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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"
  1. GRB 190813A: Fermi GBM Final Real-time Localization
  2. IPN triangulation of GRB 190805B
  3. HAWC-190806A: Upper limits from Insight-HXMT/HE observations
  4. FRB 190806: MASTER optical observation
  5. Konus-Wind observation of GRB 190810A
  6. IPN triangulation of GRB 190810A (short)
  7. Fermi trigger No 587084236 Global MASTER-Net observations report
  8. GRB 190810A: Fermi GBM Final Real-time Localization
  9. HAWC-190806A: upper limits from INTEGRAL SPI-ACS and IBIS prompt observation
  10. HAWC-190806A: Upper limits from Fermi-GBM Observations
  11. HAWC-190806A: Swift-XRT observations
  12. HAWC Burst Alert 1008846_957: Konus-Wind observations
  13. GRB 190726A: Insight-HXMT/HE detection
  14. Correction to Swift GCN 25303
  15. Trigger_11505: Tiled Swift observations
  16. LIGO/Virgo S190728q: New optical candidates from the DESGW program
  17. LIGO/Virgo S190808ae: Retraction of GW compact binary merger candidate
  18. LIGO/Virgo S190808ae: Coverage and upper limits from MAXI/GSC observations
  19. LIGO/Virgo S190808ae: CLU/NED Galaxies in the 50% Localization Volume
  20. LIGO/Virgo S190808ae: No counterpart candidates in HAWC observations
  21. LIGO/Virgo S190808ae: One Coincident Neutrino Candidate from IceCube Search
  22. LIGO/Virgo S190808ae: Identification of a GW compact binary merger candidate
  23. LIGO/Virgo S190808ae Global MASTER-Net observations report
  24. GRB 190808B: BALROG localization (Fermi Trigger 586980202 / GRB 190808752)
  25. Fermi trigger No 586980202 Global MASTER-Net observations report
  26. GRB 190808B: Fermi GBM Final Real-time Localization
  27. HAWC Burst Alert 1008846_957: IceCube Neutrino Search
  28. GRB 190808A: Fermi GBM Final Real-time Localization
  29. GRB 190804A: AstroSat CZTI detection
  30. Fermi trigger No 586896678 Global MASTER-Net observations report
  31. GRB 190805B: AstroSat CZTI detection
  32. GRB 190804B: Swift-XRT afterglow detection
  33. Konus-Wind observation of GRB 190805B
  34. Alert from the HAWC Burst Monitor
  35. HAWC Alert 190806.56 Global MASTER-Net observations report
  36. Fermi trigger No 586788607 Global MASTER-Net observations report
  37. Fermi trigger No 586800758 Global MASTER-Net observations report
  38. GRB 190806A: Fermi GBM Final Real-time Localization
  39. GRB 190805B: Swift-XRT observations
  40. Fermi trigger No 586676451 Global MASTER-Net observations report
  41. GRB 190805B: Fermi GBM detection
  42. LIGO/Virgo S190728q: AT2019lvw 10.4m GTC spectroscopy
  43. GRB 190805B: Tiled Swift observations
  44. Konus-Wind observation of GRB 190731A
  45. GRB 190804B: Swift-XRT observations
  46. GRB 190805B: BALROG localization (Fermi Trigger 586673165 / GRB 190805199)
  47. GRB 190805B: MAXI/GSC detection
  48. GRB 190805B: Fermi GBM Final Real-time Localization
  49. GRB 190805A: Fermi GBM Final Real-time Localization
  50. Fermi trigger No 586638042 Global MASTER-Net observations report
  51. MAXI GRB190804.33 Global MASTER-Net observations report
  52. Fermi trigger No 586600841 Global MASTER-Net observations report
  53. GRB 190804C: BALROG localization (Fermi Trigger 586638042 / GRB 190804792)
  54. GRB 190804C: Fermi GBM Final Real-time Localization
  55. GRB 190804B: Tiled Swift observations
  56. GRB 190804B: MAXI/GSC detection
  57. LIGO/Virgo S190728q: AT2019lzc 10.4m GTC spectroscopy
  58. Fermi trigger No 586574612 Global MASTER-Net observations report
  59. GRB 190804A: Fermi GBM Final Real-time Localization
  60. GRB 190731A: AstroSat CZTI detection
  61. GRB 190731A: Swift/UVOT Upper Limits
  62. GRB 190731A: no OT detected by MASTER
  63. IceCube 190730A: No counterpart candidates or blazar activity in GOTO observations
  64. GRB 190720B: AstroSat CZTI detection
  65. LIGO/Virgo S190728q: AT2019lzt 10.4m GTC spectroscopy
  66. GRB 190719C: VLT/X-shooter spectroscopic redshift of the host galaxy
  67. GRB 190731A: Swift-XRT afterglow detection
  68. IPN Triangulation of GRB 190731A
  69. LIGO/Virgo S190727h: Updated sky localization
  70. GRB 190731A: Fermi GBM detection
  71. GRB 190726B: AstroSat CZTI detection
  72. GRB 190731A: CALET Gamma-Ray Burst Monitor detection
  73. GRB 190731A: Swift ToO observations
  74. GRB190731A: Fermi-LAT detection
  75. Fermi trigger No 586305505 Global MASTER-Net observations report
  76. Fermi trigger No 586305505 Global MASTER-Net observations report
  77. IceCube-190730A: Upper limits from a search for additional neutrino events in IceCube
  78. GRB 190731A: Fermi GBM Final Real-time Localization
  79. Fermi-LAT Gamma-ray Observations of IceCube-190730A
  80. IceCube-190730A - HAWC follow-up
  81. LIGO/Virgo S190728q: No counterpart candidates in H.E.S.S. observations
  82. LIGO/Virgo S190728q: Correction to GCN #25235: also PS19dxm and DG19zrjmb are not associated with S190728q
  83. LIGO/Virgo S190728q: ZTF Forced Photometry for PS1 and DECam-GROWTH optical candidates, and a note on DECam Photometry from GCN 25215
  84. Fermi trigger No 586240252 Global MASTER-Net observations report
  85. IceCube 190730A: not observable by Fermi-GBM
  86. IceCube 190730A: one weakly associated counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
  87. IceCube-190730A: MASTER optical observation
  88. LIGO/Virgo S190707q: AstroSat CZTI upper limits
  89. LIGO/Virgo S190718y: AstroSat CZTI upper limits
  90. LIGO/Virgo S190727h: AstroSat CZTI upper limits
  91. LIGO/Virgo S190720a: AstroSat CZTI upper limits
  92. LIGO/Virgo S190728q: MITSuME Okayama and Bisei Follow-Up of ZTF19abjethn (AT2019lvs)
  93. IceCube-190730A - IceCube observation of a high-energy neutrino candidate event
  94. LIGO/Virgo S190728q: Optical transients from Pan-STARRS coverage during first 2 nights
  95. LIGO/Virgo S190727h: Gaia Photometric Alerts transient candidate
  96. LIGO/Virgo S190728q: GRAWITA VST-ESO PARANAL observations
  97. LIGO/Virgo s190728q: ePESSTO+ NTT classification of AT2019lvt as a type-Ia SN
  98. LIGO/Virgo S190728q/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  99. Fermi Gamma-ray Burst Monitor trigger 190729668/586108936 is not a GRB
  100. Konus-Wind observation of GRB 190727B

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