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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 181022A: Swift detection of a burst
  2. GRB 181020A: Swift detection of a burst with an optical counterpart
  3. IceCube-181014A - IceCube observation of a high-energy neutrino candidate event
  4. GRB 181013A: Swift detection of a probable burst
  5. GRB 181010A: MASTER-Argentina OT detection
  6. GRB 181010A: Swift detection of a burst with an optical counterpart
  7. GRB 181002A: Swift detection of a burst
  8. GRB 180930A: KAIT Optical Upper Limit
  9. GRB 180930A: Swift detection of a burst
  10. GRB 180925A: Swift detection of a burst
  11. GRB 180924A: Swift detection of a burst
  12. Swift Trigger 863053 is not an astrophysical event
  13. GRB 180923A: MASTER inspection MAXI/GSC error box
  14. GRB 180914B: KAIT Optical Afterglow Candidate
  15. GRB 180914B: Tiled Swift observations
  16. GRB 180914A: MASTER automatic inspection
  17. GRB 180914A: Tiled Swift observations
  18. Fermi-LAT Gamma-ray Observations of IceCube-180908A
  19. INTEGRAL observation of IceCube-180908A
  20. Search for counterpart to IceCube-180908A with ANTARES
  21. GRB 180715A: 15 GHz upper limits from the AMI Short GRB Program
  22. GRB 180718A: 15 GHz upper limits from the AMI Short GRB Program
  23. IceCube-180908A - IceCube observation of a high-energy neutrino candidate event
  24. GRB 180905A: Swift detection of a burst
  25. GRB 180904A: NOT optical observations, candidate host galaxy
  26. GRB 180904A: Swift detection of a burst
  27. GRB 180829A: Tiled Swift observations
  28. GRB 180828A: Swift detection of a GRB or possible Galactic Transient Swift J1754.9-2548
  29. GRB 180818B: TSHAO optical upper limit
  30. GRB 180823A: Swift detection of a burst
  31. GRB 180821A: iTelescope counterpart is not the afterglow
  32. GRB 180818B: 1.5m OSN optical afterglow candidate
  33. GRB 180821A: Swift detection of a burst
  34. GRB 180818B: Swift detection of a burst
  35. GRB 180818A: Swift detection of a burst
  36. GRB 180809A: further Swift/XRT observations
  37. Correction: Chandra X-ray observations of GW170817 at 1 year post-merger: increasingly rapid fading
  38. LIGO/Virgo GW170817: A steep decline in the radio light curve and prediction for the X-rays
  39. Chandra X-ray observations of GW170817 at 1 year post-merger: increasingly rapid fading
  40. GRB 180812A: Swift detection of a burst
  41. Swift Trigger 852625: a possible GRB
  42. GRB 180809B: Swift detection of a burst with an optical afterglow
  43. GRB 180809A: Tiled Swift observations
  44. GRB 180806A: NOT optical observations
  45. GRB 180806A: Swift ToO observations
  46. GRB 180805B: Swift detection of a burst
  47. GRB 180805A: Swift detection of a burst
  48. GRB 180728A: A long GRB of the X-ray flash (XRF) subclass, expecting supernova appearance
  49. GRB 180728B: MASTER optical observations short GRB IPN error box
  50. GRB 180727A: Swift detection of a burst
  51. GRB 180721A: KAIT Optical Upper Limit
  52. GRB 180720B: Testing the universality of the newly born neutron star in BdHNe
  53. GRB 180722A: Tiled Swift observations
  54. ANTARES neutrino Alert180713.02: MASTER optical observation
  55. GRB 180721A: Swift detection of a burst
  56. GRB 180720C: Swift detection of a burst or possible Galactic Transient
  57. GRB 180720B: LCO Haleakala possible bright optical candidate
  58. Swift detects a flare from AX 1631.9-4752
  59. GRB 180718A: Swift ToO observations
  60. GRB 180718B: Swift ToO observations
  61. GRB 180715A: LCO Sutherland possible optical candidate
  62. GRB 180703A: optical afterglow confirmation
  63. GRB 180709A: Swift detection of a burst
  64. Trigger 846740: Swift trigger near NGC5055
  65. GRB 180706A: Swift detection of a burst with optical counterpart
  66. GRB 180703A: LCO Sutherland possible optical candidate
  67. GRB 180703A: Tiled Swift observations
  68. GRB 180630A: Swift detection of a burst with an optical counterpart
  69. GRB 180626A: Swift detection of a burst with an optical counterpart
  70. GRB 180624A: GROND observations
  71. GRB 180624A: LCO Siding Springs afterglow candidate
  72. GRB 180624A: Swift detection of a burst
  73. GRB 180623A: Swift detection of a burst
  74. GRB 180620B: Swift detection of a burst with an optical counterpart
  75. GRB 180620A: ISON-MN afterglow confirmation
  76. GRB 180620A: Swift detection of a burst with an optical counterpart
  77. GRB 180618A: Swift detection of a burst with an optical counterpart
  78. GRB 180614A: Swift detection of a burst
  79. GRB 180613A: Swift detection of a burst
  80. GRB 180602A: Swift detection of a burst
  81. Swift Trigger 834937 is not a GRB
  82. GRB 180514A: CrAO/ZTSH optical observations and afterglow candidate
  83. GRB 180514A: Swift detection of a burst
  84. GRB 180510B: Swift detection of a burst with an optical counterpart
  85. GRB 180510A: Swift detection of a burst
  86. Chandra observations of GW170817 reveal a fading afterglow
  87. Chandra observations of GW170817 260 days since merger: first statistically significant evidence for an X-ray decay
  88. GRB 180504A: ePESSTO NTT NIR observations
  89. GRB 180504A: NOT afterglow candidate
  90. GRB 180504A: Swift detection of a burst
  91. GRB 180425A: Swift detection of a burst
  92. LIGO/Virgo G299232: LOFAR follow-up
  93. GRB 180418A: KAIT Optical Afterglow Candidate
  94. GRB 180410A: Swift detection of a burst or a Galactic transient.
  95. GRB 180409A: Tiled Swift observations
  96. GRB 180404B: Swift detection of a burst with an optical counterpart
  97. GRB 180404A: Swift detection of a burst with an optical afterglow
  98. GRB 180402A: KAIT Optical Upper Limit
  99. GRB 180402A: Swift detection of a possibly short burst
  100. GRB 180331B: Swift detection of a burst

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