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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"

6098 results found.

  1. LIGO/Virgo S190425z - GROWTH-India follow-up of two ZTF candidates
  2. LIGO/Virgo S190425z: KPED Follow-Up Observations
  3. LIGO/Virgo S190425z: Lulin Follow-Up Observations
  4. LIGO/Virgo S190425z: AGILE-GRID Observations
  5. LIGO/Virgo S190421ar: Fermi-LAT search for a high-energy gamma-ray counterpart
  6. GRB 190422A: Fermi GBM detection
  7. GRB 190422A: Swift-XRT refined Analysis
  8. LIGO/Virgo S190421ar: INTEGRAL prompt observation
  9. LIGO/Virgo S190408an: INTEGRAL follow-up observations
  10. GRB 190326A: Swift XRT and UVOT follow-up observations
  11. LIGO/Virgo S190412m: Fermi-LAT search for a high-energy gamma-ray counterpart
  12. INTEGRAL prompt observation of S190412m
  13. GRB 190409A: ground analysis reveals a likely spurious event
  14. LIGO/Virgo ST190408an: Fermi-LAT search for a high-energy gamma-ray counterpart
  15. GRB 190409A: Swift detection of a possible burst
  16. INTEGRAL observation of S190408an
  17. GRB 190404C: Swift-XRT afterglow detection
  18. GRB 190404C: Swift-XRT observations
  19. Swift GRB 190331B: Further Swift-XRT observations
  20. GRB 190331B: Swift observations of a ground-detected burst
  21. Fermi-LAT Gamma-ray Observations of IceCube-190331A
  22. GRB 190331A: Fermi GBM detection
  23. MAGIC follow-up of the X-ray flares of LS I +61�303 dete
  24. GRB 190326B: Fermi GBM detection
  25. GRB 190324A: Swift-XRT refined Analysis
  26. GRB 190324A: Fermi GBM observation
  27. Further Chandra observations of GW170817 ~581-583 days since merger
  28. GRB 190320A: Swift-XRT refined Analysis
  29. GRB 190320A: Fermi GBM observation
  30. GRB 190311A: Fermi GBM observation
  31. GRB 190311A: Swift-XRT refined Analysis
  32. GRB 190311A: NEXT-0.6m optical afterglow detection
  33. GRB 190305A: Swift-XRT afterglow detection
  34. GRB 190306A: Swift-XRT observations
  35. GRB 190305A: Swift-XRT observations
  36. INTEGRAL observation of IceCube-190221A
  37. IceCube-190221A: Fermi-LAT Gamma-ray observations
  38. GRB 190220B: Fermi GBM observation
  39. GRB 190220A: Swift-XRT refined Analysis
  40. GRB 190219A: Swift-XRT refined Analysis
  41. GRB 190215A: Fermi GBM detection
  42. GRB 190211A: DOAO optical observation
  43. GRB 190211A: Swift-XRT refined Analysis
  44. GRB 190211A: NEXT-0.6m optical afterglow detection
  45. GRB 190202A: SAO RAS further optical observations
  46. GRB 190204A: SAO RAS optical observations
  47. GRB 190203A: Swift-XRT refined Analysis
  48. GRB 190204A: Swift-XRT refined Analysis
  49. GRB 190202A: R and I band observation from HCT
  50. GRB 190203A: SAO RAS optical observations, afterglow fading
  51. GRB 190202A: SAO RAS optical observations
  52. GRB 190202A: Swift-XRT refined Analysis
  53. GRB 190202A: Fermi GBM observation
  54. GRB 190129B: Swift-XRT candidate afterglow detection
  55. Fermi GBM Observations of IceCube-190124A
  56. GRB 190129A: Fermi GBM detection
  57. INTEGRAL observation of IceCube-190124A
  58. Fermi-LAT Gamma-ray Observations of IceCube-190124A
  59. GRB 190123A: Swift-XRT refined Analysis
  60. GRB 190123A: Fermi GBM observation
  61. GRB 190122A: Fermi GBM observation
  62. GRB 190122A: Fermi-LAT detection
  63. GRB 190114C: RTT150 optical observations
  64. GRB 190114B: Swift-XRT refined Analysis
  65. GRB 190114C: Mondy optical observations
  66. GRB 190114C: A type 1 BdHN with TeV emission
  67. GRB 190114C: Fermi-LAT detection
  68. GRB 190114C: Fermi GBM detection
  69. GRB 190114C: Swift-XRT refined Analysis
  70. INTEGRAL observation of IceCube-190104A
  71. GRB 190114A: Swift-XRT refined Analysis
  72. GRB 190110A: Fermi GBM detection
  73. GRB 190109B: Fermi GBM observation
  74. GRB 190106A: OSN Afterglow Observations
  75. GRB 190109B: Swift-XRT refined Analysis
  76. GRB 190109A: Fermi GBM observation
  77. GRB 190109A: Swift-XRT refined Analysis
  78. GRB 190106A: Swift-XRT refined Analysis
  79. Fermi LAT Gamma-ray Observations of IceCube-190104A
  80. GRB 190103B: Swift-XRT refined Analysis
  81. GRB 181231A: Fermi GBM detection
  82. GRB 181231A: Fermi-LAT detection
  83. GRB 181225A: further Swift-XRT observations
  84. GRB 181228A: Swift-XRT refined Analysis
  85. GRB 181222B: Swift follow-up observations of MASTER optical transient J204928.79+245744.0
  86. GRB 181228A: Fermi GBM observation
  87. GRB 181227A: Fermi GBM detection
  88. GRB 181225A: Swift observations and X-ray candidate afterglow
  89. GRB 181225A: Fermi GBM detection
  90. GRB 181225A: Fermi-LAT Detection
  91. Konus-Wind observation of GRB 181222B
  92. GRB 181222B : Fermi GBM detection
  93. GRB 181222A: Fermi GBM observation
  94. GRB 181213A: Swift-XRT refined Analysis
  95. GRB 181212A: Fermi GBM Detection
  96. GRB 181126B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 564897175)
  97. GRB 181203A: Swift-XRT refined Analysis
  98. GRB 181201A: Swift/UVOT Detection
  99. GRB 181202A: Swift-XRT refined Analysis
  100. GRB 181201A: optical observations in Chilescope observatory

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