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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"

28040 results found.

  1. Fermi GRB190530.43 Global MASTER-Net observations report
  2. GRB 190530A: Bright afterglow confirmed by OSN
  3. GRB 190530A: AGILE/GRID analysis
  4. Fermi Trigger 580904353 / GRB 190530430 / GRB190530A: BALROG localization
  5. LIGO/Virgo S190521r: CNEOST follow-up observations
  6. GRB 190525A: Insight-HXMT/HE detection
  7. LIGO/Virgo S190521r: Kanata optical/NIR follow-up observations of the CNEOST Transient
  8. LIGO/Virgo S190521r: No optical counterpart from SVOM/GWAC-F30 observations.
  9. LIGO/Virgo S190521r: No optical counterpart from SVOM/GWAC observations.
  10. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC-F30 observations.
  11. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC observations.
  12. Konus-Wind observation of GRB 190519A
  13. LIGO/Virgo S190521g: Upper limits from Insight-HXMT/HE observations
  14. LIGO/Virgo S190521r: RATIR Optical and NIR Observations of the CNEOST Transient
  15. LIGO/Virgo S190521g: Swift/BAT Counterpart Search
  16. LIGO/Virgo S190521r: Swift/BAT Counterpart Search
  17. LIGO/Virgo S190521g: No Counterparts in DDOTI/OAN Optical Observations
  18. LIGO/Virgo S190521r: Coverage and upper limits from Fermi-LAT observations
  19. LIGO/Virgo S190521r: Upper limits from Fermi-GBM observations
  20. LIGO/Virgo S190521g : Upper limits from Fermi-GBM observations
  21. LIGO/Virgo S190521g: Updated sky localization
  22. LIGO/Virgo S190521g: No candidate counterpart in Fermi-LAT observations
  23. LIGO/Virgo S190521r: Upper limits from AGILE-GRID observations
  24. LIGO/Virgo S190521r: No counterpart candidate in AGILE-MCAL observations
  25. LIGO/Virgo S190521r: Coverage and upper limits from MAXI/GSC observations
  26. LIGO/Virgo S190521r: No neutrino counterpart candidates in ANTARES search
  27. LIGO/Virgo S190521r: IceCube Neutrino Search
  28. LIGO/Virgo S190521r: Identification of a GW compact binary merger candidate
  29. LIGO/Virgo S190521r: No counterpart candidates in HAWC observations
  30. LIGO/Virgo S190521r: No counterpart candidates in INTEGRAL SPI/ACS prompt observation
  31. LIGO/Virgo S190521g: No neutrino counterpart candidates in ANTARES search
  32. LIGO/Virgo S190519bj: Fermi-LAT search for a high-energy gamma-ray counterpart
  33. LIGO-Virgo S190521g: Upper Limits from AGILE-GRID observations
  34. IGO/Virgo S190521g: Coverage and upper limits from MAXI/GSC observations
  35. LIGO/Virgo S190521g: No counterpart candidates in INTEGRAL SPI/ACS & IBIS/PICsIT prompt observations
  36. LIGO/Virgo S190521g: No counterpart candidates in AGILE-MCAL observations
  37. LIGO/Virgo S190521g: No counterpart candidates in HAWC observations
  38. LIGO/Virgo S190521g: Identification of a GW compact binary merger candidate
  39. LIGO/Virgo S190521g: INTEGRAL SPI/ACS prompt observation
  40. LIGO/Virgo S190521g: IceCube Neutrino Search
  41. S190519bj: No transient candidates from CALET observations
  42. LIGO/Virgo S190519bj: Upper limits from Insight-HXMT/HE observations
  43. LIGO/Virgo S190512at: SVOM/GWAC-F60A observations
  44. GRB 190519A: Swift/UVOT Upper Limits
  45. LIGO/Virgo S190519bj: Swift/BAT Counterpart Search
  46. LIGO/Virgo S190519bj: MAXI/GSC Observations
  47. GRB 190519A: Swift-XRT refined Analysis
  48. GRB 190519A: Swift-BAT refined analysis
  49. LIGO/Virgo S190519bj: Fermi GBM Observations
  50. LIGO-Virgo S190519bj: AGILE GRID observations
  51. LIGO/Virgo S190519bj: AGILE MCAL observations
  52. LIGO/Virgo S190519bj: ANTARES neutrino search
  53. LIGO/Virgo S190519bj: HAWC follow-up
  54. LIGO/Virgo S190519bj: INTEGRAL SPI/ACS prompt observation
  55. LIGO/Virgo S190519bj: IceCube Neutrino Search
  56. LIGO/Virgo S190519bj: Identification of a GW compact binary merger candidate
  57. GRB 190519A: Enhanced Swift-XRT position
  58. GRB 190519A: Swift detection of a burst
  59. LIGO/Virgo S190517h: INTEGRAL prompt observation
  60. Fermi GRB190517.81 Global MASTER-Net observations report
  61. Fermi Trigger 579814215 / GRB 190517813 / GRB190517A: BALROG localization
  62. LIGO/Virgo S190512at: Updated sky localization
  63. LIGO/Virgo S190517h: Fermi-LAT search for a high-energy gamma-ray counterpart
  64. LIGO/Virgo S190517h: Swift/BAT Counterpart Search
  65. LIGO/Virgo S190517h: ANTARES neutrino search
  66. LIGO/Virgo S190517h: Insight-HXMT/HE observations
  67. LIGO/Virgo S190517h: Fermi GBM Observations
  68. LIGO/Virgo S190517h: HAWC follow-up
  69. LIGO/Virgo S190517h: MAXI/GSC Observations
  70. LIGO-Virgo S190517h: AGILE GRID observations
  71. LIGO/Virgo S190517h: AGILE MCAL observations
  72. LIGO/Virgo S190517h: INTEGRAL/SPI-ACS prompt observation
  73. LIGO/Virgo S190517h: Identification of a GW compact binary merger candidate
  74. GRB 190515B: Swift/UVOT Upper Limits
  75. Fermi GRB190515.49 Global MASTER-Net observations report
  76. GRB 190515B: Swift-BAT refined analysis
  77. GRB 190515A: Insight-HXMT/HE detection
  78. GRB 190515B: Swift-XRT refined Analysis
  79. GRB 190515B: Optical observations from OSN
  80. GRB 190515B: Enhanced Swift-XRT position
  81. GRB 190515B: Kitab Observatory optical upper limit
  82. GRB 190515B: Swift detection of a burst
  83. LIGO/Virgo S190513bm : TAROT-Calern and TAROT-Chile (TCA/TCH)/GRANDMA observation report.
  84. LIGO/Virgo S190513bm: CALET Observations
  85. LIGO/Virgo S190513bm: Swift/BAT Counterpart Search
  86. LIGO/Virgo S190513bm: Insight-HXMT/HE observation
  87. LIGO/Virgo S190510g: Swift-XRT observations and results
  88. LIGO/Virgo S190513bm: ANTARES neutrino search
  89. LIGO/Virgo S190513bm: Fermi GBM Observations
  90. LIGO/Virgo S190513bm: Fermi-LAT search for a high-energy gamma-ray counterpart
  91. LIGO/Virgo S190512at: CALET Observations
  92. LIGO/Virgo S190513bm: MAXI/GSC Observations
  93. LIGO/Virgo S190510g: Further KMTNet observation of DECam-GROWTH and DESGW candidates
  94. LIGO/Virgo S190513bm: AGILE GRID observations
  95. LIGO/Virgo S190513bm: INTEGRAL prompt observation
  96. LIGO/Virgo S190513bm: AGILE MCAL observation
  97. LIGO/Virgo S190513bm: HAWC follow-up
  98. LIGO/Virgo S190513bm: Identification of a GW compact binary merger candidate
  99. LIGO/Virgo S190512at: Insight-HXMT/HE observation
  100. GRB 190512A: Swift-BAT refined analysis

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