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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"

3051 results found.

  1. Fermi trigger No 586574612 Global MASTER-Net observations report
  2. GRB 190731A: no OT detected by MASTER
  3. Fermi trigger No 586305505 Global MASTER-Net observations report
  4. LIGO/Virgo S190728q: ZTF Forced Photometry for PS1 and DECam-GROWTH optical candidates, and a note on DECam Photometry from GCN 25215
  5. LIGO/Virgo S190728q: Optical transients from Pan-STARRS coverage during first 2 nights
  6. LIGO/Virgo S190728q: No counterpart candidates in KAIT observations
  7. Fermi trigger No 585988241 Global MASTER-Net observations report
  8. LIGO/Virgo S190727h: No counterpart candidates in KAIT observations
  9. GRB 190727B: Swift detection of a burst
  10. GRB 190720A: CALET Gamma-Ray Burst Monitor detection
  11. IPN triangulation of GRB 190720A
  12. LIGO/Virgo S190720a: No counterpart candidates in KAIT observations
  13. GRB 190720A: Fermi GBM detection
  14. GRB 190720A: BALROG localization (Fermi Trigger 585326534 / GRB 190720613)
  15. GRB 190720A: Fermi GBM Final Real-time Localization
  16. LIGO/Virgo S190718y: No counterpart candidates in CNEOST
  17. LIGO/Virgo S190720a Global MASTER-Net observations report
  18. LIGO/Virgo S190718y: No counterpart candidates in KAIT observations
  19. GRB 190719A: Fermi GBM Final Real-time Localization
  20. Swift GRB190718.2 Global MASTER-Net observations report
  21. GRB 190718A: Swift detection of a burst
  22. Fermi trigger No 585007213 Global MASTER-Net observations report
  23. Fermi trigger No 584977168 Global MASTER-Net observations report
  24. Fermi trigger No 584804684 Global MASTER-Net observations report
  25. GRB 190706C: Insight-HXMT/HE detection
  26. IceCube Alert 190712.05 Global MASTER-Net observations report
  27. Fermi trigger No 584590606 Global MASTER-Net observations report
  28. Fermi trigger No 584583925 Global MASTER-Net observations report
  29. Konus-Wind observation of GRB 190706C
  30. GRB 190706C: CALET Gamma-Ray Burst Monitor detection
  31. GRB 190708B: MAXI/GSC detection
  32. IPN triangulation of GRB 190706D (short)
  33. IPN triangulation of GRB 190706C (long/very bright)
  34. LIGO/Virgo S190706ai: No counterpart candidates in KAIT observations
  35. IPN triangulation of GRB 190704A (short)
  36. GRB 190706B: Swift detection of a burst
  37. Fermi trigger No 583854113 Global MASTER-Net observations report
  38. LIGO/Virgo S190630ag: no counterpart candidate in the SVOM/GWAC observations
  39. LIGO/Virgo S190701ah: Coverage and upper limits from MAXI/GSC observations
  40. GRB 190630B: Tien Shan and Koshka Zeiss-1000 optical upper limits
  41. GRB 190630C: ISON-Castelgrande optical upper limit
  42. LIGO/Virgo S190630ag: No counterpart candidates in AGILE-GRID observations
  43. GRB 190701A: MAXI/GSC detection
  44. Fermi trigger No 583567803 Global MASTER-Net observations report
  45. GRB 190627A: Koshka Zeiss-1000 optical counterpart observations
  46. GRB 190627A: Optical imaging and spectroscopy from Calar Alto
  47. Fermi trigger No 583327924 Global MASTER-Net observations report
  48. Fermi trigger No 583221986 Global MASTER-Net observations report
  49. Fermi trigger No 583111521 Global MASTER-Net observations report
  50. Swift GRB190624.86 Global MASTER-Net observations report
  51. Swift trigger 911102: D50 optical limit
  52. Fermi trigger No 582856902 Global MASTER-Net observations report
  53. GRB 190615B: AstroSat CZTI detection
  54. Fermi trigger No 582615488 Global MASTER-Net observations report
  55. Fermi trigger No 582615488 Global MASTER-Net observations report
  56. Fermi trigger No 582596766 Global MASTER-Net observations report
  57. GRB 190615B: Insight-HXMT/HE detection
  58. Fermi trigger No 582115625 Global MASTER-Net observations report
  59. Fermi trigger No 581986074 Global MASTER-Net observations report
  60. GRB 190604A: Insight-HXMT/HE detection
  61. Fermi trigger No 581469752 Global MASTER-Net observations report
  62. GRB 190604A: AstroSat CZTI detection
  63. GRB190604A: BALROG localization (Fermi Trigger 581337762 / GRB 190604446)
  64. GRB 190604A: Fermi GBM Final Real-time Localization
  65. Fermi Fermi trigger No 581002688 Global MASTER-Net observations report
  66. LIGO/Virgo S190521r: CNEOST follow-up observations
  67. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC observations.
  68. LIGO/Virgo S190512at: SVOM/GWAC-F60A observations
  69. LIGO/Virgo S190519bj: MAXI/GSC Observations
  70. LIGO/Virgo S190519bj Global MASTER-Net observations report
  71. Fermi GRB190517.81 Global MASTER-Net observations report
  72. LIGO/Virgo S190517h Global MASTER-Net observations report
  73. LIGO/Virgo S190517h: IceCube Neutrino Search
  74. Fermi GRB190514.67 Global MASTER-Net observations report
  75. LIGO/Virgo S190513bm: Lick/KAIT Follow-Up Observations
  76. LIGO/Virgo S190513bm: Insight-HXMT/HE observation
  77. LIGO/Virgo S190510g: Further KMTNet observation of DECam-GROWTH and DESGW candidates
  78. LIGO/Virgo S190513bm Global MASTER-Net observations report
  79. LIGO/Virgo S190510g: Pan-STARRS and ATLAS observations and candidates
  80. LIGO/Virgo S190512at Global MASTER-Net observations report
  81. Fermi GRB190512.61 Global MASTER-Net observations report
  82. IPN triangulation of GRB 190510A (short)
  83. LIGO/Virgo S190510g: Update on candidate significance
  84. LIGO/Virgo S190510g: Las Cumbres Observatory Galaxy Targeted Counterpart Search
  85. LIGO/Virgo S190510g: Dabancheng/HMT Follow-Up Observations
  86. LIGO/Virgo S190510g: Xinglong/Schmidt Follow-Up Observations
  87. LIGO/Virgo S190510g: SOAR/Goodman follow-up observations
  88. LIGO/Virgo S190510g: CNEOST Follow-Up Observations
  89. LIGO/Virgo S190510g: Lick/KAIT Follow-Up Observations
  90. LIGO/Virgo S190510g: Lulin Optical Follow-up Observations
  91. LIGO/Virgo S190510g Global MASTER-Net observations report
  92. LIGO/Virgo S190503bf: TAROT-GRANDMA observation report
  93. Fermi GRB190507.27 Global MASTER-Net observations report
  94. IceCube-190504A: MASTER optical monitoring analysis
  95. Fermi GRB190505.05 Global MASTER-Net observations report
  96. Fermi GRB190504.68 Global MASTER-Net observations report
  97. LIGO/Virgo S190503bf Global MASTER-Net observations report
  98. IceCube-190503A: Lick/KAIT Follow-Up Observations
  99. Fermi GRB190429.74 Global MASTER-Net observations report
  100. LIGO/Virgo S190426c: YAHPT Optical Observation

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