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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"

27776 results found.

  1. GRB 240805A: Fermi-LAT detection
  2. GRB 240805A: INTEGRAL spectral analysis
  3. EP240804a: LCOGT optical counterpart detection
  4. GRB 240805A: A long GRB detected by INTEGRAL
  5. EP240804a: NOT optical counterpart detection
  6. EP240804a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  7. GRB 240805A: Swift detection of a burst
  8. GRB 240805A: Fermi GBM Final Real-time Localization
  9. GRB 240804A: Fermi GBM Final Real-time Localization
  10. IPN triangulation of GRB 240802A / EP 240802a
  11. EP240802a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  12. GRB 240802A: AstroSat CZTI detection of a long burst
  13. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  14. GRB 240730A: Swift-BAT refined analysis
  15. EP240801a: GSP follow-up observations of the candidate counterpart
  16. EP240801a: TRT optical counterpart detection
  17. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  18. GRB 240801B: AstroSat CZTI detection of a bright long burst
  19. GRB 240801A: Fermi GBM Final Real-time Localization
  20. GRB 240730C: AstroSat CZTI detection of a long burst
  21. GRB 240731A: Fermi GBM Final Localization
  22. GRB 240731A: AstroSat CZTI detection
  23. GRB240730A: BOOTES-5/JGT early optical upper limit
  24. GRB 240730B: Fermi GBM Final Real-time Localization
  25. Swift GRB 240730A: Global MASTER-Net observations report
  26. GRB 240730A: Swift-XRT refined Analysis
  27. GRB 240715A: Swift-XRT afterglow detection
  28. GRB 240730A: KAIT Optical Upper Limit
  29. GRB 240727C: GRBAlpha detection
  30. GRB 240730A: Swift/UVOT Upper Limits
  31. GRB 240730A: Enhanced Swift-XRT position
  32. GRB 240730A: Swift detection of a burst
  33. GRB 240727A: Swift-BAT refined analysis
  34. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  35. GRB 240727A: observations of optical counterpart.
  36. GRB 240727B: Swift-XRT observations
  37. GRB 240727A: Swift/UVOT detection
  38. GRB 240727A: NOT optical observation
  39. GRB 240727A: JinShan optical upper limits
  40. GRB 240727A Bassano Bresciano Observatory upper limit
  41. GRB 240727A: Fermi GBM Final Real-time Localization
  42. GRB 240727C: AstroSat CZTI detection of a long burst
  43. GRB 240727A: Swift-XRT refined Analysis
  44. GRB 240720B: GRBAlpha detection
  45. GRB 240718A: GRBAlpha detection
  46. GRB 240710B: GRBAlpha detection
  47. GRB 240627A: GRBAlpha detection
  48. GRB 240727A: Enhanced Swift-XRT position
  49. GRB 240727B: Fermi GBM Observation
  50. Swift GRB240727.16: Global MASTER-Net observations report
  51. GRB240529A: VIRT optical transient detection
  52. GRB 240727B: Swift ToO observations
  53. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  54. GRB 240727B: AstroSat CZTI detection
  55. GRB 240726B: AstroSat CZTI detection of a short burst
  56. GRB240727A: Skynet Optical Afterglow Observations
  57. GRB 240727A: TRT optical afterglow detection
  58. GRB 240727A: KAIT Optical Afterglow Candidate
  59. GRB 240727A: Swift detection of a burst
  60. GRB 240726A: AstroSat CZTI detection of a short burst
  61. GRB 240726A: Fermi GBM Final Real-time Localization
  62. IceCube-240725A - IceCube observation of a high-energy neutrino candidate track-like event
  63. Swift Trigger 1244778 is not a GRB
  64. Swift GRB240725.11: Global MASTER-Net observations report
  65. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  66. GRB 240720A: Swift-BAT refined analysis
  67. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  68. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  69. IceCube-240721A - IceCube observation of a high-energy neutrino candidate track-like event
  70. GRB 240721A: Fermi GBM Final Real-time Localization
  71. GRB 240720B: AstroSat CZTI detection of a short burst
  72. GRB 240720A: AstroSat CZTI detection
  73. GRB 240720A: Fermi GBM observation
  74. GRB 240720A: Swift detection of a burst
  75. Swift GRB240720.02: Global MASTER-Net observations report
  76. Konus-Wind detection of GRB 240718A
  77. GRB 240718A: Fermi-LAT Detection
  78. GRB 240718A: Fermi GBM Final Real-time Localization
  79. GRB 240712A: Swift-BAT refined analysis
  80. GRB 240716A: GECAM-B detection of a long burst
  81. GRB 240713A: 2.2m CAHA optical limit
  82. GRB 240715A: Swift/UVOT observations of the XRT sources.
  83. GRB 240715A: Swift-XRT observations
  84. GRB240713A: Swift/UVOT Upper LImits
  85. EP240708a: X-ray follow-up observations with Swift/XRT
  86. GRB 240715A: GECAM-C detection of a short burst
  87. Konus-Wind detection of GRB 240715A
  88. GRB 240713A: Swift-XRT observations
  89. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  90. GRB 240712A: Swift-XRT refined Analysis
  91. GRB 240715A: Swift ToO observations
  92. GRB 240712A ATCA radio observations
  93. IPN triangulation of GRB 240715A (short)
  94. GW s240422ed: Swift UVOT follow-up
  95. GRB 240712A: Swift/UVOT Upper Limits
  96. EP-WXT flaring star and the optical flaring activity during its decay phase
  97. The EP-WXT source triggered on July 14th is likely a flaring star
  98. GRB 240715A: Fermi GBM Final Real-time Localization
  99. GRB 240713A: Tiled Swift observations
  100. GRB 240713A: OHP/T120 optical upper limit

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