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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

6098 results found.

  1. Fermi-LAT Gamma-ray Observations of IceCube-190712A
  2. IceCube-190712A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  3. GRB 190708B: Swift-XRT observations
  4. LIGO/Virgo S190707q: No counterpart candidates in Fermi-LAT observations
  5. LIGO/Virgo S190707q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observations
  6. LIGO/Virgo S190706ai: No counterpart candidates in Fermi-LAT observations
  7. LIGO/Virgo S190701ah: No counterpart candidates in Fermi-LAT observations
  8. LIGO/Virgo S190706ai: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observations
  9. GRB 190706B: Swift-XRT refined Analysis
  10. IceCube-190704A - HAWC follow-up
  11. Fermi-LAT Gamma-ray Observations of IceCube-190704A and detection of the new gamma-ray source 1WHSP J104516.2+275133
  12. LIGO/Virgo IceCube-190704A: No counterpart candidates in INTEGRAL SPI- ACS and IBIS prompt observation
  13. Fermi-LAT Gamma-ray Observations of IceCube-190629A
  14. GRB 190701A: Swift-XRT refined Analysis
  15. GRB 190630C: Swift-XRT refined Analysis
  16. LIGO/Virgo S190701ah: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  17. LIGO/Virgo S190630ag: No counterpart candidates in Fermi-LAT observations
  18. LIGO/Virgo S190630ag: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  19. GRB 190630B: Swift-XRT refined Analysis
  20. GRB 190627A: Swift-XRT refined Analysis
  21. GRB 190627A: Optical imaging and spectroscopy from Calar Alto
  22. Swift Trigger 911102 is likely not an astrophysical event
  23. Fermi-LAT Gamma-ray Observations of IceCube-190619A
  24. IceCube-190619A - HAWC follow-up
  25. IceCube-190619A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  26. GRB 190610A: Swift-XRT observations
  27. GRB 190613B: Swift-XRT refined Analysis
  28. GRB 190613A: Fermi GBM detection
  29. GRB 190613B: Fermi GBM observation
  30. GRB 190613A: Swift-XRT refined Analysis
  31. GRB 190611B: Fermi GBM detection
  32. GRB 190611A: Swift-XRT refined Analysis
  33. GRB 190530A: Further OAJ/OSN photometry and analysis
  34. GRB 190604B: VLT Afterglow Detection
  35. GRB 190606A: Fermi-LAT detection
  36. GRB 190604B: Swift-XRT refined Analysis
  37. LIGO/Virgo S190602aq: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  38. LIGO/Virgo S190602aq: No counterpart candidates in Fermi-LAT observations
  39. GRB 190530A: SAO RAS optical observations
  40. GRB 190531B: Swift-XRT afterglow detection
  41. GRB 190531B: Fermi GBM observations
  42. GRB 190530A: Swift/UVOT Detection
  43. GRB 190531B: Fermi-LAT detection
  44. GRB 190530A: Fermi GBM observation
  45. GRB 190530A: Swift-XRT afterglow detection
  46. GRB 190530A: OAJ optical detection
  47. GRB 190530A: Fermi-LAT detection
  48. IceCube-190504A: Kanata optical/NIR follow-up observations
  49. LIGO/Virgo S190521r: Coverage and upper limits from Fermi-LAT observations
  50. LIGO/Virgo S190521g: No candidate counterpart in Fermi-LAT observations
  51. LIGO/Virgo S190521r: No counterpart candidates in INTEGRAL SPI/ACS prompt observation
  52. LIGO/Virgo S190519bj: Fermi-LAT search for a high-energy gamma-ray counterpart
  53. LIGO/Virgo S190521g: No counterpart candidates in INTEGRAL SPI/ACS & IBIS/PICsIT prompt observations
  54. LIGO/Virgo S190521g: INTEGRAL SPI/ACS prompt observation
  55. GRB 190519A: Swift-XRT refined Analysis
  56. LIGO/Virgo S190519bj: INTEGRAL SPI/ACS prompt observation
  57. GRB 190519A: Fermi GBM observation
  58. LIGO/Virgo S190426c: NICER X-ray Follow-Up of ZTF19aassfws
  59. LIGO/Virgo S190517h: INTEGRAL prompt observation
  60. GRB 190511A: Swift/UVOT further analysis
  61. LIGO/Virgo S190517h: Fermi-LAT search for a high-energy gamma-ray counterpart
  62. LIGO/Virgo S190517h: INTEGRAL/SPI-ACS prompt observation
  63. GRB 190515B: Swift-XRT refined Analysis
  64. GRB 190515A: Fermi-LAT detection
  65. LIGO/Virgo S190510g: Swift-XRT observations and results
  66. LIGO/Virgo S190513bm: Fermi-LAT search for a high-energy gamma-ray counterpart
  67. LIGO/Virgo S190513bm: INTEGRAL prompt observation
  68. LIGO-Virgo S190512at: AGILE GRID observations
  69. LIGO/Virgo S190512at: Fermi-LAT search for a high-energy gamma-ray counterpart
  70. GRB 190512A: Fermi GBM observation
  71. GRB 190511A: Swift-XRT refined Analysis
  72. GRB 190511A: Swift/UVOT Detection
  73. GRB 190511A: Fermi-LAT detection
  74. GRB 190511A: Fermi GBM observation
  75. LIGO/Virgo S190510g: Unconfirmed OT in PGC 094244
  76. LIGO/Virgo S190510g: MASTER possible OT in PGC094244 galaxy
  77. LIGO/Virgo S190510g: J-GEM optical/NIR follow-up observations
  78. LIGO/Virgo S190510g: Fermi-LAT search for a high-energy gamma-ray counterpart
  79. GRB 190501A: Swift XRT and UVOT Observations
  80. LIGO/Virgo S190426c: Konus-Wind observations
  81. LIGO/Virgo S190425z: Konus-Wind observations
  82. Fermi-LAT Gamma-ray Observations of IceCube-190504A
  83. LIGO/Virgo S190503bf: Fermi-LAT search for a high-energy gamma-ray counterpart
  84. Fermi-LAT Gamma-ray Observations of IceCube-190503A
  85. IceCube-190503A: INTEGRAL prompt observation
  86. LIGO/Virgo S190503bf: INTEGRAL prompt observation
  87. LIGO/Virgo S190425z: Insight-HXMT observation and counterpart search
  88. LIGO/Virgo S190412m: Further J-GEM optical/NIR observations
  89. LIGO/Virgo S190425z: KPED Follow-Up of ZTF transients
  90. LIGO/Virgo S190426c: Fermi-LAT search for a high-energy gamma-ray counterpart
  91. LIGO/Virgo S190425z: VISTA K-band observations of the Swift/UVOT Transient
  92. LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometric follow-up observation of the Swift/UVOT Transient
  93. LIGO/Virgo S190425z: KPED Follow-Up of ZTF transients
  94. LIGO/Virgo S190425z: Swift/UVOT and XRT pre-images at the position of the potential Swift/UVOT counterpart
  95. GRB 190427A: Fermi GBM detection
  96. LIGO/Virgo S190426c: Swift-XRT sources
  97. LIGO/Virgo S190425z: Fermi-LAT search for a high-energy gamma-ray counterpart
  98. GRB 190427A: NOT optical observations
  99. LIGO/Virgo S190426c: INTEGRAL prompt observation
  100. LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometry of ZTF19aarykkb and ZTF19aarzaod

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