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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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 190530A: AbAO optical observations
  2. GRB 190530A: Xinglong 2.16m optical observation
  3. Fermi Trigger 581026217 / GRB 190531840 / GRB190531A: BALROG localization
  4. GRB 190531B: Fermi GBM Final Real-time Localization
  5. GRB 190530A: AstroSat CZTI detection
  6. GRB 190530A: optical afterglow detection by 5 MASTER telescopes
  7. GRB 190530A: Fermi GBM observation
  8. GRB 190531A: Fermi GBM Final Real-time Localization
  9. GRB 190530A: COATLI Optical Detection of the Fading Afterglow
  10. GRB 190530A: Swift-XRT afterglow detection
  11. GRB 190530A: GWAC-F30 optical detection
  12. GRB 190530A: OAJ optical detection
  13. GRB 190530A: NOT photometry and spectroscopy
  14. Fermi GRB190530.43 Global MASTER-Net observations report
  15. GRB 190530A: Bright afterglow confirmed by OSN
  16. GRB 190530A: AGILE/GRID analysis
  17. LIGO/Virgo S190503bf: Gaia Photometric Alerts transient candidate
  18. GRB 190530A: Swift ToO observations
  19. GRB 190530A: MASTER OT detection
  20. GRB 190530A: Fermi-LAT detection
  21. GRB 190530A: AGILE-MCAL detection
  22. Fermi Trigger 580904353 / GRB 190530430 / GRB190530A: BALROG localization
  23. GRB 190530A: Fermi GBM Final Real-time Localization
  24. IceCube-190504A: Kanata optical/NIR follow-up observations
  25. IceCube 41485283_132628.amon retraction
  26. LIGO/Virgo S190425z: No counterpart candidate in Zadko-GRANDMA observations.
  27. LIGO/Virgo S190521r : Gaia Photometric Alerts transient candidate
  28. LIGO/Virgo S190518bb: AstroSat CZTI upper limits
  29. LIGO/Virgo S190521g: AstroSat CZTI upper limits
  30. LIGO/Virgo S190517h: AstroSat CZTI upper limits
  31. LIGO/Virgo S190519bj: AstroSat CZTI upper limits
  32. GRB 190525A: AstroSat CZTI detection
  33. LIGO/Virgo S190521r: CNEOST follow-up observations
  34. GRB 190525A: Insight-HXMT/HE detection
  35. Fermi GRB190525.67 Global MASTER-Net observations report
  36. Fermi GRB190525.03 Global MASTER-Net observations report
  37. GRB 190525A: Fermi GBM Final Real-time Localization
  38. LIGO/Virgo S190521r: Kanata optical/NIR follow-up observations of the CNEOST Transient
  39. LIGO/Virgo S190521r: No optical counterpart from SVOM/GWAC-F30 observations.
  40. LIGO/Virgo S190521r: No optical counterpart from SVOM/GWAC observations.
  41. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC-F30 observations.
  42. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC observations.
  43. SUBJECT: LIGO/Virgo S190524q: Retraction of GW compact binary merger candidate
  44. LIGO/Virgo S190524q Global MASTER-Net observations report
  45. LIGO/Virgo S190517h: Gaia Photometric Alerts transient candidate
  46. LIGO/Virgo S190521r: No candidate counterparts from ATLAS observations of the skymap
  47. Konus-Wind observation of GRB 190519A
  48. LIGO/Virgo S190521g: Upper limits from Insight-HXMT/HE observations
  49. LIGO/Virgo S190521r: RATIR Optical and NIR Observations of the CNEOST Transient
  50. LIGO/Virgo S190521r: No transient candidates from CALET observations
  51. LIGO/Virgo S190521g: Upper limits from CALET observations
  52. LIGO/Virgo S190521r: One optical transient from CNEOST
  53. LIGO/Virgo S190521g: Swift/BAT Counterpart Search
  54. LIGO/Virgo S190521r: Swift/BAT Counterpart Search
  55. LIGO/Virgo S190521g: No Counterparts in DDOTI/OAN Optical Observations
  56. LIGO/Virgo S190521r: Coverage and upper limits from Fermi-LAT observations
  57. LIGO/Virgo S190521r: Upper limits from Fermi-GBM observations
  58. LIGO/Virgo S190521g : Upper limits from Fermi-GBM observations
  59. LIGO/Virgo S190521g: Updated sky localization
  60. LIGO/Virgo S190521g: No candidate counterpart in Fermi-LAT observations
  61. LIGO/Virgo S190521r: Upper limits from AGILE-GRID observations
  62. LIGO/Virgo S190521r Global MASTER-Net observations report
  63. LIGO/Virgo S190521r: No counterpart candidate in AGILE-MCAL observations
  64. LIGO/Virgo S190521r: Coverage and upper limits from MAXI/GSC observations
  65. LIGO/Virgo S190521r: No neutrino counterpart candidates in ANTARES search
  66. LIGO/Virgo S190521r: IceCube Neutrino Search
  67. LIGO/Virgo S190521r: Identification of a GW compact binary merger candidate
  68. LIGO/Virgo S190517h : No counterpart candidate in TAROT-GRANDMA observations.
  69. LIGO/Virgo S190521r: No counterpart candidates in HAWC observations
  70. LIGO/Virgo S190521r: No counterpart candidates in INTEGRAL SPI/ACS prompt observation
  71. LIGO/Virgo S190521g: No neutrino counterpart candidates in ANTARES search
  72. LIGO/Virgo S190519bj: Fermi-LAT search for a high-energy gamma-ray counterpart
  73. LIGO-Virgo S190521g: Upper Limits from AGILE-GRID observations
  74. IGO/Virgo S190521g: Coverage and upper limits from MAXI/GSC observations
  75. LIGO/Virgo S190521g: No counterpart candidates in INTEGRAL SPI/ACS & IBIS/PICsIT prompt observations
  76. LIGO/Virgo S190521g: No counterpart candidates in AGILE-MCAL observations
  77. LIGO/Virgo S190521g: No counterpart candidates in HAWC observations
  78. LIGO/Virgo S190521g: Identification of a GW compact binary merger candidate
  79. LIGO/Virgo S190521g: INTEGRAL SPI/ACS prompt observation
  80. LIGO/Virgo S190521g Global MASTER-Net observations report
  81. LIGO/Virgo S190521g: IceCube Neutrino Search
  82. S190519bj: No transient candidates from CALET observations
  83. LIGO/Virgo S190519bj: Upper limits from Insight-HXMT/HE observations
  84. LIGO/Virgo S190512at: SVOM/GWAC-F60A observations
  85. Fermi GRB190520.6 Global MASTER-Net observations report
  86. GRB 190519A: AstroSat CZTI detection
  87. GRB 190519A: Swift/UVOT Upper Limits
  88. GRB 190519A: CALET Gamma-Ray Burst Monitor detection
  89. LIGO/Virgo S190519bj: Swift/BAT Counterpart Search
  90. LIGO/Virgo S190519bj: MAXI/GSC Observations
  91. GRB 190519A: Swift-XRT refined Analysis
  92. LIGO/Virgo S190519bj Global MASTER-Net observations report
  93. GRB 190519A: Swift-BAT refined analysis
  94. LIGO/Virgo S190519bj: Fermi GBM Observations
  95. LIGO-Virgo S190519bj: AGILE GRID observations
  96. LIGO/Virgo S190519bj: AGILE MCAL observations
  97. LIGO/Virgo S190519bj: ANTARES neutrino search
  98. LIGO/Virgo S190519bj: HAWC follow-up
  99. LIGO/Virgo S190519bj: INTEGRAL SPI/ACS prompt observation
  100. LIGO/Virgo S190519bj: IceCube Neutrino Search

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