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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"

7447 results found.

  1. GRB 180721A: Swift detection of a burst
  2. GRB 180720C: Swift detection of a burst or possible Galactic Transient
  3. GRB 180720B: LCO Haleakala possible bright optical candidate
  4. Swift detects a flare from AX 1631.9-4752
  5. GRB 180718A: Swift ToO observations
  6. GRB 180718B: Swift ToO observations
  7. GRB 180715A: LCO Sutherland possible optical candidate
  8. GRB 180703A: optical afterglow confirmation
  9. GRB 180709A: Swift detection of a burst
  10. Trigger 846740: Swift trigger near NGC5055
  11. GRB 180706A: Swift detection of a burst with optical counterpart
  12. GRB 180703A: LCO Sutherland possible optical candidate
  13. GRB 180703A: Tiled Swift observations
  14. GRB 180630A: Swift detection of a burst with an optical counterpart
  15. GRB 180626A: Swift detection of a burst with an optical counterpart
  16. GRB 180624A: GROND observations
  17. GRB 180624A: LCO Siding Springs afterglow candidate
  18. GRB 180624A: Swift detection of a burst
  19. GRB 180623A: Swift detection of a burst
  20. GRB 180620B: Swift detection of a burst with an optical counterpart
  21. GRB 180620A: ISON-MN afterglow confirmation
  22. GRB 180620A: Swift detection of a burst with an optical counterpart
  23. GRB 180618A: Swift detection of a burst with an optical counterpart
  24. GRB 180614A: Swift detection of a burst
  25. GRB 180613A: Swift detection of a burst
  26. GRB 180602A: Swift detection of a burst
  27. Swift Trigger 834937 is not a GRB
  28. GRB 180514A: CrAO/ZTSH optical observations and afterglow candidate
  29. GRB 180514A: Swift detection of a burst
  30. GRB 180510B: Swift detection of a burst with an optical counterpart
  31. GRB 180510A: Swift detection of a burst
  32. Chandra observations of GW170817 reveal a fading afterglow
  33. Chandra observations of GW170817 260 days since merger: first statistically significant evidence for an X-ray decay
  34. GRB 180504A: ePESSTO NTT NIR observations
  35. GRB 180504A: NOT afterglow candidate
  36. GRB 180504A: Swift detection of a burst
  37. GRB 180425A: Swift detection of a burst
  38. LIGO/Virgo G299232: LOFAR follow-up
  39. GRB 180418A: KAIT Optical Afterglow Candidate
  40. GRB 180410A: Swift detection of a burst or a Galactic transient.
  41. GRB 180409A: Tiled Swift observations
  42. GRB 180404B: Swift detection of a burst with an optical counterpart
  43. GRB 180404A: Swift detection of a burst with an optical afterglow
  44. GRB 180402A: KAIT Optical Upper Limit
  45. GRB 180402A: Swift detection of a possibly short burst
  46. GRB 180331B: Swift detection of a burst
  47. GRB 180331A: Swift detection of a burst
  48. GRB 180329B: Swift detection of a burst with an optical afterglow
  49. GRB 180325A: Swift detection of a burst with an optical counterpart
  50. GRB 180324A: KAIT Optical Upper Limit
  51. GRB 180324A: Swift detection of a burst
  52. GRB 180316A: Swift detection of a burst
  53. GRB 180314B: Swift detection of a burst
  54. GRB 180314A: TAROT La Silla observatory optical observations
  55. GRB 180314A: Swift detection of a burst with an optical counterpart
  56. GRB 180311A: Swift detection of a burst
  57. GRB 180305A: Mondy optical observations
  58. GRB 180305A: RATIR Optical Afterglow Candidate
  59. GRB 180305A: Swift ToO observations
  60. Swift Trigger 811686 is probably not an astrophysical source.
  61. GRB 180224A: Swift detection of a burst with an optical counterpart
  62. GRB 180222A: Swift detection of a burst
  63. Swift trigger 811074 (possible GRB 180221A): Swift refined analysis
  64. GRB 180210A: Tiled Swift observations
  65. GRB 180210A: Swift ToO observations
  66. Trigger 809374: Swift detection of a possible non-burst faint source
  67. GRB 180205A: Swift detection of a burst with a bright optical counterpart
  68. GRB 180204A: Swift detection of a short burst
  69. GW170817/GRB170817A: Updated results from the full Chandra dataset
  70. LIGO/Virgo GW170817: Chandra X-ray Emission Continues to Rise ~156 Days Post-Merger
  71. GRB 180115A: MITSuME Akeno optical upper limits
  72. GRB 180113A: Swift ToO observations
  73. GRB 180115A: Swift detection of a burst with an optical counterpart.
  74. GRB 180113A: KAIT Optical Observations
  75. GRB 180111A: Swift detection of a burst with an optical counterpart
  76. GRB 180103A: Swift ToO observations
  77. GRB 180102A: Swift detection of a burst
  78. IceCube-171106A: Konus-Wind upper limits
  79. IceCube-171015A: Konus-Wind upper limits
  80. IceCube-170922A: Konus-Wind upper limits
  81. GRB 171222A: Swift detection of a burst
  82. GRB 171216A: Swift detection of a burst
  83. GRB 171212A: Swift detection of a burst or a Galactic transient
  84. GRB 171210A: Swift-XRT and UVOT observations
  85. GRB 171210A: Swift ToO observations
  86. GRB 171209A: Enhanced Swift-XRT position
  87. Swift Trigger 796115 is probably not a GRB
  88. GRB 171209A: LCO 1-m telescope observations
  89. GRB 171209A: Swift detection of a burst
  90. LIGO/Virgo G298048: Brightening X-ray Emission from GW170817/GRB170817A/SSS17a
  91. LIGO/Virgo GW170817: Chandra X-ray brightening of the counterpart 108 days since merger
  92. GRB 171205A: Swift detection of a burst
  93. Pan-STARRS follow-up of IceCube-171106A
  94. LIGO/Virgo G299232: LOFAR follow-up
  95. GRB 171124A: Swift ToO observations
  96. GRB 171123A: Swift detection of a burst
  97. GRB 171120A: Swift detection of a burst
  98. GRB 171115A: Swift detection of a burst
  99. LIGO/Virgo G288732/GW170608: updated localization from parameter estimation
  100. INTEGRAL observation of IceCube-171106A

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