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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"

28114 results found.

  1. GRB 250114B: Liverpool Telescope optical upper limit
  2. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  3. GRB 250114B: Swift-XRT observations
  4. GRB 250114A: LCO optical counterpart detection.
  5. GRB 250114B: OHP/T193 optical upper limit
  6. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  7. GRB 250114A: Swift-XRT refined Analysis
  8. GRB 250114A: LCOGT optical afterglow i-band detection
  9. GRB 250114B: Swift ToO observations
  10. GRB 250114A: Enhanced Swift-XRT position
  11. GRB 250113A: INTEGRAL/SPI-ACS detection
  12. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  13. GRB 250114A: REM detection of the optical and NIR counterpart
  14. Swift GRB250114A: Global MASTER-Net OT detection
  15. GRB 250114A: LCO optical observations
  16. GRB 250114A: TRT optical observations
  17. GRB 250114A: Swift detection of a burst with an optical counterpart
  18. GRB 250101A: Terskol Zeiss-2000 optical observations
  19. GRB 250107A: VZLUSAT-2 detection
  20. GRB 250109A / EP250109a: GRBAlpha detection
  21. GRB 250107D: GRBAlpha detection
  22. GRB 250106A: Swift-XRT afterglow detection
  23. EP250111a: KAIT optical observations
  24. GRB 250109A / EP250109a: Mephisto optical upper limits
  25. EP250108a: Mephisto detection
  26. EP250111a: Swift/XRT detection and fading
  27. EP250108a / AT 2025kg: Swift UVOT detections
  28. EP250111a: a new X-ray transient detected by Einstein Probe
  29. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  30. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  31. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  32. GRB 250108A: Swift/XRT afterglow fading
  33. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  34. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  35. Konus-Wind detection of GRB 250107C
  36. GRB 250101A: CMO RC-500 optical observations
  37. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  38. EP250108a: NOT optical observations
  39. EP250109a: Swift/UVOT non-detection
  40. Konus-Wind detection of GRB 250107D (short/hard)
  41. EP250108a: Liverpool Telescope likely optical counterpart
  42. GRB 250108B: Gemini-North likely redshift z = 2.197
  43. GRB 250108B: 1.3m DFOT upper limit
  44. GRB 250108B: REM optical/NIR upper limits
  45. GRB 250109A /EP250109a: Fermi GBM Final Localization
  46. GRB 250101A: Terskol K-800 optical observations
  47. EP250109a: GOTO optical upper limits
  48. EP250109a: Swift/XRT non-detection
  49. GRB 250108A: Swift/UVOT Upper Limits
  50. EP250109a: EP-WXT detection of an X-ray transient
  51. GRB 250108A: NOT optical upper limit
  52. EP250108a: EP-WXT detection of an X-ray transient
  53. GRB 250108B: Swift-XRT refined Analysis
  54. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  55. GRB 250103A: 1.6m Mephisto optical observations
  56. GRB 250108A: Swift-XRT afterglow detection
  57. GRB 250108A:SVOM/VT optical candidate
  58. GRB 250108B: Swift/UVOT Upper Limits
  59. GRB 250103A: Swift-XRT afterglow detection
  60. GRB 250108B: Enhanced Swift-XRT position
  61. GRB 250108B: Swift detection of a burst
  62. GRB 250108A: Swift ToO observations
  63. GRB 250108A: SVOM detection of a soft long burst
  64. GRB 241228B: Fermi-LAT detection
  65. GRB 250107A: Swift ToO observations
  66. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  67. GRB 250107B: Fermi GBM Final Real-time Localization
  68. GRB 250106A: SVOM/VT 2nd optical deep observation
  69. GRB 250101A: J band upper limit by SYSU 80cm telescope
  70. GRB 250107A: Fermi GBM Final Real-time Localization
  71. EPWXT01709129925: Xinglong optical observations
  72. GRB 250106A: NOT optical observations
  73. GRB 250103B: REM optical/NIR upper limits
  74. GRB 250101A: REM optical/NIR counterpart detection
  75. GRB 250106A: Swift-XRT observations
  76. GRB 250106A: SVOM/VT optical candidate
  77. GRB 250106A: Swift ToO observations
  78. GRB 250106A: SVOM detection of a long burst
  79. GRB 241229A: SVOM/VT optical upperlimit
  80. GRB 250103B: Swift-XRT refined Analysis
  81. GRB 250103B: LCO/1m optical afterglow candidate detection
  82. GRB 250103B: VLT/X-shooter spectroscopic redshift z = 1.416
  83. GRB 250103A: Swift-XRT observations
  84. GRB 250101A: 1.3m DFOT optical afterglow detection
  85. GRB 241229A: 1.3m DFOT upper limit
  86. GRB 241228B: 1.3m DFOT Optical observations
  87. GRB 241228A: 1.3m DFOT upper limit
  88. GRB 250103A: NOT spectroscopic redshift
  89. GRB 250103B：SVOM/VT optical counterpart
  90. GRB 250103A: Montarrenti Observatory optical detection
  91. GRB 250101A: further LCOGT optical afterglow observations
  92. GRB 250103A: NOT optical observations
  93. GRB 250103A: TSHAO optical upper limit
  94. GRB 250103B: LCOGT Optical Upper Limit
  95. GRB 250103A: Swift ToO observations
  96. GRB 250101a: Liverpool Telescope optical follow-up
  97. GRB 250103B: SVOM detection of a long burst
  98. GRB 250103B: Swift detection of a burst
  99. GRB 250103A: GOTO optical upper limit
  100. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits

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