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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"

8272 results found.

  1. LIGO/Virgo S190412m/G329483: ANTARES neutrino search
  2. LIGO-Virgo S190412m: Search for neutrino counterparts with IceCube
  3. LIGO/Virgo S190412m: HAWC follow-up
  4. LIGO/Virgo S190412m: Identification of a GW binary merger candidate
  5. LIGO/Virgo S190408an: GROND Observations of MASTER OT J154209.55-431742.2
  6. IceCube-190331A: Swift-XRT Follow-up Observations
  7. LIGO/Virgo S190408an: DDOTI/OAN Optical Observations
  8. LIGO/Virgo ST190408an: Fermi-LAT search for a high-energy gamma-ray counterpart
  9. GRB 190409A: Swift detection of a possible burst
  10. LIGO/Virgo S190408an: MASTER OT is 27 day old ATLAS SN candidate and unrelated
  11. LIGO/Virgo S190408an: Identification of a GW binary merger candidate
  12. Search for neutrino counterparts to GW candidate S190408an with IceCube
  13. LIGO-Virgo S190408an: HAWC follow-up
  14. GRB 190404C: Swift-XRT observations
  15. GRB 190404B: Tiled Swift observations
  16. LIGO/Virgo: Announcing the start of Observing Run 3 (O3) and the beginning of the public gravitational-wave alert era
  17. Search for additional neutrino events from the direction of IceCube-190331A with IceCube
  18. GRB 190331B: Swift ToO observations
  19. IceCube-190331A - IceCube observation of a high-energy neutrino candidate event
  20. Swift Trigger 895503 is not a GRB
  21. GRB 190326A: Swift-BAT refined analysis - a soft-short GRB or an SGR
  22. Swift Trigger 895257: Detection of GRO J2058+42 in outburst
  23. GRB 190324A: Swift/UVOT afterglow candidate
  24. Swift Trigger 894268: Detection of GRO J2058+42 in outburst
  25. GRB 190311A: Mondy optical observations
  26. GRB 190311A: Swift detection of a burst with optical counterpart
  27. GRB 190306A: Tiled Swift observations
  28. GRB 190305A: Tiled Swift observations
  29. INTEGRAL observation of IceCube-190221A
  30. Search for additional neutrino events from the direction of IceCube-190221A with IceCube
  31. IceCube-190221A: Swift-XRT Follow-up Observations
  32. GRB 190219A: CrAO and AbAO optical upper limit
  33. GRB 190220B: Kitab Observatory optical upper limit
  34. IceCube-190221A - IceCube observation of a high-energy neutrino candidate event
  35. GRB 190220B: BOOTES-4 optical observation
  36. GRB 190219A: NOT optical afterglow candidate
  37. GRB 190220A: Swift detection of a burst with an optical counterpart
  38. GRB 190219A: Swift detection of a burst
  39. GRB 190215A: Fermi GBM detection
  40. Konus-Wind observation of GRB 190206A
  41. GRB 190203A: COATLI Optical Observations
  42. GRB 190204A: COATLI Optical Detection of the Fading Afterglow
  43. GRB 190202A: R and I band observation from HCT
  44. GRB 190204A: Swift detection of a burst with a possible optical counterpart
  45. Swift Trigger 887541: Swift detection of Swift J1728.9-3613
  46. GRB 190203A: Koshka Zeiss-1000 optical upper limit
  47. GRB 190203A: Swift detection of a burst with an optical counterpart
  48. GRB 190202A: Swift detection of a burst with an optical counterpart
  49. Improved IPN error box for GRB 190129B
  50. GRB 190129B: DDOTI Detection of the Possible Afterglow and Suggestion of Fading
  51. GRB 190129B: Swift/UVOT Upper Limits
  52. GRB 190129B: ePESSTO NTT optical observations
  53. GRB 190129B: GROND possible host candidate
  54. GRB 190129B: Swift-XRT candidate afterglow detection
  55. GRB 190129B: Tiled Swift observations
  56. INTEGRAL observation of IceCube-190124A
  57. Trigger 886266: Another Swift trigger on MAXI J1348-630
  58. GRB 190114C: Optical follow-up from HCT
  59. Swift Trigger 885960: A third Swift trigger on MAXI J1348-630
  60. Search for counterparts to IceCube-190124A with IceCube
  61. Search for counterpart to IceCube-190124A with ANTARES
  62. IceCube-190124A - IceCube observation of a high-energy neutrino candidate event
  63. Konus-Wind observation of GRB 190122A
  64. GRB 190123A: Swift detection of a burst
  65. GRB 190122A: Fermi GBM observation
  66. Trigger 884906: Swift detection of MAXI J1631-479
  67. GRB 190114C: MeerKAT radio observation
  68. GRB 190114C: Optical detection from HCT
  69. GRB190114C, Long follow up urged
  70. INTEGRAL observation of IceCube-190104A
  71. GRB 190114C: Swift detection of a very bright burst with a bright optical counterpart
  72. GRB 190114B: Swift detection of a burst
  73. GRB 190114A: Possible UVOT Detection
  74. GRB 190114A: Swift detection of a burst
  75. GRB 190109B: Swift detection of a burst
  76. GRB 190109A: Swift detection of a burst
  77. IceCube-190104A: Swift-XRT observations
  78. GRB 190106A: Swift-BAT refined analysis
  79. GRB 190106A: Swift detection of a burst with an optical counterpart
  80. Search for Counterparts to IceCube-190104A with IceCube
  81. Search for counterpart to IceCube-190104A with ANTARES
  82. IceCube-190104A - IceCube observation of a high-energy neutrino candidate event
  83. GRB 190103B: Swift detection of a burst
  84. GRB 181225A: KAIT Follow-Up Observations with Upper Limit
  85. GRB 181228A: KAIT Optical Upper Limit
  86. GRB 181228A: Swift detection of a burst
  87. GRB 181222B: Swift ToO observations
  88. GRB 181225A: Swift observations and X-ray candidate afterglow
  89. GRB 181225A: Swift ToO observations
  90. Swift Trigger 878504 is not astrophysical
  91. GRB 181126A: MeerKAT radio observation
  92. GRB181213A: Swift/UVOT Detection
  93. Swift Trigger 874754 is likely not an astrophysical event
  94. Fermi-GBM Observations During Four New GW-Detected BBH Mergers (Correction)
  95. Fermi-GBM Observations During Four New GW-Detected BBH Mergers
  96. GRB 181203A: Swift detection of a burst
  97. GRB 181201A: GROND detection of the afterglow and redshift upper limit of z < 3
  98. GRB 181202A: Swift detection of a burst with an optical counterpart
  99. GRB 181201A: Swift ToO observations
  100. GRB 181126A: Swift detection of a burst

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