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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"

3873 results found.

  1. GRB 231210B: Swift detection of a burst with optical counterpart
  2. IPN triangulation of GRB 231129C
  3. GRB 231208A: GRBAlpha detection
  4. GRB 231208A: Glowbug gamma-ray detection
  5. GRB 231208A: AstroSat CZTI detection of a faint burst
  6. GRB 231205B: REM optical/NIR upper limits
  7. GRB 231129C: ASIM MXGS observation and localization
  8. GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
  9. GRB 231205B : MITSuME Akeno optical upper limits
  10. Fermi trigger No 723435916: Global MASTER-Net observations report
  11. Fermi trigger No 723326169: Global MASTER-Net observations report
  12. Fermi trigger No 723149952: Global MASTER-Net observations report
  13. GRB 231129A: VZLUSAT-2 detection
  14. GRB 231129C: AGILE detection
  15. GRB 231129A : MITSuME Akeno optical upper limits
  16. GRB 231129C: MASTER OT detection
  17. GRB 231129A: BOOTES-5/JGT optical upper limit
  18. GRB 231129C: Fermi-LAT detection
  19. GRB 231129A: JinShan optical upper limit
  20. GRB 231129C: GRBAlpha detection
  21. GRB 231129C: Glowbug gamma-ray detection
  22. GRB 231129A: optical upper limit in Mondy observatory
  23. GRB 231129C: AstroSat CZTI detection
  24. GRB 231129C: CALET Gamma-Ray Burst Monitor detection
  25. GRB 231129C: Fermi GBM Observation of a very bright GRB
  26. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  27. GRB 231129C: MAXI/GSC detection
  28. GRB 231129C: BALROG localization (Fermi Trigger / GRB 231129799)
  29. GRB 231129C: Fermi GBM detection of a very bright burst
  30. GRB 231129C: Fermi GBM Final Real-time Localization
  31. Fermi trigger No 722977823: Global MASTER-Net observations report
  32. GRB 231129B: MAXI/GSC detection
  33. Integral GRB231129.21: Global MASTER-Net observations report
  34. LIGO/Virgo/KAGRA S231129ac: Identification of a GW compact binary merger candidate
  35. Fermi trigger No 722507896: Global MASTER-Net observations report
  36. Fermi trigger No 722462310: Global MASTER-Net observations report
  37. Fermi trigger No 722349867: Global MASTER-Net observations report
  38. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  39. GRB 231118A: Fermi GBM Final Real-time Localization
  40. LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate
  41. GRB 231117A: AKO Optical Upper Limit
  42. Swift GRB 231117A: Global MASTER-Net observations report
  43. GRB 231115A: GBM/Fermi Observations of a probable Giant Flare of Magnetar
  44. GRB 231115A : MITSuME Akeno and Okayama optical upper limits
  45. GRB 231115A: archival HST observations
  46. GECAM-B observation of a short burst from SGR J1555-5402
  47. SGRJ1555-5402: Swift/BAT-GUANO arcminute localization of a SGR flare
  48. GRB 231111A: GMG observation (correction)
  49. GRB 231111A: GMG observation upper limit
  50. Fermi GRB 231108A: Global MASTER-Net observations report
  51. Fermi GRB 231106A: Global MASTER-Net observations report
  52. GRB 231104A: 3.6m DOT optical upper limit
  53. Fermi GRB 231103A: Global MASTER-Net observations report
  54. GRB 231104A: Fermi-LAT detection
  55. LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate
  56. IceCube Alert 231103.39: Global MASTER-Net observations report
  57. Fermi trigger No 720498201: Global MASTER-Net observations report
  58. GRB 231024A: AKO Optical Counterpart Candidate
  59. Fermi GRB 231030A: Global MASTER-Net observations report
  60. LIGO/Virgo/KAGRA S231029y: One counterpart neutrino candidate from IceCube neutrino searches
  61. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  62. LIGO/Virgo/KAGRA S231029y: Identification of a GW compact binary merger candidate
  63. LIGO/Virgo/KAGRA S231029k: Global MASTER-Net observations report
  64. Fermi trigger No 720224759: Global MASTER-Net observations report
  65. LIGO/Virgo/KAGRA S231025t: Global MASTER-Net observations report
  66. LIGO/Virgo/KAGRA S231025a: Global MASTER-Net observations report
  67. IC231004A: GRANDMA observations of AT2023uqf/ZTF23abidzvf candidate
  68. LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
  69. LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
  70. Fermi GRB 231019A: Global MASTER-Net observations report
  71. LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate
  72. GRB 230827B: 10.4m GTC spectroscopic redshift
  73. LIGO/Virgo/KAGRA S230927l: Identification of a GW compact binary merger candidate
  74. LIGO/Virgo/KAGRA S230922g: DECam GW-MMADS candidates
  75. IPN triangulation of GRB 230919A (short)
  76. transient AT2023sva: imaging and spectroscopic observations from MISTRAL at Observatoire de Haute-Provence
  77. LIGO/Virgo/KAGRA S230920al: Identification of a GW compact binary merger candidate
  78. LIGO/Virgo/KAGRA S230919bj: Identification of a GW compact binary merger candidate
  79. IceCube-230914A: Upper limits from a search for additional neutrino events in IceCube
  80. GRB 230911A: Swift-XRT afterglow detection
  81. Fermi trigger No 716449174: Global MASTER-Net observations report
  82. IceCube Alert 230914.22: Global MASTER-Net observations report
  83. GRB 230911A: GOTO optical counterpart candidate
  84. GRB 230906A: Chandra detection of the X-ray afterglow
  85. GRB 230903A: VLT/X-shooter optical observations
  86. GRB 230904C: Fermi GBM Final Localization
  87. Fermi GRB 230903A: Global MASTER-Net observations report
  88. GRB 230904B is not a GRB
  89. GRB 230904B: BALROG localization (Fermi Trigger 715526984 / GRB 230904562)
  90. GRB 230828A: AstroSat CZTI detection
  91. GRB 230828A: GRBAlpha detection
  92. Swift Trigger 1188089 is not a GRB
  93. Fermi GRB 230827A: Global MASTER-Net observations report
  94. GRB 230824A: AKO Photometric Follow-up Observations
  95. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  96. GRB 230818B: VZLUSAT-2 detection
  97. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
  98. GRB 230818A: SAO RAS Zeiss-1000 observations
  99. Fermi GRB 230818A: Global MASTER-Net observations report
  100. GRB 230818A: Swift detection of a burst

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