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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"

19572 results found.

  1. GRB 200716C: Enhanced Swift-XRT position
  2. GRB 200716C: Swift detection of a burst with an optical counterpart
  3. IPN triangulation of GRB 200716A
  4. GRB 200715A: Swift ToO observations
  5. GRB 200714E: Swift ToO observations
  6. Fermi GRB 200714D: Global MASTER-Net observations report
  7. GRB 200713A: Enhanced Swift-XRT position
  8. GRB 200713A: Swift detection of a burst
  9. GRB 200711A: AbAO optical upper limit
  10. GRB 200711A: Swift/UVOT Upper Limits
  11. GRB 200711A: Swift-BAT refined analysis
  12. GRB 200711A: Swift-XRT refined Analysis
  13. GRB 200711A: Swift detection of a burst
  14. Update of alert from the HAWC Burst Monitor HAWC-200709A
  15. GRB 200709B/HAWC-200907A: Swift-XRT further observations
  16. HAWC-200907A: No Neutrino Counterpart detected with ANTARES
  17. GRB 200709B: Tiled Swift observations
  18. Trigger 980513: Swift detection of SGR Swift J1818.0-1607
  19. GRB 200630A: Swift/UVOT Upper Limits
  20. GRB 200623A: Swift XRT further observations
  21. GRB 200630A: Enhanced Swift-XRT position
  22. GRB 200630A: Swift detection of a burst
  23. GRB 200625A: Fermi-LAT detection is likely a flare from PKS 1127-14
  24. GRB 200623A: LBT optical observations
  25. GRB 200625A: Swift ToO observations
  26. GRB 200623A: MMT observations at XRT Source #3
  27. GRB 200623A: Swift/UVOT Upper Limits
  28. IPN triangulation of GRB 200623B (short)
  29. GRB 200623A: OAJ deep multi-color imaging, XRT #2 is pre-detected
  30. GRB 200623A: TNG optical observations
  31. GRB 200623A: AbAO afterglow candidate within XRT #2
  32. GRB 200623A: Swift ToO observations
  33. IceCube-200620A: No significant detection in HAWC
  34. Fermi-LAT Gamma-ray Observations of IceCube-200620A
  35. GRB 200613A: R-band observations from HCT
  36. GRB 200613A: Further Liverpool Telescope observations
  37. GRB 200613A: SAO RAS optical observations
  38. IceCube-200530A - SN2020lls likely unrelated
  39. Swift/UVOT Observations of IceCube 200615A
  40. Swift-XRT observations of IceCube 200615A
  41. IceCube-200615A: No significant detection in HAWC
  42. GRB 200613A: Jet-break from Xinglong-2.16m optical observations
  43. Fermi-LAT Gamma-ray Observations of IceCube-200615A
  44. IceCube-200614A: No significant detection in HAWC
  45. Fermi-LAT Gamma-ray Observations of IceCube-200614A and detection of a new gamma-ray source, Fermi J0202.8+3132
  46. GRB 200613A: MITSuME Akeno optical upper limits
  47. IceCube-200615A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  48. IceCube-200614A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  49. GRB 200613A: Continued Xinglong-2.16m optical observations
  50. GRB 200613A: Swift/UVOT Detection
  51. GRB 200613A: Xinglong-2.16m optical observations
  52. GRB 200613A: Liverpool Telescope observations
  53. GRB 200613A: Swift-XRT afterglow detection
  54. GRB 200613A: Swift ToO observations
  55. GRB 200612A: Swift/UVOT Upper Limits
  56. GRB 200612A: Enhanced Swift-XRT position
  57. GRB 200612A: Swift detection of a burst
  58. GRB 200608A: Swift detection of a burst
  59. IPN triangulation of GRB 200605A (short)
  60. GRB 200529A: Swift/UVOT Upper Limits
  61. Fermi-LAT Gamma-ray Observations of IceCube-200530A
  62. GRB 200529A: MITSuME Akeno optical upper limits
  63. IceCube-200530A: No significant detection in HAWC
  64. IceCube-200530A: No ANTARES neutrino counterpart
  65. IceCube-200530A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  66. GRB 200529A: Swift-XRT refined Analysis
  67. GRB 200528A: Assy optical upper limit
  68. GRB 200529A: Enhanced Swift-XRT position
  69. GRB 200529A: KAIT Optical Afterglow Confirmation
  70. GRB 200529A: NOT optical afterglow
  71. GRB 200529A: Swift detection of a burst
  72. GRB 200528A: NOT optical upper limits
  73. GRB 200528A: Swift/UVOT Upper Limits
  74. GRB 200528A: Nanshan/NEXT optical upper limit
  75. GRB 200528A: Enhanced Swift-XRT position
  76. GRB 200528A: MITSuME Akeno optical upper limits
  77. GRB 200528A: Swift detection of a burst
  78. GRB 200524A: Assy optical observations
  79. GRB 200522A: Hubble Space Telescope Near-IR F160W Observations
  80. GRB 200524A: optical upper limits from further MITSuME Akeno observation
  81. GRB 200522A: Gemini North optical imaging
  82. GRB 200524A: Further Liverpool Telescope observations
  83. Fermi-LAT Gamma-ray Observations of IceCube-190523A
  84. GRB 200524A: KAIT Optical Observations
  85. GRB 200524A: MITSuME Akeno optical observation
  86. GRB 200524A: Swift-XRT afterglow detection
  87. GRB 200524A: OAJ multicolor afterglow detection
  88. GRB 200524: Swift/UVOT observations missed the ZTF20abbiixp position
  89. GRB 200524A: CAHA multicolor afterglow detection
  90. GRB 200524A: Correction to the GCN 27800
  91. GRB 200524A: 3.6m DOT observations of the afterglow candidate ZTF20abbiixp
  92. GRB 200524A: GROWTH-India confirmation of optical afterglow
  93. GRB 200524A: Swift ToO observations
  94. GRB 200522A: Swift/UVOT Upper Limits
  95. GRB 200522A: Enhanced Swift-XRT position
  96. GRB 200522A: Swift detection of a short burst
  97. GRB 200519A: Swift/UVOT Detection
  98. GRB 200519A: GROWTH-India optical follow-up
  99. GRB 200519A: Enhanced Swift-XRT position
  100. GRB 200519A: iTelescope optical afterglow detection

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