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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').
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"

4183 results found.

  1. GRB 250129A: Early afterglow detection by LCO.
  2. GRB 250129A: LCO optical observations
  3. GRB 250129A: GOTO optical observations show brightening afterglow
  4. Swift GRB 250129A: Global MASTER-Net observations report
  5. The EP-WXT trigger 01709131085 is likely a flaring star
  6. Fermi GRB 250128B: Global MASTER-Net observations report
  7. Swift GRB 250129A: Global MASTER-Net OT detection
  8. GRB 250127A: EP-FXT afterglow detection
  9. Fermi GRB 250127B: Global MASTER-Net observations report
  10. GRB 250126A: MAXI/GSC detection
  11. GECAM-A detection of a bright burst from SGR 1E1841-045
  12. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  13. IPN triangulation of a bright burst from SGR 1E1841-045
  14. IPN triangulation of GRB 250119B
  15. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  16. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  17. GRB 250116A: GECAM-B detection of a long burst
  18. GRB 250114B: OHP/T193 optical upper limit
  19. EP250111a: Global MASTER-Net observations report
  20. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  21. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  22. IPN triangulation of GRB 250107D (short/hard)
  23. EP250109a: SVOM/VT optical candidate
  24. GRB 250106A: SVOM detection of a long burst
  25. Fermi trigger No 757753930: Global MASTER-Net observations report
  26. LIGO/Virgo/KAGRA S250104v: Identification of a GW compact binary merger candidate
  27. Swift GRB 250103B: Global MASTER-Net observations report
  28. EP241231b and EP250101a: EP-WXT detection of two X-ray transients
  29. Fermi GRB 250101B: Global MASTER-Net observations report
  30. GRB 250101A: SAO RAS optical observations
  31. LIGO/Virgo/KAGRA S241231bg: Identification of a GW compact binary merger candidate
  32. GRB 241228B: SAO RAS optical observations
  33. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  34. IceCube-Cascade 241228A: Upper limits from a search for additional neutrino events in IceCube
  35. GRB 241229A: EP-FXT afterglow candidates
  36. Fermi Gamma-ray Burst Monitor trigger 757207662/241229978 (GRB 241229C) is not a GRB
  37. GRB 241229C: Fermi GBM Final Real-time Localization
  38. GRB 241229B: Fermi GBM Observation
  39. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  40. Swift GRB 241229B: Global MASTER-Net observations report
  41. GRB 241229A: GOTO optical upper limits
  42. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  43. GRB 241229B: Fermi GBM Final Real-time Localization
  44. GRB 241223A: GRBAlpha detection
  45. LIGO/Virgo/KAGRA S241225v: Identification of a GW compact binary merger candidate
  46. GRB 241029A: AbAO AS-32 optical observations
  47. Fermi trigger No 756678579: Global MASTER-Net observations report
  48. IceCube Alert 241224.30: Global MASTER-Net observations report
  49. Fermi Gamma-ray Burst Monitor trigger 756678579 / 241223854 is not a GRB
  50. Fermi trigger No 756447119: Global MASTER-Net observations report
  51. Fermi GRB 241221A: Global MASTER-Net observations report
  52. EP241217a: Liverpool Telescope optical upper limit
  53. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  54. GRB 241218A: NUTTelA-TAO / BSTI Optical Limits
  55. EP241119a: 7DT Optical upper limits
  56. GRB 241213A: REM optical/NIR upper limits
  57. GRB 241207A: TSHAO Zeiss-1000 optical observations
  58. GRB 241129A: Fermi GBM Observation
  59. GRB 241209A: Swift-XRT refined Analysis
  60. LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
  61. EP241208a: Global MASTER-Net observations report
  62. LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate
  63. Fermi GRB 241209E: Global MASTER-Net observations report
  64. Fermi GRB 241209A: Global MASTER-Net observations report
  65. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  66. Fermi GRB 241207A: Global MASTER-Net observations report
  67. GRB 241204A: DDOTI Upper Limits on the Afterglow
  68. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  69. EP241202b: Global MASTER-Net observations report
  70. GRB 241128A: AbAO optical upper limit
  71. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  72. GRB 241128A: Swift-BAT refined analysis
  73. GRB 241128A: Mondy optical observations
  74. Swift GRB 241128A: Global MASTER-Net observations report
  75. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  76. GRB 241129A: Fermi GBM Final Real-time Localization
  77. SVOM/GRM observation of GRB 241126B or a short burst from magnetar
  78. EP241126a: TRT optical counterpart detection
  79. LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
  80. SVOM/GRM detection of a short burst from SGR 1830
  81. GECAM detection of a short burst from SGR 1830
  82. Konus-Wind detection of GRB 241115D / EP 241115a
  83. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  84. Fermi GRB 241118A: Global MASTER-Net observations report
  85. EP241113b: Global MASTER-Net observations report
  86. SVOM/GRM detection of a short burst from SGR 1E1841-045
  87. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  88. Fermi trigger No 752990530: Global MASTER-Net observations report
  89. Fermi trigger No 752878030: Global MASTER-Net observations report
  90. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  91. EP241107a: FTW Optical and NIR observations of the optical counterpart
  92. GRB 241030A: Mondy optical observations
  93. Fermi GRB 241105A: Global MASTER-Net observations report
  94. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  95. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  96. EP241021a: OHP/T193 further optical observations
  97. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  98. EP241103a: Global MASTER-Net observations report
  99. GRB 241029A: GRBAlpha detection
  100. GRB241030A: OHP/T193 optical observations

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