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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"

39059 results found.

  1. GRB 241215A: A long GRB detected by INTEGRAL
  2. Integral GRB241215.58: Global MASTER-Net observations report
  3. GRB 241213B: Swift-XRT observations
  4. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  5. GRB 241209B: SVOM/VT optical continuous fading
  6. GRB 241213A: SVOM/VT optical candidate
  7. GRB 241213B: Tiled Swift observations
  8. GRB 241213A: Swift/UVOT Upper Limits
  9. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  10. GRB 241213A: Swift-XRT refined Analysis
  11. GRB 241212A: Fermi GBM detection
  12. GRB 241212A: Swift ToO observations
  13. GRB 241213A: LCOGT Optical Upper Limits
  14. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
  15. GRB 241213B: MAXI/GSC detection
  16. GRB 241213A: REM optical/NIR upper limits
  17. GRB 241213A: Enhanced Swift-XRT position
  18. GRB241212A: OHP/T193 optical observations
  19. GRB 241213A: SAO RAS optical upper limit
  20. Swift GRB 241213A: Global MASTER-Net observations report
  21. GRB 241213A: Swift detection of a burst
  22. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  23. GRB 241212A : SVOM/VT bright optical afterglow
  24. GRB 241212A: AstroSat CZTI detection
  25. GRB 241209B: GRANDMA/TRT upper limit
  26. GRB 241207A: TSHAO Zeiss-1000 optical observations
  27. GRB 241212A: SVOM detection of a bright long burst
  28. GRB 241212A: Fermi GBM Final Real-time Localization
  29. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  30. GRB 241209A: Chandra X-ray Detection
  31. Konus-Wind detection of GRB 241209B
  32. GRB 241207A: EIRSAT-1 GMOD Detection
  33. GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
  34. GRB 241209B: GRBAlpha detection
  35. GRB 241206C: GRBAlpha detection
  36. GRB 241211A: Fermi GBM Final Real-time Localization
  37. GRB 241129A: Fermi GBM Observation
  38. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  39. GRB 241209D: REM optical/NIR upper limits
  40. Konus-Wind detection of GRB 241209D
  41. GRB 241209B: Swift-XRT afterglow detection
  42. GRB 241209C: Fermi GBM Observation
  43. GRB 241209A: Swift-XRT refined Analysis
  44. Fermi Gamma-ray Burst Monitor trigger 755485387 / 241210044 is not a GRB
  45. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  46. GRB 241209D: AstroSat CZTI detection
  47. GRB 241209A: EP-FXT follow-up observations
  48. GRB 241209B: SVOM/VT afterglow detection
  49. EP241208a: Global MASTER-Net observations report
  50. EP241208a: EP-FXT follow-up observations
  51. Fermi trigger No 755485387: Global MASTER-Net observations report
  52. GRB 241207B: Fermi GBM Observation
  53. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  54. GRB 241209D: Swift-XRT refined Analysis
  55. GRB 241209D: Fermi GBM Observation
  56. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  57. GRB 241209D: COLIBRÍ detection of the afterglow
  58. GRB 241209A: COLIBRÍ Optical Upper Limit
  59. Fermi GRB 241209D: Global MASTER-Net observations report
  60. GRB 241209A: Fermi GBM Observation
  61. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  62. GRB 241209A: GRANDMA/TAROT upper limit
  63. GRB 241209B: BOOTES-5 optical upper limit
  64. Swift GRB 241209D: Global MASTER-Net observations report
  65. Fermi GRB 241209C: Global MASTER-Net observations report
  66. Fermi GRB 241209E: Global MASTER-Net observations report
  67. GRB 241209E: Fermi GBM Final Real-time Localization
  68. GRB 241209B: Swift ToO observations
  69. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  70. GRB 241209A: REM optical/NIR observations
  71. GRB 241209D: Enhanced Swift-XRT position
  72. GRB 241209C: AstroSat CZTI detection
  73. GRB 241209D: Swift detection of a burst
  74. GRB 241209D: Fermi GBM Final Real-time Localization
  75. GRB 241209A: VLT/X-shooter spectroscopy
  76. GRB 241209A: Enhanced Swift-XRT position
  77. GRB 241114B: cubesat Avion detection
  78. GRB 241209A: VLT optical observations
  79. Fermi GRB 241209A: Global MASTER-Net observations report
  80. GRB 241209C: Fermi GBM Final Real-time Localization
  81. GRB 241209A: GOTO optical upper limits
  82. GRB 241209A: Prompt enhanced Swift-XRT position
  83. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  84. GRB 241209A: Swift detection of a short burst
  85. Swift GRB241209.23: Global MASTER-Net observations report
  86. GRB 241209A: Fermi GBM Final Real-time Localization
  87. Fermi GRB 241207B: Global MASTER-Net observations report
  88. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  89. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  90. GRB 241201A: AstroSat CZTI detection
  91. GRB 241206A: DDOTI Upper Limit on the Afterglow
  92. GRB 241207C: MASTER optical observations
  93. Fermi trigger No 755225799: Global MASTER-Net observations report
  94. GRB 241207C: Tiled Swift observations
  95. GRB 241207C: MAXI/GSC detection
  96. GRB 241207B: Fermi GBM Final Real-time Localization
  97. Fermi trigger No 755277791: Global MASTER-Net observations report
  98. Fermi GRB 241207A: Global MASTER-Net observations report
  99. EP241206a: Global MASTER-Net observations report
  100. GRB 241206A: Fermi GBM observation

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