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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"

35325 results found.

  1. GRB 241228A: Swift-BAT refined analysis
  2. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  3. GRB 241229B: Swift detection of a burst
  4. GRB 241229B: Fermi GBM Final Real-time Localization
  5. GRB 241229A: SVOM detection of a long burst
  6. Fermi GRB 241228B: Global MASTER-Net observations report
  7. GRB 241228A: Fermi GBM Observation
  8. GRB241228B: GROWTH-India Telescope optical observations
  9. Swift GRB 241228A: Global MASTER-Net observations report
  10. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  11. GRB 241228B: GOTO24jmz optical follow-up observations
  12. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  13. GRB 241228A: GROWTH-India telescope optical upper limit
  14. GRB 241228B: Swift ToO observations
  15. GRB 241228B: TRT optical counterpart confirmation
  16. GRB 241228A: Swift-XRT refined Analysis
  17. GRB 241228A: Swift/UVOT Upper Limits
  18. GRB 241228B: GOTO possible optical counterpart candidate
  19. GRB 241228A: Enhanced Swift-XRT position
  20. GRB 241228B: Fermi GBM Final Real-time Localization
  21. GRB 241228A: Swift detection of a burst
  22. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  23. GRB 241223A: GRBAlpha detection
  24. GRB 241212A: VZLUSAT-2 detection
  25. GRB 241217A/EP241217b: continued SOAR observations
  26. Fermi GRB 241226A: Global MASTER-Net observations report
  27. GRB 241226A: Fermi GBM Final Real-time Localization
  28. EP241223a: Mondy AZT-33IK optical observations
  29. GRB 241029A: LCO optical observation
  30. GRB 241223A: Swift-XRT observations
  31. GRB 241029A: AbAO AS-32 optical observations
  32. GRB 241223A: Fermi GBM Detection
  33. GRB 241219A: SVOM/GRM observation
  34. GRB241113A: 7DT Optical upper limits
  35. Fermi Gamma-ray Burst Monitor trigger 756678579 / 241223854 is not a GRB
  36. Fermi GRB 241223A: Global MASTER-Net observations report
  37. GRB 241223A: GOTO optical observations summary
  38. GRB 241105A: JWST photometric observations of the host galaxy
  39. GRB 241223A: Swift ToO observations
  40. GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
  41. GRB 241223A: Fermi GBM Final Real-time Localization
  42. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  43. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  44. Fermi Gamma-ray Burst Monitor trigger 756447119/241221175 is not a GRB
  45. Fermi GRB 241221A: Global MASTER-Net observations report
  46. GRB 241221A: Fermi GBM Final Real-time Localization
  47. GRB 241217A/EP241217b: SOAR afterglow detection
  48. GRB 241218A: Mondy AZT-33IK optical upper limit
  49. EP241217a : Leavitt Observatory optical upper limit
  50. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  51. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  52. GRB 241218A: Swift/UVOT Upper Limits
  53. GRB 241209B: EP-FXT afterglow detection
  54. Konus-Wind detection of GRB 241204A (short/hard)
  55. GRB 241218A: NOT optical upper limits
  56. GRB 241218A: Swift-BAT refined analysis
  57. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  58. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  59. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  60. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  61. GRB 241217A / EP241217b: NOT optical upper limits
  62. GRB 241218A: REM optical upper limit
  63. GRB 241217A/EP241217b: REM optical/NIR upper limits
  64. GRB 241218a: Liverpool Telescope optical follow-up
  65. GRB 241217a: Liverpool Telescope optical follow-up
  66. GRB 241218A: Swift-XRT refined Analysis
  67. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  68. GRB 241209A: ATCA radio follow-up observations
  69. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  70. GRB 241218A: LCOGT Optical Upper Limit
  71. GRB 241218A: Enhanced Swift-XRT position
  72. GRB 241217A: GMG Optical Upper Limit
  73. GRB 241218A: Swift detection of a burst
  74. GRB 241217A : SVOM/VT optical afterglow detection
  75. GRB 241217A: Swift-XRT afterglow detection
  76. GRB 241217A: LCO optical upper limit
  77. GRB 241217A: GRANDMA/TAROT optical upperlimits
  78. EP241217A: Non-detection from Fermi-GBM Observations
  79. GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
  80. GRB 241214A: GRBAlpha detection
  81. GRB 241213A (EP241213a): GRBAlpha detection
  82. GRB 241209D: GRBAlpha detection
  83. GRB 241213A: Swift-BAT refined analysis
  84. GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
  85. Konus-Wind detection of GRB 241213A (EP 241213a)
  86. GRB 241215A: Mondy AZT-33IK optical observations
  87. GRB 241212A: Swift-XRT observations
  88. GRB 241214A: SVOM/GRM observation
  89. GRB 241215A: Nanshan/HMT optical upper limit
  90. GRB 241215A: Montarrenti Observatory optical upper limit
  91. GRB 241215A: GROWTH-India telescope optical upper limit
  92. GRB 241215A: A long GRB detected by INTEGRAL
  93. GRB 241213B: Swift-XRT observations
  94. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  95. GRB 241209B: SVOM/VT optical continuous fading
  96. GRB 241213A: SVOM/VT optical candidate
  97. GRB 241213B: Tiled Swift observations
  98. GRB 241213A: Swift/UVOT Upper Limits
  99. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  100. GRB 241213A: Swift-XRT refined Analysis

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