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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').
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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"

28301 results found.

  1. GRB 250129A: AKO Optical Afterglow Detection
  2. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  3. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  4. GRB 250128B: VLA radio upper limit
  5. Ep250125A: 1.3m DFOT optical upper limit
  6. GRB 250129A: Skynet optical observations
  7. GRB 250129A: Swift-XRT refined Analysis
  8. GRB 250128B: Gemini-North optical extended source detection
  9. GRB 250128B: TNG optical upper limit
  10. GRB 250129A: Swift/UVOT Detection
  11. GRB 250128B: VLT/HAWKI near-infrared observations
  12. GRB 250127A: CrAO and Terskol optical upper limits
  13. GRB 250129A: Enhanced Swift-XRT position
  14. GRB 250128B: NOT optical upper limit
  15. GRB 250128B: VLT/FORS2 optical observations
  16. GRB 250129A: REM optical/NIR afterglow detection
  17. GRB 250129A: OHP/T193 optical and spectroscopy observations
  18. GRB 250129A: Early afterglow detection by LCO.
  19. GRB 250128B: OHP/T193 optical upper limit
  20. GRB 250129A: LCO optical observations
  21. GRB 250128B: Enhanced Swift-XRT position
  22. GRB 250129A: Swift detection of a burst with an optical counterpart
  23. Swift GRB 250129A: Global MASTER-Net OT detection
  24. GRB 250128B: Swift-XRT refined Analysis
  25. GRB 250128B: GOTO optical upper limit
  26. EP250125a: Upper limits from Swift/BAT-GUANO
  27. GRB 250128B: LCO optical observations
  28. GRB 250128B: Swift detection of a short burst
  29. GRB 250127A: Swift-XRT observations
  30. GRB 250127B: DDOTI Upper Limit on the Afterglow
  31. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  32. Fermi GRB 250128A: Global MASTER-Net observations report
  33. GRB 250117A: Fermi GBM Observation
  34. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  35. IPN triangulation of GRB 250119C
  36. GRB 250127A: LCO optical upper limit
  37. GRB 241223A: cubesat Avion detection
  38. EP250125A: Non-detection from Fermi-GBM Observations
  39. GRB 250126A: MAXI/GSC detection
  40. GRB 250126A: BALROG localization (Fermi Trigger 759560335 / GRB 250126208)
  41. EP250125a: Optical upper limit with Kinder observations
  42. EP250125a: REM optical counterpart detection
  43. GRB 250119C: Fermi GBM Observation
  44. EP250125a: Swift/XRT detection of a fading counterpart
  45. EP250125a: a new X-ray transient detected by Einstein Probe
  46. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  47. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  48. EP250108a: AbAO, CMO and Terskol optical upper limits
  49. GRB 250121A: Fermi GBM Observation
  50. IPN triangulation of GRB 250118B
  51. IPN triangulation of GRB 250119B
  52. GRB 250114A: Swift-BAT refined analysis
  53. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  54. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  55. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  56. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  57. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  58. GRB 250119B: Fermi GBM Observation
  59. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  60. IPN triangulation of GRB 250117A (short)
  61. LIGO/Virgo/KAGRA S250119cv: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  62. EP 250108A: Late-time optical observation by LCO
  63. LIGO/Virgo/KAGRA S250105bn: 1 counterpart neutrino candidate event from an IceCube neutrino search
  64. LIGO/Virgo/KAGRA S250119cv: Updated NED Galaxies in the Localization Volume
  65. LIGO/Virgo/KAGRA S250119cv: Updated Sky localization and EM Bright Classification
  66. LIGO/Virgo/KAGRA S250119cv: NED Galaxies in the Localization Volume
  67. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  68. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  69. LIGO/Virgo/KAGRA S250119ag: Updated Sky localization
  70. GRB 250117A: GECAM observation of a short burst
  71. LIGO/Virgo/KAGRA S250118dp: Updated Sky localization
  72. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  73. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  74. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  75. LIGO/Virgo/KAGRA S250118t: Updated Sky localization
  76. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  77. EP250108a / AT2025kg: GMG Optical Observations
  78. LIGO/Virgo/KAGRA S250118t: Identification of a GW compact binary merger candidate
  79. GRB 241217A / EP241217B: radio detection with the VLA
  80. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  81. GRB 250114B: Swift-XRT afterglow detection
  82. EP250108a: MeerKAT radio upper limit
  83. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  84. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  85. LIGO/Virgo/KAGRA S250114ax: Updated Sky localization
  86. IPN triangulation of GRB 250113A
  87. GRB 250114B: Liverpool Telescope optical upper limit
  88. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  89. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  90. GRB 250114B: Swift-XRT observations
  91. GRB 250114A: LCO optical counterpart detection.
  92. GRB 250114B: OHP/T193 optical upper limit
  93. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  94. GRB 250114A: Swift-XRT refined Analysis
  95. GRB 250114A: LCOGT optical afterglow i-band detection
  96. GRB 250114B : GIT optical upper limit
  97. EP250111a: SAO RAS optical upper limit
  98. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  99. GRB 250114B: a short GRB detected with INTEGRAL
  100. GRB 250114A: Enhanced Swift-XRT position

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