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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"

4169 results found.

  1. GRB 231208A: AstroSat CZTI detection of a faint burst
  2. GRB 231205B: REM optical/NIR upper limits
  3. GRB 231129C: ASIM MXGS observation and localization
  4. GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
  5. GRB 231205B : MITSuME Akeno optical upper limits
  6. Fermi trigger No 723435916: Global MASTER-Net observations report
  7. Fermi trigger No 723326169: Global MASTER-Net observations report
  8. Fermi trigger No 723149952: Global MASTER-Net observations report
  9. GRB 231129A: VZLUSAT-2 detection
  10. GRB 231129C: AGILE detection
  11. GRB 231129A : MITSuME Akeno optical upper limits
  12. GRB 231129C: MASTER OT detection
  13. GRB 231129A: BOOTES-5/JGT optical upper limit
  14. GRB 231129C: Fermi-LAT detection
  15. GRB 231129A: JinShan optical upper limit
  16. GRB 231129C: GRBAlpha detection
  17. GRB 231129C: Glowbug gamma-ray detection
  18. GRB 231129A: optical upper limit in Mondy observatory
  19. GRB 231129C: AstroSat CZTI detection
  20. GRB 231129C: CALET Gamma-Ray Burst Monitor detection
  21. GRB 231129C: Fermi GBM Observation of a very bright GRB
  22. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  23. GRB 231129C: MAXI/GSC detection
  24. GRB 231129C: BALROG localization (Fermi Trigger / GRB 231129799)
  25. GRB 231129C: Fermi GBM detection of a very bright burst
  26. GRB 231129C: Fermi GBM Final Real-time Localization
  27. Fermi trigger No 722977823: Global MASTER-Net observations report
  28. GRB 231129B: MAXI/GSC detection
  29. Integral GRB231129.21: Global MASTER-Net observations report
  30. LIGO/Virgo/KAGRA S231129ac: Identification of a GW compact binary merger candidate
  31. Fermi trigger No 722507896: Global MASTER-Net observations report
  32. Fermi trigger No 722462310: Global MASTER-Net observations report
  33. Fermi trigger No 722349867: Global MASTER-Net observations report
  34. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  35. GRB 231118A: Fermi GBM Final Real-time Localization
  36. LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate
  37. GRB 231117A: AKO Optical Upper Limit
  38. Swift GRB 231117A: Global MASTER-Net observations report
  39. GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
  40. GRB 231115A : MITSuME Akeno and Okayama optical upper limits
  41. GRB 231115A: archival HST observations
  42. GECAM-B observation of a short burst from SGR J1555-5402
  43. SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare
  44. GRB 231111A: GMG observation (correction)
  45. GRB 231111A: GMG observation upper limit
  46. Fermi GRB 231108A: Global MASTER-Net observations report
  47. Fermi GRB 231106A: Global MASTER-Net observations report
  48. GRB 231104A: 3.6m DOT optical upper limit
  49. Fermi GRB 231103A: Global MASTER-Net observations report
  50. GRB 231104A: Fermi-LAT detection
  51. LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate
  52. IceCube Alert 231103.39: Global MASTER-Net observations report
  53. Fermi trigger No 720498201: Global MASTER-Net observations report
  54. GRB 231024A: AKO Optical Counterpart Candidate
  55. Fermi GRB 231030A: Global MASTER-Net observations report
  56. LIGO/Virgo/KAGRA S231029y: One counterpart neutrino candidate from IceCube neutrino searches
  57. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  58. LIGO/Virgo/KAGRA S231029y: Identification of a GW compact binary merger candidate
  59. LIGO/Virgo/KAGRA S231029k: Global MASTER-Net observations report
  60. Fermi trigger No 720224759: Global MASTER-Net observations report
  61. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  62. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  63. IC231004A: GRANDMA observations of AT2023uqf/ZTF23abidzvf candidate
  64. LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
  65. LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
  66. Fermi GRB 231019A: Global MASTER-Net observations report
  67. LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate
  68. GRB 230827B: 10.4m GTC spectroscopic redshift
  69. LIGO/Virgo/KAGRA S230927l: Identification of a GW compact binary merger candidate
  70. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  71. IPN triangulation of GRB 230919A (short)
  72. transient AT2023sva: imaging and spectroscopic observations from MISTRAL at Observatoire de Haute-Provence
  73. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  74. LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate
  75. IceCube-230914A: Upper limits from a search for additional neutrino events in IceCube
  76. GRB 230911A: Swift-XRT afterglow detection
  77. Fermi trigger No 716449174: Global MASTER-Net observations report
  78. IceCube Alert 230914.22: Global MASTER-Net observations report
  79. GRB 230911A: GOTO optical counterpart candidate
  80. GRB 230906A: Chandra detection of the X-ray afterglow
  81. GRB 230903A: VLT/X-shooter optical observations
  82. GRB 230904C: Fermi GBM Final Localization
  83. Fermi GRB 230903A: Global MASTER-Net observations report
  84. GRB 230904B is not a GRB
  85. GRB 230904B: BALROG localization (Fermi Trigger 715526984 / GRB 230904562)
  86. GRB 230828A: AstroSat CZTI detection
  87. GRB 230828A: GRBAlpha detection
  88. Swift Trigger 1188089 is not a GRB
  89. Fermi GRB 230827A: Global MASTER-Net observations report
  90. GRB 230824A: AKO Photometric Follow-up Observations
  91. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  92. GRB 230818B: VZLUSAT-2 detection
  93. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
  94. GRB 230818A: SAO RAS Zeiss-1000 observations
  95. Fermi GRB 230818A: Global MASTER-Net observations report
  96. GRB 230818A: Swift detection of a burst
  97. Fermi GRB 230817A: Global MASTER-Net observations report
  98. GRB 230816A: TShAO and Assy optical observations
  99. GRB 230816A: SAO RAS optical observations
  100. IPN triangulation of GRB 230815B

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