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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"

14925 results found.

  1. GRB 250302A: Fermi GBM Final Real-time Localization
  2. GRB 250228A: Fermi GBM Final Localization
  3. Konus-Wind detection of GRB 250226A
  4. GRB 250225B: EIRSAT-1 GMOD Detection
  5. EP250227a: Optical upper limits with Kinder observations
  6. EP250227a: Einstein Probe detected of a fast X-ray transient
  7. EP250225a: EP-FXT follow-up observation
  8. EP250228a: Einstein Probe detection of an X-ray transient
  9. GRB 250226A / EP250226a: LCO detection of the afterglow
  10. GRB 250226B: INTEGRAL SPI-ACS and PICsIT detection
  11. EP250226a/GRB 250226A: INTEGRAL SPI-ACS and PICsIT detection
  12. GRB 250225B: INTEGRAL SPI-ACS detection
  13. EP250225a: TRT optical upper limits
  14. LIGO/Virgo/KAGRA S250206dm: Upper limits from SVOM/GRM Observations
  15. LIGO/Virgo/KAGRA S250223dk: Insight-HXMT/HE sub-threshold detection of a burst (HEB 250223501)
  16. LIGO/Virgo/KAGRA S250227y: Retraction of GW compact binary merger candidate
  17. GRB 250226B: Fermi GBM Final Real-time Localization
  18. GRB 250221A: ATCA Detections and Upper Limits
  19. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Updated Sky localization and Coincidence with External Event
  20. Konus-Wind detection of GRB 250225B
  21. GRB 250225B: VLT/FORS2 candidate optical afterglow
  22. GRB 250226A: GECAM-B detection
  23. GRB 250221A: EP-FXT detection of the X-ray afterglow
  24. EP250226a/GRB 250226A: GSP detects optical counterpart
  25. EP250226a/GRB 250226A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  26. EP250226a / GRB 250226A: VLT/X-shooter redshift of z = 3.315
  27. EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
  28. GRB 250226A: Fermi GBM Final Real-time Localization
  29. EP250225a: GSP optical upper limit
  30. EP250225a: Einstein Probe detected of a fast X-ray transient
  31. GRB 250225B: Swift detection of a burst
  32. GRB 250225A: Fermi GBM Final Real-time Localization
  33. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
  34. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  35. GRB 250119B: VZLUSAT-2 detection
  36. GRB 250223C: Fermi GBM Final Real-time Localization
  37. GRB 250202B: VZLUSAT-2 detection
  38. GRB 250219A: EP-FXT afterglow detection
  39. EP250223a: COLIBRÍ/DDRAGO Detection of the Optical Counterpart and Slow Fading
  40. GRB 250210A: VZLUSAT-2 detection
  41. GRB 250206A: VZLUSAT-2 detection
  42. GRB 250221A: TNOT detection of the optical counterpart
  43. The EP-WXT trigger 01709131882 is likely a flaring star
  44. EP250223a: LCO detection of the afterglow
  45. EP250223a: early optical detection by BOOTES-4
  46. EP250223a: NOT redshift z = 2.756
  47. GRB 250223B: Fermi GBM Final Localization
  48. GRB 250221A: VLA radio detection
  49. GRB 250223A: Fermi GBM Final Real-time Localization
  50. EP250223a: Einstein Probe detection of an X-ray transient
  51. GRB 250221A: Optical counterpart detection by LCO.
  52. Konus-Wind detection of GRB 250221A
  53. EP250220a: EP-FXT follow-up observations
  54. GRB 250221A: GRANDMA/TAROT Detection
  55. GRB 250221A: 1.6m Mephisto optical detection
  56. GRB 250221A: Swift/UVOT Detection
  57. GRB 250221A: REM optical/NIR afterglow detection
  58. EP250220a: Liverpool Telescope optical upper limits
  59. EP250220a: Optical upper limit with Kinder observations
  60. SVOM trigger sb25022102 is not an astrophysical event
  61. SVOM/sb25022102: SVOM detection of an X-ray transient
  62. GRB 250221A: Swift detection of a burst with an optical counterpart
  63. Swift GRB250221.15: Global MASTER-Net OT detection
  64. EP250220a: Xinglong optical upper limit
  65. GRB 250220B: Fermi GBM Final Real-time Localization
  66. GRB 250220A: Fermi GBM Final Real-time Localization
  67. EP250220a: EP-WXT detection of a fast X-ray transient
  68. Konus-Wind detection of GRB 250217C (short)
  69. GRB 250219A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  70. GRB 250219A: 1.6m Mephisto optical upper limits
  71. GRB 250219A: SVOM detection of a burst
  72. Konus-Wind detection of GRB 250215A / EP250215a
  73. SVOM/sb25021804: QSO variability in Liverpool Telescope observations
  74. IPN triangulation of GRB 250217C (short)
  75. Transient SVOM/sb25021804: COLIBRÍ/DDRAGO Optical Upper Limits on the Optical Counterpart
  76. SVOM/sb25021804: SVOM detection of a long X-ray transient
  77. GRB 250216A: AstroSat CZTI detection
  78. GRB 250217C: AstroSat CZTI detection of a short burst
  79. GRB 250217C: Fermi GBM Final Real-time Localization
  80. GRANDMA/OPD observations of GRB250215A
  81. GRB 250217B: Fermi GBM Final Real-time Localization
  82. GRB 250217A: Fermi GBM Final Real-time Localization
  83. GRB 250215A / EP250215a: LCO detection of the afterglow
  84. GRB 250216A: Fermi GBM Final Real-time Localization
  85. GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  86. EP250215a / GRB 250215A : GTC redshift z = 4.61
  87. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  88. EP250215a / GRB 250215A: AstroSat CZTI detection
  89. EP250215A/GRB 250215A: INTEGRAL SPI-ACS detection
  90. EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
  91. GRB 250215A: Fermi GBM Final Real-time Localization
  92. EP250207b: Xinglong optical upper limit
  93. GRB 250214A: Fermi GBM Final Real-time Localization
  94. EP250212a: Xinglong optical upper limit
  95. GRB 250213A: SVOM detection of a burst
  96. GRB 250205A: VIRT Optical Upper Limit
  97. GRB 250205A: Leavitt Observatory optical upper limit
  98. GRB 250210A: GRBAlpha detection
  99. LIGO/Virgo/KAGRA S250206dm: FTW observations of counterpart candidates AT2025bbo and AT2025bcx, and of NED galaxies
  100. EP250212a: Liverpool Telescope optical upper limits

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