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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"

43117 results found.

  1. GRB 250206A: VZLUSAT-2 detection
  2. EP250223a: REM NIR upper limit
  3. EP250223a: TRT optical afterglow observation
  4. EP250223a: refined analysis of the EP-WXT and FXT observations
  5. EP250223a: 1.6m Mephisto and 50cm array observations
  6. GRB 250221A: TNOT detection of the optical counterpart
  7. EP250223a: SVOM/VT optical observation
  8. LIGO/Virgo/KAGRA S250223dk: DDOTI Upper Limits on the Optical Counterpart
  9. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO trigger with ID 762004910: Identification of a GW compact binary merger candidate possibly associated with a sub-threshold Swift/BAT-GUANO trigger
  10. The EP-WXT trigger 01709131882 is likely a flaring star
  11. EP250223a: OASDG optical observations
  12. EP250223a: LCO detection of the afterglow
  13. EP250223a: early optical detection by BOOTES-4
  14. EP250223a: NOT redshift z = 2.756
  15. EP250223a: Swift/XRT localization
  16. EP250223a: NOT optical afterglow candidate
  17. GRB 250223B: Fermi GBM Final Localization
  18. EP250223a: Global MASTER-Net observations report
  19. Fermi GRB 250223A: Global MASTER-Net observations report
  20. Fermi trigger No 762020305: Global MASTER-Net observations report
  21. GRB 250223A: Fermi GBM Final Real-time Localization
  22. EP250223a: Einstein Probe detection of an X-ray transient
  23. LIGO/Virgo/KAGRA S250206dm: Upper limits from IceCube neutrino searches
  24. GRB 250221A: Optical counterpart detection by LCO.
  25. Konus-Wind detection of GRB 250221A
  26. EP250220a: FTW optical and NIR observations and upper limits
  27. EP250220a: EP-FXT follow-up observations
  28. GRB 250219A: NUTTelA-TAO / BSTI Optical Limits
  29. GRB 250221A: VLT/X-shooter redshift z = 0.768
  30. GRB 250221A: GRANDMA/TAROT Detection
  31. Fermi trigger No 761805304: Global MASTER-Net observations report
  32. GRB 250221A: Swift-XRT refined Analysis
  33. GRB 250221A: NOT optical observations
  34. GRB 250221A: 1.6m Mephisto optical detection
  35. LIGO/Virgo/KAGRA S250221gb: Retraction of GW compact binary merger candidate
  36. GRB 250221A: AKO Optical Upper Limit
  37. GRB 250221A: Swift/UVOT Detection
  38. EP250220a: Liverpool Telescope upper limits
  39. GRB 250219A: GRANDMA/Kilonova-Catcher upper limits
  40. GRB 250221A: REM optical/NIR afterglow detection
  41. IceCube-250207A: MASTER flaring blazar QSOJ0854+2006 with Zhirkov effect
  42. GRB 250221A: Enhanced Swift-XRT position
  43. LIGO/Virgo/KAGRA S250221eb: Retraction of GW compact binary merger candidate
  44. EP250220a: 1.6m Mephisto observations
  45. EP250220a: Liverpool Telescope optical upper limits
  46. EP250220a: Optical upper limit with Kinder observations
  47. SVOM trigger sb25022102 is not an astrophysical event
  48. SVOM/sb25022102: SVOM detection of an X-ray transient
  49. GRB 250221A: COLIBRÍ/DDRAGO Confirmation of a Bright Optical Counterpart
  50. GRB 250221A: Swift detection of a burst with an optical counterpart
  51. Swift GRB250221.15: Global MASTER-Net OT detection
  52. Swift GRB250221.15: Global MASTER-Net observations report
  53. GRB 250220B: Fermi GBM Final Real-time Localization
  54. GRB 250220A: Fermi GBM Final Real-time Localization
  55. EP250220a: Global MASTER-Net observations report
  56. EP250220a: EP-WXT detection of a fast X-ray transient
  57. Konus-Wind detection of GRB 250217C (short)
  58. GRB 250219A: Swift/UVOT Upper Limits
  59. GRB 250219A: OHP/T193 optical upper limit
  60. GRB 250219A: NOT optical observations
  61. GRB 250219A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  62. GRB 250219A: 1.6m Mephisto optical upper limits
  63. GRB 250219A: SVOM/VT optical counterpart
  64. GRB 250219A: Swift-XRT observations
  65. LIGO/Virgo/KAGRA S250206dm: Upper limits from MSU cubesats observations
  66. GRB 250219A: Swift ToO observations
  67. GRB 250219A: SVOM detection of a burst
  68. Konus-Wind detection of GRB 250215A / EP250215a
  69. SVOM/sb25021804: COLIBRÍ/DDRAGO Confirmation of Variability
  70. GRB 250217C: Swift-XRT observations
  71. SVOM/sb25021804: QSO variability in Liverpool Telescope observations
  72. GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
  73. GRB 250217C: DDOTI Upper Limits on the Optical Afterglow
  74. GRB 250217C: SVOM/GRM observation
  75. GRB 250217C: Tiled Swift observations
  76. GRB 250217C: Fermi GBM Observation
  77. GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61
  78. IPN triangulation of GRB 250217C (short)
  79. Transient SVOM/sb25021804: COLIBRÍ/DDRAGO Optical Upper Limits on the Optical Counterpart
  80. SVOM/sb25021804: SVOM detection of a long X-ray transient
  81. GRB 250213A: Swift-XRT observations
  82. LIGO/Virgo/KAGRA S250206dm: AZT-33IK Target Optical Observations
  83. GRB 250216A: AstroSat CZTI detection
  84. GRB 250217C: AstroSat CZTI detection of a short burst
  85. Fermi GRB 250217C: Global MASTER-Net observations report
  86. GRB 250217C: Fermi GBM Final Real-time Localization
  87. IceCube-Cascade 250215A: Upper limits from a search for additional neutrino events in IceCube
  88. LIGO/Virgo/KAGRA S250206dm: observation in AbAO, optical transient near NED/GLADE+ galaxy WISEA J021210.14+514821.7
  89. Fermi GRB 250217A: Global MASTER-Net observations report
  90. GRANDMA/OPD observations of GRB250215A
  91. GRB 250217B: Fermi GBM Final Real-time Localization
  92. The EP-WXT trigger 01709131775 is likely a flaring star
  93. GRB 250217A: Fermi GBM Final Real-time Localization
  94. Fermi GRB 250216A: Global MASTER-Net observations report
  95. GRB 250215A / EP250215a: LCO detection of the afterglow
  96. GRB 250216A: Fermi GBM Final Real-time Localization
  97. EP250212a: FTW optical and NIR upper limits
  98. GRB 250215A: Swift/UVOT Upper Limits
  99. GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  100. EP250215a / GRB 250215A : GTC redshift z = 4.61

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