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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"

26730 results found.

  1. Konus-Wind detection of GRB 250225B
  2. LIGO/Virgo/KAGRA S250223dk: DECam optical detections of Swift X-ray sources
  3. EP250223a: CrAO ZTSH optical observation
  4. GRB 250225B: VLT optical and near-infrared candidate counterpart
  5. GRB 250225B: SVOM/GRM observation of a long burst
  6. GRB 250221A: EP-FXT detection of the X-ray afterglow
  7. EP250226a/GRB 250226A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  8. EP250226a / GRB 250226A: TRT optical counterpart observation
  9. LIGO/Virgo S250223dk: Swift XRT observations, 7 X-ray sources
  10. EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
  11. EP250223a: GMG Optical Observation
  12. EP250225a: Einstein Probe detected of a fast X-ray transient
  13. EP250223a: GROWTH-India Telescope optical observations
  14. EP250215A: J band upper limit by SYSU 80cm telescope
  15. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: DECam GW-MMADS candidates
  16. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
  17. EP250223a: Kinder optical follow-up observations
  18. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  19. GRB 250119B: VZLUSAT-2 detection
  20. GOTO observations of LVK S250223dk/Swift-BAT RAVEN alert
  21. GRB 250202B: VZLUSAT-2 detection
  22. GRB 250219A: EP-FXT afterglow detection
  23. GRB 250222A: SVOM/GRM observation of a burst
  24. EP250223a: COLIBRÍ/DDRAGO Detection of the Optical Counterpart and Slow Fading
  25. GRB 250210A: VZLUSAT-2 detection
  26. GRB 250206A: VZLUSAT-2 detection
  27. EP250223a: REM NIR upper limit
  28. EP250223a: TRT optical afterglow observation
  29. EP250223a: refined analysis of the EP-WXT and FXT observations
  30. EP250223a: 1.6m Mephisto and 50cm array observations
  31. LIGO/Virgo/KAGRA S250223dk: DDOTI Upper Limits on the Optical Counterpart
  32. 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
  33. The EP-WXT trigger 01709131882 is likely a flaring star
  34. EP250223a: OASDG optical observations
  35. EP250223a: Swift/XRT localization
  36. EP250223a: NOT optical afterglow candidate
  37. EP250223a: Einstein Probe detection of an X-ray transient
  38. LIGO/Virgo/KAGRA S250206dm: Upper limits from IceCube neutrino searches
  39. GRB 250221A: Optical counterpart detection by LCO.
  40. Konus-Wind detection of GRB 250221A
  41. EP250220a: EP-FXT follow-up observations
  42. GRB 250219A: NUTTelA-TAO / BSTI Optical Limits
  43. GRB 250221A: GRANDMA/TAROT Detection
  44. GRB 250221A: Swift-XRT refined Analysis
  45. GRB 250221A: 1.6m Mephisto optical detection
  46. GRB 250221A: AKO Optical Upper Limit
  47. GRB 250221A: Swift/UVOT Detection
  48. EP250220a: Liverpool Telescope upper limits
  49. GRB 250219A: GRANDMA/Kilonova-Catcher upper limits
  50. GRB 250221A: REM optical/NIR afterglow detection
  51. GRB 250221A: Enhanced Swift-XRT position
  52. EP250220a: 1.6m Mephisto observations
  53. EP250220a: Liverpool Telescope optical upper limits
  54. EP250220a: Optical upper limit with Kinder observations
  55. SVOM trigger sb25022102 is not an astrophysical event
  56. SVOM/sb25022102: SVOM detection of an X-ray transient
  57. GRB 250221A: COLIBRÍ/DDRAGO Confirmation of a Bright Optical Counterpart
  58. GRB 250221A: Swift detection of a burst with an optical counterpart
  59. EP250220a: Xinglong optical upper limit
  60. EP250220a: EP-WXT detection of a fast X-ray transient
  61. GRB 250219A: Swift/UVOT Upper Limits
  62. GRB 250219A: OHP/T193 optical upper limit
  63. GRB 250219A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  64. GRB 250219A: 1.6m Mephisto optical upper limits
  65. GRB 250219A: Swift-XRT observations
  66. LIGO/Virgo/KAGRA S250206dm: Upper limits from MSU cubesats observations
  67. GRB 250219A: SVOM detection of a burst
  68. SVOM/sb25021804: COLIBRÍ/DDRAGO Confirmation of Variability
  69. GRB 250217C: Swift-XRT observations
  70. SVOM/sb25021804: QSO variability in Liverpool Telescope observations
  71. GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
  72. GRB 250217C: DDOTI Upper Limits on the Optical Afterglow
  73. GRB 250217C: SVOM/GRM observation
  74. GRB 250217C: Fermi GBM Observation
  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 250213A: Swift-XRT observations
  78. IceCube-Cascade 250215A: Upper limits from a search for additional neutrino events in IceCube
  79. GRANDMA/OPD observations of GRB250215A
  80. The EP-WXT trigger 01709131775 is likely a flaring star
  81. GRB 250215A / EP250215a: LCO detection of the afterglow
  82. GRB 250215A: Swift/UVOT Upper Limits
  83. GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  84. EP250215a / GRB 250215A : GTC redshift z = 4.61
  85. GRB 250215A: Fermi GBM Observation
  86. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  87. GRB 250213A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  88. GRB 250215A: Swift-XRT refined Analysis
  89. GRB 250215A: SVOM/GRM observation
  90. EP250215a / GRB 250215A (potentially): NOT likely optical counterpart
  91. EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
  92. EP250207b: Xinglong optical upper limit
  93. EP250212a: Xinglong optical upper limit
  94. LIGO/Virgo/KAGRA S250206dm: DECam GW-MMADS candidates
  95. GRB 250213A: SVOM detection of a burst
  96. GRB 250205A: VIRT Optical Upper Limit
  97. GRB 250205A: Leavitt Observatory optical upper limit
  98. EP250207B: Chandra localization of the X-ray counterpart
  99. EP250212a: Liverpool Telescope optical upper limits
  100. EP250212a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient

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