst
  66. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  67. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  68. EP260110a: TRT optical upper limits
  69. Swift Trigger 1439093: is probably not GRB 260113A
  70. GRB 260111A: COLIBRÍ optical afterglow candidate
  71. The EP-WXT trigger 01709251266 is likely a flaring star
  72. GRB 260111A: GOTO optical upper limits
  73. GRB 251230A: Mondy Optical Observations
  74. Swift trigger 1436759 is not an astrophysical event
  75. EP260110a: KAIT optical upper limit
  76. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  77. EP 260110a: COLIBRÍ optical observations
  78. EP260110a: SVOM/C-GFT upper limit
  79. EP260110a: Einstein Probe detection of an X-ray transient
  80. GRB 260109C: LCO optical upper limits
  81. GRB 260109C: Kilonova-Catcher optical upper limit
  82. Swift Trigger 1434591: possible GRB 260109C
  83. GRB 260109B: Fermi GBM Final Real-time Localization
  84. GRB 260102A: Swift-XRT afterglow detection
  85. GRB 260109A: Fermi GBM Final Real-time Localization
  86. GRB 260102A: AbAO optical observations
  87. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  88. The EP-WXT trigger 01709251112 is likely a flaring star
  89. GRB 260105A: SVOM/GRM observation
  90. GRB 260105B: SVOM/GRM observation
  91. The EP-WXT trigger 01709251028 is likely a flaring star
  92. FRB 20251229A: COLIBRÍ optical upper limits
  93. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  94. EP260105a: LCO Optical Upper limit
  95. EP260104a: Einstein Probe detection of a fast X-ray transient
  96. GRB 260101A: COLIBRÍ optical upper limits
  97. EP260105a: Einstein Probe detection of an X-ray transient
  98. GRB 260104A: COLIBRÍ optical upper limits
  99. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  100. GRB 260104A: Enhanced Swift-XRT position

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