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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"

32501 results found.

  1. GRB 230405B: AstroSat CZTI detection
  2. Swift GRB 230405B: Global MASTER-Net observations report
  3. GRB 230307A: JWST observations consistent with the presence of a kilonova
  4. Fermi GRB 230405A: Global MASTER-Net observations report
  5. GRB 230404A: AstroSat CZTI detection
  6. GRB 230402A: CALET Gamma-Ray Burst Monitor detection
  7. GRB 230402A: AstroSat CZTI detection
  8. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  9. GRB 230328B: Multa observatory optical afterglow observation
  10. GRB 230307A: Chandra late-time detection of the X-ray afterglow
  11. GRB 230228A: detection by GTC of the potential host galaxy
  12. GRB 230328B: Swift/UVOT Detection
  13. GRB 230402A: AGILE detection
  14. Fermi GRB 230402A: Global MASTER-Net observations report
  15. GRB 230328B : GRANDMA/Kilonova-Catcher optical detection
  16. GRB 230328B: CAHA 2.2m/CAFOS detection
  17. GRB 230328B: 3.6m DOT multiband optical observation
  18. Konus-Wind detection of GRB 230328B
  19. GRB 230328B: GRBAlpha detection
  20. GRB 230328B: Swift-BAT refined analysis
  21. GRB 230328B: Nanshan/NEXT 2nd optical observation
  22. GRB 230328B NUTTelA-TAO / BSTI Early Measurements
  23. GRB 230328B: Liverpool Telescope afterglow detection
  24. GRB 230328B: OHP/T120 optical observations
  25. GRB 230328B: GIT optical follow-up
  26. GRB 230328B: OASDG optical observations
  27. GRB 230328B: Nanshan/NEXT optical upper limit
  28. GRB 230328B: Swift-XRT refined Analysis
  29. GRB 230328B: AstroSat CZTI detection
  30. GRB 230328B: Fermi GBM observation
  31. GRB 230328B: Mondy, AbAO and Kitab optical observations
  32. GRB 230328B: Mondy optical afterglow confirmation
  33. Fermi GRB 230328A: Global MASTER-Net observations report
  34. GRB 230325A: Swift-BAT refined analysis
  35. GRB 230325A: Swift/UVOT Upper Limits
  36. GRB 230325A: X-shooter optical afterglow and redshift
  37. GRB 230325A: Swift-XRT refined Analysis
  38. GRB 230322B: Swift-BAT refined analysis
  39. GRB 230320B: Fermi GBM Observation
  40. GRB 230322B: Swift/UVOT Detection
  41. Konus-Wind detection of GRB 230309A
  42. Konus-Wind detection of GRB 230308A
  43. Konus-Wind detection of GRB 230304B
  44. GRB 230322B: Swift-XRT refined Analysis
  45. Swift GRB 230322B: Global MASTER-Net observations report
  46. GRB 230320B: GRBAlpha detection
  47. GRB 230321A: CALET Gamma-Ray Burst Monitor detection
  48. GRB 230320B: CALET Gamma-Ray Burst Monitor detection
  49. GRB 230320B: Swift/BAT-GUANO detection outside the coded FOV
  50. Fermi GRB 230320A: Global MASTER-Net observations report
  51. Fermi GRB 230321A: Global MASTER-Net observations report
  52. SGR 1806-20: Correction to GCN 33494
  53. GRB 230314A: TURBO Optical Upper Limit
  54. GRB 230307A: Continued Gemini-South observations confirm rapid optical fading
  55. IPN triangulation of GRB 230309A
  56. Fermi GRB 230316A: Global MASTER-Net observations report
  57. IPN triangulation of GRB 230304B
  58. GRB 230313A: AstroSat CZTI detection
  59. GRB 230307A: Far off-axis NuSTAR detection of the GRB
  60. IPN triangulation of GRB 230308A (short/bright)
  61. Fermi GRB 230314A: Global MASTER-Net observations report
  62. GRB 230307A: ATCA radio detection
  63. VZLUSAT-2 detection of SGR 1806-20
  64. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  65. GRB 230307A: Swift/UVOT detection
  66. Fermi GRB 230313A: Global MASTER-Net observations report
  67. GRB 230307A: soft X-ray detection with LEIA
  68. GRB 230307A: Swift-XRT afterglow detection
  69. Further improved IPN localization for GRB 230307A
  70. GRB 230307A: SOAR/Goodman detection of the possible host galaxy
  71. TESS Detection of the Optical Afterglow of GRB230307A
  72. GRB 230308A: CALET Gamma-Ray Burst Monitor detection
  73. GRB 230310A: AstroSat CZTI detection
  74. GRB 230307A: GECKO optical observations and detections of the afterglow
  75. GRB 230307A: MAXI/GSC upper limit
  76. GRB 230307A: Gemini-South Confirmation of the Optical Afterglow
  77. Fermi GRB 230310A: Global MASTER-Net observations report
  78. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  79. GRB 230307A: Erratum of the GCN 33441
  80. GRB 230204B: MASTER detection of an object near NTT Optical Afterglow Candidate
  81. GRB 230308A: Fermi GBM detection
  82. GRB 230307A: Possible optical afterglow
  83. GRB 230228A: NUTTelA-TAO / BSTI Optical Limits
  84. GRB 230308A: AGILE/MCAL detection
  85. GRB 230217A: ATCA rapid-response radio detection
  86. GRB 230307A: Swift/BAT upper limits on the early afterglow
  87. GRB 230307A: Upper limits from a neutrino search with IceCube
  88. GRB 230307A: Swift-XRT observations
  89. Fermi GRB 230307A: Global MASTER-Net observations report
  90. Konus-Wind detection of GRB 230307A
  91. GRB 230228A: VIRT Optical Upper Limit
  92. GRB 230307A: VZLUSAT-2 detection
  93. GRB 230304B: CALET Gamma-Ray Burst Monitor detection
  94. Fermi GRB 230308A: Global MASTER-Net observations report
  95. GRB 230307A: Tiled Swift observations
  96. GRB 230307A: Detection by GRBAlpha
  97. GRB 230307A: BALROG localization (Fermi Trigger 699896651/ GRB 230307656)
  98. GRB 230307A: AstroSat CZTI detection
  99. GRB 230307A: possibly the second highest GRB energy fluence ever identified
  100. IPN triangulation of GRB 230307A (long/very bright)

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