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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"

3117 results found.

  1. LIGO/Virgo S200105ae: Upper Limits from the Zwicky Transient Facility
  2. LIGO/Virgo S200105ae: no counterpart candidates in the Swift/BAT observations
  3. LIGO/Virgo S200105ae: Global MASTER-Net observations report
  4. LIGO/Virgo S200105ae: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  5. Fermi trigger No 599761015: Global MASTER-Net observations report
  6. IceCube Alert 200101.46: Global MASTER-Net observations report
  7. IPN triangulation of GRB 191227B (short)
  8. Fermi trigger No 598988276: Global MASTER-Net observations report
  9. LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
  10. LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
  11. LIGO/Virgo S191216ap: No significant candidates found in Pan-STARRS observations
  12. LIGO/Virgo S191222n: no counterpart candidates in the Swift/BAT observations
  13. Baksan Neutrino Observatory Alert 191222.09: Global MASTER-Net observations report
  14. Fermi trigger No 598648473: Global MASTER-Net observations report
  15. LIGO/Virgo S191216ap: MASTER optical observation
  16. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  17. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  18. LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
  19. LIGO/Virgo S191216ap: no counterpart candidates in the Swift/BAT observations
  20. LIGO/Virgo S191216ap: No Candidates from the Zwicky Transient Facility
  21. LIGO/Virgo S191216ap: Coverage and upper limits from MAXI/GSC observations
  22. LIGO/Virgo S191216ap: Upper limits from Fermi-GBM Observations
  23. LIGO/Virgo S191215w: no counterpart candidates in the Swift/BAT observations
  24. LIGO/Virgo S191215w: Global MASTER-Net observations report
  25. LIGO/Virgo S191213g: Additional candidates from the Zwicky Transient Facility
  26. LIGO/Virgo S191213g: Lulin Follow-up Observations of ZTF19acykzsk/AT2019wqj
  27. LIGO/Virgo S191213g: Candidates from the Zwicky Transient Facility
  28. LIGO/Virgo S191213g: no counterpart candidates in the Swift/BAT observations
  29. LIGO/Virgo S191213g: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  30. LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
  31. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  32. LIGO/Virgo S191205ah: no counterpart candidates in the Swift/BAT observations
  33. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  34. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  35. LIGO/Virgo S191205ah: Global MASTER-Net observations report
  36. LIGO/Virgo S191204r: no counterpart candidates in the Swift/BAT observations
  37. IceCube Alert 191204.95: Global MASTER-Net observations report
  38. GRB 191203A: Fermi GBM Final Real-time Localization
  39. Fermi trigger No 596786686: Global MASTER-Net observations report
  40. Fermi trigger No 596808579: Global MASTER-Net observations report
  41. Baksan Neutrino Observatory Alert 191128.17: Global MASTER-Net observations report
  42. Baksan Neutrino Observatory Alert 191127.25: Global MASTER-Net observations report
  43. LIGO/Virgo S191124be: Global MASTER-Net observations report
  44. IceCube-191119A: No significant detection in HAWC
  45. LIGO/Virgo S191110af: Upper limits from IceCube MeV neutrino searches
  46. LIGO/Virgo S191110af: no counterpart candidates in the Swift/BAT observations
  47. LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
  48. LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
  49. LIGO/Virgo S191109d: no counterpart candidates in the Swift/BAT observations
  50. LIGO/Virgo S191109d: Coverage and upper limits from MAXI/GSC observations
  51. LIGO/Virgo S191105e: no counterpart candidates in the Swift/BAT observations
  52. Fermi trigger No 594592184: Global MASTER-Net observations report
  53. Trigger 933276: Swift detection of further activity from SGR 1935+2154
  54. GRB 191101A: Swift-BAT refined analysis
  55. Fermi trigger No 594563923: Global MASTER-Net observations report
  56. Fermi trigger No 594557071: Global MASTER-Net observations report
  57. GRB 191031D: Zwicky Transient Facility Follow-Up of a Swift Short GRB (Trigger 594249816/191031891)
  58. GRB 191101A: Prompt enhanced Swift-XRT position
  59. GRB 191031D: COATLI Optical Observations
  60. IPN triangulation of GRB 191025B (short)
  61. GRB 191023A: MASTER optical observation
  62. Possible GRB 191025A: FRAM-Auger optical limit
  63. Swift Trigger 931384: possible GRB 191025A
  64. Fermi trigger No 592818648: Global MASTER-Net observations report
  65. ANTARES 191011A: MASTER optical observation befor and after trigger
  66. GRB 191011A: Fermi GBM Final Real-time Localization
  67. LIGO/Virgo S190930t: Continued Swift observations of AT2019sbk
  68. Konus-Wind observation of GRB 191004B
  69. GRB 191004A: Optical Detection with LCO
  70. LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
  71. LIGO/Virgo S190930t: Magellan/IMACS imaging of Swift J224718-581442 (AT2019sbk)
  72. LIGO/Virgo S190930t: Swift discovery of Swift J224718-581442 (AT2019sbk): a fading UV transient with an X-ray counterpart
  73. LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO continued optical photometry
  74. GRB 191001B: Optical Upper Limits with LCO
  75. IceCube-191001A: Candidate Counterparts with the Zwicky Transient Facility
  76. LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO optical photometry
  77. LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
  78. LIGO/Virgo S190930t: Candidates from the Zwicky Transient Facility
  79. Fermi trigger No 591604915: Global MASTER-Net observations report
  80. LIGO/Virgo S190930s: no counterpart candidates in the Swift/BAT observations
  81. LIGO/Virgo S190930t: no counterpart candidates in the Swift/BAT observations
  82. LIGO/Virgo S190930t: Upper limits from Fermi-GBM Observations
  83. LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  84. Fermi trigger No 591391412: Global MASTER-Net observations report
  85. Fermi trigger No 591321287: Global MASTER-Net observations report
  86. LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
  87. LIGO/Virgo S190923y: no counterpart candidates in the Swift/BAT observations
  88. LIGO/Virgo S190924h: no counterpart candidates in the Swift/BAT observations
  89. LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits
  90. IceCube-190922B: Identification of a Candidate Supernova from the Zwicky Transient Facility
  91. LIGO/Virgo S190923y: Upper limits from IceCube neutrino searches
  92. Fermi trigger No 590777160: Global MASTER-Net observations report
  93. Baksan Neutrino Observatory Alert 190920.65: Global MASTER-Net observations report
  94. GRB 190919B: FRAM-Auger optical detection
  95. GRB 190919B: Swift-XRT observations
  96. Integral GRB190919.99: Global MASTER-Net observations report
  97. LIGO/Virgo S190915ak: No significant candidates in TAROT-GRANDMA observations
  98. LIGO/Virgo S190910h: No significant candidates in TAROT-GRANDMA observations
  99. LIGO/Virgo S190915ak: no counterpart candidates in the Swift/BAT observations
  100. LIGO/Virgo S190910d : No significant candidates in TAROT-GRANDMA observations

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