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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

37714 results found.

  1. GRB 241229B: SVOM/GRM observation
  2. GRB 241229B: SAO RAS optical upper limit
  3. GRB 241228B: SAO RAS optical observations
  4. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  5. GRB 241229A: SAO RAS optical observations
  6. GRB 241229B: SVOM/VT optical candidate
  7. GRB 241229A: Swift-XRT observations
  8. Konus-Wind detection of GRB 241228A
  9. GRB 241229A: EP-FXT afterglow candidates
  10. GRB 240606B: 7DT Optical upper limits
  11. Fermi trigger No 757231333: Global MASTER-Net observations report
  12. GRB 241229B: Swift-BAT refined analysis
  13. Fermi Gamma-ray Burst Monitor trigger 757207662/241229978 (GRB 241229C) is not a GRB
  14. GRB241229B: UVOT upper limits
  15. GRB 241229C: Fermi GBM Final Real-time Localization
  16. GRB 241228B: D50 optical detection
  17. GRB 241228B: Fermi GBM Observation
  18. GRB 241228B: Swift-XRT afterglow detection
  19. GRB 241229B: Fermi GBM Observation
  20. GRB 241229A: Swift ToO observations
  21. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  22. GRB 241228A: Mondy optical afterglow observations
  23. GRB 241229B: Swift-XRT refined Analysis
  24. Swift GRB 241229B: Global MASTER-Net observations report
  25. GRB 241229A: GOTO optical upper limits
  26. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  27. GRB 241228A: NOT optical upper limits
  28. GRB 241228B: LCO optical observation
  29. GRB 241228A: Swift-BAT refined analysis
  30. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  31. GRB 241229B: Swift detection of a burst
  32. GRB 241229B: Fermi GBM Final Real-time Localization
  33. GRB 241229A: SVOM detection of a long burst
  34. Fermi GRB 241228B: Global MASTER-Net observations report
  35. GRB 241228A: Fermi GBM Observation
  36. GRB241228B: GROWTH-India Telescope optical observations
  37. Swift GRB 241228A: Global MASTER-Net observations report
  38. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  39. GRB 241228B: GOTO24jmz optical follow-up observations
  40. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  41. GRB 241228A: GROWTH-India telescope optical upper limit
  42. GRB 241228B: Swift ToO observations
  43. GRB 241228B: TRT optical counterpart confirmation
  44. GRB 241228A: Swift-XRT refined Analysis
  45. GRB 241228A: Swift/UVOT Upper Limits
  46. GRB 241228B: GOTO possible optical counterpart candidate
  47. GRB 241228A: Enhanced Swift-XRT position
  48. GRB 241228B: Fermi GBM Final Real-time Localization
  49. GRB 241228A: Swift detection of a burst
  50. GRB 241223A: GRBAlpha detection
  51. GRB 241212A: VZLUSAT-2 detection
  52. GRB 241217A/EP241217b: continued SOAR observations
  53. Fermi GRB 241226A: Global MASTER-Net observations report
  54. GRB 241226A: Fermi GBM Final Real-time Localization
  55. EP241223a: Mondy AZT-33IK optical observations
  56. GRB 241029A: LCO optical observation
  57. GRB 241223A: Swift-XRT observations
  58. GRB 241029A: AbAO AS-32 optical observations
  59. GRB 241223A: Fermi GBM Detection
  60. Fermi trigger No 756678579: Global MASTER-Net observations report
  61. IceCube-241224A - IceCube observation of a high-energy neutrino candidate track-like event
  62. GRB 241219A: SVOM/GRM observation
  63. GRB241113A: 7DT Optical upper limits
  64. Fermi Gamma-ray Burst Monitor trigger 756678579 / 241223854 is not a GRB
  65. Fermi GRB 241223A: Global MASTER-Net observations report
  66. GRB 241223A: GOTO optical observations summary
  67. GRB 241105A: JWST photometric observations of the host galaxy
  68. GRB 241223A: Swift ToO observations
  69. GRB 241223A: BALROG localization (Fermi Trigger 756648531 / GRB 241223506)
  70. GRB 241223A: Fermi GBM Final Real-time Localization
  71. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  72. Fermi trigger No 756447119: Global MASTER-Net observations report
  73. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  74. Fermi Gamma-ray Burst Monitor trigger 756447119/241221175 is not a GRB
  75. Fermi GRB 241221A: Global MASTER-Net observations report
  76. GRB 241221A: Fermi GBM Final Real-time Localization
  77. GRB 241217A/EP241217b: SOAR afterglow detection
  78. GRB 241218A: Mondy AZT-33IK optical upper limit
  79. EP241217a : Leavitt Observatory optical upper limit
  80. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  81. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  82. GRB 241218A: Swift/UVOT Upper Limits
  83. GRB 241209B: EP-FXT afterglow detection
  84. Konus-Wind detection of GRB 241204A (short/hard)
  85. GRB 241218A: NOT optical upper limits
  86. GRB 241218A: Swift-BAT refined analysis
  87. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  88. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  89. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  90. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  91. GRB 241217A / EP241217b: NOT optical upper limits
  92. GRB 241218A: REM optical upper limit
  93. GRB 241217A/EP241217b: REM optical/NIR upper limits
  94. GRB 241218a: Liverpool Telescope optical follow-up
  95. GRB 241217a: Liverpool Telescope optical follow-up
  96. GRB 241218A: Swift-XRT refined Analysis
  97. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  98. GRB 241209A: ATCA radio follow-up observations
  99. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  100. GRB 241218A: LCOGT Optical Upper Limit

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