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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"

19548 results found.

  1. GRB 190422A: Enhanced Swift-XRT position
  2. GRB 190422A: Swift detection of a burst
  3. LIGO/Virgo S190421ar: HAWC follow-up
  4. AT LIGO-Virgo S190421ar: AGILE GRID observations
  5. LIGO/Virgo S190412m: SVOM/GWAC observations of the initial skymap
  6. Fermi trigger 576241792 / GRB 190406B: MASTER optical observation
  7. GRB 190406B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 576241792)
  8. IPN Triangulation of GRB 190415A
  9. LIGO/Virgo S190412m: Palomar Gattini-IR Wide-field Infrared Follow-up
  10. LIGO/Virgo S190412m: GOTO optical coverage - no notable counterparts
  11. LIGO/Virgo S190412m: Fermi-LAT search for a high-energy gamma-ray counterpart
  12. LIGO/Virgo S190412m: Swift/BAT data search
  13. LIGO/Virgo S190412m: J-GEM optical/NIR follow-up observations
  14. LIGO/Virgo S190412m/G329483: ANTARES neutrino search
  15. LIGO/Virgo S190412m: Hobby-Eberly Telescope VIRUS observations of target galaxies.
  16. LIGO/Virgo S190412m: HAWC follow-up
  17. INTEGRAL prompt observation of S190412m
  18. LIGO-Virgo S190412m: AGILE preliminary analysis
  19. LIGO/Virgo S190408an: GROND Observations of MASTER OT J154209.55-431742.2
  20. IPN triangulation of GRB 190409B (short)
  21. IceCube-190331A: Swift-XRT Follow-up Observations
  22. GRB 190409A: ground analysis reveals a likely spurious event
  23. LIGO/Virgo S190408an: MAXI/GSC Observations
  24. GRB 190404C: MITSuME Akeno and Okayama optical upper limits
  25. LIGO/Virgo S190408an: CALET Observations
  26. LIGO/Virgo S190408an: TMTS Optical Observation
  27. LIGO/Virgo S190408an: DDOTI/OAN Optical Observations
  28. LIGO/Virgo S190408an: HMT optical observations
  29. LIGO/Virgo S190408an: MASTER 3 OT's more detection
  30. LIGO/Virgo ST190408an: Fermi-LAT search for a high-energy gamma-ray counterpart
  31. GRB 190409A: Swift detection of a possible burst
  32. LIGO/Virgo S190408an: SAGUARO follow-up observations
  33. LIGO/Virgo S190408an: MASTER OT detection
  34. LIGO/Virgo S190408an: Swift/BAT data search
  35. LIGO-Virgo S190408an: HAWC follow-up
  36. INTEGRAL observation of S190408an
  37. LIGO-Virgo GW S190408an: J-GEM optical/NIR follow-up observations
  38. LIGO-Virgo S190408an: AGILE MCAL observations
  39. GRB 190404C: Swift-XRT afterglow detection
  40. Fermi TriggNum 576054086 (GRB 1904204.29) / MASTER OT J071404.52+550304.2: CrAO optical observations
  41. GRB190404C: GROWTH-India discovery of optical counterpart
  42. GRB 190404B: Tiled Swift observations
  43. GRB 190330A: MITSuME Akeno and Okayama optical upper limits
  44. Trigger 896552: Swift detection of PSR B1055-52
  45. LIGO/Virgo: Announcing the start of Observing Run 3 (O3) and the beginning of the public gravitational-wave alert era
  46. Konus-Wind observation of GRB 190329A
  47. GRB 190331B: Swift observations of a ground-detected burst
  48. Fermi-LAT Gamma-ray Observations of IceCube-190331A
  49. GRB 190331B: Swift ToO observations
  50. Swift Trigger 895503 is not a GRB
  51. Swift Trigger 895479: Detection of GRO J2058+42
  52. GRB 190326A: Swift-BAT refined analysis - a soft-short GRB or an SGR
  53. Swift Trigger 895257: Detection of GRO J2058+42 in outburst
  54. GRB 190324A: Swift/UVOT Observations
  55. GRB 190324A: Enhanced Swift-XRT position
  56. Further Chandra observations of GW170817 ~581-583 days since merger
  57. GRB 190324A: Swift-XRT observations
  58. Swift detection of LS I +61 303
  59. Correction: Chandra observations of GW170817 ~581 days since merger
  60. Chandra observations of GW170817 ~581 days since merger
  61. Swift Trigger 894268: Detection of GRO J2058+42 in outburst
  62. GRB 190320A: Swift/UVOT Upper Limits
  63. GRB 190320A: Enhanced Swift-XRT position
  64. GRB 190320A: Swift-XRT observations
  65. GRB 190311A: Swift/UVOT Detection
  66. GRB190311A: OAO observations
  67. GRB 190311A: GMG observation
  68. GRB 190311A: Enhanced Swift-XRT position
  69. GRB 190311A: NEXT-0.6m optical afterglow detection
  70. GRB 190311A: Mondy optical observations
  71. GRB 190311A: Swift detection of a burst with optical counterpart
  72. GRB 190305A: Swift-XRT afterglow detection
  73. IPN Triangulation of GRB 190304A (long)
  74. GRB 190306A: Swift-XRT observations
  75. GRB 190306A: Tiled Swift observations
  76. IPN Triangulation of GRB 190305A
  77. GRB 190305A: MAXI/GSC detection
  78. GRB 190305A: Tiled Swift observations
  79. Trigger 890732: Swift detection of MAXI J1631-479
  80. INTEGRAL observation of IceCube-190221A
  81. IceCube-190221A: Swift-XRT Follow-up Observations
  82. IceCube-190221A: Fermi-LAT Gamma-ray observations
  83. GRB 190220B: Fermi GBM observation
  84. GRB 190219A: CrAO and AbAO optical upper limit
  85. GRB 190220B: Kitab Observatory optical upper limit
  86. GRB 190220A: Swift-XRT refined Analysis
  87. GRB 190220A: Enhanced Swift-XRT position
  88. GRB 190219A: NOT optical afterglow candidate
  89. GRB 190219A: NEXT-0.6m optical upper limit
  90. GRB 190220A: Swift detection of a burst with an optical counterpart
  91. GRB 190219A: Enhanced Swift-XRT position
  92. GRB 190219A: Swift detection of a burst
  93. Trigger 889483: Swift detection of Swift J1858.6-0814
  94. GRB190211A: GROWTH-India detection of optical afterglow
  95. GRB 190211A: Tautenburg observations
  96. GRB 190211A: Swift/UVOT Detection
  97. GRB 190211A: NOT optical observations
  98. GRB 180703A: VLT/MUSE host galaxy redshift measurement
  99. GRB190211A: MASTER Global Robotic Net optical observation
  100. GRB 190211A: NEXT-0.6m optical afterglow detection

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