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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"

11529 results found.

  1. Konus-Wind detection of GRB 210204A / ZTF21aagwbjr
  2. GRB 210204A: Optical Observations from HCT
  3. GRB 210204A / ZTF21aagwbjr: Swift-XRT observations
  4. GRB 210204A: Swift ToO observations
  5. VLT/X-shooter redshift of 1.466 for ZTF21aagwbjr/AT2021buv, strengthening its association with GRB 210204A
  6. GRB 210204A: AstroSat CZTI Detection
  7. IPN triangulation of GRB 210204A
  8. ZTF21aagwbjr/AT2021buv: ZTF discovery of a fast optical transient likely associated with GRB 210104A
  9. Fermi GRB 210204B: Global MASTER-Net observations report
  10. Fermi GRB 210204A: Global MASTER-Net observations report
  11. GRB 210204B: Fermi GBM Final Real-time Localization
  12. GRB 210204: Fermi GBM observation
  13. GRB 210204A: GECAM detection
  14. GRB 210204A: BALROG localization (Fermi Trigger 634112970 / GRB 210204270)
  15. GRB 210204A: Fermi GBM Final Real-time Localization
  16. GRB 210202A: AGILE/MCAL detection
  17. Fermi GBM Observations of a bright burst from SGR J1935+2154
  18. GRB 210202A: Fermi GBM detection
  19. GRB 210202A: Fermi-LAT detection
  20. Fermi GRB 210202A: Global MASTER-Net observations report
  21. Fermi trigger No 633963272: Global MASTER-Net observations report
  22. Recent activity of SGR 1935+2154 as observed by CGBM
  23. GRB 210202A: BALROG localization (Fermi Trigger / GRB 210202841)
  24. GRB 210202A: Fermi GBM Final Real-time Localization
  25. Fermi trigger No 633879387: Global MASTER-Net observations report
  26. Fermi GBM Observations of SGR J1935+2154
  27. GRB 140330A: Swift-XRT refined Analysis
  28. GRB 140402A: Swift-XRT refined Analysis
  29. GRB 140104B: Swift-XRT refined Analysis
  30. GRB 210126A: AstroSat CZTI detection
  31. GRB 210123A: AstroSat CZTI detection
  32. GRB 210127A: Fermi GBM Final Real-time Localization
  33. GRB 210120A: Fermi GBM detection
  34. Fermi trigger No 633348010: Global MASTER-Net observations report
  35. GRB 210126A: GECAM detection
  36. GRB 210126A: BALROG localization (Fermi Trigger / GRB 210126417)
  37. Fermi trigger No 633257525: Global MASTER-Net observations report
  38. GRB 210123A: Fermi GBM Final Localization
  39. GRB 210120A : 1.3m DFOT optical observations
  40. GRB 210120A(MASTER OT J105242.66+152355.0 / AT2021axc): Mondy optical observations
  41. GRB 210120A: MASTER OT (possibly) discovery
  42. GECAM In-Flight Trigger of GRB 210120A
  43. Fermi GRB 210120A: Global MASTER-Net observations report
  44. GRB 210120A: BALROG localization (Fermi Trigger 632819449 / GRB 210120299)
  45. GRB 210120A: Fermi GBM Final Real-time Localization
  46. GECAM detection of a short GRB 210119A or a new SGR candidate Swift J1851.2-6148
  47. GRB 210119A: Insight-HXMT/HE detection
  48. GRB 210119A: Fermi GBM observation
  49. Short Fermi GRB 210119A or new SGR Swift J1851.2-6148: Possible MASTER Short OT detection
  50. Fermi GRB 210119A: Global MASTER-Net observations report
  51. GRB 210119A: Fermi GBM Final Real-time Localization
  52. GRB 200613A: Host galaxy redshift from OSIRIS/GTC
  53. GRB 210104A: Late-time CAHA 2.2m detection
  54. Fermi trigger No 632573937: Global MASTER-Net observations report
  55. GRB 210104A: AstroSat CZTI detection
  56. GRB 210104A: Mondy optical observations, light curve
  57. GRB 210104A: Assy continued optical observations, correction to GCN circ. 29265
  58. GRB 210108A: BALROG localization (Fermi Trigger 631793415 / GRB 210108424)
  59. GRB 210104A: SAO RAS optical observations
  60. GRB 201227A: ASIM observation
  61. GRB210104A: VIRT optical transient detection.
  62. GRB 210104A: SARA-KP 0.9m Optical Afterglow Detection
  63. Fermi trigger No 631602681: Global MASTER-Net observations report
  64. GRB 210104A: CALET Gamma-Ray Burst Monitor detection
  65. Fermi trigger No 631584650: Global MASTER-Net observations report
  66. GRB 210104A: Assy continued optical observations
  67. Fermi GRB 210105A: Global MASTER-Net observations report
  68. GRB 210105A: Fermi GBM Final Real-time Localization
  69. Konus-Wind detection of GRB 210104A
  70. GRB 210104A: 1.3m DFOT Optical Afterglow Detection
  71. GRB 210104A: MASTER OT rebrightening detection
  72. GRB 210104A: Fermi GBM detection
  73. GRB 210104A: MITSuME Ishigaki optical observation
  74. Fermi GRB 210104A: Global MASTER-Net observations report
  75. GRB 210104A: Assy optical observations
  76. GRB 210104A: MITSuME Akeno optical observation
  77. GRB 210104A: BOOTES-4/MET early optical afterglow detection
  78. GRB 210104A: BALROG localization (Fermi Trigger 631452424 / GRB 210104477)
  79. GRB 210104A: Fermi GBM Final Real-time Localization
  80. Fermi GRB 210102C: Global MASTER-Net observations report
  81. GRB 210102C: Fermi GBM detection
  82. Fermi GRB 210101A: Global MASTER-Net observations report
  83. Fermi trigger No 631226368: Global MASTER-Net observations report
  84. Fermi trigger No 631119348: Global MASTER-Net observations report
  85. GRB 210101A: BALROG localization (Fermi Trigger 631205591 / GRB 210101620)
  86. GRB 210101A: Fermi GBM Final Real-time Localization
  87. Fermi trigger No 631113166: Global MASTER-Net observations report
  88. Fermi trigger No 631118376: Global MASTER-Net observations report
  89. Fermi trigger No 631104264: Global MASTER-Net observations report
  90. GRB 201227A: GRAWITA VST-ESO PARANAL observations
  91. GRB 201227A: Fermi GBM observation
  92. Fermi GRB 201229B: Global MASTER-Net observations report
  93. GRB 201229B: BALROG localization (Fermi Trigger 630948017 / GRB 201229639)
  94. GRB 201229B: Fermi GBM Final Real-time Localization
  95. GRB 201020B: Assy, Koshka, Mondy and Maidanak optical observations
  96. Fermi GRB 201228B: Global MASTER-Net observations report
  97. GRB 201228B: Fermi GBM Final Real-time Localization
  98. GRB 201227A: Insight-HXMT/HE detection
  99. GRB 201226A: Insight-HXMT/HE detection
  100. GRB 201228A: Fermi GBM Final Real-time Localization

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