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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"

36262 results found.

  1. GRB 250103A: SVOM/VT optical counterpart confirmation
  2. GRB 250103A: Swift ToO observations
  3. GRB 250101a: Liverpool Telescope optical follow-up
  4. GRB 250103B: SVOM detection of a long burst
  5. GRB 250103B: Swift detection of a burst
  6. GRB 250103A: Xinglong 2.16m Optical Candidate
  7. Fermi GRB 250102A: Global MASTER-Net observations report
  8. GRB 250101B: SVOM/GRM observation
  9. GRB 250103A: GOTO optical upper limit
  10. GRB 250103A: SVOM/C-GFT optical upper limit
  11. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  12. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  13. GRB 250103A: SVOM detection of a long burst
  14. GRB 250102A: Fermi GBM Final Real-time Localization
  15. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO
  16. GRB 250101A: Swift-BAT refined analysis
  17. GRB 250101A: further SAO RAS optical observations
  18. GRB 250101A: LCO optical counterpart detection
  19. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  20. GRB 250101A: GMG spectroscopic redshift at z ~ 2.481
  21. GRB 250101A: Swift/UVOT Detection
  22. GRB 250101A: 1.6m Mephisto multi-band optical followup
  23. GRB 250101A: Swift-XRT refined Analysis
  24. Fermi Gamma-ray Burst Monitor trigger 757464861/250101954 is not a GRB
  25. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  26. GRB 250101A: LCOGT optical afterglow detection
  27. GRB 250101A: OASDG optical observations
  28. Fermi GRB 250101B: Global MASTER-Net observations report
  29. GRB 250101B: Fermi GBM Final Real-time Localization
  30. GRB 250101A: SAO RAS observations of optical brightening
  31. GRB 250101A: BOOTES-4/MET optical afterglow detection
  32. GRB 250101A: AKO Optical Afterglow Detection
  33. GRB 250101A: SAO RAS optical observations
  34. GRB 250101A: Enhanced Swift-XRT position
  35. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  36. GRB 250101A: SVOM/C-GFT early optical observations
  37. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  38. GRB 250101A: MASTER earlier OT observations with SOSS emission features
  39. GRB 250101A: Nanshan/HMT optical observations
  40. GRB 250101A : GIT optical detection
  41. GRB 250101A: GMG Optical Observation
  42. GRB 250101A: Swift detection of a burst with an optical counterpart
  43. GRB 241217a/EP241217b: ATCA Radio Detection
  44. GRB 241229B: Continued CrAO ZTSh observations
  45. GRB 241229A: EP-FXT X-ray afterglow confirmation
  46. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  47. GRB 241229B: SVOM/GRM observation
  48. GRB 241229B: SAO RAS optical upper limit
  49. GRB 241228B: SAO RAS optical observations
  50. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  51. GRB 241229A: SAO RAS optical observations
  52. GRB 241229B: SVOM/VT optical candidate
  53. GRB 241229A: Swift-XRT observations
  54. Konus-Wind detection of GRB 241228A
  55. GRB 241229A: EP-FXT afterglow candidates
  56. GRB 240606B: 7DT Optical upper limits
  57. GRB 241229B: Swift-BAT refined analysis
  58. Fermi Gamma-ray Burst Monitor trigger 757207662/241229978 (GRB 241229C) is not a GRB
  59. GRB241229B: UVOT upper limits
  60. GRB 241229C: Fermi GBM Final Real-time Localization
  61. GRB 241228B: D50 optical detection
  62. GRB 241228B: Fermi GBM Observation
  63. GRB 241228B: Swift-XRT afterglow detection
  64. GRB 241229B: Fermi GBM Observation
  65. GRB 241229A: Swift ToO observations
  66. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  67. GRB 241228A: Mondy optical afterglow observations
  68. GRB 241229B: Swift-XRT refined Analysis
  69. Swift GRB 241229B: Global MASTER-Net observations report
  70. GRB 241229A: GOTO optical upper limits
  71. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  72. GRB 241228A: NOT optical upper limits
  73. GRB 241228B: LCO optical observation
  74. GRB 241228A: Swift-BAT refined analysis
  75. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  76. GRB 241229B: Swift detection of a burst
  77. GRB 241229B: Fermi GBM Final Real-time Localization
  78. GRB 241229A: SVOM detection of a long burst
  79. Fermi GRB 241228B: Global MASTER-Net observations report
  80. GRB 241228A: Fermi GBM Observation
  81. GRB241228B: GROWTH-India Telescope optical observations
  82. Swift GRB 241228A: Global MASTER-Net observations report
  83. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  84. GRB 241228B: GOTO24jmz optical follow-up observations
  85. GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
  86. GRB 241228A: GROWTH-India telescope optical upper limit
  87. GRB 241228B: Swift ToO observations
  88. GRB 241228B: TRT optical counterpart confirmation
  89. GRB 241228A: Swift-XRT refined Analysis
  90. GRB 241228A: Swift/UVOT Upper Limits
  91. GRB 241228B: GOTO possible optical counterpart candidate
  92. GRB 241228A: Enhanced Swift-XRT position
  93. GRB 241228B: Fermi GBM Final Real-time Localization
  94. GRB 241228A: Swift detection of a burst
  95. GRB 241223A: GRBAlpha detection
  96. GRB 241212A: VZLUSAT-2 detection
  97. GRB 241217A/EP241217b: continued SOAR observations
  98. Fermi GRB 241226A: Global MASTER-Net observations report
  99. GRB 241226A: Fermi GBM Final Real-time Localization
  100. EP241223a: Mondy AZT-33IK optical observations

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