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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"

28106 results found.

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

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

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