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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"

3387 results found.

  1. Fermi trigger No 637027080: Global MASTER-Net observations report
  2. GRB 210308A: Swift/UVOT Detection
  3. GRB 210308A: Swift detection of a burst with an optical counterpart
  4. GRB 210307A: LCO Optical Upper Limits
  5. Fermi trigger No 636459103: Global MASTER-Net observations report
  6. Fermi trigger No 636187116: Global MASTER-Net observations report
  7. Fermi trigger No 636168178: Global MASTER-Net observations report
  8. GRB 210217A: Liverpool Telescope First Hour Observations
  9. GRB 210204A (ZTF21aagwbjr/AT2021buv): continued CrAO and AbAO optical observations
  10. Fermi GRB 210207A: Global MASTER-Net observations report
  11. VLT/X-shooter redshift of 1.466 for ZTF21aagwbjr/AT2021buv, strengthening its association with GRB 210204A
  12. Recent activity of SGR 1935+2154 as observed by CGBM
  13. Konus-Wind detection of two bright bursts from SGR 1935+2154
  14. Fermi GRB 210120A: Global MASTER-Net observations report
  15. Konus-Wind detection of GRB 210112A
  16. GRB 201227A: ASIM observation
  17. GW170817: HST observations at 3.4 years from merger
  18. GRB 210104A: early ATLAS detections of the bright afterglow
  19. GRB 210104A: 1.3m DFOT Optical Afterglow Detection
  20. GRB 210104A: MITSuME Akeno optical observation
  21. GRB 210104A: GWAC-F60A optical afterglow observations
  22. GRB 210104A: Swift detection of a burst with a bright optical counterpart
  23. Fermi GRB 210102C: Global MASTER-Net observations report
  24. MAXI GRB210102.38: Global MASTER-Net observations report
  25. Fermi trigger No 631119348: Global MASTER-Net observations report
  26. Fermi trigger No 631113166: Global MASTER-Net observations report
  27. Fermi trigger No 631118376: Global MASTER-Net observations report
  28. GRB 201216C: TSHAO, Terskol, Mondy optical upper limits
  29. GRB 201227A: Chilescope optical observations, possible optical counterpart
  30. GRB 201227A: GRAWITA VST-ESO PARANAL observations
  31. GRB 201227A: Swift-XRT observations
  32. Konus-Wind observation of GRB 201227A
  33. Baksan Neutrino Observatory Alert 201228.36: Global MASTER-Net observations report
  34. Fermi GRB 201228B: Global MASTER-Net observations report
  35. GRB 201228B: Fermi GBM Final Real-time Localization
  36. GRB 201228A: Fermi GBM Final Real-time Localization
  37. Fermi trigger No 630389391: Global MASTER-Net observations report
  38. Fermi GRB 201222B: Global MASTER-Net observations report
  39. GRB 201221D: Lowell Discovery Telescope afterglow observations
  40. GRB 201221E: Fermi GBM Final Real-time Localization
  41. Fermi GBM Sub-Threshold Detection of GRB 201221A
  42. Konus-Wind detection of GRB 201216C
  43. Baksan Neutrino Observatory Alert 201216.94: Global MASTER-Net observations report
  44. Fermi GRB 201216A: Global MASTER-Net observations report
  45. GRB 201215A: BALROG localization (Fermi Trigger 629706213 / GRB 201215266)
  46. GRB 201215A: Fermi GBM Final Real-time Localization
  47. Integral GRB201214.26: Global MASTER-Net observations report
  48. GRB 201208A: LCO observations
  49. GRB201130A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 628407054)
  50. GRB 201128B: Swift/BAT-GUANO detection and arcminute localization
  51. IceCube Alert 201130.85: Global MASTER-Net observations report
  52. GRB 201130A: DDOTI Observations
  53. Fermi trigger No 628278856: Global MASTER-Net observations report
  54. GRB 201128A: DDOTI Observations
  55. GRB 200826A: TNG and LBT constraints on a supernova bump
  56. Fermi GRB 201121A: Global MASTER-Net observations report
  57. Fermi GRB 201120B: Global MASTER-Net observations report
  58. INTEGRAL Weak#8825: AROMA-N Optical Observation
  59. Konus-Wind detection of GRB 201116A
  60. Fermi trigger No 627198169: Global MASTER-Net observations report
  61. GRB 201114A: AstroSat CZTI detection
  62. GRB 201108A: Fermi GBM Final Real-time Localization
  63. ZTF20acozryr/AT2020yxz (GRB 201103B): Assy optical observations
  64. GRB 201104B: Kitab optical observations
  65. GRB 201103B (ZTF20acozryr/AT2020yxz): Nanshan/NEXT-0.6m optical observations
  66. ZTF20acozryr/AT2020yxz: Zwicky Transient Facility discovery of a fast optical transient with no associated GRB
  67. GRB 201029A: Swift-BAT refined analysis
  68. GRB 201024A: Redshift from GTC/OSIRIS
  69. Swift GRB201024.12: Global MASTER-Net observations report
  70. GRB 201020B: Nanshan/NEXT optical afterglow confirmation
  71. GRB 201020A: DOAO optical afterglow observations
  72. GRB 201020A: MITSuME Akeno optical observation
  73. IceCube-201014A: No significant detection in HAWC
  74. Fermi GRB 201016B: Global MASTER-Net observations report
  75. Fermi GRB 201007A: Global MASTER-Net observations report
  76. Baksan Neutrino Observatory Alert 201006.88: Global MASTER-Net observations report
  77. Fermi trigger No 623470566: Global MASTER-Net observations report
  78. Fermi trigger No 623493962: Global MASTER-Net observations report
  79. IceCube-200926A: JCMT/SCUBA2 observations
  80. IceCube-200929A: Upper limits from a search for additional neutrino events in IceCube
  81. GRB 200928B: AstroSat CZTI detection
  82. GRB 200928B: BALROG localization (Fermi Trigger 622991684 / GRB 200928552)
  83. GRB 200928B: Fermi GBM Final Real-time Localization
  84. GRB 200928A: Fermi GBM Final Localization
  85. Fermi GRB 200925A: Global MASTER-Net observations report
  86. Fermi GRB 200924A: Global MASTER-Net observations report
  87. GRB 200924B: Fermi GBM Final Localization
  88. Fermi trigger No 622618714: Global MASTER-Net observations report
  89. Fermi GRB 200923A: Global MASTER-Net observations report
  90. Fermi GRB 200922B: Global MASTER-Net observations report
  91. Fermi-GBM Sub-Threshold Detection of GRB 200917A
  92. GRB 200917A: Swift detection of a burst
  93. GRB 200916A: Fermi GBM Final Real-time Localization
  94. Fermi GRB 200914A: Global MASTER-Net observations report
  95. IceCube Alert 200914.00: Global MASTER-Net observations report
  96. Swift GRB200909.97: Global MASTER-Net observations report
  97. Fermi GRB 200907C: Global MASTER-Net observations report
  98. GRB 200907C: Fermi GBM Final Real-time Localization
  99. Fermi GRB 200906A: Global MASTER-Net observations report
  100. IPN triangulation of GRB 200903E

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