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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"

20008 results found.

  1. Konus-Wind detection of GRB 250308A
  2. GRB 250313A: Fermi-LAT detection
  3. GRB 250313A: Swift ToO observations
  4. GRB 250312B: Swift/BAT-GUANO localization skymap of a burst
  5. EP250304a: SVOM/VT optical observation
  6. EP250302a: Chandra X-ray Detection
  7. GRB 250312A: Swift-XRT refined Analysis
  8. GRB 250312A: Enhanced Swift-XRT position
  9. LIGO/Virgo/KAGRA S250304cb: Upper limits from Swift/BAT-GUANO
  10. GRB 250226B: Fermi GBM Observation
  11. Swift GRB 250312A: Global MASTER-Net observations report
  12. GRB 250302A: Fermi GBM Observation
  13. GRB 250312A: Swift detection of a burst
  14. GRB 250223B: Fermi GBM Observation
  15. GRB 250311A: Swift-XRT observations
  16. GRB 250228A: Fermi GBM Observation
  17. GRB 250309B: 1.3m DFOT Optical observations
  18. GRB 250308A: Swift/BAT-GUANO localization skymap of a short burst
  19. GRB 250302A: Swift/BAT-GUANO localization skymap of a burst
  20. GRB 250228A: Swift/BAT-GUANO localization skymap of a likely short burst
  21. GRB 250226B: Swift/BAT-GUANO localization skymap of a likely long GRB
  22. GRB 250226A: Swift/BAT-GUANO localization skymap of a long GRB
  23. GRB 250223B: Swift/BAT-GUANO localization skymap of a short burst
  24. EP250304a: Chandra detection
  25. GRB 250225B: Swift-BAT refined analysis
  26. GRB 250311A: Tiled Swift observations
  27. IPN triangulation of GRB 250308A (short)
  28. GRB 250309B: Swift-XRT refined Analysis
  29. GRB 250309B / AT2025dws: Swift-UVOT detection
  30. GRB250309B: One candidate counterpart from the Zwicky Transient Facility
  31. Correction to GCN 39633 - Swift is observing GRB 250309B/IceCube-250309A!
  32. GRB 230509B: Tiled Swift observations
  33. GRB 250306A: EIRSAT-1 GMOD detection
  34. Konus-Wind detection of GRB 250306A
  35. GRB 250306A: Swift-BAT refined analysis
  36. GRB 250306A: NuSTAR detection of the prompt emission
  37. GRB 250306A: AstroSat CZTI detection
  38. Swift GRB 250306A: Global MASTER-Net observations report
  39. GRB 250306A: Swift detection of a burst
  40. IPN triangulation of GRB 250222A
  41. EP250304a: Swift/UVOT detection of an optical counterpart with a rising light curve
  42. EP250304a: Swift-XRT detection of a fading X-ray source
  43. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Swift/UVOT Upper Limits
  44. EP250302a: Swift/UVOT detection
  45. EP250302a: Swift-XRT observations of a fading X-ray source
  46. EP250228a: Optical observations with Kinder and Swift/UVOT
  47. GRB 250225B: EIRSAT-1 GMOD Detection
  48. GRB 250225B: VLT/HAWKI near-infrared observations
  49. EP250228a: updates on the EP observations
  50. EP250228a: Swift/XRT localisation
  51. GRB 250225B: INTEGRAL SPI-ACS detection
  52. LIGO/Virgo/KAGRA S250223dk: Insight-HXMT/HE sub-threshold detection of a burst (HEB 250223501)
  53. GRB 250225B: Fermi GBM Observation
  54. GRB 250221A: ATCA Detections and Upper Limits
  55. GRB 250225B: REM NIR upper limits
  56. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Updated Sky localization and Coincidence with External Event
  57. Konus-Wind detection of GRB 250225B
  58. LIGO/Virgo/KAGRA S250223dk: DECam optical detections of Swift X-ray sources
  59. GRB 250225B: VLT/FORS2 candidate optical afterglow
  60. GRB 250225B: SVOM/GRM observation of a long burst
  61. GRB 250221A: EP-FXT detection of the X-ray afterglow
  62. LIGO/Virgo S250223dk: Swift XRT observations, 7 X-ray sources
  63. Swift GRB 250225B: Global MASTER-Net observations report
  64. GRB 250225B: Swift detection of a burst
  65. GRB 250221A: Swift-BAT refined analysis
  66. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: DECam GW-MMADS candidates
  67. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
  68. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Magellan upper limits.
  69. GRB 250207a: ATCA Radio Upper Limits
  70. LIGO/Virgo/KAGRA S250223dk: DECam DESGW Candidates
  71. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  72. GRB 250119B: VZLUSAT-2 detection
  73. GOTO observations of LVK S250223dk/Swift-BAT RAVEN alert
  74. GRB 250219A: EP-FXT afterglow detection
  75. EP250223a: COLIBRÍ/DDRAGO Detection of the Optical Counterpart and Slow Fading
  76. EP250223a: REM NIR upper limit
  77. EP250223a: TRT optical afterglow observation
  78. EP250223a: refined analysis of the EP-WXT and FXT observations
  79. EP250223a: SVOM/VT optical observation
  80. LIGO/Virgo/KAGRA S250223dk: DDOTI Upper Limits on the Optical Counterpart
  81. 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
  82. EP250223a: OASDG optical observations
  83. EP250223a: LCO detection of the afterglow
  84. EP250223a: early optical detection by BOOTES-4
  85. EP250223a: NOT redshift z = 2.756
  86. EP250223a: Swift/XRT localization
  87. GRB 250221A: VLA radio detection
  88. GRB 250221A: continued Assy optical observations, brightening afterglow confirmation
  89. GRB 250221A: continued Mondy optical observations, brightening afterglow
  90. GRB 250221A: Optical counterpart detection by LCO.
  91. GRB 250221A: Mondy optical observations
  92. Konus-Wind detection of GRB 250221A
  93. GRB 250221A: Assy optical observations
  94. GRB 250221A: GRANDMA/TAROT Detection
  95. GRB 250221A: Swift-XRT refined Analysis
  96. GRB 250221A: NOT optical observations
  97. GRB 250221A: 1.6m Mephisto optical detection
  98. GRB 250221A: AKO Optical Upper Limit
  99. GRB 250221A: Swift/UVOT Detection
  100. GRB 250219A: GRANDMA/Kilonova-Catcher upper limits

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