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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"

35442 results found.

  1. GRB 241213A: Swift-BAT refined analysis
  2. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  3. Konus-Wind detection of GRB 241213A (EP 241213a)
  4. GRB 241215A: Mondy AZT-33IK optical observations
  5. GRB 241212A: Swift-XRT observations
  6. GRB 241214A: SVOM/GRM observation
  7. GRB 241215A: Nanshan/HMT optical upper limit
  8. GRB 241215A: Montarrenti Observatory optical upper limit
  9. GRB 241215A: GROWTH-India telescope optical upper limit
  10. GRB 241215A: A long GRB detected by INTEGRAL
  11. GRB 241213B: Swift-XRT observations
  12. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  13. GRB 241209B: SVOM/VT optical continuous fading
  14. GRB 241213A: SVOM/VT optical candidate
  15. GRB 241213B: Tiled Swift observations
  16. GRB 241213A: Swift/UVOT Upper Limits
  17. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  18. GRB 241213A: Swift-XRT refined Analysis
  19. GRB 241212A: Fermi GBM detection
  20. GRB 241212A: Swift ToO observations
  21. GRB 241213A: LCOGT Optical Upper Limits
  22. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
  23. GRB 241213B: MAXI/GSC detection
  24. GRB 241213A: REM optical/NIR upper limits
  25. GRB 241213A: Enhanced Swift-XRT position
  26. GRB241212A: OHP/T193 optical observations
  27. GRB 241213A: SAO RAS optical upper limit
  28. Swift GRB 241213A: Global MASTER-Net observations report
  29. GRB 241213A: Swift detection of a burst
  30. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  31. GRB 241212A : SVOM/VT bright optical afterglow
  32. GRB 241212A: AstroSat CZTI detection
  33. GRB 241209B: GRANDMA/TRT upper limit
  34. GRB 241207A: TSHAO Zeiss-1000 optical observations
  35. GRB 241212A: SVOM detection of a bright long burst
  36. GRB 241212A: Fermi GBM Final Real-time Localization
  37. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  38. GRB 241209A: Chandra X-ray Detection
  39. Konus-Wind detection of GRB 241209B
  40. GRB 241207A: EIRSAT-1 GMOD Detection
  41. GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
  42. GRB 241209B: GRBAlpha detection
  43. GRB 241206C: GRBAlpha detection
  44. GRB 241211A: Fermi GBM Final Real-time Localization
  45. GRB 241129A: Fermi GBM Observation
  46. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  47. GRB 241209D: REM optical/NIR upper limits
  48. Konus-Wind detection of GRB 241209D
  49. GRB 241209B: Swift-XRT afterglow detection
  50. GRB 241209C: Fermi GBM Observation
  51. GRB 241209A: Swift-XRT refined Analysis
  52. Fermi Gamma-ray Burst Monitor trigger 755485387 / 241210044 is not a GRB
  53. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  54. GRB 241209D: AstroSat CZTI detection
  55. GRB 241209A: EP-FXT follow-up observations
  56. GRB 241209B: SVOM/VT afterglow detection
  57. GRB 241207B: Fermi GBM Observation
  58. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  59. GRB 241209D: Swift-XRT refined Analysis
  60. GRB 241209D: Fermi GBM Observation
  61. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  62. GRB 241209D: COLIBRÍ detection of the afterglow
  63. GRB 241209A: COLIBRÍ Optical Upper Limit
  64. Fermi GRB 241209D: Global MASTER-Net observations report
  65. GRB 241209A: Fermi GBM Observation
  66. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  67. GRB 241209A: GRANDMA/TAROT upper limit
  68. GRB 241209B: BOOTES-5 optical upper limit
  69. Swift GRB 241209D: Global MASTER-Net observations report
  70. Fermi GRB 241209C: Global MASTER-Net observations report
  71. Fermi GRB 241209E: Global MASTER-Net observations report
  72. GRB 241209E: Fermi GBM Final Real-time Localization
  73. GRB 241209B: Swift ToO observations
  74. GRB 241209A: REM optical/NIR observations
  75. GRB 241209D: Enhanced Swift-XRT position
  76. GRB 241209C: AstroSat CZTI detection
  77. GRB 241209D: Swift detection of a burst
  78. GRB 241209D: Fermi GBM Final Real-time Localization
  79. GRB 241209A: VLT/X-shooter spectroscopy
  80. GRB 241209A: Enhanced Swift-XRT position
  81. GRB 241114B: cubesat Avion detection
  82. GRB 241209A: VLT optical observations
  83. Fermi GRB 241209A: Global MASTER-Net observations report
  84. GRB 241209C: Fermi GBM Final Real-time Localization
  85. GRB 241209A: GOTO optical upper limits
  86. GRB 241209A: Prompt enhanced Swift-XRT position
  87. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  88. GRB 241209A: Swift detection of a short burst
  89. GRB 241209A: Fermi GBM Final Real-time Localization
  90. Fermi GRB 241207B: Global MASTER-Net observations report
  91. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  92. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  93. GRB 241201A: AstroSat CZTI detection
  94. GRB 241206A: DDOTI Upper Limit on the Afterglow
  95. GRB 241207C: MASTER optical observations
  96. GRB 241207C: Tiled Swift observations
  97. GRB 241207C: MAXI/GSC detection
  98. GRB 241207B: Fermi GBM Final Real-time Localization
  99. Fermi GRB 241207A: Global MASTER-Net observations report
  100. GRB 241206A: Fermi GBM observation

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