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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

38918 results found.

  1. GRB 250126A: Fermi GBM Final Real-time Localization
  2. GRB 250118A: Fermi GBM Observation
  3. EP250125a: REM optical counterpart detection
  4. GRB 250119C: Fermi GBM Observation
  5. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  6. GRB 250121A: CALET Gamma-Ray Burst Monitor detection
  7. EP250108a: AbAO, CMO and Terskol optical upper limits
  8. Konus-Wind detection of GRB 250118B
  9. GRB 250121A: Fermi GBM Observation
  10. IPN triangulation of GRB 250118B
  11. Konus-Wind detection of GRB 250119B
  12. IPN triangulation of GRB 250119B
  13. GRB 250122A: Fermi GBM Final Real-time Localization
  14. Improved IPN triangulation of GRB 250107C
  15. GRB 250114A: Swift-BAT refined analysis
  16. GRB 250121A: INTEGRAL/SPI-ACS detection
  17. GRB 250121A: Fermi-LAT detection
  18. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  19. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  20. GRB 250121A: Fermi GBM Final Real-time Localization
  21. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  22. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  23. GRB 250119B: Fermi GBM Observation
  24. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  25. Konus-Wind detection of GRB 250117A
  26. IPN triangulation of GRB 250117A (short)
  27. ATCA detection of possible radio counterpart to GRB 250114A
  28. GRB 250119B: INTEGRAL/SPI-ACS detection
  29. EP 250108A: Late-time optical observation by LCO
  30. GRB 250117A: SVOM/GRM observation of a short burst
  31. GRB 250119C: Fermi GBM Final Real-time Localization
  32. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  33. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  34. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  35. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  36. GRB 250117A: GECAM observation of a short burst
  37. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  38. GRB 250119B: Fermi GBM Final Real-time Localization
  39. GRB 250119A: Fermi GBM Final Real-time Localization
  40. GRB 250118A: Fermi GBM Final Real-time Localization
  41. EP250108a / AT2025kg: VLA radio upper limit
  42. Fermi Gamma-ray Burst Monitor trigger 758829338/250117747 is not a GRB
  43. Konus-Wind detection of GRB 250116A
  44. GRB 250116A: GECAM-B detection of a long burst
  45. GRB 241217A / EP241217B: radio detection with the VLA
  46. GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection
  47. Swift Trigger 1282245 is not a GRB
  48. GRB 250116A: Fermi-LAT detection
  49. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  50. GRB 250114B: Swift-XRT afterglow detection
  51. GRB 250114B: SVOM/VT upper limit
  52. Fermi Gamma-ray Burst Monitor trigger 758659047/250115776 is not a GRB
  53. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  54. Konus-Wind detection of GRB 250113A
  55. IPN triangulation of GRB 250113A
  56. GRB 250114B: Liverpool Telescope optical upper limit
  57. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  58. GRB 250114B: Swift-XRT observations
  59. GRB 250114A: LCO optical counterpart detection.
  60. GRB 250114B: OHP/T193 optical upper limit
  61. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  62. GRB 250114A: Swift-XRT refined Analysis
  63. Integral GRB250114.55: Global MASTER-Net observations report
  64. GRB 250114A: LCOGT optical afterglow i-band detection
  65. GRB 250114B : GIT optical upper limit
  66. GRB 250114B: Swift ToO observations
  67. EP250111a: SAO RAS optical upper limit
  68. GRB 250114B: a short GRB detected with INTEGRAL
  69. GRB 250114A: Enhanced Swift-XRT position
  70. GRB 250113A: INTEGRAL/SPI-ACS detection
  71. GRB 250114A: VLT/X-shooter spectroscopic redshift z = 4.732
  72. GRB 250114A: REM detection of the optical and NIR counterpart
  73. Swift GRB250114A: Global MASTER-Net OT detection
  74. GRB 250114A: LCO optical observations
  75. GRB 250114A: TRT optical observations
  76. Swift GRB 250114A: Global MASTER-Net observations report
  77. GRB 250114A: Swift detection of a burst with an optical counterpart
  78. GRB 250101A: Terskol Zeiss-2000 optical observations
  79. EP250108a / AT 2025kg: SAO RAS optical observations
  80. GRB 250113A: SVOM/GRM observation of a long burst
  81. GRB 250107A: VZLUSAT-2 detection
  82. GRB 250109A / EP250109a: GRBAlpha detection
  83. GRB 250107D: GRBAlpha detection
  84. GRB 250106A: Swift-XRT afterglow detection
  85. Fermi trigger No 758442826: Global MASTER-Net observations report
  86. EP250111a: KAIT optical observations
  87. GRB 250109A / EP250109a: Mephisto optical upper limits
  88. EP250108a: Mephisto detection
  89. EP250111a: Mondy optical observation
  90. EP250108a / AT 2025kg: LCO optical observations
  91. EP250111a: Global MASTER-Net observations report
  92. EP250109a/GRB 250109A:SVOM/VT optical counterpart
  93. GRB 250101B: Fermi GBM Observation
  94. EP250108a: further NOT optical observations
  95. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  96. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  97. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  98. GRB 250108A: Swift/XRT afterglow fading
  99. GRB 250107D: CALET Gamma-Ray Burst Monitor detection
  100. GRB 250107C: CALET Gamma-Ray Burst Monitor detection

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