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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"

36213 results found.

  1. GRB 250101A: 1.3m DFOT optical afterglow detection
  2. GRB 241229A: 1.3m DFOT upper limit
  3. GRB 241228B: 1.3m DFOT Optical observations
  4. GRB 241228A: 1.3m DFOT upper limit
  5. GRB 250103A: NOT spectroscopic redshift
  6. GRB 250103B：SVOM/VT optical counterpart
  7. GRB 250103A: Montarrenti Observatory optical detection
  8. GRB 250101A: further LCOGT optical afterglow observations
  9. GRB 250103A: Redshift 4.01 from OSIRIS+/GTC
  10. GRB 250103A: NOT optical observations
  11. GRB 250103A: TSHAO optical upper limit
  12. GRB 250103A: Fermi GBM Observation
  13. GRB 250103B: LCOGT Optical Upper Limit
  14. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  15. Swift GRB 250103B: Global MASTER-Net observations report
  16. GRB 250103A: SVOM/VT optical counterpart confirmation
  17. GRB 250103A: Swift ToO observations
  18. IceCube-250101A: Upper limits from a search for additional neutrino events in IceCube
  19. GRB 250101a: Liverpool Telescope optical follow-up
  20. GRB 250103B: SVOM detection of a long burst
  21. GRB 250103B: Swift detection of a burst
  22. GRB 250103A: Xinglong 2.16m Optical Candidate
  23. Fermi GRB 250102A: Global MASTER-Net observations report
  24. GRB 250101B: SVOM/GRM observation
  25. GRB 250103A: GOTO optical upper limit
  26. GRB 250103A: SVOM/C-GFT optical upper limit
  27. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  28. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  29. GRB 250103A: SVOM detection of a long burst
  30. GRB 250102A: Fermi GBM Final Real-time Localization
  31. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO
  32. GRB 250101A: Swift-BAT refined analysis
  33. GRB 250101A: further SAO RAS optical observations
  34. GRB 250101A: LCO optical counterpart detection
  35. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  36. GRB 250101A: GMG spectroscopic redshift at z ~ 2.481
  37. GRB 250101A: Swift/UVOT Detection
  38. GRB 250101A: 1.6m Mephisto multi-band optical followup
  39. GRB 250101A: Swift-XRT refined Analysis
  40. Fermi Gamma-ray Burst Monitor trigger 757464861/250101954 is not a GRB
  41. GRB 250101A: Montarrenti Observatory optical observations and rebrightening
  42. GRB 250101A: LCOGT optical afterglow detection
  43. GRB 250101A: OASDG optical observations
  44. Fermi GRB 250101B: Global MASTER-Net observations report
  45. GRB 250101B: Fermi GBM Final Real-time Localization
  46. GRB 250101A: SAO RAS observations of optical brightening
  47. GRB 250101A: BOOTES-4/MET optical afterglow detection
  48. GRB 250101A: AKO Optical Afterglow Detection
  49. GRB 250101A: SAO RAS optical observations
  50. GRB 250101A: Enhanced Swift-XRT position
  51. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  52. GRB 250101A: SVOM/C-GFT early optical observations
  53. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  54. GRB 250101A: MASTER earlier OT observations with SOSS emission features
  55. GRB 250101A: Nanshan/HMT optical observations
  56. GRB 250101A : GIT optical detection
  57. GRB 250101A: GMG Optical Observation
  58. GRB 250101A: Swift detection of a burst with an optical counterpart
  59. GRB 241217a/EP241217b: ATCA Radio Detection
  60. GRB 241229B: Continued CrAO ZTSh observations
  61. GRB 241229A: EP-FXT X-ray afterglow confirmation
  62. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  63. GRB 241229B: SVOM/GRM observation
  64. GRB 241229B: SAO RAS optical upper limit
  65. GRB 241228B: SAO RAS optical observations
  66. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  67. GRB 241229A: SAO RAS optical observations
  68. GRB 241229B: SVOM/VT optical candidate
  69. GRB 241229A: Swift-XRT observations
  70. Konus-Wind detection of GRB 241228A
  71. GRB 241229A: EP-FXT afterglow candidates
  72. GRB 240606B: 7DT Optical upper limits
  73. GRB 241229B: Swift-BAT refined analysis
  74. Fermi Gamma-ray Burst Monitor trigger 757207662/241229978 (GRB 241229C) is not a GRB
  75. GRB241229B: UVOT upper limits
  76. GRB 241229C: Fermi GBM Final Real-time Localization
  77. GRB 241228B: D50 optical detection
  78. GRB 241228B: Fermi GBM Observation
  79. GRB 241228B: Swift-XRT afterglow detection
  80. GRB 241229B: Fermi GBM Observation
  81. GRB 241229A: Swift ToO observations
  82. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  83. GRB 241228A: Mondy optical afterglow observations
  84. GRB 241229B: Swift-XRT refined Analysis
  85. Swift GRB 241229B: Global MASTER-Net observations report
  86. GRB 241229A: GOTO optical upper limits
  87. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  88. GRB 241228A: NOT optical upper limits
  89. GRB 241228B: LCO optical observation
  90. GRB 241228A: Swift-BAT refined analysis
  91. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  92. GRB 241229B: Swift detection of a burst
  93. GRB 241229B: Fermi GBM Final Real-time Localization
  94. GRB 241229A: SVOM detection of a long burst
  95. Fermi GRB 241228B: Global MASTER-Net observations report
  96. GRB 241228A: Fermi GBM Observation
  97. GRB241228B: GROWTH-India Telescope optical observations
  98. Swift GRB 241228A: Global MASTER-Net observations report
  99. GRB 241228B: LCOGT photometry of the likely optical counterpart GOTO24jmz
  100. GRB 241228B: GOTO24jmz optical follow-up observations

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