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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"

3411 results found.

  1. LIGO/Virgo S190930t: Continued Swift observations of AT2019sbk
  2. LIGO/Virgo S190930t: Swift XRT observations, no secure afterglow found
  3. GRB 191004B: Swift-XRT refined Analysis
  4. GRB 191004A: Swift-XRT refined Analysis
  5. GRB 191001A: Swift-XRT observations
  6. LIGO/Virgo S190930t: Continued Swift/UVOT observations of Swift J221951-484240
  7. LIGO/Virgo S190930t: Transient found in Swift/UVOT counterpart search
  8. LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
  9. LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
  10. GRB 190926A: Swift-XRT refined Analysis
  11. LIGO/Virgo S190924h: No counterpart candidates in Fermi-LAT observations
  12. LIGO/Virgo S190923y: No counterpart candidates in Fermi-LAT observations
  13. GRB 190919B: Swift-XRT observations
  14. GRB 190919B: GROND detection of the NIR afterglow
  15. LIGO/Virgo S190915ak: No counterpart candidates in Fermi-LAT observations
  16. LIGO/Virgo S190910h: No counterpart candidates in Fermi-LAT observations
  17. LIGO/Virgo S190910d: No counterpart candidates in Fermi-LAT observations
  18. GRB 190823A: Swift-XRT afterglow detection
  19. Chandra observations of GW170817 ~740-743 days since merger
  20. LIGO/Virgo S190901ap: No counterpart candidates in Fermi-LAT observations
  21. GRB 190829A: TNG imaging of the NIR afterglow
  22. GRB 190829A: Fermi-LAT Upper Limits
  23. GRB 190829A: GROND detection of the Optical/NIR Afterglow
  24. GRB 190829A: Swift-XRT refined Analysis
  25. GRB 190828B: Swift-XRT refined Analysis
  26. GRB 190828A: Swift-XRT observations
  27. LIGO/Virgo S190828l: No counterpart candidates in Fermi-LAT observations
  28. LIGO/Virgo S190828j: No counterpart candidates in Fermi-LAT observations
  29. LIGO/Virgo S190814bv: no variation of DESGW candidates AT 2019onj and AT 2019okr from ENGRAVE VLT/HAWK-I observations, and archival detection
  30. GRB 190823A: Swift-XRT observations
  31. GRB 190816A: Swift-XRT afterglow detection
  32. GRB 190824A: Swift-XRT refined Analysis
  33. LIGO/Virgo S190814bv: GROND follow-up observations of AT2019npv
  34. LIGO/Virgo S190814bv: ENGRAVE VLT/HAWK-I observations and archival detection of the CFHT candidate
  35. GRB 190821A: Swift-XRT refined Analysis
  36. Fermi GBM-190816: No counterpart candidates in Fermi-LAT observations
  37. LIGO/Virgo S190814bv: No strong counterpart candidates in Swift/XRT observations
  38. GRB 190816A: Swift-XRT observations
  39. LIGO/Virgo S190814bv: Fermi-LAT search for a high-energy gamma-ray counterpart
  40. LIGO/Virgo S190814bv: GRAWITA TNG infrared imaging of desgw-190814e, DG19sevhc and selected galaxies
  41. LIGO/Virgo S190814bv: GRAWITA TNG infrared imaging of selected galaxies
  42. HAWC-190806A: Swift-XRT observations
  43. GRB 190804B: Swift-XRT afterglow detection
  44. GRB 190805B: Swift-XRT observations
  45. GRB 190804B: Swift-XRT observations
  46. GRB 190731A: Swift-XRT afterglow detection
  47. LIGO/Virgo S190728q: No counterpart candidates in Fermi-LAT observations
  48. LIGO/Virgo S190727h: No counterpart candidates in Fermi-LAT observations
  49. LIGO/Virgo S190718y: Swift XRT observations, 45 X-ray sources
  50. LIGO/Virgo S190720a: No counterpart candidates in Fermi-LAT observations
  51. GRB 190719C: Swift-XRT refined Analysis
  52. LIGO/Virgo S190718y: No counterpart candidates in Fermi-LAT observations
  53. GRB 190718A: Swift-XRT refined Analysis
  54. GRB 190714A: an X-ray flare from 2E 1624.6+1504/UCAC4 525-061488
  55. GRB 190708B: confirmation of the X-ray afterglow
  56. GRB 190708B: Swift-XRT observations
  57. LIGO/Virgo S190707q: No counterpart candidates in Fermi-LAT observations
  58. LIGO/Virgo S190706ai: No counterpart candidates in Fermi-LAT observations
  59. LIGO/Virgo S190701ah: No counterpart candidates in Fermi-LAT observations
  60. GRB 190706B: Swift-XRT refined Analysis
  61. GRB 190701A: Swift-XRT refined Analysis
  62. GRB 190630C: Swift-XRT refined Analysis
  63. LIGO/Virgo S190630ag: No counterpart candidates in Fermi-LAT observations
  64. GRB 190630B: Swift-XRT refined Analysis
  65. GRB 190627A: Swift-XRT refined Analysis
  66. Swift Trigger 911102 is likely not an astrophysical event
  67. GRB 190610A: Swift-XRT observations
  68. GRB 190613B: Swift-XRT refined Analysis
  69. GRB 190613A: Swift-XRT refined Analysis
  70. GRB 190611A: Swift-XRT refined Analysis
  71. Fermi trigger No 581645543 Global MASTER-Net observations report
  72. GRB 190604B: Swift-XRT refined Analysis
  73. LIGO/Virgo S190602aq: No counterpart candidates in Fermi-LAT observations
  74. GRB 190531B: Swift-XRT afterglow detection
  75. GRB 190530A: Swift/UVOT Detection
  76. GRB 190530A: Swift-XRT afterglow detection
  77. IceCube-190504A: Kanata optical/NIR follow-up observations
  78. LIGO/Virgo S190521r: Coverage and upper limits from Fermi-LAT observations
  79. LIGO/Virgo S190521g: No candidate counterpart in Fermi-LAT observations
  80. LIGO/Virgo S190519bj: Fermi-LAT search for a high-energy gamma-ray counterpart
  81. GRB 190519A: Swift-XRT refined Analysis
  82. LIGO/Virgo S190426c: NICER X-ray Follow-Up of ZTF19aassfws
  83. LIGO/Virgo S190517h: Fermi-LAT search for a high-energy gamma-ray counterpart
  84. GRB 190515B: Swift-XRT refined Analysis
  85. LIGO/Virgo S190510g: Swift-XRT observations and results
  86. LIGO/Virgo S190513bm: Fermi-LAT search for a high-energy gamma-ray counterpart
  87. LIGO-Virgo S190512at: AGILE GRID observations
  88. LIGO/Virgo S190512at: Fermi-LAT search for a high-energy gamma-ray counterpart
  89. GRB 190511A: Swift-XRT refined Analysis
  90. GRB 190511A: Swift/UVOT Detection
  91. LIGO/Virgo S190510g: J-GEM optical/NIR follow-up observations
  92. LIGO/Virgo S190510g: Fermi-LAT search for a high-energy gamma-ray counterpart
  93. GRB 190501A: Swift XRT and UVOT Observations
  94. LIGO/Virgo S190503bf: Fermi-LAT search for a high-energy gamma-ray counterpart
  95. LIGO/Virgo S190425z: Insight-HXMT observation and counterpart search
  96. LIGO/Virgo S190412m: Further J-GEM optical/NIR observations
  97. LIGO/Virgo S190426c: Fermi-LAT search for a high-energy gamma-ray counterpart
  98. LIGO/Virgo S190425z: VISTA K-band observations of the Swift/UVOT Transient
  99. LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometric follow-up observation of the Swift/UVOT Transient
  100. LIGO/Virgo S190425z: Swift/UVOT and XRT pre-images at the position of the potential Swift/UVOT counterpart

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