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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"

14864 results found.

  1. GRB 250106A: Swift-XRT afterglow detection
  2. EP250108a: Mephisto detection
  3. EP250111a: Swift/XRT detection and fading
  4. EP250111a: a new X-ray transient detected by Einstein Probe
  5. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  6. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  7. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  8. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  9. Konus-Wind detection of GRB 250107C
  10. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  11. EP250109a: Swift/UVOT non-detection
  12. Konus-Wind detection of GRB 250107D (short/hard)
  13. EP250108a: Liverpool Telescope likely optical counterpart
  14. GRB 250108B: Gemini-North likely redshift z = 2.197
  15. GRB 250108B: 1.3m DFOT upper limit
  16. GRB 250109A /EP250109a: Fermi GBM Final Localization
  17. EP250109a: Swift/XRT non-detection
  18. EP250109a: EP-WXT detection of an X-ray transient
  19. EP250108a: EP-WXT detection of an X-ray transient
  20. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  21. GRB 250103A: 1.6m Mephisto optical observations
  22. GRB 250108A: Swift-XRT afterglow detection
  23. GRB 250103A: Swift-XRT afterglow detection
  24. GRB 250108B: Swift detection of a burst
  25. GRB 250108A: SVOM detection of a soft long burst
  26. GRB 241228B: Fermi-LAT detection
  27. GRB 250107B: Fermi GBM Final Real-time Localization
  28. GRB 250107A: Fermi GBM Final Real-time Localization
  29. EPWXT01709129925: Xinglong optical observations
  30. GRB 250101A: REM optical/NIR counterpart detection
  31. The EP-WXT trigger 01709129925 is likely a flaring star
  32. GRB 250106A: SVOM detection of a long burst
  33. GRB 250103B: LCO/1m optical afterglow candidate detection
  34. GRB 250103B: VLT/X-shooter spectroscopic redshift z = 1.416
  35. GRB 250101A: 1.3m DFOT optical afterglow detection
  36. GRB 241229A: 1.3m DFOT upper limit
  37. GRB 241228B: 1.3m DFOT Optical observations
  38. GRB 241228A: 1.3m DFOT upper limit
  39. GRB 250103A: NOT spectroscopic redshift
  40. GRB 250103A: Montarrenti Observatory optical detection
  41. GRB 250103A: TSHAO optical upper limit
  42. GRB 250101a: Liverpool Telescope optical follow-up
  43. GRB 250103B: SVOM detection of a long burst
  44. GRB 250103B: Swift detection of a burst
  45. GRB 250103A: GOTO optical upper limit
  46. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  47. GRB 250103A: SVOM detection of a long burst
  48. EP250101a: Xinglong optical upper limit
  49. GRB 250102A: Fermi GBM Final Real-time Localization
  50. IceCube-250102A - IceCube observation of a high-energy neutrino candidate track-like event
  51. GRB 250101A: LCO optical counterpart detection
  52. EP241231b and EP250101a: EP-WXT detection of two X-ray transients
  53. GRB 250101A: Swift/UVOT Detection
  54. IceCube-250101A - IceCube observation of a high-energy neutrino candidate track-like event
  55. GRB 250101A: LCOGT optical afterglow detection
  56. GRB 250101B: Fermi GBM Final Real-time Localization
  57. GRB 250101A: BOOTES-4/MET optical afterglow detection
  58. GRB 250101A: AKO Optical Afterglow Detection
  59. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  60. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  61. GRB 250101A : GIT optical detection
  62. GRB 250101A: Swift detection of a burst with an optical counterpart
  63. GRB 241217a/EP241217b: ATCA Radio Detection
  64. EP241217a: VLA Radio Detection

  65. Konus-Wind detection of GRB 241228A
  66. EP240702a: 7DT Optical upper limits
  67. GRB 240606B: 7DT Optical upper limits
  68. GRB 241229C: Fermi GBM Final Real-time Localization
  69. GRB 241228B: D50 optical detection
  70. GRB 241228B: Fermi GBM Observation
  71. GRB 241228B: Swift-XRT afterglow detection
  72. IceCube-241224A: No transient candidates from the Zwicky Transient Facility
  73. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  74. GRB 241229B: Swift detection of a burst
  75. GRB 241229B: Fermi GBM Final Real-time Localization
  76. GRB 241229A: SVOM detection of a long burst
  77. GRB 241228B: Fermi GBM Final Real-time Localization
  78. GRB 241228A: Swift detection of a burst
  79. GRB 241223A: GRBAlpha detection
  80. GRB 241212A: VZLUSAT-2 detection
  81. GRB 241226A: Fermi GBM Final Real-time Localization
  82. GRB 241029A: LCO optical observation
  83. GRB 241223A: Fermi GBM Detection
  84. EP241223a
  85. IceCube-241224A - IceCube observation of a high-energy neutrino candidate track-like event
  86. GRB 241219A: SVOM/GRM observation
  87. EP241223a: EP-WXT detection of a fast X-ray transient
  88. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  89. GRB241113A: 7DT Optical upper limits
  90. EP241217a: e-MERLIN radio observations
  91. GRB 241223A: Fermi GBM Final Real-time Localization
  92. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  93. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  94. GRB 241221A: Fermi GBM Final Real-time Localization
  95. GRB 241217A/EP241217b: SOAR afterglow detection
  96. EP241021a: VLA radio detection
  97. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  98. EP241217a: 1.6m Mephisto multi-band optical observations
  99. GRB 241209B: EP-FXT afterglow detection
  100. Konus-Wind detection of GRB 241204A (short/hard)

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