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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"

21926 results found.

  1. GRB 250128B: TNG optical upper limit
  2. GRB 250129A: Swift/UVOT Detection
  3. GRB 250128B: VLT/HAWKI near-infrared observations
  4. GRB 250127A: CrAO and Terskol optical upper limits
  5. GRB 250129A: Enhanced Swift-XRT position
  6. GRB 250128B: NOT optical upper limit
  7. GRB 250128B: VLT/FORS2 optical observations
  8. GRB 250129A: REM optical/NIR afterglow detection
  9. GRB 250129A: OHP/T193 optical and spectroscopy observations
  10. GRB 250129A: Early afterglow detection by LCO.
  11. GRB 250128B: OHP/T193 optical upper limit
  12. GRB 250129A: LCO optical observations
  13. GRB 250129A: GOTO optical observations show brightening afterglow
  14. GRB 250129A: VLT/X-shooter redshift of z = 2.151
  15. GRB 250128B: Enhanced Swift-XRT position
  16. GRB 250129A: Swift detection of a burst with an optical counterpart
  17. Swift GRB 250129A: Global MASTER-Net OT detection
  18. GRB 250128B: Swift-XRT refined Analysis
  19. GRB 250128B: GOTO optical upper limit
  20. EP250125a: Upper limits from Swift/BAT-GUANO
  21. GRB 250128B: LCO optical observations
  22. GRB 250128B: Swift detection of a short burst
  23. GRB 250127A: Swift-XRT observations
  24. GRB 250127B: DDOTI Upper Limit on the Afterglow
  25. IPN triangulation of GRB 250119C
  26. GRB 250127A: LCO optical upper limit
  27. GRB 241223A: cubesat Avion detection
  28. GRB 250127A: SVOM detection of a long burst
  29. EP250125a: Optical upper limit with Kinder observations
  30. EP250125a: REM optical counterpart detection
  31. EP250125a: a new X-ray transient detected by Einstein Probe
  32. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  33. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  34. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  35. EP250108a: AbAO, CMO and Terskol optical upper limits
  36. IPN triangulation of GRB 250118B
  37. IPN triangulation of GRB 250119B
  38. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  39. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  40. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  41. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  42. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  43. Konus-Wind detection of GRB 250117A
  44. IPN triangulation of GRB 250117A (short)
  45. EP 250108A: Late-time optical observation by LCO
  46. LIGO/Virgo/KAGRA S250119cv: Updated Sky localization and EM Bright Classification
  47. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  48. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  49. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  51. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  52. EP250108a / AT2025kg: GMG Optical Observations
  53. LIGO/Virgo/KAGRA S250118t: Identification of a GW compact binary merger candidate
  54. Konus-Wind detection of GRB 250116A
  55. GRB 241217A / EP241217B: radio detection with the VLA
  56. GRB 250116A: Fermi-LAT detection
  57. GRB 250114B: Swift-XRT afterglow detection
  58. EP250108a: MeerKAT radio upper limit
  59. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  60. Konus-Wind detection of GRB 250113A
  61. IPN triangulation of GRB 250113A
  62. GRB 250114B: Liverpool Telescope optical upper limit
  63. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  64. GRB 250114A: LCO optical counterpart detection.
  65. GRB 250114B: OHP/T193 optical upper limit
  66. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  67. GRB 250114A: LCOGT optical afterglow i-band detection
  68. GRB 250114B : GIT optical upper limit
  69. EP250111a: SAO RAS optical upper limit
  70. GRB 250114A: Enhanced Swift-XRT position
  71. GRB 250114A: REM detection of the optical and NIR counterpart
  72. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  73. Swift GRB250114A: Global MASTER-Net OT detection
  74. GRB 250114A: LCO optical observations
  75. GRB 250114A: TRT optical observations
  76. GRB 250114A: Swift detection of a burst with an optical counterpart
  77. GRB 250101A: Terskol Zeiss-2000 optical observations
  78. EP250108a / AT 2025kg: SAO RAS optical observations
  79. EP241021a: SMA radio observation
  80. GRB 250113A: SVOM/GRM observation of a long burst
  81. GRB 250107A: VZLUSAT-2 detection
  82. EP250109b: optical upper limits with the Liverpool Telescope
  83. GRB 250109A / EP250109a: GRBAlpha detection
  84. GRB 250107D: GRBAlpha detection
  85. GRB 250106A: Swift-XRT afterglow detection
  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: Swift/XRT detection and fading
  92. EP250111a: NOT likely optical counterpart
  93. GRB 250101B: Fermi GBM Observation
  94. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  95. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  96. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  97. Konus-Wind detection of GRB 250107C
  98. EP-WXT trigger EP250108a：Xinglong optical follow-up observations
  99. GRB 250101A: CMO RC-500 optical observations
  100. EP250108a: EP-FXT follow-up observation

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