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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"

28105 results found.

  1. GRB 250101A: Swift-XRT refined Analysis
  2. IceCube-250101A - IceCube observation of a high-energy neutrino candidate track-like event
  3. GRB 250101A: LCOGT optical afterglow detection
  4. GRB 250101B: Fermi GBM Final Real-time Localization
  5. GRB 250101A: SAO RAS observations of optical brightening
  6. GRB 250101A: BOOTES-4/MET optical afterglow detection
  7. GRB 250101A: AKO Optical Afterglow Detection
  8. GRB 250101A: Enhanced Swift-XRT position
  9. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  10. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  11. GRB 250101A : GIT optical detection
  12. GRB 250101A: Swift detection of a burst with an optical counterpart
  13. GRB 241217a/EP241217b: ATCA Radio Detection
  14. EP241217a: VLA Radio Detection

  15. GRB 241229A: EP-FXT X-ray afterglow confirmation
  16. EP241217A: J band upper limit by SYSU 80cm telescope
  17. GRB 241228B: SAO RAS optical observations
  18. GRB 241229A: SAO RAS optical observations
  19. GRB 241229B: SVOM/VT optical candidate
  20. GRB 241229A: Swift-XRT observations
  21. Konus-Wind detection of GRB 241228A
  22. GRB 241229A: EP-FXT afterglow candidates
  23. EP240702a: 7DT Optical upper limits
  24. GRB 240606B: 7DT Optical upper limits
  25. GRB241229B: UVOT upper limits
  26. GRB 241229C: Fermi GBM Final Real-time Localization
  27. GRB 241228B: D50 optical detection
  28. GRB 241228B: Fermi GBM Observation
  29. GRB 241228B: Swift-XRT afterglow detection
  30. GRB 241229A: Swift ToO observations
  31. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  32. GRB 241228A: Mondy optical afterglow observations
  33. GRB 241229B: Swift-XRT refined Analysis
  34. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  35. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  36. GRB 241228A: NOT optical upper limits
  37. GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
  38. GRB 241229B: Swift detection of a burst
  39. GRB 241229B: Fermi GBM Final Real-time Localization
  40. GRB 241229A: SVOM detection of a long burst
  41. GRB241228B: GROWTH-India Telescope optical observations
  42. GRB 241228A: GROWTH-India telescope optical upper limit
  43. GRB 241228B: Swift ToO observations
  44. GRB 241228A: Swift-XRT refined Analysis
  45. GRB 241228A: Swift/UVOT Upper Limits
  46. GRB 241228A: Enhanced Swift-XRT position
  47. GRB 241228B: Fermi GBM Final Real-time Localization
  48. GRB 241228A: Swift detection of a burst
  49. GRB 241223A: GRBAlpha detection
  50. GRB 241212A: VZLUSAT-2 detection
  51. GRB 241226A: Fermi GBM Final Real-time Localization
  52. GRB 241029A: LCO optical observation
  53. GRB 241223A: Swift-XRT observations
  54. GRB 241223A: Fermi GBM Detection
  55. EP241223a
  56. IceCube-241224A - IceCube observation of a high-energy neutrino candidate track-like event
  57. EP241223a: EP-WXT detection of a fast X-ray transient
  58. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  59. GRB241113A: 7DT Optical upper limits
  60. GRB 241223A: GOTO optical observations summary
  61. GRB 241105A: JWST photometric observations of the host galaxy
  62. GRB 241223A: Swift ToO observations
  63. EP241217a: e-MERLIN radio observations
  64. GRB 241223A: Fermi GBM Final Real-time Localization
  65. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  66. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  67. GRB 241221A: Fermi GBM Final Real-time Localization
  68. GRB 241217A/EP241217b: SOAR afterglow detection
  69. EP241021a: VLA radio detection
  70. GRB 241218A: Mondy AZT-33IK optical upper limit
  71. EP241217a : Leavitt Observatory optical upper limit
  72. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  73. EP241217a: 1.6m Mephisto multi-band optical observations
  74. GRB 241218A: Swift/UVOT Upper Limits
  75. EP241217a: optical upper limit with the Liverpool Telescope
  76. GRB 241209B: EP-FXT afterglow detection
  77. Konus-Wind detection of GRB 241204A (short/hard)
  78. GRB 241218A: NOT optical upper limits
  79. EP 241217a: NIR detection with P200/WIRC
  80. EP 241217a: Possible J-band detection with WINTER
  81. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  82. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  83. GRB 241217A / EP241217b: Nanshan/HMT optical upper limit
  84. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  85. GRB 241217A / EP241217b: NOT optical upper limits
  86. GRB 241218A: REM optical upper limit
  87. GRB 241217A/EP241217b: REM optical/NIR upper limits
  88. EP241217a: REM optical/NIR upper limits
  89. GRB 241218a: Liverpool Telescope optical follow-up
  90. GRB 241217a: Liverpool Telescope optical follow-up
  91. EP241217a: Liverpool Telescope optical follow-up
  92. GRB 241218A: Swift-XRT refined Analysis
  93. EP241119a: 7DT Optical upper limits
  94. GRB 241209A: ATCA radio follow-up observations
  95. EP241217b/GRB 241217A: EP detection of the prompt X-ray emssion
  96. GRB 241218A: LCOGT Optical Upper Limit
  97. GRB 241218A: Enhanced Swift-XRT position
  98. GRB 241218A: Swift detection of a burst
  99. GRB 241217A : SVOM/VT optical afterglow detection
  100. GRB 241217A: Swift-XRT afterglow detection

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