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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"

36260 results found.

  1. EP250111a: SAO RAS optical upper limit
  2. GRB 250114B: a short GRB detected with INTEGRAL
  3. GRB 250114A: Enhanced Swift-XRT position
  4. GRB 250113A: INTEGRAL/SPI-ACS detection
  5. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  6. GRB 250114A: REM detection of the optical and NIR counterpart
  7. GRB 250114A: LCO optical observations
  8. GRB 250114A: TRT optical observations
  9. Swift GRB 250114A: Global MASTER-Net observations report
  10. GRB 250114A: Swift detection of a burst with an optical counterpart
  11. GRB 250101A: Terskol Zeiss-2000 optical observations
  12. EP250108a / AT 2025kg: SAO RAS optical observations
  13. GRB 250113A: SVOM/GRM observation of a long burst
  14. GRB 250107A: VZLUSAT-2 detection
  15. GRB 250109A / EP250109a: GRBAlpha detection
  16. GRB 250107D: GRBAlpha detection
  17. GRB 250106A: Swift-XRT afterglow detection
  18. EP250111a: KAIT optical observations
  19. GRB 250109A / EP250109a: Mephisto optical upper limits
  20. EP250111a: Mondy optical observation
  21. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  22. GRB 250101B: Fermi GBM Observation
  23. EP250108a: further NOT optical observations
  24. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  25. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  26. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  27. GRB 250108A: Swift/XRT afterglow fading
  28. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  29. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  30. Konus-Wind detection of GRB 250107C
  31. GRB 250101A: CMO RC-500 optical observations
  32. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  33. GRB 250109A: Fermi GBM Observation
  34. EP250108a: NOT optical observations
  35. GRB 250109a: GMG Optical Upper Limit
  36. Konus-Wind detection of GRB 250107D (short/hard)
  37. IPN triangulation of GRB 250107D (short/hard)
  38. IPN triangulation of GRB 250107C
  39. GRB 250108B: Gemini-North likely redshift z = 2.197
  40. GRB 250108B: Swift-BAT refined analysis
  41. GRB 250108B: 1.3m DFOT upper limit
  42. GRB 250108B: REM optical/NIR upper limits
  43. GRB 250109A /EP250109a: Fermi GBM Final Localization
  44. GRB 250107C: SVOM/GRM observation
  45. GRB 250101A: Terskol K-800 optical observations
  46. EP250109a: Swift/XRT non-detection
  47. GRB 250108A: Swift/UVOT Upper Limits
  48. GRB 250108A: NOT optical upper limit
  49. GRB 250108B: Swift-XRT refined Analysis
  50. Swift GRB 250108B: Global MASTER-Net observations report
  51. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  52. LIGO/Virgo/KAGRA S250108ha: Retraction of GW compact binary merger candidate
  53. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  54. GRB 250103A: 1.6m Mephisto optical observations
  55. GRB 250108A: Swift-XRT afterglow detection
  56. GRB 250108A:SVOM/VT optical candidate
  57. GRB 250108B: Swift/UVOT Upper Limits
  58. GRB 250103A: Swift-XRT afterglow detection
  59. GRB 250108B: Enhanced Swift-XRT position
  60. GRB 250108B: Swift detection of a burst
  61. GRB 250108A: Swift ToO observations
  62. GRB 250108A: SVOM detection of a soft long burst
  63. GRB 250107A: Fermi GBM Observation
  64. GRB 241228B: Fermi-LAT detection
  65. Fermi GRB 250107B: Global MASTER-Net observations report
  66. GRB 250107A: Swift ToO observations
  67. GRB 250107A: Swift/BAT-GUANO arcminute localization of a burst
  68. GRB 250107B: Fermi GBM Final Real-time Localization
  69. GRB 250106A: SVOM/VT 2nd optical deep observation
  70. GRB 250101A: J band upper limit by SYSU 80cm telescope
  71. GRB 250107A: Fermi GBM Final Real-time Localization
  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 250103A: Bassano Bresciano Observatory upper limit
  83. GRB 250103B: VLT/X-shooter spectroscopic redshift z = 1.416
  84. GRB 250103A: Swift-XRT observations
  85. GRB 250101A: 1.3m DFOT optical afterglow detection
  86. GRB 241229A: 1.3m DFOT upper limit
  87. GRB 241228B: 1.3m DFOT Optical observations
  88. GRB 241228A: 1.3m DFOT upper limit
  89. GRB 250103A: NOT spectroscopic redshift
  90. GRB 250103B：SVOM/VT optical counterpart
  91. GRB 250103A: Montarrenti Observatory optical detection
  92. GRB 250101A: further LCOGT optical afterglow observations
  93. GRB 250103A: Redshift 4.01 from OSIRIS+/GTC
  94. GRB 250103A: NOT optical observations
  95. GRB 250103A: TSHAO optical upper limit
  96. GRB 250103A: Fermi GBM Observation
  97. GRB 250103B: LCOGT Optical Upper Limit
  98. Swift GRB 250103B: Global MASTER-Net observations report
  99. GRB 250103A: SVOM/VT optical counterpart confirmation
  100. GRB 250103A: Swift ToO observations

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