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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"

36344 results found.

  1. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  2. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  3. GRB 250121A: Fermi GBM Final Real-time Localization
  4. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  5. GRB 250119B: Fermi GBM Observation
  6. Konus-Wind detection of GRB 250117A
  7. IPN triangulation of GRB 250117A (short)
  8. ATCA detection of possible radio counterpart to GRB 250114A
  9. GRB 250119B: INTEGRAL/SPI-ACS detection
  10. EP 250108A: Late-time optical observation by LCO
  11. GRB 250117A: SVOM/GRM observation of a short burst
  12. GRB 250119C: Fermi GBM Final Real-time Localization
  13. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  14. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  15. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  16. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  17. GRB 250117A: GECAM observation of a short burst
  18. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  19. GRB 250119B: Fermi GBM Final Real-time Localization
  20. GRB 250119A: Fermi GBM Final Real-time Localization
  21. GRB 250118A: Fermi GBM Final Real-time Localization
  22. EP250108a / AT2025kg: VLA radio upper limit
  23. Fermi Gamma-ray Burst Monitor trigger 758829338/250117747 is not a GRB
  24. Konus-Wind detection of GRB 250116A
  25. GRB 250116A: GECAM-B detection of a long burst
  26. GRB 241217A / EP241217B: radio detection with the VLA
  27. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  28. Swift Trigger 1282245 is not a GRB
  29. GRB 250116A: Fermi-LAT detection
  30. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  31. GRB 250114B: Swift-XRT afterglow detection
  32. GRB 250114B: SVOM/VT upper limit
  33. Fermi Gamma-ray Burst Monitor trigger 758659047/250115776 is not a GRB
  34. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  35. Konus-Wind detection of GRB 250113A
  36. IPN triangulation of GRB 250113A
  37. GRB 250114B: Liverpool Telescope optical upper limit
  38. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  39. GRB 250114B: Swift-XRT observations
  40. GRB 250114A: LCO optical counterpart detection.
  41. GRB 250114B: OHP/T193 optical upper limit
  42. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  43. GRB 250114A: Swift-XRT refined Analysis
  44. GRB 250114A: LCOGT optical afterglow i-band detection
  45. GRB 250114B : GIT optical upper limit
  46. GRB 250114B: Swift ToO observations
  47. EP250111a: SAO RAS optical upper limit
  48. GRB 250114B: a short GRB detected with INTEGRAL
  49. GRB 250114A: Enhanced Swift-XRT position
  50. GRB 250113A: INTEGRAL/SPI-ACS detection
  51. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  52. GRB 250114A: REM detection of the optical and NIR counterpart
  53. GRB 250114A: LCO optical observations
  54. GRB 250114A: TRT optical observations
  55. Swift GRB 250114A: Global MASTER-Net observations report
  56. GRB 250114A: Swift detection of a burst with an optical counterpart
  57. GRB 250101A: Terskol Zeiss-2000 optical observations
  58. EP250108a / AT 2025kg: SAO RAS optical observations
  59. GRB 250113A: SVOM/GRM observation of a long burst
  60. GRB 250107A: VZLUSAT-2 detection
  61. GRB 250109A / EP250109a: GRBAlpha detection
  62. GRB 250107D: GRBAlpha detection
  63. GRB 250106A: Swift-XRT afterglow detection
  64. EP250111a: KAIT optical observations
  65. GRB 250109A / EP250109a: Mephisto optical upper limits
  66. EP250111a: Mondy optical observation
  67. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  68. GRB 250101B: Fermi GBM Observation
  69. EP250108a: further NOT optical observations
  70. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  71. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  72. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  73. GRB 250108A: Swift/XRT afterglow fading
  74. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  75. GRB 250107C: CALET Gamma-Ray Burst Monitor detection
  76. Konus-Wind detection of GRB 250107C
  77. GRB 250101A: CMO RC-500 optical observations
  78. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  79. GRB 250109A: Fermi GBM Observation
  80. EP250108a: NOT optical observations
  81. GRB 250109a: GMG Optical Upper Limit
  82. Konus-Wind detection of GRB 250107D (short/hard)
  83. IPN triangulation of GRB 250107D (short/hard)
  84. IPN triangulation of GRB 250107C
  85. GRB 250108B: Gemini-North likely redshift z = 2.197
  86. GRB 250108B: Swift-BAT refined analysis
  87. GRB 250108B: 1.3m DFOT upper limit
  88. GRB 250108B: REM optical/NIR upper limits
  89. GRB 250109A /EP250109a: Fermi GBM Final Localization
  90. GRB 250107C: SVOM/GRM observation
  91. GRB 250101A: Terskol K-800 optical observations
  92. EP250109a: Swift/XRT non-detection
  93. GRB 250108A: Swift/UVOT Upper Limits
  94. GRB 250108A: NOT optical upper limit
  95. GRB 250108B: Swift-XRT refined Analysis
  96. Swift GRB 250108B: Global MASTER-Net observations report
  97. Fermi Gamma-ray Burst Monitor trigger 758061038/250108855 is not a GRB
  98. LIGO/Virgo/KAGRA S250108ha: Retraction of GW compact binary merger candidate
  99. GRB 250108B: Gemini-North Candidate Optical Afterglow Detection
  100. GRB 250103A: 1.6m Mephisto optical observations

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