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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"

41974 results found.

  1. GRB 250804B: Tiled Swift observations
  2. Fermi trigger No 776041355: Global MASTER-Net observations report
  3. GRB 250804B: SVOM/GRM observation of a short burst
  4. GRB 250804A: Fermi GBM Final Localization
  5. EP250802a: additional Liverpool Telescope upper limits
  6. EP250730a: SVOM/VT optical upper limit
  7. EP250802a: Liverpool Telescope optical upper limits
  8. EP250802a: Global MASTER-Net observations report
  9. EP250802a: GROWTH-India Telescope optical upper limit
  10. EP250802a: Einstein Probe detection of an X-ray transient
  11. The EP-WXT trigger 01709198251 is likely a flaring star
  12. LIGO/Virgo/KAGRA S250802dn: Identification of a GW compact binary merger candidate
  13. The EP-WXT trigger 01709198202 is likely a flaring star
  14. LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
  15. GRB 250702B: SMA observations
  16. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS candidates
  17. LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
  18. EP250711a: CrAO and Assy optical observations
  19. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  20. EP250730a: Global MASTER-Net observations report
  21. EP250730a: COLIBRÍ optical upper limit
  22. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  23. EP250730a: Einstein Probe detection of an X-ray transient
  24. LIGO/Virgo/KAGRA S250725j: DECam DESGW Epoch 1-2 Candidates
  25. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  26. GRB 250725A: AstroSat CZTI detection
  27. GRB 250727A: EP-FXT follow-up observation
  28. GRB 250725A: PRIME near-infrared observations
  29. LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS upper limits of AT 2025smm
  30. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  31. GRB: Clarification on Gamma-Ray Burst Naming Convention
  32. GRB 250728A: Swift-XRT observations
  33. GRB 250727A: SVOM/ECLAIRs refined analysis
  34. EP-WXT trigger 01709195487: confirmation of a stellar flare by BOOTES-6 & BOOTES-7
  35. GRB 250728A: COLIBRÍ optical upper limit
  36. GRB 250728A: Fermi GBM Observation
  37. Fermi trigger No 775387550: Global MASTER-Net observations report
  38. LIGO/Virgo/KAGRA S250727dc: Updated Sky localization
  39. LIGO/Virgo/KAGRA S250727dc: Swift-UVOT detection of a new source, AT 2025smm
  40. GRB 250728A: Swift ToO observations
  41. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
  42. GRB 250727A: AST3-2 Upper limit
  43. GRB 250727A: EP-FXT counterpart detection
  44. GRB250727A: SVOM/VT optical upper limit
  45. GRB 250727A: Swift-XRT observations
  46. LIGO/Virgo/KAGRA S250727dc: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S250727cl: Identification of a GW compact binary merger candidate
  48. LIGO/Virgo/KAGRA S250725j: DECam GW-MMADS candidates
  49. GRB 250727A: SVOM detection of a burst
  50. The EP-WXT trigger 01709195487 is likely a flaring star
  51. Swift detection of the Soft Gamma Repeater PSR J1647-4552
  52. LIGO/Virgo/KAGRA S250726ak: Identification of a GW compact binary merger candidate
  53. GRB 250725A: Swift-XRT refined Analysis
  54. GRB 250725A: Fermi GBM Observation
  55. LIGO/Virgo/KAGRA S250725j: Updated Sky localization
  56. GRB 250725A: Swift-BAT refined analysis
  57. Konus-Wind detection of GRB 250725A
  58. LIGO/Virgo/KAGRA S250725j: NED Galaxies in the 3-Initial Localization Volume
  59. GRB 250725A: SVOM/GRM observation
  60. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  61. GRB 250725A: Swift/UVOT Upper Limits
  62. GRB 250725A: Fermi-LAT detection
  63. GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
  64. GRB 250725A: BOOTES-7 early optical detection
  65. GRB 250725A: SVOM/VT optical candidate
  66. LIGO/Virgo/KAGRA S250725l: Identification of a GW compact binary merger candidate
  67. LIGO/Virgo/KAGRA S250725j: Identification of a GW compact binary merger candidate
  68. GRB 250725A: Enhanced Swift-XRT position
  69. GRB 250725A: Swift detection of a burst
  70. GRB 250725A: Fermi GBM Final Real-time Localization
  71. Fermi GRB 250725A: Global MASTER-Net observations report
  72. Swift GRB 250725A: Global MASTER-Net observations report
  73. EP250702a/GRB250702 B,E,D: MeerKAT radio observations at 3.06 GHz
  74. EP250702a/GRB250702 B,D,E: uGMRT Radio detection in 1.26 GHz
  75. SVOM J195836+32283/sb25072103: Second VT observation
  76. SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
  77. GRB 250723B: Fermi GBM Final Real-time Localization
  78. GRB 250721A: Fermi GBM Observation
  79. GRB 250723A: Fermi GBM Final Real-time Localization
  80. SVOM J195836+32283/sb25072103: Swift XRT/UVOT upper limits
  81. SVOM J195836+32283/sb25072103: NIR observations with WINTER
  82. GRB 250721A: Swift-XRT observations
  83. GRB 250722A: Fermi GBM Final Real-time Localization
  84. GRB 250713A : SVOM/ECLAIRs refined analysis
  85. GRB 250717B: SVOM/GRM observation
  86. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  87. GRB 250721A: Tiled Swift observations
  88. GRB 250721A: MAXI/GSC detection
  89. GRB 250721A: Fermi GBM Final Localization
  90. GRB 250720B: Fermi GBM Final Localization Correction
  91. GRB 250720A: Fermi GBM Final Localization
  92. Fermi trigger No 774730635: Global MASTER-Net observations report
  93. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  94. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  95. GRB 250717B: COLIBRÍ optical upper limit
  96. GRB 250717B: Swift-XRT observations
  97. GRB 250718B: Fermi GBM Final Localization Correction
  98. GRB 250718B: Fermi GBM Final Real-time Localization
  99. Swift Trigger 1334535 / GRB 250718A: COLIBRÍ optical upper limits
  100. Swift Trigger 1334535: a possible GRB 250718A

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