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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"

45890 results found.

  1. EP250711a: CrAO and Assy optical observations
  2. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  3. EP250730a: Global MASTER-Net observations report
  4. EP250730a: COLIBRÍ optical upper limit
  5. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  6. EP250730a: Einstein Probe detection of an X-ray transient
  7. LIGO/Virgo/KAGRA S250725j: DECam DESGW Epoch 1-2 Candidates
  8. LIGO/Virgo/KAGRA S250727dc: Swift-UVOT follow up of AT 2025smm
  9. LIGO/Virgo/KAGRA S250726ak: Upper limits from Swift/BAT-GUANO
  10. LIGO/Virgo/KAGRA S250725l: Upper limits from Swift/BAT-GUANO
  11. LIGO/Virgo/KAGRA S250727dc: Upper limits from Swift/BAT-GUANO
  12. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  13. GRB 250725A: AstroSat CZTI detection
  14. GRB 250727A: EP-FXT follow-up observation
  15. GRB 250725A: PRIME near-infrared observations
  16. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS upper limits of AT 2025smm
  17. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  18. GRB: Clarification on Gamma-Ray Burst Naming Convention
  19. GRB 250728A: Swift-XRT observations
  20. GRB 250727A: SVOM/ECLAIRs refined analysis
  21. EP-WXT trigger 01709195487: confirmation of a stellar flare by BOOTES-6 & BOOTES-7
  22. GRB 250728A: COLIBRÍ optical upper limit
  23. GRB 250728A: Fermi GBM Observation
  24. Fermi trigger No 775387550: Global MASTER-Net observations report
  25. LIGO/Virgo/KAGRA S250727dc: Updated Sky localization
  26. LIGO/Virgo/KAGRA S250727dc: Swift-UVOT detection of a new source, AT 2025smm
  27. GRB 250728A: Swift ToO observations
  28. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
  29. GRB 250727A: AST3-2 Upper limit
  30. LIGO/Virgo/KAGRA S250727cl: Updated Sky localization
  31. GRB 250727A: EP-FXT counterpart detection
  32. GRB250727A: SVOM/VT optical upper limit
  33. GRB 250727A: Swift-XRT observations
  34. LIGO/Virgo/KAGRA S250727dc: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S250727cl: Identification of a GW compact binary merger candidate
  36. LIGO/Virgo/KAGRA S250725j: DECam GW-MMADS candidates
  37. GRB 250727A: SVOM detection of a burst
  38. LIGO/Virgo/KAGRA S250725l: Updated Sky localization
  39. LIGO/Virgo/KAGRA S250726ak: Updated Sky localization
  40. The EP-WXT trigger 01709195487 is likely a flaring star
  41. Swift detection of the Soft Gamma Repeater PSR J1647-4552
  42. LIGO/Virgo/KAGRA S250726ak: Identification of a GW compact binary merger candidate
  43. GRB 250725A: Swift-XRT refined Analysis
  44. GRB 250725A: Fermi GBM Observation
  45. LIGO/Virgo/KAGRA S250725j: Updated Sky localization
  46. GRB 250725A: Swift-BAT refined analysis
  47. Konus-Wind detection of GRB 250725A
  48. LIGO/Virgo/KAGRA S250725j: NED Galaxies in the 3-Initial Localization Volume
  49. GRB 250725A: SVOM/GRM observation
  50. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  51. GRB 250725A: Swift/UVOT Upper Limits
  52. GRB 250725A: Fermi-LAT detection
  53. GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
  54. GRB 250725A: BOOTES-7 early optical detection
  55. GRB 250725A: SVOM/VT optical candidate
  56. GRB 250725A: MASTER-OAFA optical detection of very fast afterglow
  57. LIGO/Virgo/KAGRA S250725l: Identification of a GW compact binary merger candidate (duplicate submission)
  58. LIGO/Virgo/KAGRA S250725l: Identification of a GW compact binary merger candidate
  59. LIGO/Virgo/KAGRA S250725j: Identification of a GW compact binary merger candidate
  60. GRB 250725A: Enhanced Swift-XRT position
  61. GRB 250725A: Swift detection of a burst
  62. Swift GRB 250725A: Global MASTER-Net OT detection
  63. GRB 250725A: Fermi GBM Final Real-time Localization
  64. Fermi GRB 250725A: Global MASTER-Net observations report
  65. Swift GRB 250725A: Global MASTER-Net observations report
  66. EP250702a/GRB250702 B,E,D: MeerKAT radio observations at 3.06 GHz
  67. SVOM J195836+32283 is not a real source
  68. EP250702a/GRB250702 B,D,E: uGMRT Radio detection in 1.26 GHz
  69. SVOM J195836+32283/sb25072103: Second VT observation
  70. SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
  71. GRB 250723B: Fermi GBM Final Real-time Localization
  72. GRB 250721A: Fermi GBM Observation
  73. GRB 250723A: Fermi GBM Final Real-time Localization
  74. SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits
  75. SVOM J195836+32283/sb25072103: NIR observations with WINTER
  76. Swift-BAT trigger 1334535 is not a GRB
  77. GRB 250721A: Swift-XRT observations
  78. GRB 250722A: Fermi GBM Final Real-time Localization
  79. GRB 250713A : SVOM/ECLAIRs refined analysis
  80. GRB 250717B: SVOM/GRM observation
  81. LIGO/Virgo/KAGRA S250711q: Updated Sky localization
  82. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  83. GRB 250721A: Tiled Swift observations
  84. GRB 250721A: MAXI/GSC detection
  85. GRB 250721A: Fermi GBM Final Localization
  86. GRB 250720B: Fermi GBM Final Localization Correction
  87. GRB 250720A: Fermi GBM Final Localization
  88. Fermi trigger No 774730635: Global MASTER-Net observations report
  89. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  90. Fermi Gamma-ray Burst Monitor trigger 774670514/250720094 is not a GRB
  91. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  92. GRB 250717B: COLIBRÍ optical upper limit
  93. LIGO/Virgo/KAGRA S250711q: Upper limits from Swift/BAT-GUANO
  94. GRB 250717B: Swift-XRT observations
  95. GRB 250718B: Fermi GBM Final Localization Correction
  96. GRB 250718B: Fermi GBM Final Real-time Localization
  97. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  98. Swift Trigger 1334535: a possible GRB 250718A
  99. Swift GRB250718.01: Global MASTER-Net observations report
  100. GRB 250717B: Swift ToO observations

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