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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"

7301 results found.

  1. GRB 180331A: Swift detection of a burst
  2. GRB 180329B: Swift detection of a burst with an optical afterglow
  3. GRB 180325A: Swift detection of a burst with an optical counterpart
  4. GRB 180324A: KAIT Optical Upper Limit
  5. GRB 180324A: Swift detection of a burst
  6. GRB 180316A: Swift detection of a burst
  7. GRB 180314B: Swift detection of a burst
  8. GRB 180314A: TAROT La Silla observatory optical observations
  9. GRB 180314A: Swift detection of a burst with an optical counterpart
  10. GRB 180311A: Swift detection of a burst
  11. GRB 180305A: Mondy optical observations
  12. GRB 180305A: RATIR Optical Afterglow Candidate
  13. GRB 180305A: Swift ToO observations
  14. Swift Trigger 811686 is probably not an astrophysical source.
  15. GRB 180224A: Swift detection of a burst with an optical counterpart
  16. GRB 180222A: Swift detection of a burst
  17. Swift trigger 811074 (possible GRB 180221A): Swift refined analysis
  18. GRB 180210A: Tiled Swift observations
  19. GRB 180210A: Swift ToO observations
  20. Trigger 809374: Swift detection of a possible non-burst faint source
  21. GRB 180205A: Swift detection of a burst with a bright optical counterpart
  22. GRB 180204A: Swift detection of a short burst
  23. GW170817/GRB170817A: Updated results from the full Chandra dataset
  24. LIGO/Virgo GW170817: Chandra X-ray Emission Continues to Rise ~156 Days Post-Merger
  25. GRB 180115A: MITSuME Akeno optical upper limits
  26. GRB 180113A: Swift ToO observations
  27. GRB 180115A: Swift detection of a burst with an optical counterpart.
  28. GRB 180113A: KAIT Optical Observations
  29. GRB 180111A: Swift detection of a burst with an optical counterpart
  30. GRB 180103A: Swift ToO observations
  31. GRB 180102A: Swift detection of a burst
  32. IceCube-171106A: Konus-Wind upper limits
  33. IceCube-171015A: Konus-Wind upper limits
  34. IceCube-170922A: Konus-Wind upper limits
  35. GRB 171222A: Swift detection of a burst
  36. GRB 171216A: Swift detection of a burst
  37. GRB 171212A: Swift detection of a burst or a Galactic transient
  38. GRB 171210A: Swift-XRT and UVOT observations
  39. GRB 171210A: Swift ToO observations
  40. GRB 171209A: Enhanced Swift-XRT position
  41. Swift Trigger 796115 is probably not a GRB
  42. GRB 171209A: LCO 1-m telescope observations
  43. GRB 171209A: Swift detection of a burst
  44. LIGO/Virgo G298048: Brightening X-ray Emission from GW170817/GRB170817A/SSS17a
  45. LIGO/Virgo GW170817: Chandra X-ray brightening of the counterpart 108 days since merger
  46. GRB 171205A: Swift detection of a burst
  47. Pan-STARRS follow-up of IceCube-171106A
  48. LIGO/Virgo G299232: LOFAR follow-up
  49. GRB 171124A: Swift ToO observations
  50. GRB 171123A: Swift detection of a burst
  51. GRB 171120A: Swift detection of a burst
  52. GRB 171115A: Swift detection of a burst
  53. LIGO/Virgo G288732/GW170608: updated localization from parameter estimation
  54. INTEGRAL observation of IceCube-171106A
  55. Fermi-GBM Trigger 531686417 / 171106778 is not related to ICECUBE-171106A
  56. IceCube-171106A - IceCube observation of a high-energy neutrino candidate
  57. Fermi GBM detections of Swift J0243.6+6124 and modification of the GBM trigger configuration
  58. GRB 171010A: VLT spectroscopic identification of the associated SN 2017htp
  59. GRB 171102B: Swift detection of a burst
  60. GRB 171030A: Swift ToO observations
  61. Fermi-GBM triggers due to Swift J0243.6+6124
  62. AMI-LA observations of the new Be X-ray binary Swift J0243.6+6124
  63. Swift Trigger 783893 is probably not a GRB
  64. Retraction of high energy neutrino candidate IceCube-171028
  65. GRB 171027A: VLT optical upper limits
  66. GRB 171027A: LCO 1-m telescope observations
  67. GRB 171027A: RATIR Detection of a NIR Afterglow Candidate
  68. GRB 171027A: Swift detection of a burst
  69. Numerous Fermi-GBM Subthreshold Notices are due to Swift J0243.6+6
  70. GRB 171020A: Swift detection of a burst
  71. Search for counterpart to IceCube-171015A with ANTARES
  72. INTEGRAL SPI-ACS observation of IceCube-171015A
  73. Swift trigger 779171 is probably a noise fluctuation
  74. IceCube-171015A - IceCube observation of a high-energy neutrino candidate event
  75. GRB 171010A : Optical observations from HCT
  76. GRB 171010A: RATIR Optical and NIR Observations
  77. GRB 171013A: Swift detection of a possible burst
  78. GRB 171010B: Swift ToO observations
  79. GRB 171010A: optical observations
  80. GRB 171010A: Swift ToO observations
  81. LIGO/Virgo G298048/GW170817: updated localization from parameter estimation
  82. GRB 171007A: Swift detection of a burst
  83. GRB 171004A: Swift detection of a burst
  84. LIGO/Virgo G299232: LOFAR follow-up
  85. GRB 171003A: Swift detection of a burst or a Galactic Transient
  86. GRB 171001A: Swift detection of a burst
  87. 3.6m Devasthal Optical Telescope observations of GRB 170428A
  88. LIGO/Virgo G297595/GW170814: updated localization from parameter estimation
  89. LIGO/Virgo G298048: Summary of Pi of the Sky observations
  90. Search for counterpart to IceCube-170922A with ANTARES
  91. INTEGRAL SPI-ACS observation of AMON IceCube-170922A
  92. IceCube-170922A - IceCube observation of a high-energy neutrino candidate event
  93. GRB 170921A: Swift detection of a burst
  94. Swift trigger 773082 is probably not astrophysical
  95. LIGO/Virgo G297595: PIRATE observations
  96. LIGO/Virgo G299232: Khureltogot observations
  97. LIGO/Virgo G299232: Pierre Auger Observatory follow-up
  98. LIGO/Virgo G298389: Pierre Auger Observatory neutrino follow-up
  99. GRB 170912B: Swift detection of a burst
  100. GRB 170912A: Swift detection of a burst

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