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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"

39152 results found.

  1. GRB 241213A: Swift/UVOT Upper Limits
  2. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  3. GRB 241213A: Swift-XRT refined Analysis
  4. GRB 241212A: Fermi GBM detection
  5. GRB 241212A: Swift ToO observations
  6. GRB 241213A: LCOGT Optical Upper Limits
  7. EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
  8. GRB 241213B: MAXI/GSC detection
  9. GRB 241213A: REM optical/NIR upper limits
  10. GRB 241213A: Enhanced Swift-XRT position
  11. GRB241212A: OHP/T193 optical observations
  12. GRB 241213A: SAO RAS optical upper limit
  13. Swift GRB 241213A: Global MASTER-Net observations report
  14. GRB 241213A: Swift detection of a burst
  15. GRB 241212A : SVOM/C-GFT optical upper limit at early phase
  16. GRB 241212A : SVOM/VT bright optical afterglow
  17. GRB 241212A: AstroSat CZTI detection
  18. GRB 241209B: GRANDMA/TRT upper limit
  19. GRB 241207A: TSHAO Zeiss-1000 optical observations
  20. GRB 241212A: SVOM detection of a bright long burst
  21. GRB 241212A: Fermi GBM Final Real-time Localization
  22. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  23. GRB 241209A: Chandra X-ray Detection
  24. Konus-Wind detection of GRB 241209B
  25. GRB 241207A: EIRSAT-1 GMOD Detection
  26. GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
  27. GRB 241209B: GRBAlpha detection
  28. GRB 241206C: GRBAlpha detection
  29. GRB 241211A: Fermi GBM Final Real-time Localization
  30. GRB 241129A: Fermi GBM Observation
  31. GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
  32. GRB 241209D: REM optical/NIR upper limits
  33. Konus-Wind detection of GRB 241209D
  34. GRB 241209B: Swift-XRT afterglow detection
  35. GRB 241209C: Fermi GBM Observation
  36. GRB 241209A: Swift-XRT refined Analysis
  37. Fermi Gamma-ray Burst Monitor trigger 755485387 / 241210044 is not a GRB
  38. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  39. GRB 241209D: AstroSat CZTI detection
  40. GRB 241209A: EP-FXT follow-up observations
  41. GRB 241209B: SVOM/VT afterglow detection
  42. EP241208a: Global MASTER-Net observations report
  43. EP241208a: EP-FXT follow-up observations
  44. Fermi trigger No 755485387: Global MASTER-Net observations report
  45. GRB 241207B: Fermi GBM Observation
  46. GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
  47. GRB 241209D: Swift-XRT refined Analysis
  48. GRB 241209D: Fermi GBM Observation
  49. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  50. GRB 241209D: COLIBRÍ detection of the afterglow
  51. GRB 241209A: COLIBRÍ Optical Upper Limit
  52. Fermi GRB 241209D: Global MASTER-Net observations report
  53. GRB 241209A: Fermi GBM Observation
  54. GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
  55. GRB 241209A: GRANDMA/TAROT upper limit
  56. GRB 241209B: BOOTES-5 optical upper limit
  57. Swift GRB 241209D: Global MASTER-Net observations report
  58. Fermi GRB 241209C: Global MASTER-Net observations report
  59. Fermi GRB 241209E: Global MASTER-Net observations report
  60. GRB 241209E: Fermi GBM Final Real-time Localization
  61. GRB 241209B: Swift ToO observations
  62. LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
  63. GRB 241209A: REM optical/NIR observations
  64. GRB 241209D: Enhanced Swift-XRT position
  65. GRB 241209C: AstroSat CZTI detection
  66. GRB 241209D: Swift detection of a burst
  67. GRB 241209D: Fermi GBM Final Real-time Localization
  68. GRB 241209A: VLT/X-shooter spectroscopy
  69. GRB 241209A: Enhanced Swift-XRT position
  70. GRB 241114B: cubesat Avion detection
  71. GRB 241209A: VLT optical observations
  72. Fermi GRB 241209A: Global MASTER-Net observations report
  73. GRB 241209C: Fermi GBM Final Real-time Localization
  74. GRB 241209A: GOTO optical upper limits
  75. GRB 241209A: Prompt enhanced Swift-XRT position
  76. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  77. GRB 241209A: Swift detection of a short burst
  78. Swift GRB241209.23: Global MASTER-Net observations report
  79. GRB 241209A: Fermi GBM Final Real-time Localization
  80. Fermi GRB 241207B: Global MASTER-Net observations report
  81. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  82. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  83. GRB 241201A: AstroSat CZTI detection
  84. GRB 241206A: DDOTI Upper Limit on the Afterglow
  85. GRB 241207C: MASTER optical observations
  86. Fermi trigger No 755225799: Global MASTER-Net observations report
  87. GRB 241207C: Tiled Swift observations
  88. GRB 241207C: MAXI/GSC detection
  89. GRB 241207B: Fermi GBM Final Real-time Localization
  90. Fermi trigger No 755277791: Global MASTER-Net observations report
  91. Fermi GRB 241207A: Global MASTER-Net observations report
  92. EP241206a: Global MASTER-Net observations report
  93. GRB 241206A: Fermi GBM observation
  94. GRB 241206C: SVOM/GRM observation of a likely short burst
  95. GRB 241207A: Fermi GBM Final Real-time Localization
  96. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  97. GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
  98. GRB 241206B: GWAC-F50A optical upper limit
  99. GRB 241206B: SVOM/ECLAIRs detection of a long soft transient
  100. Fermi GRB 241206A: Global MASTER-Net observations report

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