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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"

3798 results found.

  1. IPN Triangulation of GRB 190731A
  2. LIGO/Virgo S190728q: No counterpart candidates in KAIT observations
  3. LIGO/Virgo S190728q: no counterpart candidates in AGILE-GRID observations
  4. LIGO/Virgo S190728q: Coverage and upper limits from MAXI/GSC observations
  5. LIGO/Virgo S190728q Global MASTER-Net observations report
  6. LIGO/Virgo S190727h: No counterpart candidates in KAIT observations
  7. LIGO/Virgo S190727h: Coverage and upper limits from MAXI/GSC observations
  8. Fermi trigger No 585864875 Global MASTER-Net observations report
  9. Fermi trigger No 585856427 Global MASTER-Net observations report
  10. LIGO/Virgo S190720a: Thacher Observatory follow-up observations
  11. IPN triangulation of GRB 190724A (short)
  12. LIGO/Virgo S190720a: No counterpart candidates in KAIT observations
  13. LIGO/Virgo S190720a: Upper limits from Fermi-GBM Observations
  14. LIGO/Virgo S190720a: Coverage and upper limits from MAXI/GSC observations
  15. LIGO/Virgo S190718y: No counterpart candidates in CNEOST
  16. LIGO/Virgo S190718y: No counterpart candidates in KAIT observations
  17. LIGO/Virgo S190718y: Coverage and upper limits from MAXI/GSC observations
  18. Swift GRB190718.2 Global MASTER-Net observations report
  19. Fermi trigger No 585007213 Global MASTER-Net observations report
  20. GRB 190714A: an X-ray flare from 2E 1624.6+1504/UCAC4 525-061488
  21. Fermi trigger No 584929684 Global MASTER-Net observations report
  22. GRB 190708B: confirmation of the X-ray afterglow
  23. GRB 190714A: Tiled Swift observations
  24. GRB 190714A: MAXI/GSC detection
  25. Fermi trigger No 584637077 Global MASTER-Net observations report
  26. GRB 190708B: Swift-XRT observations
  27. LIGO/Virgo S190706ai: Upper limits from Insight-HXMT/HE observations
  28. Konus-Wind observation of GRB 190708B
  29. GRB 190708B: Tiled Swift observations
  30. MAXI GRB190708.83 Global MASTER-Net observations report
  31. GRB 190708B: MAXI/GSC detection
  32. LIGO/Virgo S190706ai: No counterpart candidates in KAIT observations
  33. LIGO/Virgo S190707q: Coverage and upper limits from MAXI/GSC observations
  34. LIGO/Virgo S190706ai: Coverage and upper limits from MAXI/GSC observations
  35. GRB 190706A: MAXI/GSC detection
  36. Fermi trigger No 584007338 Global MASTER-Net observations report
  37. LIGO/Virgo S190630ag: no counterpart candidate in the SVOM/GWAC observations
  38. LIGO/Virgo S190701ah: Coverage and upper limits from MAXI/GSC observations
  39. GRB 190630C: Swift-BAT refined analysis
  40. GRB 190701A: MAXI/GSC detection
  41. LIGO/Virgo S190630ag: Coverage and upper limits from MAXI/GSC observations
  42. Fermi trigger No 583567803 Global MASTER-Net observations report
  43. GRB 190627A: Koshka Zeiss-1000 optical counterpart observations
  44. Fermi trigger No 583327924 Global MASTER-Net observations report
  45. Fermi trigger No 582856902 Global MASTER-Net observations report
  46. Fermi trigger No 582759998 Global MASTER-Net observations report
  47. Fermi trigger No 582615488 Global MASTER-Net observations report
  48. Fermi trigger No 582115625 Global MASTER-Net observations report
  49. IPN Triangulation of GRB 190611B
  50. GRB 190612A: Fermi GBM Final Real-time Localization
  51. Fermi trigger No 581889628 Global MASTER-Net observations report
  52. GRB 190610A: Swift detection of a short burst
  53. Fermi trigger No 581645543 Global MASTER-Net observations report
  54. IPN Triangulation of GRB 190606A (short)
  55. GRB 190604B: BOOTES-3 early optical limits
  56. GRB 190604B: Swift detection of a burst
  57. LIGO/Virgo S190602aq: Coverage and upper limits from MAXI/GSC observations
  58. LIGO/Virgo S190602aq: No counterpart candidates in HAWC observations
  59. GRB 190530A: Mondy and AbAO optical observations
  60. GRB 190531B: VLT optical upper limit
  61. GRB 190531B: MASTER optical observation
  62. GRB 190531B: Swift-XRT afterglow detection
  63. LIGO/Virgo S190425z: No counterpart candidate in Zadko-GRANDMA observations.
  64. LIGO/Virgo S190521r : Gaia Photometric Alerts transient candidate
  65. LIGO/Virgo S190521r: CNEOST follow-up observations
  66. Fermi GRB190525.67 Global MASTER-Net observations report
  67. Fermi GRB190525.03 Global MASTER-Net observations report
  68. LIGO/Virgo S190521r: No optical counterpart from SVOM/GWAC-F30 observations.
  69. LIGO/Virgo S190521g: No optical counterpart from SVOM/GWAC observations.
  70. LIGO/Virgo S190521r: Coverage and upper limits from MAXI/GSC observations
  71. IGO/Virgo S190521g: Coverage and upper limits from MAXI/GSC observations
  72. LIGO/Virgo S190519bj: MAXI/GSC Observations
  73. LIGO/Virgo S190519bj Global MASTER-Net observations report
  74. GRB 190519A: Swift-BAT refined analysis
  75. GRB 190519A: Fermi GBM Final Real-time Localization
  76. Fermi GRB190517.81 Global MASTER-Net observations report
  77. LIGO/Virgo S190517h: MAXI/GSC Observations
  78. LIGO/Virgo S190517h Global MASTER-Net observations report
  79. LIGO/Virgo S190513bm: Swope follow-up observations
  80. LIGO/Virgo S190513bm: Lick/KAIT Follow-Up Observations
  81. Konus-Wind observation of GRB 190511A
  82. LIGO/Virgo S190513bm: MAXI/GSC Observations
  83. LIGO/Virgo S190510g: Further KMTNet observation of DECam-GROWTH and DESGW candidates
  84. LIGO/Virgo S190512at: MAXI/GSC Observations
  85. LIGO/Virgo S190512at Global MASTER-Net observations report
  86. Fermi GRB190512.61 Global MASTER-Net observations report
  87. LIGO/Virgo S190510g: DOAO Observation
  88. LIGO/Virgo S190510g: KMTNet observation of DECam-GROWTH and DESGW candidates
  89. LIGO/Virgo S190510g: Las Cumbres Observatory Galaxy Targeted Counterpart Search
  90. LIGO/Virgo S190510g: GRAWITA REM and Loiano optical observations
  91. LIGO/Virgo S190510g: GRAWITA VST-ESO PARANAL optical observations
  92. LIGO/Virgo S190510g: Xinglong/Schmidt Follow-Up Observations
  93. LIGO/Virgo S190510g: Lick/KAIT Follow-Up Observations
  94. LIGO/Virgo S190510g: Lulin Optical Follow-up Observations
  95. LIGO/Virgo S190510g: GRAWITA REM optical observations
  96. LIGO/Virgo S190510g: MAXI/GSC Observations
  97. Fermi GRB190507.97 Global MASTER-Net observations report
  98. Fermi GRB190507.27 Global MASTER-Net observations report
  99. IceCube-190504A: MASTER optical monitoring analysis
  100. Fermi GRB190506.58 Global MASTER-Net observations report

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