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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"

3040 results found.

  1. Fermi trigger No 737788024: Global MASTER-Net observations report
  2. Fermi trigger No 737559855: Global MASTER-Net observations report
  3. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  4. Fermi trigger No 737523389: Global MASTER-Net observations report
  5. LAT GRB240513.31: Global MASTER-Net observations report
  6. Fermi trigger No 737277727: Global MASTER-Net observations report
  7. Fermi trigger No 737258655: Global MASTER-Net observations report
  8. Fermi trigger No 737247400: Global MASTER-Net observations report
  9. Fermi trigger No 737196587: Global MASTER-Net observations report
  10. Fermi trigger No 737152719: Global MASTER-Net observations report
  11. Fermi trigger No 736967879: Global MASTER-Net observations report
  12. Fermi trigger No 736564880: Global MASTER-Net observations report
  13. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  14. GRB 240502C: GOTO possible optical counterpart candidates
  15. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  16. Fermi GRB 240501A: Global MASTER-Net observations report
  17. Fermi trigger No 736197684: Global MASTER-Net observations report
  18. LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam
  19. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  20. IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
  21. LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap
  22. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  23. GRB 240421B: Swift-BAT refined analysis
  24. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  25. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  26. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  27. IceCube Alert 240424.08: Global MASTER-Net observations report
  28. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  29. LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
  30. GRB 240419A: Swift-BAT refined analysis
  31. GRB 240421B: ATCA radio observations
  32. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  33. Fermi trigger No 735470374: Global MASTER-Net observations report
  34. Fermi trigger No 735280430: Global MASTER-Net observations report
  35. IceCube Alert 240419.98: Global MASTER-Net observations report
  36. GRB 240411A: GOTO early optical upper limits
  37. Fermi GRB 240417A: Global MASTER-Net observations report
  38. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  39. EP240416A: Khureltogoot optical upper limit
  40. Improved IPN triangulation of GRB 240411A
  41. EP240416A: MASTER optical observations
  42. GRB 240414A: Swift-BAT refined analysis
  43. Fermi GRB 240415A: Global MASTER-Net observations report
  44. GRB 240415A: Fermi GBM Final Real-time Localization
  45. Fermi trigger No 734754044: Global MASTER-Net observations report
  46. GRB 240414A : OHP/T193 redshift determination
  47. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  48. IceCube Alert 240412.23: Global MASTER-Net observations report
  49. EP240408a: Swift follow-up observation
  50. Fermi GRB 240405B: Global MASTER-Net observations report
  51. GRB 240403B: Glowbug gamma-ray detection
  52. GRB 240403A: Glowbug gamma-ray detection
  53. Konus-Wind detection of LXT 240402A/GRB 240402B
  54. GRB 240403A: Fermi GBM Detection
  55. GRB 240403A: BALROG localization (Fermi Trigger 733838255 / GRB 240403498)
  56. Fermi GRB 240402A: Global MASTER-Net observations report
  57. Fermi trigger No 733097506: Global MASTER-Net observations report
  58. Fermi GRB 240320A: Global MASTER-Net observations report
  59. Fermi GRB 240317B: Global MASTER-Net observations report
  60. Fermi trigger No 732299243: Global MASTER-Net observations report
  61. Fermi GRB 240314A: Global MASTER-Net observations report
  62. Fermi GRB 240310A: Global MASTER-Net observations report
  63. Fermi GRB 240306A: Global MASTER-Net observations report
  64. Fermi GRB 240305A: Global MASTER-Net observations report
  65. Swift J151857.0-572147: Swift-BAT refined analysis
  66. Fermi GRB 240229A: Global MASTER-Net observations report
  67. IceCube Alert 240229.66: Global MASTER-Net observations report
  68. Fermi trigger No 730618809: Global MASTER-Net observations report
  69. GRB 240216A: Glowbug gamma-ray detection
  70. GRB 240218A: Swift-BAT refined analysis
  71. GRB 240215A: Fermi GBM Observation
  72. GRB 240216A: GRBAlpha detection
  73. Fermi trigger No 729914426: Global MASTER-Net observations report
  74. GRB 240216A: Fermi GBM Final Real-time Localization
  75. GRB 240214A/1H 0451-560: MAXI/GSC detection
  76. Fermi trigger No 729152364: Global MASTER-Net observations report
  77. Fermi trigger No 729012023: Global MASTER-Net observations report
  78. Konus-Wind detection of GRB 240205B (long / very soft)
  79. GRB 240204A: Swift-BAT refined analysis
  80. Fermi trigger No 728749569: Global MASTER-Net observations report
  81. GRB 240204a: Liverpool Telescope optical afterglow detection
  82. IceCube Alert 240123.48: Global MASTER-Net observations report
  83. Swift triggers 1209631, 1209632, 1209635 and 1209644 are not interesting astrophysical events
  84. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A
  85. Swift Triggers 1209371 through 1209374 are not astrophysical events
  86. Fermi GRB 240115A: Global MASTER-Net observations report
  87. GRB 240114A: MAXI/GSC detection
  88. Fermi GRB 240112D: Global MASTER-Net observations report
  89. Konus-Wind detection of GRB 240101C
  90. GRB 231215A: radio detection with the VLA
  91. Swift GRB240109.17: Global MASTER-Net observations report
  92. IPN triangulation of GRB 240101C (short)
  93. GRB GRB240101C: Fermi GBM observation
  94. GRB 240101C: Swift/BAT-GUANO detection of a short burst
  95. GRB 240101C: AstroSat CZTI detection
  96. GRB 240101C: GRBAlpha detection
  97. GRB 240101C: Fermi GBM Final Localization
  98. Swift GRB240101.85: Global MASTER-Net observations report
  99. Fermi trigger No 725806648: Global MASTER-Net observations report
  100. Fermi trigger No 725592555: Global MASTER-Net observations report

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