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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"

14868 results found.

  1. GRB 250114A: Swift detection of a burst with an optical counterpart
  2. GRB 250107A: VZLUSAT-2 detection
  3. GRB 250109A / EP250109a: GRBAlpha detection
  4. GRB 250107D: GRBAlpha detection
  5. GRB 250106A: Swift-XRT afterglow detection
  6. EP250108a: Mephisto detection
  7. EP250111a: Swift/XRT detection and fading
  8. EP250111a: a new X-ray transient detected by Einstein Probe
  9. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  10. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  11. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  12. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  13. Konus-Wind detection of GRB 250107C
  14. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  15. EP250109a: Swift/UVOT non-detection
  16. Konus-Wind detection of GRB 250107D (short/hard)
  17. EP250108a: Liverpool Telescope likely optical counterpart
  18. GRB 250108B: Gemini-North likely redshift z = 2.197
  19. GRB 250108B: 1.3m DFOT upper limit
  20. GRB 250109A /EP250109a: Fermi GBM Final Localization
  21. EP250109a: Swift/XRT non-detection
  22. EP250109a: EP-WXT detection of an X-ray transient
  23. EP250108a: EP-WXT detection of an X-ray transient
  24. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  25. GRB 250103A: 1.6m Mephisto optical observations
  26. GRB 250108A: Swift-XRT afterglow detection
  27. GRB 250103A: Swift-XRT afterglow detection
  28. GRB 250108B: Swift detection of a burst
  29. GRB 250108A: SVOM detection of a soft long burst
  30. GRB 241228B: Fermi-LAT detection
  31. GRB 250107B: Fermi GBM Final Real-time Localization
  32. GRB 250107A: Fermi GBM Final Real-time Localization
  33. EPWXT01709129925: Xinglong optical observations
  34. GRB 250101A: REM optical/NIR counterpart detection
  35. The EP-WXT trigger 01709129925 is likely a flaring star
  36. GRB 250106A: SVOM detection of a long burst
  37. GRB 250103B: LCO/1m optical afterglow candidate detection
  38. GRB 250103B: VLT/X-shooter spectroscopic redshift z = 1.416
  39. GRB 250101A: 1.3m DFOT optical afterglow detection
  40. GRB 241229A: 1.3m DFOT upper limit
  41. GRB 241228B: 1.3m DFOT Optical observations
  42. GRB 241228A: 1.3m DFOT upper limit
  43. GRB 250103A: NOT spectroscopic redshift
  44. GRB 250103A: Montarrenti Observatory optical detection
  45. GRB 250103A: TSHAO optical upper limit
  46. GRB 250101a: Liverpool Telescope optical follow-up
  47. GRB 250103B: SVOM detection of a long burst
  48. GRB 250103B: Swift detection of a burst
  49. GRB 250103A: GOTO optical upper limit
  50. GRB 250103A: SVOM detection of a long burst (duplicate submission)
  51. GRB 250103A: SVOM detection of a long burst
  52. EP250101a: Xinglong optical upper limit
  53. GRB 250102A: Fermi GBM Final Real-time Localization
  54. IceCube-250102A - IceCube observation of a high-energy neutrino candidate track-like event
  55. GRB 250101A: LCO optical counterpart detection
  56. EP241231b and EP250101a: EP-WXT detection of two X-ray transients
  57. GRB 250101A: Swift/UVOT Detection
  58. IceCube-250101A - IceCube observation of a high-energy neutrino candidate track-like event
  59. GRB 250101A: LCOGT optical afterglow detection
  60. GRB 250101B: Fermi GBM Final Real-time Localization
  61. GRB 250101A: BOOTES-4/MET optical afterglow detection
  62. GRB 250101A: AKO Optical Afterglow Detection
  63. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  64. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  65. GRB 250101A : GIT optical detection
  66. GRB 250101A: Swift detection of a burst with an optical counterpart
  67. GRB 241217a/EP241217b: ATCA Radio Detection
  68. EP241217a: VLA Radio Detection

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

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