Skip to main content
Circulars over Kafka event name backfill. See news and announcements

GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

24603 results found.

  1. GRB 240218A: CMO SAI NIR upper limit
  2. GRB 240225B: Nanshan/HMT optical afterglow detection
  3. GRB 240225B: Swift-XRT observations
  4. Transient EPW20240219aa: Kp-band imaging observations with NIRES
  5. Transient EPW20240219aa: J-band upper limits from WINTER
  6. Transient EPW20240219aa: REM optical/NIR upper limits
  7. GRB 240225B: AstroSat CZTI detection
  8. GRB 240225B: MAXI/GSC detection
  9. Transient EPW20240219aa: Xinglong-2.16m optical upper limit
  10. GRB 240225A: Swift/BAT-GUANO detection of a short burst
  11. Transient EPW20240219aa: GECKO: LOAO Optical Upper Limits
  12. Transient EPW20240219aa: 7DT Optical Upper Limits
  13. VLA X-band observation of EPW20240219aa
  14. Transient EPW20240219aa: Mondy optical observations
  15. Transient EPW20240219aa: upper limit in gamma-ray range from SPI-ACS/INTEGRAL observations
  16. Insight-HXMT/HE Sub-Threshold Detection of Transient EPW20240219aa
  17. Transient EPW20240219aa: Liverpool Telescope non-detection and limiting magnitude
  18. GRB 240222A: GECAM detection of a burst
  19. GRB 240222A: Swift-BAT refined analysis
  20. GRB 240222A: Swift-XRT refined Analysis
  21. GRB 240222A: Fermi GBM Observation
  22. GRB 240222A: Swift/UVOT Upper Limits
  23. Fermi GBM Sub-Threshold Detection of EPW20240219aa as a likely GRB
  24. GRB 240222A: REM optical and NIR early-time observations
  25. GRB 240222A: Swift detection of a burst
  26. GRB 240218A: MeerLICHT upper limits
  27. GRB 240216A: Glowbug gamma-ray detection
  28. GRB 240215B: Fermi GBM Observation
  29. GRB 240218A: LBT H-band detection
  30. GRB 240218A: Swift-BAT refined analysis
  31. GRB 240218A: Swift-XRT refined Analysis
  32. GRB 240218A: VLT/X-shooter redshift of z = 6.782
  33. GRB 240218A: Fermi GBM Detection
  34. GRB 240215A: Fermi GBM Observation
  35. GRB 240218A: Enhanced Swift-XRT position
  36. GRB 240218A: REM detection of a NIR afterglow candidate
  37. GRB 240218A : r-band upper limit from Observatoire de Haute-Provence
  38. GRB240218A: VLT/X-shooter upper limits
  39. GRB 240218A: Swift detection of a burst
  40. GRB 240215B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  41. GRB 240215A: Swift/BAT-GUANO localization of a burst
  42. GRB 240213A: Glowbug gamma-ray detection
  43. GRB 240128A: Further Swift-XRT observations
  44. GRB 240214A/1H 0451-560: MAXI/GSC detection
  45. GRB 240213A: BALROG localization (Fermi Trigger / GRB 240213841)
  46. GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
  47. GRB 240209A: GOTO optical counterpart candidate
  48. Konus-Wind detection of GRB 240204A
  49. IPN triangulation of GRB 240205A (short)
  50. Fermi-LAT gamma-ray observations of IceCube-240204A
  51. GRB 240205B: PRIME near infrared detection
  52. GRB 240205A (short): Glowbug gamma-ray detection
  53. GRB240204A: Swift/UVOT Upper Limits
  54. GRB 240205B: Swift-BAT refined analysis
  55. Konus-Wind detection of GRB 240205B (long / very soft)
  56. GRB 240205B: VLT/X-shooter redshift
  57. GRB 240205B: REM detection of the optical/NIR afterglow
  58. GRB 240205B: Fermi GBM Observation
  59. GRB 240204A : OHP/T193/T120 optical afterglow fading detection
  60. GRB 240205B: GECAM detection of a long burst
  61. GRB 240204A: Swift-BAT refined analysis
  62. GRB 240205B: Skynet Optical Afterglow Observations
  63. Fermi trigger No 728749569: Global MASTER-Net observations report
  64. GRB 240204A: Fermi GBM Observation
  65. GRB 240204a: Liverpool Telescope optical afterglow detection
  66. GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
  67. IceCube-240204A: Upper limits from a search for additional neutrino events in IceCube
  68. GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
  69. GRB 240204A: Montarrenti Observatory optical observations
  70. GRB 240204A: Enhanced Swift-XRT position
  71. GRB 240204A: Mondy optical afterglow candidate
  72. GRB 240204A: Swift detection of a burst
  73. Konus-Wind detection of GRB 240123C
  74. IPN triangulation of GRB 240124B
  75. GRB 240129A: Fermi GBM Observation
  76. GRB 240129A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  77. GRB 240128A: Glowbug gamma-ray detection
  78. GRB 240128A: Swift-XRT observations
  79. GRB 240125A: GRBAlpha detection
  80. IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
  81. GRB 240125A: AstroSat CZTI detection of a short burst
  82. GRB 240124B: AstroSat CZTI detection
  83. GRB 240123C: AstroSat CZTI detection
  84. GRB240122A: PRIME near infrared detection
  85. GRB 240123B: Fermi GBM Observation
  86. GRB 240123A: Glowbug gamma-ray detection
  87. GRB 240125A (short): Glowbug gamma-ray detection
  88. GRB 240123B: Swift/BAT-GUANO detection of a long burst
  89. IPN triangulation of GRB 240123C (short)
  90. Fermi-LAT gamma-ray observations of IceCube-240123A
  91. GRB 240123A: further SAO RAS optical observations
  92. GRB 240123A: Swift-BAT refined analysis
  93. IceCube Alert 240123.48: Global MASTER-Net observations report
  94. GRB 240123A: SAO RAS optical observations
  95. GRB 240123A : MITSuME Akeno optical afterglow candidate detection
  96. GRB 240123A: Enhanced Swift-XRT position
  97. GRB 240124A?: BALROG localization (Fermi Trigger 727752941 / GRB 240124066)
  98. GRB 240122A: Swift/UVOT Upper Limits
  99. GRB 240123A: Swift-XRT refined Analysis
  100. Fermi GBM Sub-Threshold Detection of GRB 240123A

Advanced

Download all Circulars as a .tar.gz archive:
Looking for U.S. government information and services? Visit USA.gov