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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.

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

28246 results found.

  1. GRB 250127C: SVOM/GRM observation of a burst
  2. GRB 250204B: SVOM/GRM observation of a likely short burst
  3. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  4. GRB 250205A: Swift/XRT detection
  5. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  6. GRB250205A: SVOM/VT optical afterglow detection
  7. GRB 250205A: OHP/T193 optical counterpart candidate
  8. LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
  9. GRB 250205A: SVOM detection of a burst
  10. LIGO/Virgo/KAGRA S250205bk: NED Galaxies in the Localization Volume
  11. IPN triangulation of GRB 250201A
  12. LIGO/Virgo/KAGRA S250205bk: Updated Sky localization
  13. LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
  14. GRB 250129A: Swift-BAT refined analysis
  15. EP 250108A: Upper limits from Fermi-GBM Observations
  16. IPN triangulation of GRB 250204B (short/hard)
  17. IPN triangulation of GRB 250202B
  18. LIGO/Virgo/KAGRA S250204ax: Updated Sky localization
  19. GRB 250204B: AstroSat CZTI detection of a short burst
  20. GRB 250129A: LCO late afterglow detection
  21. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  22. LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
  23. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  24. GRB 250202B: NuSTAR detection of the prompt emission
  25. GRB 250202B: Fermi GBM Detection
  26. GRB 250129a: Liverpool Telescope optical follow-up
  27. GRB 240129A: further SAO RAS optical observations
  28. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  29. LIGO/Virgo/KAGRA S250202cu: Updated Sky localization
  30. LIGO/Virgo/KAGRA S250202cu: Identification of a GW compact binary merger candidate
  31. GRB 250129A: SVOM/C-GFT optical observations
  32. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  33. Swift GRB250129A: MASTER 4 days observations report
  34. GRB 250129A: 1.3m DFOT Optical observations
  35. GRB 250201A: BALROG localization (Fermi Trigger 760096791 / GRB 250201417)
  36. GRB 250201A: Fermi GBM Final Real-time Localization
  37. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  38. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  39. EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
  40. GRB 250129A: SAO RAS optical observations
  41. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  42. GRB 250129A: COLIBRÍ Optical Observations
  43. GRB 250129A: iTelescope optical observation
  44. GRB 250129a: Liverpool Telescope optical follow-up
  45. GRB 250129A: TNG NIR afterglow detection
  46. GRB 250129A: AKO Optical Afterglow Detection
  47. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  48. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  49. GRB 250128B: VLA radio upper limit
  50. Ep250125A: 1.3m DFOT optical upper limit
  51. GRB 250129A: Skynet optical observations
  52. GRB 250129A: Swift-XRT refined Analysis
  53. GRB 250128B: Gemini-North optical extended source detection
  54. GRB 250128B: TNG optical upper limit
  55. GRB 250129A: Swift/UVOT Detection
  56. GRB 250128B: VLT/HAWKI near-infrared observations
  57. GRB 250127A: CrAO and Terskol optical upper limits
  58. GRB 250129A: Enhanced Swift-XRT position
  59. GRB 250128B: NOT optical upper limit
  60. GRB 250128B: VLT/FORS2 optical observations
  61. GRB 250129A: REM optical/NIR afterglow detection
  62. GRB 250129A: OHP/T193 optical and spectroscopy observations
  63. GRB 250129A: Early afterglow detection by LCO.
  64. GRB 250128B: OHP/T193 optical upper limit
  65. GRB 250129A: LCO optical observations
  66. GRB 250128B: Enhanced Swift-XRT position
  67. GRB 250129A: Swift detection of a burst with an optical counterpart
  68. Swift GRB 250129A: Global MASTER-Net OT detection
  69. GRB 250128B: Swift-XRT refined Analysis
  70. GRB 250128B: GOTO optical upper limit
  71. EP250125a: Upper limits from Swift/BAT-GUANO
  72. GRB 250128B: LCO optical observations
  73. GRB 250128B: Swift detection of a short burst
  74. GRB 250127A: Swift-XRT observations
  75. GRB 250127B: DDOTI Upper Limit on the Afterglow
  76. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  77. Fermi GRB 250128A: Global MASTER-Net observations report
  78. GRB 250117A: Fermi GBM Observation
  79. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  80. IPN triangulation of GRB 250119C
  81. GRB 250127A: LCO optical upper limit
  82. GRB 241223A: cubesat Avion detection
  83. EP250125A: Non-detection from Fermi-GBM Observations
  84. GRB 250126A: MAXI/GSC detection
  85. GRB 250126A: BALROG localization (Fermi Trigger 759560335 / GRB 250126208)
  86. EP250125a: Optical upper limit with Kinder observations
  87. EP250125a: REM optical counterpart detection
  88. GRB 250119C: Fermi GBM Observation
  89. EP250125a: Swift/XRT detection of a fading counterpart
  90. EP250125a: a new X-ray transient detected by Einstein Probe
  91. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  92. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  93. EP250108a: AbAO, CMO and Terskol optical upper limits
  94. GRB 250121A: Fermi GBM Observation
  95. IPN triangulation of GRB 250118B
  96. IPN triangulation of GRB 250119B
  97. GRB 250114A: Swift-BAT refined analysis
  98. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  99. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  100. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst

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