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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"

28269 results found.

  1. EP250223a: J band upper limit by SYSU 80cm telescope
  2. EP250228a: Swift/XRT localisation
  3. EP250228a: Einstein Probe detection of an X-ray transient
  4. GRB 250226A / EP250226a: LCO detection of the afterglow
  5. LIGO/Virgo/KAGRA S250227e: Updated Sky localization
  6. LIGO/Virgo/KAGRA S250226dl: Updated Sky localization
  7. GRB 250225B: VLT/Xshooter imaging
  8. GRB 250205A / EP250205A: further radio observations with the VLA
  9. EP250225a: NOT optical candidate counterpart
  10. EP250226a/GRB 250226A:Xinglong optical follow-up observations
  11. EP250226a/GRB 250226A: refined analysis of the EP-WXT and FXT observations
  12. EP250225a: TRT optical upper limits
  13. EP250226a/GRB 250226A: 1.6m Mephisto observations
  14. LIGO/Virgo/KAGRA S250206dm: Upper limits from SVOM/GRM Observations
  15. EP250226a/GRB 250226A: Kinder optical follow-up observations
  16. LIGO/Virgo/KAGRA S250223dk: Insight-HXMT/HE sub-threshold detection of a burst (HEB 250223501)
  17. LIGO/Virgo/KAGRA S250227e: Identification of a GW compact binary merger candidate
  18. LIGO/Virgo/KAGRA S250226dl: Identification of a GW compact binary merger candidate
  19. GRB 250225B: Fermi GBM Observation
  20. GRB 250225B: REM NIR upper limits
  21. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Updated Sky localization and Coincidence with External Event
  22. LIGO/Virgo/KAGRA S250223dk: DECam optical detections of Swift X-ray sources
  23. EP250223a: CrAO ZTSH optical observation
  24. GRB 250225B: VLT optical and near-infrared candidate counterpart
  25. GRB 250225B: SVOM/GRM observation of a long burst
  26. EP250226a/GRB 250226A: GSP detects optical counterpart
  27. EP250226a/GRB 250226A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  28. EP250226a / GRB 250226A: TRT optical counterpart observation
  29. LIGO/Virgo S250223dk: Swift XRT observations, 7 X-ray sources
  30. EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
  31. EP250225a: GSP optical upper limit
  32. EP250223a: GMG Optical Observation
  33. EP250225a: Einstein Probe detected of a fast X-ray transient
  34. GRB 250225B: Swift detection of a burst
  35. EP250223a: GROWTH-India Telescope optical observations
  36. GRB 250221A: Swift-BAT refined analysis
  37. EP250215A: J band upper limit by SYSU 80cm telescope
  38. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: DECam GW-MMADS candidates
  39. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
  40. EP250223a: Kinder optical follow-up observations
  41. LIGO/Virgo/KAGRA S250223dk: DECam DESGW Candidates
  42. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  43. GRB 250119B: VZLUSAT-2 detection
  44. GOTO observations of LVK S250223dk/Swift-BAT RAVEN alert
  45. GRB 250202B: VZLUSAT-2 detection
  46. GRB 250222A: SVOM/GRM observation of a burst
  47. EP250223a: COLIBRÍ/DDRAGO Detection of the Optical Counterpart and Slow Fading
  48. GRB 250206A: VZLUSAT-2 detection
  49. EP250223a: REM NIR upper limit
  50. EP250223a: TRT optical afterglow observation
  51. EP250223a: refined analysis of the EP-WXT and FXT observations
  52. EP250223a: 1.6m Mephisto and 50cm array observations
  53. LIGO/Virgo/KAGRA S250223dk: DDOTI Upper Limits on the Optical Counterpart
  54. 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
  55. EP250223a: OASDG optical observations
  56. EP250223a: LCO detection of the afterglow
  57. EP250223a: Swift/XRT localization
  58. EP250223a: NOT optical afterglow candidate
  59. EP250223a: Einstein Probe detection of an X-ray transient
  60. LIGO/Virgo/KAGRA S250206dm: Upper limits from IceCube neutrino searches
  61. GRB 250221A: Optical counterpart detection by LCO.
  62. GRB 250219A: NUTTelA-TAO / BSTI Optical Limits
  63. GRB 250221A: GRANDMA/TAROT Detection
  64. GRB 250221A: Swift-XRT refined Analysis
  65. GRB 250221A: NOT optical observations
  66. GRB 250221A: 1.6m Mephisto optical detection
  67. GRB 250221A: AKO Optical Upper Limit
  68. GRB 250221A: Swift/UVOT Detection
  69. EP250220a: Liverpool Telescope upper limits
  70. GRB 250219A: GRANDMA/Kilonova-Catcher upper limits
  71. GRB 250221A: REM optical/NIR afterglow detection
  72. IceCube-250207A: MASTER flaring blazar QSOJ0854+2006 with Zhirkov effect
  73. GRB 250221A: Enhanced Swift-XRT position
  74. EP250220a: 1.6m Mephisto observations
  75. EP250220a: Liverpool Telescope optical upper limits
  76. EP250220a: Optical upper limit with Kinder observations
  77. SVOM trigger sb25022102 is not an astrophysical event
  78. GRB 250221A: COLIBRÍ/DDRAGO Confirmation of a Bright Optical Counterpart
  79. GRB 250221A: Swift detection of a burst with an optical counterpart
  80. Swift GRB250221.15: Global MASTER-Net OT detection
  81. EP250220a: Xinglong optical upper limit
  82. GRB 250219A: Swift/UVOT Upper Limits
  83. GRB 250219A: OHP/T193 optical upper limit
  84. GRB 250219A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  85. GRB 250219A: 1.6m Mephisto optical upper limits
  86. GRB 250219A: Swift-XRT observations
  87. LIGO/Virgo/KAGRA S250206dm: Upper limits from MSU cubesats observations
  88. Konus-Wind detection of GRB 250215A / EP250215a
  89. SVOM/sb25021804: COLIBRÍ/DDRAGO Confirmation of Variability
  90. GRB 250217C: Swift-XRT observations
  91. SVOM/sb25021804: QSO variability in Liverpool Telescope observations
  92. GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
  93. GRB 250217C: DDOTI Upper Limits on the Optical Afterglow
  94. GRB 250217C: SVOM/GRM observation
  95. Transient SVOM/sb25021804: COLIBRÍ/DDRAGO Optical Upper Limits on the Optical Counterpart
  96. SVOM/sb25021804: SVOM detection of a long X-ray transient
  97. GRB 250213A: Swift-XRT observations
  98. GRB 250216A: AstroSat CZTI detection
  99. GRB 250217C: AstroSat CZTI detection of a short burst
  100. IceCube-Cascade 250215A: Upper limits from a search for additional neutrino events in IceCube

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