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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"

4572 results found.

  1. Swift J1727.8-1613 (GRB 230824A): Madrona Peak Observatory - optical follow-up
  2. Transient EPW20240219aa: J-band upper limits from WINTER
  3. GRB 240225B: GOTO detection of a candidate optical afterglow
  4. GRB 240222A: ATCA radio observations
  5. VLA X-band observation of EPW20240219aa
  6. GRB 240222A: Swift-XRT refined Analysis
  7. Fermi trigger No 729914426: Global MASTER-Net observations report
  8. GRB 240215A: Swift/BAT-GUANO localization of a burst
  9. Fermi trigger No 729703985: Global MASTER-Net observations report
  10. GRB 240214A/1H 0451-560: MAXI/GSC detection
  11. Fermi trigger No 729152364: Global MASTER-Net observations report
  12. Fermi trigger No 729012023: Global MASTER-Net observations report
  13. Fermi trigger No 728796365: Global MASTER-Net observations report
  14. Konus-Wind detection of GRB 240123C
  15. IPN triangulation of GRB 240125B (short)
  16. GRB 240122A: ATCA detection of radio counterpart
  17. IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
  18. GRB 240124B: AstroSat CZTI detection
  19. IPN triangulation of GRB 240123C (short)
  20. IceCube Alert 240123.48: Global MASTER-Net observations report
  21. GRB 240123A: SAO RAS optical observations
  22. GRB 240123A : MITSuME Akeno optical afterglow candidate detection
  23. GRB 240124A?: BALROG localization (Fermi Trigger 727752941 / GRB 240124066)
  24. GRB 240123A: Swift-XRT refined Analysis
  25. GRB 240122A: Swift-XRT afterglow detection
  26. Fermi GRB 240115A: Global MASTER-Net observations report
  27. GRB 240112C: Swift/UVOT Detection
  28. GRB 240112C: Swift-XRT refined Analysis
  29. GRB 240112D: Fermi GBM Final Real-time Localization
  30. Fermi trigger No 726774492: Global MASTER-Net observations report
  31. GRB 240112C: Swift detection of a burst with an optical counterpart
  32. GRB 230818A: further radio observations with the VLA
  33. GRB 230812B: further radio observations with the VLA
  34. GRB 240107A: MAXI/GSC detection
  35. IPN triangulation of GRB 240101C (short)
  36. IceCube Alert 240105.52: Global MASTER-Net observations report
  37. GRB 240102A: Swift-XRT refined Analysis
  38. Fermi trigger No 725857207: Global MASTER-Net observations report
  39. GRB 240101A: Terskol Zeiss-2000 optical observations
  40. GRB 240101C: GRBAlpha detection
  41. GRB 240101A: Swift-XRT refined Analysis
  42. GRB 231230A: Swift-XRT refined Analysis
  43. Fermi trigger No 725592555: Global MASTER-Net observations report
  44. Fermi trigger No 725143760: Global MASTER-Net observations report
  45. GRB 231224A: Fermi GBM Final Real-time Localization
  46. LIGO/Virgo/KAGRA S231224e: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S231223j: Identification of a GW compact binary merger candidate
  48. Fermi trigger No 724781422: Global MASTER-Net observations report
  49. GRB 231210B: new optical transient detected with the Greenhill Observatory University of Tasmania within the BAT-Swift enhanced position
  50. GRB 231214B: Fermi GBM observation
  51. GRB 231216A: optical upper limits from the INAF Asiago Observatory
  52. GRB 231216A: Swift-XRT refined analysis correction
  53. GRB 231216A: R-band observations from T120 at Observatoire de Haute-Provence
  54. Swift GRB231216.77: Global MASTER-Net observations report
  55. GRB 231215A: Swift-XRT refined Analysis
  56. GRB 231214A: Fermi GBM observation
  57. GRB 231215A : MITSuME Akeno optical afterglow candidate detection
  58. GRB 231214A: Swift-XRT refined Analysis
  59. GRB 231214A: AstroSat CZTI detection
  60. GRB 231214A: Fermi-LAT detection
  61. GRB 231214A: Swift detection of a burst
  62. GRB 231214A: Fermi GBM Final Real-time Localization
  63. IceCube Alert 231211.03: Global MASTER-Net observations report
  64. GRB 231210B: Swift-XRT refined Analysis
  65. Swift GRB231210.90: Global MASTER-Net observations report
  66. Fermi trigger No 723581802: Global MASTER-Net observations report
  67. GRB 231205B: Swift-XRT refined Analysis
  68. GRB 231205B : MITSuME Akeno optical upper limits
  69. Fermi trigger No 723435916: Global MASTER-Net observations report
  70. Fermi trigger No 723326169: Global MASTER-Net observations report
  71. GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
  72. GRB 231128A: VZLUSAT-2 detection
  73. GRB 231129A : MITSuME Akeno optical upper limits
  74. GRB 231129C: MAXI/GSC detection
  75. GRB 231129A: Swift-XRT refined Analysis
  76. Fermi trigger No 722977823: Global MASTER-Net observations report
  77. IceCube-231125A: Upper limits from a search for additional neutrino events in IceCube
  78. GRB 231124A: GRBAlpha detection
  79. Fermi trigger No 722653947: Global MASTER-Net observations report
  80. Fermi trigger No 722507896: Global MASTER-Net observations report
  81. GRB 231124A: Glowbug gamma-ray detection
  82. Fermi trigger No 722462310: Global MASTER-Net observations report
  83. GRB 231124A: CALET Gamma-Ray Burst Monitor detection
  84. GRB 231124A: Fermi GBM Final Real-time Localization
  85. Fermi trigger No 722400249: Global MASTER-Net observations report
  86. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  87. GRB 231118A: MeerLICHT afterglow detection
  88. LIGO/Virgo/KAGRA S231118an: Identification of a GW compact binary merger candidate
  89. GRB 231117A : MITSuME Akeno optical upper limits
  90. Fermi GRB 231116A: Global MASTER-Net observations report
  91. GRB 231115A : MITSuME Akeno and Okayama optical upper limits
  92. GRB 231111A: Swift-XRT refined Analysis
  93. IceCube-231103A: No candidates from the Zwicky Transient Facility
  94. Fermi trigger No 721204446: Global MASTER-Net observations report
  95. Fermi GRB 231108A: Global MASTER-Net observations report
  96. GRB 231104A: 3.6m DOT optical upper limit
  97. Fermi GRB 231103A: Global MASTER-Net observations report
  98. GRB 231104A: AstroSat CZTI detection
  99. GRB 231104A: Swift-XRT refined Analysis
  100. IceCube Alert 231103.39: Global MASTER-Net observations report

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